hpcu: add a selection unifier

So far not supporting large selections.

README

@@ -173,6 +173,22 @@ The result of testing hid with telnet, OpenSSL s_client, OpenBSD nc, GNU nc and
 Ncat is that neither of them can properly shutdown the connection.  We need
 a good implementation with TLS support.
 
+hpcu -- PRIMARY-CLIPBOARD unifier
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+An improved replacement for autocutsel in selection synchronization "mode":
+
+ - using only one OS process;
+ - not polling selections twice a second unnecessarily;
+ - calling SetSelectionOwner on change even when it already owns the selection,
+   so that XFIXES SelectionNotify events are delivered;
+ - not using cut buffers for anything.
+
+Only UTF8_STRING-convertible selections are synchronized.
+
+ht -- terminal emulator
+~~~~~~~~~~~~~~~~~~~~~~~
+Similar scope to st(1).  Clever display of internal padding for better looks.
+
 hib and hic -- IRC bouncer and client
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 An IRC client is a good starting application for building a GUI toolkit, as the
@@ -241,6 +257,7 @@ most basic features includes a VFS for archives.  The editing widget in read-
 -only mode could be used for F3.  The shell is going to work very simply,
 creating a PTY device and running things under TERM=dumb while decoding SGR,
 or one could decide to run a new terminal emulator with a different shortcut.
+ht could probably also be integrated.
 
 Eventually the number of panels should be arbitrary with proper shortcuts for
 working with them.  We might also integrate a special view for picture previews,
@@ -255,10 +272,6 @@ Indexing and search may be based on a common database, no need to get all fancy:
 http://rachbelaid.com/postgres-full-text-search-is-good-enough/
 https://www.sqlite.org/fts3.html#full_text_index_queries (FTS4 seems better)
 
-ht -- terminal emulator
-~~~~~~~~~~~~~~~~~~~~~~~
-Similar scope to st(1).  Clever display of internal padding for better looks.
-
 The rest
 ~~~~~~~~
 Currently there are no significant, specific plans about the other applications.

hpcu/main.go

@@ -0,0 +1,351 @@
+// hpcu unifies the PRIMARY and CLIPBOARD X11 selections for text contents.
+package main
+
+import (
+	"errors"
+	"janouch.name/haven/nexgb"
+	"janouch.name/haven/nexgb/xfixes"
+	"janouch.name/haven/nexgb/xproto"
+	"log"
+)
+
+type selectionState struct {
+	name       string           // name of the selection
+	inProgress xproto.Timestamp // timestamp of retrieved selection
+	buffer     []byte           // UTF-8 text buffer
+	incr       bool             // INCR running
+	incrFailed bool             // INCR failure indicator
+	owning     xproto.Timestamp // since when we own the selection
+}
+
+var (
+	X      *nexgb.Conn
+	setup  *xproto.SetupInfo
+	screen *xproto.ScreenInfo
+
+	atomCLIPBOARD  xproto.Atom // X11 atom for CLIPBOARD
+	atomUTF8String xproto.Atom // X11 atom for UTF8_STRING
+	atomINCR       xproto.Atom // X11 atom for INCR
+	atomTARGETS    xproto.Atom // X11 atom for TARGETS
+	atomTIMESTAMP  xproto.Atom // X11 atom for TIMESTAMP
+
+	wid        xproto.Window // auxiliary window
+	selections map[xproto.Atom]*selectionState
+	contents   string // current shared selection contents
+)
+
+// resolveAtoms resolves a few required atoms that are not in the core protocol.
+func resolveAtoms() error {
+	for _, i := range []struct {
+		placement *xproto.Atom
+		name      string
+	}{
+		{&atomCLIPBOARD, "CLIPBOARD"},
+		{&atomUTF8String, "UTF8_STRING"},
+		{&atomINCR, "INCR"},
+		{&atomTARGETS, "TARGETS"},
+		{&atomTIMESTAMP, "TIMESTAMP"},
+	} {
+		if reply, err := xproto.InternAtom(X,
+			false, uint16(len(i.name)), i.name).Reply(); err != nil {
+			return err
+		} else {
+			*i.placement = reply.Atom
+		}
+	}
+	return nil
+}
+
+// setupAuxiliaryWindow creates a window that receives notifications about
+// changed selection contents, and serves
+func setupAuxiliaryWindow() error {
+	var err error
+	if wid, err = xproto.NewWindowId(X); err != nil {
+		return err
+	}
+
+	_ = xproto.CreateWindow(X, screen.RootDepth, wid, screen.Root, 0, 0, 1, 1,
+		0, xproto.WindowClassInputOutput, screen.RootVisual, xproto.CwEventMask,
+		[]uint32{xproto.EventMaskPropertyChange})
+
+	for _, selection := range []xproto.Atom{xproto.AtomPrimary, atomCLIPBOARD} {
+		_ = xfixes.SelectSelectionInput(X, wid, selection,
+			xfixes.SelectionEventMaskSetSelectionOwner|
+				xfixes.SelectionEventMaskSelectionWindowDestroy|
+				xfixes.SelectionEventMaskSelectionClientClose)
+	}
+	return nil
+}
+
+// getProperty reads a window property in a memory-efficient manner.
+func getProperty(window xproto.Window, property xproto.Atom) (
+	*xproto.GetPropertyReply, error) {
+	// xorg-xserver doesn't seem to limit the length of replies or even
+	// the length of properties in the first place. It only has a huge
+	// (0xffffffff - sizeof(xChangePropertyReq))/4 limit for ChangeProperty
+	// requests, even though I can't XChangeProperty more than 0xffffe0
+	// bytes at a time.
+	//
+	// Since the XGB API doesn't let us provide our own buffer for
+	// value data, let us avoid multiplying the amount of consumed memory in
+	// pathological cases where properties are several gigabytes in size by
+	// chunking the requests. This has a cost of losing atomicity, although
+	// it shouldn't pose a problem except for timeout-caused INCR races.
+	var result xproto.GetPropertyReply
+	for result.Length == 0 || result.BytesAfter > 0 {
+		reply, err := xproto.GetProperty(X, false, /* delete */
+			window, property, xproto.GetPropertyTypeAny,
+			uint32(len(result.Value))/4,
+			uint32(setup.MaximumRequestLength)).Reply()
+		if err != nil {
+			return nil, err
+		}
+		if result.Length != 0 &&
+			(reply.Format != result.Format || reply.Type != result.Type) {
+			return nil, errors.New("property type changed during read")
+		}
+
+		reply.Value = append(result.Value, reply.Value...)
+		reply.ValueLen += result.ValueLen
+		result = *reply
+	}
+	return &result, nil
+}
+
+// appendText tries to append UTF-8 text to the selection state buffer.
+func appendText(state *selectionState, prop *xproto.GetPropertyReply) bool {
+	if prop.Type == atomUTF8String && prop.Format == 8 {
+		state.buffer = append(state.buffer, prop.Value...)
+		return true
+	}
+	return false
+}
+
+func requestOwnership(origin *selectionState, time xproto.Timestamp) {
+	contents = string(origin.buffer)
+	for selection, state := range selections {
+		// We might want to replace the originator as well but it might have
+		// undesirable effects, mainly with PRIMARY.
+		if state != origin {
+			// No need to GetSelectionOwner, XFIXES is more reliable.
+			_ = xproto.SetSelectionOwner(X, wid, selection, time)
+		}
+	}
+}
+
+func handleEvent(ev nexgb.Event) {
+	switch e := ev.(type) {
+	case xfixes.SelectionNotifyEvent:
+		state, ok := selections[e.Selection]
+		if !ok {
+			break
+		}
+
+		// Ownership request has been granted, don't ask ourselves for data.
+		if e.Owner == wid {
+			state.owning = e.SelectionTimestamp
+			break
+		}
+
+		// This should always be true.
+		if state.owning < e.SelectionTimestamp {
+			state.owning = 0
+		}
+
+		// Not checking whether we should give up when our current retrieval
+		// attempt is interrupted--the timeout mostly solves this.
+		if e.Owner == xproto.WindowNone {
+			break
+		}
+
+		// Don't try to process two things at once. Each request gets a few
+		// seconds to finish, then we move on, hoping that a property race
+		// doesn't commence. Ideally we'd set up a separate queue for these
+		// skipped requests and process them later.
+		if state.inProgress != 0 && e.Timestamp-state.inProgress < 5000 {
+			break
+		}
+
+		// ICCCM says we should ensure the named property doesn't exist.
+		_ = xproto.DeleteProperty(X, e.Window, e.Selection)
+
+		_ = xproto.ConvertSelection(X, e.Window, e.Selection,
+			atomUTF8String, e.Selection, e.Timestamp)
+
+		state.inProgress = e.Timestamp
+		state.incr = false
+
+	case xproto.SelectionNotifyEvent:
+		state, ok := selections[e.Selection]
+		if e.Requestor != wid || !ok || e.Time != state.inProgress {
+			break
+		}
+
+		state.inProgress = 0
+		if e.Property == xproto.AtomNone {
+			break
+		}
+
+		state.buffer = nil
+		reply, err := getProperty(e.Requestor, e.Property)
+		if err != nil {
+			break
+		}
+
+		// When you select a lot of text in VIM, it starts the ICCCM
+		// INCR mechanism, from which there is no opt-out.
+		if reply.Type == atomINCR {
+			state.inProgress = e.Time
+			state.incr = true
+			state.incrFailed = false
+		} else if appendText(state, reply) {
+			requestOwnership(state, e.Time)
+		}
+
+		_ = xproto.DeleteProperty(X, e.Requestor, e.Property)
+
+	case xproto.PropertyNotifyEvent:
+		state, ok := selections[e.Atom]
+		if e.Window != wid || e.State != xproto.PropertyNewValue ||
+			!ok || !state.incr {
+			break
+		}
+
+		reply, err := getProperty(e.Window, e.Atom)
+		if err != nil {
+			state.incrFailed = true
+			break
+		}
+
+		if !appendText(state, reply) {
+			// We need to keep deleting the property.
+			state.incrFailed = true
+		}
+
+		if reply.ValueLen == 0 {
+			if !state.incrFailed {
+				requestOwnership(state, e.Time)
+			}
+			state.inProgress = 0
+			state.incr = false
+		}
+
+		_ = xproto.DeleteProperty(X, e.Window, e.Atom)
+
+	case xproto.SelectionRequestEvent:
+		property := e.Property
+		if property == xproto.AtomNone {
+			property = e.Target
+		}
+
+		state, ok := selections[e.Selection]
+		if e.Owner != wid || !ok {
+			break
+		}
+
+		var (
+			typ    xproto.Atom
+			format byte
+			data   []byte
+		)
+
+		// XXX: We should also support the MULTIPLE target but it seems to be
+		// unimportant and largely abandoned today.
+		targets := []xproto.Atom{atomTARGETS, atomTIMESTAMP, atomUTF8String}
+
+		switch e.Target {
+		case atomTARGETS:
+			typ = xproto.AtomAtom
+			format = 32
+
+			data = make([]byte, len(targets)*4)
+			for i, atom := range targets {
+				nexgb.Put32(data[i*4:], uint32(atom))
+			}
+
+		case atomTIMESTAMP:
+			typ = xproto.AtomInteger
+			format = 32
+
+			data = make([]byte, 4)
+			nexgb.Put32(data, uint32(state.owning))
+
+		case atomUTF8String:
+			typ = atomUTF8String
+			format = 8
+
+			data = []byte(contents)
+		}
+
+		response := xproto.SelectionNotifyEvent{
+			Time:      e.Time,
+			Requestor: e.Requestor,
+			Selection: e.Selection,
+			Target:    e.Target,
+			Property:  xproto.AtomNone,
+		}
+
+		if typ == 0 || len(data) > int(setup.MaximumRequestLength)*4-64 ||
+			state.owning == 0 || e.Time < state.owning {
+			// TODO: Use the INCR mechanism for large data transfers instead
+			// of refusing the request, or at least use PropModeAppend.
+			//
+			// According to the ICCCM we need to set up a queue for concurrent
+			// (requestor, selection, target, timestamp) requests that differ
+			// only in the target property, and process them in order. The ICCCM
+			// has a nice rationale. It seems to only concern INCR. The queue
+			// might be a map[(who, what, how, when)][](where, data, offset).
+			//
+			// NOTE: Even with BigRequests support, it may technically be
+			// missing on the particular X server, and XGB copies buffers to yet
+			// another buffer, making very large transfers a very bad idea.
+		} else if xproto.ChangePropertyChecked(X, xproto.PropModeReplace,
+			e.Requestor, property, typ, format,
+			uint32(len(data)/int(format/8)), data).Check() == nil {
+			response.Property = property
+		}
+
+		_ = xproto.SendEvent(X, false /* propagate */, e.Requestor,
+			0 /* event mask */, string(response.Bytes()))
+	}
+}
+
+func main() {
+	var err error
+	if X, err = nexgb.NewConn(); err != nil {
+		log.Fatalln(err)
+	}
+	if err = xfixes.Init(X); err != nil {
+		log.Fatalln(err)
+	}
+
+	// Enable the extension.
+	_ = xfixes.QueryVersion(X, xfixes.MajorVersion, xfixes.MinorVersion)
+
+	setup = xproto.Setup(X)
+	screen = setup.DefaultScreen(X)
+
+	if err = resolveAtoms(); err != nil {
+		log.Fatalln(err)
+	}
+	if err = setupAuxiliaryWindow(); err != nil {
+		log.Fatalln(err)
+	}
+
+	// Now that we have our atoms, we can initialize state.
+	selections = map[xproto.Atom]*selectionState{
+		xproto.AtomPrimary: {name: "PRIMARY"},
+		atomCLIPBOARD:      {name: "CLIPBOARD"},
+	}
+
+	for {
+		ev, xerr := X.WaitForEvent()
+		if xerr != nil {
+			log.Printf("Error: %s\n", xerr)
+			return
+		}
+		if ev != nil {
+			handleEvent(ev)
+		}
+	}
+}

nexgb/.gitignore

@@ -0,0 +1,2 @@
+xgbgen/xgbgen
+.*.swp

nexgb/AUTHORS

@@ -0,0 +1,26 @@
+# This is the official list of neXGB authors for copyright purposes.
+# This file is distinct from the CONTRIBUTORS file.
+# See the latter for an explanation.
+
+# Names should be added to this file as
+#	Name or Organization <email address>
+# The email address is not required for organizations.
+
+Anthony Martin <ality@pbrane.org>
+Firmansyah Adiputra <frm.adiputra@gmail.com>
+Google Inc.
+Scott Lawrence <bytbox@gmail.com>
+Tor Andersson <tor.andersson@gmail.com>
+
+# The names above come from the original x-go-binding by Google.
+# The following list pertains to BurntSushi/xgb and janouch.name/haven/nexgb:
+
+Andrew Gallant <jamslam@gmail.com>
+Paul Sbarra <Sbarra.Paul@gmail.com>
+Axel Wagner <mail@merovius.de>
+snyh <snyh@snyh.org>
+Alessandro Arzilli <alessandro.arzilli@gmail.com>
+fangyuanziti <tiziyuanfang@gmail.com>
+Bryan Matsuo <bryan.matsuo@gmail.com>
+Rabin Vincent <rabin@rab.in>
+Přemysl Janouch <p@janouch.name>

nexgb/CONTRIBUTORS

@@ -0,0 +1,35 @@
+# This is the official list of people who may have contributed
+# code to the neXGB repository.
+#
+# The AUTHORS file lists the copyright holders; this file
+# lists people.  For example, Google employees are listed here
+# but not in AUTHORS, because Google holds the copyright.
+#
+# When adding J Random Contributor's name to this file,
+# either J's name or J's organization's name should be
+# added to the AUTHORS file.
+
+# Names should be added to this file like so:
+#     Name <email address>
+
+Anthony Martin <ality@pbrane.org>
+Firmansyah Adiputra <frm.adiputra@gmail.com>
+Ian Lance Taylor <iant@golang.org>
+Nigel Tao <nigeltao@golang.org>
+Robert Griesemer <gri@golang.org>
+Russ Cox <rsc@golang.org>
+Scott Lawrence <bytbox@gmail.com>
+Tor Andersson <tor.andersson@gmail.com>
+
+# The names above come from the original x-go-binding by Google.
+# The following list pertains to BurntSushi/xgb and janouch.name/haven/nexgb:
+
+Andrew Gallant <jamslam@gmail.com>
+Paul Sbarra <Sbarra.Paul@gmail.com>
+Axel Wagner <mail@merovius.de>
+snyh <snyh@snyh.org>
+Alessandro Arzilli <alessandro.arzilli@gmail.com>
+fangyuanziti <tiziyuanfang@gmail.com>
+Bryan Matsuo <bryan.matsuo@gmail.com>
+Rabin Vincent <rabin@rab.in>
+Přemysl Janouch <p@janouch.name>

nexgb/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2009 The XGB Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

nexgb/Makefile

@@ -0,0 +1,76 @@
+# This Makefile is used by the developer. It is not needed in any way to build
+# a checkout of the neXGB repository.
+# It will be useful, however, if you are hacking at the code generator.
+# i.e., after making a change to the code generator, run 'make' in the
+# xgb directory. This will build xgbgen and regenerate each sub-package.
+# 'make test' will then run any appropriate tests (just tests xproto right now).
+# 'make bench' will test a couple of benchmarks.
+# 'make build-all' will then try to build each extension. This isn't strictly
+# necessary, but it's a good idea to make sure each sub-package is a valid
+# Go package.
+
+# My path to the X protocol XML descriptions.
+ifndef XPROTO
+XPROTO=/usr/share/xcb
+endif
+
+# All of the XML files in my /usr/share/xcb directory except XKB, Xinput, SYNC.
+# This is intended to build xgbgen and generate Go code for each supported
+# extension.
+all: build-xgbgen \
+		 bigreq.xml composite.xml damage.xml dpms.xml dri2.xml \
+		 ge.xml glx.xml randr.xml record.xml render.xml res.xml \
+		 screensaver.xml shape.xml shm.xml xc_misc.xml \
+		 xevie.xml xf86dri.xml xf86vidmode.xml xfixes.xml xinerama.xml \
+		 xprint.xml xproto.xml xselinux.xml xtest.xml \
+		 xvmc.xml xv.xml
+
+build-xgbgen:
+	(cd xgbgen && go build)
+
+# Builds each individual sub-package to make sure its valid Go code.
+build-all: bigreq.b composite.b damage.b dpms.b dri2.b ge.b glx.b randr.b \
+					 record.b render.b res.b screensaver.b shape.b shm.b xcmisc.b \
+					 xevie.b xf86dri.b xf86vidmode.b xfixes.b xinerama.b \
+					 xprint.b xproto.b xselinux.b xtest.b xv.b xvmc.b
+
+%.b:
+	(cd $* ; go build)
+
+# Installs each individual sub-package.
+install: bigreq.i composite.i damage.i dpms.i dri2.i ge.i glx.i randr.i \
+					 record.i render.i res.i screensaver.i shape.i shm.i xcmisc.i \
+					 xevie.i xf86dri.i xf86vidmode.i xfixes.i xinerama.i \
+					 xprint.i xproto.i xselinux.i xtest.i xv.i xvmc.i
+	go install
+
+%.i:
+	(cd $* ; go install)
+
+# xc_misc is special because it has an underscore.
+# There's probably a way to do this better, but Makefiles aren't my strong suit.
+xc_misc.xml: build-xgbgen
+	mkdir -p xcmisc
+	xgbgen/xgbgen --proto-path $(XPROTO) $(XPROTO)/xc_misc.xml > xcmisc/xcmisc.go
+
+%.xml: build-xgbgen
+	mkdir -p $*
+	xgbgen/xgbgen --proto-path $(XPROTO) $(XPROTO)/$*.xml > $*/$*.go
+
+# Just test the xproto core protocol for now.
+test:
+	(cd xproto ; go test)
+
+# Force all xproto benchmarks to run and no tests.
+bench:
+	(cd xproto ; go test -run 'nomatch' -bench '.*' -cpu 1,2,3,6)
+
+# gofmt all non-auto-generated code.
+# (auto-generated code is already gofmt'd.)
+# Also do a column check (80 cols) after a gofmt.
+# But don't check columns on auto-generated code, since I don't care if they
+# break 80 cols.
+gofmt:
+	gofmt -w *.go xgbgen/*.go examples/*.go examples/*/*.go xproto/xproto_test.go
+	colcheck *.go xgbgen/*.go examples/*.go examples/*/*.go xproto/xproto_test.go
+

nexgb/README

@@ -0,0 +1,49 @@
+neXGB is a fork of a fork of the X Go Binding, which is a low-level API to
+communicate with the core X protocol and many of the X extensions.
+It is closely modelled after XCB and xpyb.
+
+It is thread safe and gets immediate improvement from parallelism when
+GOMAXPROCS > 1. (See the benchmarks in xproto/xproto_test.go for evidence.)
+
+Please see doc.go for more info.
+
+Quick usage
+-----------
+ go get janouch.name/haven/nexgb
+ go run $GOPATH/src/janouch.name/haven/nexgb/examples/create-window/main.go
+
+Přemysl Janouch's fork
+----------------------
+I've merged BurntSushi/xgb into haven as a subdirectory due to a/ inactivity
+upstream, and b/ intentions to make incompatible changes meant to be in sync
+with the rest of the project.
+
+It's Not Exactly XGB anymore.  Notable changes:
+ - included aarzilli's changes to support xcb-proto 1.12+, updated to 1.13
+ - improved documentation, using as much as possible from XCB's <doc> elements
+ - exporting {Major,Minor}Version of extensions for QueryVersion purposes
+
+BurntSushi's fork
+-----------------
+I've forked the XGB repository from Google Code due to inactivity upstream.
+
+Much of the code has been rewritten in an effort to support thread safety
+and multiple extensions. Namely, go_client.py has been thrown away in favor
+of an xgbgen package.
+
+The biggest parts that *haven't* been rewritten by me are the connection and
+authentication handshakes. They're inherently messy, and there's really no
+reason to re-work them. The rest of XGB has been completely rewritten.
+
+I like to release my code under the WTFPL, but since I'm starting with someone
+else's work, I'm leaving the original license/contributor/author information
+in tact.
+
+I suppose I can legitimately release xgbgen under the WTFPL. To be fair, it is
+at least as complex as XGB itself. *sigh*
+
+License
+-------
+Unless otherwise noted, the neXGB source files are distributed
+under the BSD-style license found in the LICENSE file.
+

nexgb/STYLE

@@ -0,0 +1,29 @@
+Keep all code to 80 columns or less. We, the maintainers, have plenty of screen
+real estate, but enjoy 80 columns so that we can have multiple code windows
+open side to side and not be plagued by the ugly auto-wrapping of a text editor.
+
+If you don't oblige us, we will fix any patch you submit to abide 80 columns.
+
+Note that this style restriction does not preclude gofmt, but introduces a few
+peculiarities. The first is that gofmt will occasionally add spacing (typically 
+to comments) that ends up going over 80 columns. Either shorten the comment or 
+put it on its own line.
+
+The second and more common hiccup is when a function definition extends beyond 
+80 columns. If one adds line breaks to keep it below 80 columns, gofmt will 
+indent all subsequent lines in a function definition to the same indentation 
+level of the function body. This results in a less-than-ideal separation 
+between function definition and function body. To remedy this, simply add a 
+line break like so:
+
+  func RestackWindowExtra(xu *xgbutil.XUtil, win xproto.Window, stackMode int,
+    sibling xproto.Window, source int) error {
+
+    return ClientEvent(xu, win, "_NET_RESTACK_WINDOW", source, int(sibling),
+      stackMode)
+  }
+
+Something similar should also be applied to long 'if' or 'for' conditionals, 
+although it would probably be preferrable to break up the conditional to 
+smaller chunks with a few helper variables.
+

nexgb/auth.go

@@ -0,0 +1,110 @@
+package nexgb
+
+/*
+auth.go contains functions to facilitate the parsing of .Xauthority files.
+
+It is largely unmodified from the original XGB package that I forked.
+*/
+
+import (
+	"encoding/binary"
+	"errors"
+	"io"
+	"os"
+)
+
+// readAuthority reads the X authority file for the DISPLAY.
+// If hostname == "" or hostname == "localhost",
+// then use the system's hostname (as returned by os.Hostname) instead.
+func readAuthority(hostname, display string) (
+	name string, data []byte, err error) {
+
+	// b is a scratch buffer to use and should be at least 256 bytes long
+	// (i.e. it should be able to hold a hostname).
+	b := make([]byte, 256)
+
+	// As per /usr/include/X11/Xauth.h.
+	const familyLocal = 256
+	const familyWild = 65535
+
+	if len(hostname) == 0 || hostname == "localhost" {
+		hostname, err = os.Hostname()
+		if err != nil {
+			return "", nil, err
+		}
+	}
+
+	fname := os.Getenv("XAUTHORITY")
+	if len(fname) == 0 {
+		home := os.Getenv("HOME")
+		if len(home) == 0 {
+			err = errors.New("Xauthority not found: $XAUTHORITY, $HOME not set")
+			return "", nil, err
+		}
+		fname = home + "/.Xauthority"
+	}
+
+	r, err := os.Open(fname)
+	if err != nil {
+		return "", nil, err
+	}
+	defer r.Close()
+
+	for {
+		var family uint16
+		if err := binary.Read(r, binary.BigEndian, &family); err != nil {
+			return "", nil, err
+		}
+
+		addr, err := getString(r, b)
+		if err != nil {
+			return "", nil, err
+		}
+
+		disp, err := getString(r, b)
+		if err != nil {
+			return "", nil, err
+		}
+
+		name0, err := getString(r, b)
+		if err != nil {
+			return "", nil, err
+		}
+
+		data0, err := getBytes(r, b)
+		if err != nil {
+			return "", nil, err
+		}
+
+		addrmatch := (family == familyWild) ||
+			(family == familyLocal && addr == hostname)
+		dispmatch := (disp == "") || (disp == display)
+
+		if addrmatch && dispmatch {
+			return name0, data0, nil
+		}
+	}
+	panic("unreachable")
+}
+
+func getBytes(r io.Reader, b []byte) ([]byte, error) {
+	var n uint16
+	if err := binary.Read(r, binary.BigEndian, &n); err != nil {
+		return nil, err
+	} else if n > uint16(len(b)) {
+		return nil, errors.New("bytes too long for buffer")
+	}
+
+	if _, err := io.ReadFull(r, b[0:n]); err != nil {
+		return nil, err
+	}
+	return b[0:n], nil
+}
+
+func getString(r io.Reader, b []byte) (string, error) {
+	b, err := getBytes(r, b)
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}

nexgb/bigreq/bigreq.go

@@ -0,0 +1,156 @@
+// Package bigreq is the X client API for the BIG-REQUESTS extension.
+package bigreq
+
+// This file is automatically generated from bigreq.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 0
+	MinorVersion = 0
+)
+
+// Init must be called before using the BIG-REQUESTS extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 12, "BIG-REQUESTS").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named BIG-REQUESTS could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["BIG-REQUESTS"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["BIG-REQUESTS"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["BIG-REQUESTS"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["BIG-REQUESTS"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["BIG-REQUESTS"] = make(map[int]xgb.NewErrorFun)
+}
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// EnableCookie is a cookie used only for Enable requests.
+type EnableCookie struct {
+	*xgb.Cookie
+}
+
+// Enable sends a checked request.
+// If an error occurs, it will be returned with the reply by calling EnableCookie.Reply.
+func Enable(c *xgb.Conn) EnableCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["BIG-REQUESTS"]; !ok {
+		panic("Cannot issue request 'Enable' using the uninitialized extension 'BIG-REQUESTS'. bigreq.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(enableRequest(c), cookie)
+	return EnableCookie{cookie}
+}
+
+// EnableUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func EnableUnchecked(c *xgb.Conn) EnableCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["BIG-REQUESTS"]; !ok {
+		panic("Cannot issue request 'Enable' using the uninitialized extension 'BIG-REQUESTS'. bigreq.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(enableRequest(c), cookie)
+	return EnableCookie{cookie}
+}
+
+// EnableReply represents the data returned from a Enable request.
+type EnableReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	MaximumRequestLength uint32
+}
+
+// Reply blocks and returns the reply data for a Enable request.
+func (cook EnableCookie) Reply() (*EnableReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return enableReply(buf), nil
+}
+
+// enableReply reads a byte slice into a EnableReply value.
+func enableReply(buf []byte) *EnableReply {
+	v := new(EnableReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.MaximumRequestLength = xgb.Get32(buf[b:])
+	b += 4
+
+	return v
+}
+
+// enableRequest writes a Enable request to a byte slice for transfer.
+func enableRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["BIG-REQUESTS"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}

nexgb/composite/composite.go

@@ -0,0 +1,717 @@
+// Package composite is the X client API for the Composite extension.
+package composite
+
+// This file is automatically generated from composite.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xfixes"
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 0
+	MinorVersion = 4
+)
+
+// Init must be called before using the Composite extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 9, "Composite").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named Composite could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["Composite"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["Composite"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["Composite"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["Composite"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["Composite"] = make(map[int]xgb.NewErrorFun)
+}
+
+const (
+	RedirectAutomatic = 0
+	RedirectManual    = 1
+)
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// CreateRegionFromBorderClipCookie is a cookie used only for CreateRegionFromBorderClip requests.
+type CreateRegionFromBorderClipCookie struct {
+	*xgb.Cookie
+}
+
+// CreateRegionFromBorderClip sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func CreateRegionFromBorderClip(c *xgb.Conn, Region xfixes.Region, Window xproto.Window) CreateRegionFromBorderClipCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'CreateRegionFromBorderClip' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(createRegionFromBorderClipRequest(c, Region, Window), cookie)
+	return CreateRegionFromBorderClipCookie{cookie}
+}
+
+// CreateRegionFromBorderClipChecked sends a checked request.
+// If an error occurs, it can be retrieved using CreateRegionFromBorderClipCookie.Check.
+func CreateRegionFromBorderClipChecked(c *xgb.Conn, Region xfixes.Region, Window xproto.Window) CreateRegionFromBorderClipCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'CreateRegionFromBorderClip' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(createRegionFromBorderClipRequest(c, Region, Window), cookie)
+	return CreateRegionFromBorderClipCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook CreateRegionFromBorderClipCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// createRegionFromBorderClipRequest writes a CreateRegionFromBorderClip request to a byte slice for transfer.
+func createRegionFromBorderClipRequest(c *xgb.Conn, Region xfixes.Region, Window xproto.Window) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Composite"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 5 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Region))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	return buf
+}
+
+// GetOverlayWindowCookie is a cookie used only for GetOverlayWindow requests.
+type GetOverlayWindowCookie struct {
+	*xgb.Cookie
+}
+
+// GetOverlayWindow sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetOverlayWindowCookie.Reply.
+func GetOverlayWindow(c *xgb.Conn, Window xproto.Window) GetOverlayWindowCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'GetOverlayWindow' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getOverlayWindowRequest(c, Window), cookie)
+	return GetOverlayWindowCookie{cookie}
+}
+
+// GetOverlayWindowUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetOverlayWindowUnchecked(c *xgb.Conn, Window xproto.Window) GetOverlayWindowCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'GetOverlayWindow' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getOverlayWindowRequest(c, Window), cookie)
+	return GetOverlayWindowCookie{cookie}
+}
+
+// GetOverlayWindowReply represents the data returned from a GetOverlayWindow request.
+type GetOverlayWindowReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	OverlayWin xproto.Window
+	// padding: 20 bytes
+}
+
+// Reply blocks and returns the reply data for a GetOverlayWindow request.
+func (cook GetOverlayWindowCookie) Reply() (*GetOverlayWindowReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getOverlayWindowReply(buf), nil
+}
+
+// getOverlayWindowReply reads a byte slice into a GetOverlayWindowReply value.
+func getOverlayWindowReply(buf []byte) *GetOverlayWindowReply {
+	v := new(GetOverlayWindowReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.OverlayWin = xproto.Window(xgb.Get32(buf[b:]))
+	b += 4
+
+	b += 20 // padding
+
+	return v
+}
+
+// getOverlayWindowRequest writes a GetOverlayWindow request to a byte slice for transfer.
+func getOverlayWindowRequest(c *xgb.Conn, Window xproto.Window) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Composite"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 7 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	return buf
+}
+
+// NameWindowPixmapCookie is a cookie used only for NameWindowPixmap requests.
+type NameWindowPixmapCookie struct {
+	*xgb.Cookie
+}
+
+// NameWindowPixmap sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func NameWindowPixmap(c *xgb.Conn, Window xproto.Window, Pixmap xproto.Pixmap) NameWindowPixmapCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'NameWindowPixmap' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(nameWindowPixmapRequest(c, Window, Pixmap), cookie)
+	return NameWindowPixmapCookie{cookie}
+}
+
+// NameWindowPixmapChecked sends a checked request.
+// If an error occurs, it can be retrieved using NameWindowPixmapCookie.Check.
+func NameWindowPixmapChecked(c *xgb.Conn, Window xproto.Window, Pixmap xproto.Pixmap) NameWindowPixmapCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'NameWindowPixmap' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(nameWindowPixmapRequest(c, Window, Pixmap), cookie)
+	return NameWindowPixmapCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook NameWindowPixmapCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// nameWindowPixmapRequest writes a NameWindowPixmap request to a byte slice for transfer.
+func nameWindowPixmapRequest(c *xgb.Conn, Window xproto.Window, Pixmap xproto.Pixmap) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Composite"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 6 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Pixmap))
+	b += 4
+
+	return buf
+}
+
+// QueryVersionCookie is a cookie used only for QueryVersion requests.
+type QueryVersionCookie struct {
+	*xgb.Cookie
+}
+
+// QueryVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling QueryVersionCookie.Reply.
+func QueryVersion(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint32) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func QueryVersionUnchecked(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint32) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionReply represents the data returned from a QueryVersion request.
+type QueryVersionReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	MajorVersion uint32
+	MinorVersion uint32
+	// padding: 16 bytes
+}
+
+// Reply blocks and returns the reply data for a QueryVersion request.
+func (cook QueryVersionCookie) Reply() (*QueryVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return queryVersionReply(buf), nil
+}
+
+// queryVersionReply reads a byte slice into a QueryVersionReply value.
+func queryVersionReply(buf []byte) *QueryVersionReply {
+	v := new(QueryVersionReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.MajorVersion = xgb.Get32(buf[b:])
+	b += 4
+
+	v.MinorVersion = xgb.Get32(buf[b:])
+	b += 4
+
+	b += 16 // padding
+
+	return v
+}
+
+// queryVersionRequest writes a QueryVersion request to a byte slice for transfer.
+func queryVersionRequest(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint32) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Composite"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], ClientMajorVersion)
+	b += 4
+
+	xgb.Put32(buf[b:], ClientMinorVersion)
+	b += 4
+
+	return buf
+}
+
+// RedirectSubwindowsCookie is a cookie used only for RedirectSubwindows requests.
+type RedirectSubwindowsCookie struct {
+	*xgb.Cookie
+}
+
+// RedirectSubwindows sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func RedirectSubwindows(c *xgb.Conn, Window xproto.Window, Update byte) RedirectSubwindowsCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'RedirectSubwindows' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(redirectSubwindowsRequest(c, Window, Update), cookie)
+	return RedirectSubwindowsCookie{cookie}
+}
+
+// RedirectSubwindowsChecked sends a checked request.
+// If an error occurs, it can be retrieved using RedirectSubwindowsCookie.Check.
+func RedirectSubwindowsChecked(c *xgb.Conn, Window xproto.Window, Update byte) RedirectSubwindowsCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'RedirectSubwindows' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(redirectSubwindowsRequest(c, Window, Update), cookie)
+	return RedirectSubwindowsCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook RedirectSubwindowsCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// redirectSubwindowsRequest writes a RedirectSubwindows request to a byte slice for transfer.
+func redirectSubwindowsRequest(c *xgb.Conn, Window xproto.Window, Update byte) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Composite"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 2 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	buf[b] = Update
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}
+
+// RedirectWindowCookie is a cookie used only for RedirectWindow requests.
+type RedirectWindowCookie struct {
+	*xgb.Cookie
+}
+
+// RedirectWindow sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func RedirectWindow(c *xgb.Conn, Window xproto.Window, Update byte) RedirectWindowCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'RedirectWindow' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(redirectWindowRequest(c, Window, Update), cookie)
+	return RedirectWindowCookie{cookie}
+}
+
+// RedirectWindowChecked sends a checked request.
+// If an error occurs, it can be retrieved using RedirectWindowCookie.Check.
+func RedirectWindowChecked(c *xgb.Conn, Window xproto.Window, Update byte) RedirectWindowCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'RedirectWindow' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(redirectWindowRequest(c, Window, Update), cookie)
+	return RedirectWindowCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook RedirectWindowCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// redirectWindowRequest writes a RedirectWindow request to a byte slice for transfer.
+func redirectWindowRequest(c *xgb.Conn, Window xproto.Window, Update byte) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Composite"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 1 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	buf[b] = Update
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}
+
+// ReleaseOverlayWindowCookie is a cookie used only for ReleaseOverlayWindow requests.
+type ReleaseOverlayWindowCookie struct {
+	*xgb.Cookie
+}
+
+// ReleaseOverlayWindow sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func ReleaseOverlayWindow(c *xgb.Conn, Window xproto.Window) ReleaseOverlayWindowCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'ReleaseOverlayWindow' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(releaseOverlayWindowRequest(c, Window), cookie)
+	return ReleaseOverlayWindowCookie{cookie}
+}
+
+// ReleaseOverlayWindowChecked sends a checked request.
+// If an error occurs, it can be retrieved using ReleaseOverlayWindowCookie.Check.
+func ReleaseOverlayWindowChecked(c *xgb.Conn, Window xproto.Window) ReleaseOverlayWindowCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'ReleaseOverlayWindow' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(releaseOverlayWindowRequest(c, Window), cookie)
+	return ReleaseOverlayWindowCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook ReleaseOverlayWindowCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// releaseOverlayWindowRequest writes a ReleaseOverlayWindow request to a byte slice for transfer.
+func releaseOverlayWindowRequest(c *xgb.Conn, Window xproto.Window) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Composite"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 8 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	return buf
+}
+
+// UnredirectSubwindowsCookie is a cookie used only for UnredirectSubwindows requests.
+type UnredirectSubwindowsCookie struct {
+	*xgb.Cookie
+}
+
+// UnredirectSubwindows sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func UnredirectSubwindows(c *xgb.Conn, Window xproto.Window, Update byte) UnredirectSubwindowsCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'UnredirectSubwindows' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(unredirectSubwindowsRequest(c, Window, Update), cookie)
+	return UnredirectSubwindowsCookie{cookie}
+}
+
+// UnredirectSubwindowsChecked sends a checked request.
+// If an error occurs, it can be retrieved using UnredirectSubwindowsCookie.Check.
+func UnredirectSubwindowsChecked(c *xgb.Conn, Window xproto.Window, Update byte) UnredirectSubwindowsCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'UnredirectSubwindows' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(unredirectSubwindowsRequest(c, Window, Update), cookie)
+	return UnredirectSubwindowsCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook UnredirectSubwindowsCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// unredirectSubwindowsRequest writes a UnredirectSubwindows request to a byte slice for transfer.
+func unredirectSubwindowsRequest(c *xgb.Conn, Window xproto.Window, Update byte) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Composite"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 4 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	buf[b] = Update
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}
+
+// UnredirectWindowCookie is a cookie used only for UnredirectWindow requests.
+type UnredirectWindowCookie struct {
+	*xgb.Cookie
+}
+
+// UnredirectWindow sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func UnredirectWindow(c *xgb.Conn, Window xproto.Window, Update byte) UnredirectWindowCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'UnredirectWindow' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(unredirectWindowRequest(c, Window, Update), cookie)
+	return UnredirectWindowCookie{cookie}
+}
+
+// UnredirectWindowChecked sends a checked request.
+// If an error occurs, it can be retrieved using UnredirectWindowCookie.Check.
+func UnredirectWindowChecked(c *xgb.Conn, Window xproto.Window, Update byte) UnredirectWindowCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Composite"]; !ok {
+		panic("Cannot issue request 'UnredirectWindow' using the uninitialized extension 'Composite'. composite.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(unredirectWindowRequest(c, Window, Update), cookie)
+	return UnredirectWindowCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook UnredirectWindowCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// unredirectWindowRequest writes a UnredirectWindow request to a byte slice for transfer.
+func unredirectWindowRequest(c *xgb.Conn, Window xproto.Window, Update byte) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Composite"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 3 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	buf[b] = Update
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}

nexgb/conn.go

@@ -0,0 +1,185 @@
+package nexgb
+
+/*
+conn.go contains a couple of functions that do some real dirty work related
+to the initial connection handshake with X.
+
+This code is largely unmodified from the original XGB package that I forked.
+*/
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// connect connects to the X server given in the 'display' string,
+// and does all the necessary setup handshaking.
+// If 'display' is empty it will be taken from os.Getenv("DISPLAY").
+// Note that you should read and understand the "Connection Setup" of the
+// X Protocol Reference Manual before changing this function:
+// http://goo.gl/4zGQg
+func (c *Conn) connect(display string) error {
+	err := c.dial(display)
+	if err != nil {
+		return err
+	}
+
+	return c.postConnect()
+}
+
+// connect init from to the net.Conn,
+func (c *Conn) connectNet(netConn net.Conn) error {
+	c.conn = netConn
+	return c.postConnect()
+}
+
+// do the postConnect action after Conn get it's underly net.Conn
+func (c *Conn) postConnect() error {
+	// Get authentication data
+	authName, authData, err := readAuthority(c.host, c.display)
+	noauth := false
+	if err != nil {
+		Logger.Printf("Could not get authority info: %v", err)
+		Logger.Println("Trying connection without authority info...")
+		authName = ""
+		authData = []byte{}
+		noauth = true
+	}
+
+	// Assume that the authentication protocol is "MIT-MAGIC-COOKIE-1".
+	if !noauth && (authName != "MIT-MAGIC-COOKIE-1" || len(authData) != 16) {
+		return errors.New("unsupported auth protocol " + authName)
+	}
+
+	buf := make([]byte, 12+Pad(len(authName))+Pad(len(authData)))
+	buf[0] = 0x6c
+	buf[1] = 0
+	Put16(buf[2:], 11)
+	Put16(buf[4:], 0)
+	Put16(buf[6:], uint16(len(authName)))
+	Put16(buf[8:], uint16(len(authData)))
+	Put16(buf[10:], 0)
+	copy(buf[12:], []byte(authName))
+	copy(buf[12+Pad(len(authName)):], authData)
+	if _, err = c.conn.Write(buf); err != nil {
+		return err
+	}
+
+	head := make([]byte, 8)
+	if _, err = io.ReadFull(c.conn, head[0:8]); err != nil {
+		return err
+	}
+	code := head[0]
+	reasonLen := head[1]
+	major := Get16(head[2:])
+	minor := Get16(head[4:])
+	dataLen := Get16(head[6:])
+
+	if major != 11 || minor != 0 {
+		return fmt.Errorf("x protocol version mismatch: %d.%d", major, minor)
+	}
+
+	buf = make([]byte, int(dataLen)*4+8, int(dataLen)*4+8)
+	copy(buf, head)
+	if _, err = io.ReadFull(c.conn, buf[8:]); err != nil {
+		return err
+	}
+
+	if code == 0 {
+		reason := buf[8 : 8+reasonLen]
+		return fmt.Errorf("x protocol authentication refused: %s",
+			string(reason))
+	}
+
+	// Unfortunately, it isn't really feasible to read the setup bytes here,
+	// since the code to do so is in a different package.
+	// Users must call 'xproto.Setup(X)' to get the setup info.
+	c.SetupBytes = buf
+
+	// But also read stuff that we *need* to get started.
+	c.setupResourceIdBase = Get32(buf[12:])
+	c.setupResourceIdMask = Get32(buf[16:])
+
+	return nil
+}
+
+// dial initializes the actual net connection with X.
+func (c *Conn) dial(display string) error {
+	if len(display) == 0 {
+		display = os.Getenv("DISPLAY")
+	}
+
+	display0 := display
+	if len(display) == 0 {
+		return errors.New("empty display string")
+	}
+
+	colonIdx := strings.LastIndex(display, ":")
+	if colonIdx < 0 {
+		return errors.New("bad display string: " + display0)
+	}
+
+	var protocol, socket string
+
+	if display[0] == '/' {
+		socket = display[0:colonIdx]
+	} else {
+		slashIdx := strings.LastIndex(display, "/")
+		if slashIdx >= 0 {
+			protocol = display[0:slashIdx]
+			c.host = display[slashIdx+1 : colonIdx]
+		} else {
+			c.host = display[0:colonIdx]
+		}
+	}
+
+	display = display[colonIdx+1:]
+	if len(display) == 0 {
+		return errors.New("bad display string: " + display0)
+	}
+
+	var scr string
+	dotIdx := strings.LastIndex(display, ".")
+	if dotIdx < 0 {
+		c.display = display[0:]
+	} else {
+		c.display = display[0:dotIdx]
+		scr = display[dotIdx+1:]
+	}
+
+	var err error
+	c.DisplayNumber, err = strconv.Atoi(c.display)
+	if err != nil || c.DisplayNumber < 0 {
+		return errors.New("bad display string: " + display0)
+	}
+
+	if len(scr) != 0 {
+		c.DefaultScreen, err = strconv.Atoi(scr)
+		if err != nil {
+			return errors.New("bad display string: " + display0)
+		}
+	}
+
+	// Connect to server
+	if len(socket) != 0 {
+		c.conn, err = net.Dial("unix", socket+":"+c.display)
+	} else if len(c.host) != 0 {
+		if protocol == "" {
+			protocol = "tcp"
+		}
+		c.conn, err = net.Dial(protocol,
+			c.host+":"+strconv.Itoa(6000+c.DisplayNumber))
+	} else {
+		c.conn, err = net.Dial("unix", "/tmp/.X11-unix/X"+c.display)
+	}
+
+	if err != nil {
+		return errors.New("cannot connect to " + display0 + ": " + err.Error())
+	}
+	return nil
+}

nexgb/cookie.go

@@ -0,0 +1,165 @@
+package nexgb
+
+import (
+	"errors"
+)
+
+// Cookie is the internal representation of a cookie, where one is generated
+// for *every* request sent by XGB.
+// 'cookie' is most frequently used by embedding it into a more specific
+// kind of cookie, i.e., 'GetInputFocusCookie'.
+type Cookie struct {
+	conn      *Conn
+	Sequence  uint16
+	replyChan chan []byte
+	errorChan chan error
+	pingChan  chan bool
+}
+
+// NewCookie creates a new cookie with the correct channels initialized
+// depending upon the values of 'checked' and 'reply'. Together, there are
+// four different kinds of cookies. (See more detailed comments in the
+// function for more info on those.)
+// Note that a sequence number is not set until just before the request
+// corresponding to this cookie is sent over the wire.
+//
+// Unless you're building requests from bytes by hand, this method should
+// not be used.
+func (c *Conn) NewCookie(checked, reply bool) *Cookie {
+	cookie := &Cookie{
+		conn:      c,
+		Sequence:  0, // we add the sequence id just before sending a request
+		replyChan: nil,
+		errorChan: nil,
+		pingChan:  nil,
+	}
+
+	// There are four different kinds of cookies:
+	// Checked requests with replies get a reply channel and an error channel.
+	// Unchecked requests with replies get a reply channel and a ping channel.
+	// Checked requests w/o replies get a ping channel and an error channel.
+	// Unchecked requests w/o replies get no channels.
+	// The reply channel is used to send reply data.
+	// The error channel is used to send error data.
+	// The ping channel is used when one of the 'reply' or 'error' channels
+	// is missing but the other is present. The ping channel is way to force
+	// the blocking to stop and basically say "the error has been received
+	// in the main event loop" (when the ping channel is coupled with a reply
+	// channel) or "the request you made that has no reply was successful"
+	// (when the ping channel is coupled with an error channel).
+	if checked {
+		cookie.errorChan = make(chan error, 1)
+		if !reply {
+			cookie.pingChan = make(chan bool, 1)
+		}
+	}
+	if reply {
+		cookie.replyChan = make(chan []byte, 1)
+		if !checked {
+			cookie.pingChan = make(chan bool, 1)
+		}
+	}
+
+	return cookie
+}
+
+// Reply detects whether this is a checked or unchecked cookie, and calls
+// 'replyChecked' or 'replyUnchecked' appropriately.
+//
+// Unless you're building requests from bytes by hand, this method should
+// not be used.
+func (c Cookie) Reply() ([]byte, error) {
+	// checked
+	if c.errorChan != nil {
+		return c.replyChecked()
+	}
+	return c.replyUnchecked()
+}
+
+// replyChecked waits for a response on either the replyChan or errorChan
+// channels. If the former arrives, the bytes are returned with a nil error.
+// If the latter arrives, no bytes are returned (nil) and the error received
+// is returned.
+//
+// Unless you're building requests from bytes by hand, this method should
+// not be used.
+func (c Cookie) replyChecked() ([]byte, error) {
+	if c.replyChan == nil {
+		return nil, errors.New("Cannot call 'replyChecked' on a cookie that " +
+			"is not expecting a *reply* or an error.")
+	}
+	if c.errorChan == nil {
+		return nil, errors.New("Cannot call 'replyChecked' on a cookie that " +
+			"is not expecting a reply or an *error*.")
+	}
+
+	select {
+	case reply := <-c.replyChan:
+		return reply, nil
+	case err := <-c.errorChan:
+		return nil, err
+	}
+}
+
+// replyUnchecked waits for a response on either the replyChan or pingChan
+// channels. If the former arrives, the bytes are returned with a nil error.
+// If the latter arrives, no bytes are returned (nil) and a nil error
+// is returned. (In the latter case, the corresponding error can be retrieved
+// from (Wait|Poll)ForEvent asynchronously.)
+// In all honesty, you *probably* don't want to use this method.
+//
+// Unless you're building requests from bytes by hand, this method should
+// not be used.
+func (c Cookie) replyUnchecked() ([]byte, error) {
+	if c.replyChan == nil {
+		return nil, errors.New("Cannot call 'replyUnchecked' on a cookie " +
+			"that is not expecting a *reply*.")
+	}
+
+	select {
+	case reply := <-c.replyChan:
+		return reply, nil
+	case <-c.pingChan:
+		return nil, nil
+	}
+}
+
+// Check is used for checked requests that have no replies. It is a mechanism
+// by which to report "success" or "error" in a synchronous fashion. (Therefore,
+// unchecked requests without replies cannot use this method.)
+// If the request causes an error, it is sent to this cookie's errorChan.
+// If the request was successful, there is no response from the server.
+// Thus, pingChan is sent a value when the *next* reply is read.
+// If no more replies are being processed, we force a round trip request with
+// GetInputFocus.
+//
+// Unless you're building requests from bytes by hand, this method should
+// not be used.
+func (c Cookie) Check() error {
+	if c.replyChan != nil {
+		return errors.New("Cannot call 'Check' on a cookie that is " +
+			"expecting a *reply*. Use 'Reply' instead.")
+	}
+	if c.errorChan == nil {
+		return errors.New("Cannot call 'Check' on a cookie that is " +
+			"not expecting a possible *error*.")
+	}
+
+	// First do a quick non-blocking check to see if we've been pinged.
+	select {
+	case err := <-c.errorChan:
+		return err
+	case <-c.pingChan:
+		return nil
+	default:
+	}
+
+	// Now force a round trip and try again, but block this time.
+	c.conn.Sync()
+	select {
+	case err := <-c.errorChan:
+		return err
+	case <-c.pingChan:
+		return nil
+	}
+}

nexgb/damage/damage.go

@@ -0,0 +1,592 @@
+// Package damage is the X client API for the DAMAGE extension.
+package damage
+
+// This file is automatically generated from damage.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xfixes"
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 1
+	MinorVersion = 1
+)
+
+// Init must be called before using the DAMAGE extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 6, "DAMAGE").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named DAMAGE could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["DAMAGE"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["DAMAGE"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["DAMAGE"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["DAMAGE"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["DAMAGE"] = make(map[int]xgb.NewErrorFun)
+}
+
+// BadBadDamage is the error number for a BadBadDamage.
+const BadBadDamage = 0
+
+type BadDamageError struct {
+	Sequence uint16
+	NiceName string
+}
+
+// BadDamageErrorNew constructs a BadDamageError value that implements xgb.Error from a byte slice.
+func BadDamageErrorNew(buf []byte) xgb.Error {
+	v := BadDamageError{}
+	v.NiceName = "BadDamage"
+
+	b := 1 // skip error determinant
+	b += 1 // don't read error number
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	return v
+}
+
+// SequenceId returns the sequence id attached to the BadBadDamage error.
+// This is mostly used internally.
+func (err BadDamageError) SequenceId() uint16 {
+	return err.Sequence
+}
+
+// BadId returns the 'BadValue' number if one exists for the BadBadDamage error. If no bad value exists, 0 is returned.
+func (err BadDamageError) BadId() uint32 {
+	return 0
+}
+
+// Error returns a rudimentary string representation of the BadBadDamage error.
+
+func (err BadDamageError) Error() string {
+	fieldVals := make([]string, 0, 0)
+	fieldVals = append(fieldVals, "NiceName: "+err.NiceName)
+	fieldVals = append(fieldVals, xgb.Sprintf("Sequence: %d", err.Sequence))
+	return "BadBadDamage {" + xgb.StringsJoin(fieldVals, ", ") + "}"
+}
+
+func init() {
+	xgb.NewExtErrorFuncs["DAMAGE"][0] = BadDamageErrorNew
+}
+
+type Damage uint32
+
+func NewDamageId(c *xgb.Conn) (Damage, error) {
+	id, err := c.NewId()
+	if err != nil {
+		return 0, err
+	}
+	return Damage(id), nil
+}
+
+// Notify is the event number for a NotifyEvent.
+const Notify = 0
+
+type NotifyEvent struct {
+	Sequence  uint16
+	Level     byte
+	Drawable  xproto.Drawable
+	Damage    Damage
+	Timestamp xproto.Timestamp
+	Area      xproto.Rectangle
+	Geometry  xproto.Rectangle
+}
+
+// NotifyEventNew constructs a NotifyEvent value that implements xgb.Event from a byte slice.
+func NotifyEventNew(buf []byte) xgb.Event {
+	v := NotifyEvent{}
+	b := 1 // don't read event number
+
+	v.Level = buf[b]
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Drawable = xproto.Drawable(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.Damage = Damage(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.Timestamp = xproto.Timestamp(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.Area = xproto.Rectangle{}
+	b += xproto.RectangleRead(buf[b:], &v.Area)
+
+	v.Geometry = xproto.Rectangle{}
+	b += xproto.RectangleRead(buf[b:], &v.Geometry)
+
+	return v
+}
+
+// Bytes writes a NotifyEvent value to a byte slice.
+func (v NotifyEvent) Bytes() []byte {
+	buf := make([]byte, 32)
+	b := 0
+
+	// write event number
+	buf[b] = 0
+	b += 1
+
+	buf[b] = v.Level
+	b += 1
+
+	b += 2 // skip sequence number
+
+	xgb.Put32(buf[b:], uint32(v.Drawable))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(v.Damage))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(v.Timestamp))
+	b += 4
+
+	{
+		structBytes := v.Area.Bytes()
+		copy(buf[b:], structBytes)
+		b += len(structBytes)
+	}
+
+	{
+		structBytes := v.Geometry.Bytes()
+		copy(buf[b:], structBytes)
+		b += len(structBytes)
+	}
+
+	return buf
+}
+
+// SequenceId returns the sequence id attached to the Notify event.
+// Events without a sequence number (KeymapNotify) return 0.
+// This is mostly used internally.
+func (v NotifyEvent) SequenceId() uint16 {
+	return v.Sequence
+}
+
+// String is a rudimentary string representation of NotifyEvent.
+func (v NotifyEvent) String() string {
+	fieldVals := make([]string, 0, 6)
+	fieldVals = append(fieldVals, xgb.Sprintf("Sequence: %d", v.Sequence))
+	fieldVals = append(fieldVals, xgb.Sprintf("Level: %d", v.Level))
+	fieldVals = append(fieldVals, xgb.Sprintf("Drawable: %d", v.Drawable))
+	fieldVals = append(fieldVals, xgb.Sprintf("Damage: %d", v.Damage))
+	fieldVals = append(fieldVals, xgb.Sprintf("Timestamp: %d", v.Timestamp))
+	return "Notify {" + xgb.StringsJoin(fieldVals, ", ") + "}"
+}
+
+func init() {
+	xgb.NewExtEventFuncs["DAMAGE"][0] = NotifyEventNew
+}
+
+const (
+	ReportLevelRawRectangles   = 0
+	ReportLevelDeltaRectangles = 1
+	ReportLevelBoundingBox     = 2
+	ReportLevelNonEmpty        = 3
+)
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// AddCookie is a cookie used only for Add requests.
+type AddCookie struct {
+	*xgb.Cookie
+}
+
+// Add sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func Add(c *xgb.Conn, Drawable xproto.Drawable, Region xfixes.Region) AddCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'Add' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(addRequest(c, Drawable, Region), cookie)
+	return AddCookie{cookie}
+}
+
+// AddChecked sends a checked request.
+// If an error occurs, it can be retrieved using AddCookie.Check.
+func AddChecked(c *xgb.Conn, Drawable xproto.Drawable, Region xfixes.Region) AddCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'Add' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(addRequest(c, Drawable, Region), cookie)
+	return AddCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook AddCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// addRequest writes a Add request to a byte slice for transfer.
+func addRequest(c *xgb.Conn, Drawable xproto.Drawable, Region xfixes.Region) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DAMAGE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 4 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Drawable))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Region))
+	b += 4
+
+	return buf
+}
+
+// CreateCookie is a cookie used only for Create requests.
+type CreateCookie struct {
+	*xgb.Cookie
+}
+
+// Create sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func Create(c *xgb.Conn, Damage Damage, Drawable xproto.Drawable, Level byte) CreateCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'Create' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(createRequest(c, Damage, Drawable, Level), cookie)
+	return CreateCookie{cookie}
+}
+
+// CreateChecked sends a checked request.
+// If an error occurs, it can be retrieved using CreateCookie.Check.
+func CreateChecked(c *xgb.Conn, Damage Damage, Drawable xproto.Drawable, Level byte) CreateCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'Create' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(createRequest(c, Damage, Drawable, Level), cookie)
+	return CreateCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook CreateCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// createRequest writes a Create request to a byte slice for transfer.
+func createRequest(c *xgb.Conn, Damage Damage, Drawable xproto.Drawable, Level byte) []byte {
+	size := 16
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DAMAGE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 1 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Damage))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Drawable))
+	b += 4
+
+	buf[b] = Level
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}
+
+// DestroyCookie is a cookie used only for Destroy requests.
+type DestroyCookie struct {
+	*xgb.Cookie
+}
+
+// Destroy sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func Destroy(c *xgb.Conn, Damage Damage) DestroyCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'Destroy' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(destroyRequest(c, Damage), cookie)
+	return DestroyCookie{cookie}
+}
+
+// DestroyChecked sends a checked request.
+// If an error occurs, it can be retrieved using DestroyCookie.Check.
+func DestroyChecked(c *xgb.Conn, Damage Damage) DestroyCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'Destroy' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(destroyRequest(c, Damage), cookie)
+	return DestroyCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook DestroyCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// destroyRequest writes a Destroy request to a byte slice for transfer.
+func destroyRequest(c *xgb.Conn, Damage Damage) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DAMAGE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 2 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Damage))
+	b += 4
+
+	return buf
+}
+
+// QueryVersionCookie is a cookie used only for QueryVersion requests.
+type QueryVersionCookie struct {
+	*xgb.Cookie
+}
+
+// QueryVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling QueryVersionCookie.Reply.
+func QueryVersion(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint32) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func QueryVersionUnchecked(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint32) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionReply represents the data returned from a QueryVersion request.
+type QueryVersionReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	MajorVersion uint32
+	MinorVersion uint32
+	// padding: 16 bytes
+}
+
+// Reply blocks and returns the reply data for a QueryVersion request.
+func (cook QueryVersionCookie) Reply() (*QueryVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return queryVersionReply(buf), nil
+}
+
+// queryVersionReply reads a byte slice into a QueryVersionReply value.
+func queryVersionReply(buf []byte) *QueryVersionReply {
+	v := new(QueryVersionReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.MajorVersion = xgb.Get32(buf[b:])
+	b += 4
+
+	v.MinorVersion = xgb.Get32(buf[b:])
+	b += 4
+
+	b += 16 // padding
+
+	return v
+}
+
+// queryVersionRequest writes a QueryVersion request to a byte slice for transfer.
+func queryVersionRequest(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint32) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DAMAGE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], ClientMajorVersion)
+	b += 4
+
+	xgb.Put32(buf[b:], ClientMinorVersion)
+	b += 4
+
+	return buf
+}
+
+// SubtractCookie is a cookie used only for Subtract requests.
+type SubtractCookie struct {
+	*xgb.Cookie
+}
+
+// Subtract sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func Subtract(c *xgb.Conn, Damage Damage, Repair, Parts xfixes.Region) SubtractCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'Subtract' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(subtractRequest(c, Damage, Repair, Parts), cookie)
+	return SubtractCookie{cookie}
+}
+
+// SubtractChecked sends a checked request.
+// If an error occurs, it can be retrieved using SubtractCookie.Check.
+func SubtractChecked(c *xgb.Conn, Damage Damage, Repair, Parts xfixes.Region) SubtractCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DAMAGE"]; !ok {
+		panic("Cannot issue request 'Subtract' using the uninitialized extension 'DAMAGE'. damage.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(subtractRequest(c, Damage, Repair, Parts), cookie)
+	return SubtractCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook SubtractCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// subtractRequest writes a Subtract request to a byte slice for transfer.
+func subtractRequest(c *xgb.Conn, Damage Damage, Repair, Parts xfixes.Region) []byte {
+	size := 16
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DAMAGE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 3 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Damage))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Repair))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Parts))
+	b += 4
+
+	return buf
+}

nexgb/doc.go

@@ -0,0 +1,144 @@
+/*
+Package nexgb provides the X Go Binding, which is a low-level API to communicate
+with the core X protocol and many of the X extensions.
+
+It is *very* closely modeled on XCB, so that experience with XCB (or xpyb) is
+easily translatable to neXGB. That is, it uses the same cookie/reply model
+and is thread safe. There are otherwise no major differences (in the API).
+
+Most uses of neXGB typically fall under the realm of window manager and GUI kit
+development, but other applications (like pagers, panels, tilers, etc.) may
+also require neXGB.
+
+Example
+
+This is an extremely terse example that demonstrates how to connect to X,
+create a window, listen to StructureNotify events and Key{Press,Release}
+events, map the window, and print out all events received. An example with
+accompanying documentation can be found in examples/create-window.
+
+	package main
+
+	import (
+		"fmt"
+		xgb "janouch.name/haven/nexgb"
+		"janouch.name/haven/nexgb/xproto"
+	)
+
+	func main() {
+		X, err := xgb.NewConn()
+		if err != nil {
+			fmt.Println(err)
+			return
+		}
+
+		wid, _ := xproto.NewWindowId(X)
+		screen := xproto.Setup(X).DefaultScreen(X)
+		xproto.CreateWindow(X, screen.RootDepth, wid, screen.Root,
+			0, 0, 500, 500, 0,
+			xproto.WindowClassInputOutput, screen.RootVisual,
+			xproto.CwBackPixel | xproto.CwEventMask,
+			[]uint32{ // values must be in the order defined by the protocol
+				0xffffffff,
+				xproto.EventMaskStructureNotify |
+				xproto.EventMaskKeyPress |
+				xproto.EventMaskKeyRelease})
+
+		xproto.MapWindow(X, wid)
+		for {
+			ev, xerr := X.WaitForEvent()
+			if ev == nil && xerr == nil {
+				fmt.Println("Both event and error are nil. Exiting...")
+				return
+			}
+
+			if ev != nil {
+				fmt.Printf("Event: %s\n", ev)
+			}
+			if xerr != nil {
+				fmt.Printf("Error: %s\n", xerr)
+			}
+		}
+	}
+
+Xinerama Example
+
+This is another small example that shows how to query Xinerama for geometry
+information of each active head. Accompanying documentation for this example
+can be found in examples/xinerama.
+
+	package main
+
+	import (
+		"fmt"
+		"log"
+		xgb "janouch.name/haven/nexgb"
+		"janouch.name/haven/nexgb/xinerama"
+	)
+
+	func main() {
+		X, err := xgb.NewConn()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		// Initialize the Xinerama extension.
+		// The appropriate 'Init' function must be run for *every*
+		// extension before any of its requests can be used.
+		err = xinerama.Init(X)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		reply, err := xinerama.QueryScreens(X).Reply()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		fmt.Printf("Number of heads: %d\n", reply.Number)
+		for i, screen := range reply.ScreenInfo {
+			fmt.Printf("%d :: X: %d, Y: %d, Width: %d, Height: %d\n",
+				i, screen.XOrg, screen.YOrg, screen.Width, screen.Height)
+		}
+	}
+
+Parallelism
+
+neXGB can benefit greatly from parallelism due to its concurrent design. For
+evidence of this claim, please see the benchmarks in xproto/xproto_test.go.
+
+Tests
+
+xproto/xproto_test.go contains a number of contrived tests that stress
+particular corners of neXGB that I presume could be problem areas. Namely:
+requests with no replies, requests with replies, checked errors, unchecked
+errors, sequence number wrapping, cookie buffer flushing (i.e., forcing a round
+trip every N requests made that don't have a reply), getting/setting properties
+and creating a window and listening to StructureNotify events.
+
+Code Generator
+
+Both XCB and xpyb use the same Python module (xcbgen) for a code generator.
+neXGB (before BurntSushi's fork) used the same code generator as well, but in my
+attempt to add support for more extensions, I found the code generator extremely
+difficult to work with. Therefore, I re-wrote the code generator in Go. It can
+be found in its own sub-package, xgbgen, of xgb. My design of xgbgen includes a
+rough consideration that it could be used for other languages.
+
+What works
+
+I am reasonably confident that the core X protocol is in full working form. I've
+also tested the Xinerama and RandR extensions sparingly. Many of the other
+existing extensions have Go source generated (and are compilable) and are
+included in this package, but I am currently unsure of their status. They
+*should* work.
+
+What does not work
+
+XKB is the only extension that intentionally does not work, although I suspect
+that GLX also does not work (however, there is Go source code for GLX that
+compiles, unlike XKB). I don't currently have any intention of getting XKB
+working, due to its complexity and my current mental incapacity to test it.
+
+*/
+package nexgb

nexgb/dpms/dpms.go

@@ -0,0 +1,712 @@
+// Package dpms is the X client API for the DPMS extension.
+package dpms
+
+// This file is automatically generated from dpms.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 0
+	MinorVersion = 0
+)
+
+// Init must be called before using the DPMS extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 4, "DPMS").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named DPMS could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["DPMS"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["DPMS"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["DPMS"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["DPMS"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["DPMS"] = make(map[int]xgb.NewErrorFun)
+}
+
+const (
+	DPMSModeOn      = 0
+	DPMSModeStandby = 1
+	DPMSModeSuspend = 2
+	DPMSModeOff     = 3
+)
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// CapableCookie is a cookie used only for Capable requests.
+type CapableCookie struct {
+	*xgb.Cookie
+}
+
+// Capable sends a checked request.
+// If an error occurs, it will be returned with the reply by calling CapableCookie.Reply.
+func Capable(c *xgb.Conn) CapableCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'Capable' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(capableRequest(c), cookie)
+	return CapableCookie{cookie}
+}
+
+// CapableUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func CapableUnchecked(c *xgb.Conn) CapableCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'Capable' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(capableRequest(c), cookie)
+	return CapableCookie{cookie}
+}
+
+// CapableReply represents the data returned from a Capable request.
+type CapableReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	Capable bool
+	// padding: 23 bytes
+}
+
+// Reply blocks and returns the reply data for a Capable request.
+func (cook CapableCookie) Reply() (*CapableReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return capableReply(buf), nil
+}
+
+// capableReply reads a byte slice into a CapableReply value.
+func capableReply(buf []byte) *CapableReply {
+	v := new(CapableReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	if buf[b] == 1 {
+		v.Capable = true
+	} else {
+		v.Capable = false
+	}
+	b += 1
+
+	b += 23 // padding
+
+	return v
+}
+
+// capableRequest writes a Capable request to a byte slice for transfer.
+func capableRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DPMS"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 1 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}
+
+// DisableCookie is a cookie used only for Disable requests.
+type DisableCookie struct {
+	*xgb.Cookie
+}
+
+// Disable sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func Disable(c *xgb.Conn) DisableCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'Disable' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(disableRequest(c), cookie)
+	return DisableCookie{cookie}
+}
+
+// DisableChecked sends a checked request.
+// If an error occurs, it can be retrieved using DisableCookie.Check.
+func DisableChecked(c *xgb.Conn) DisableCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'Disable' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(disableRequest(c), cookie)
+	return DisableCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook DisableCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// disableRequest writes a Disable request to a byte slice for transfer.
+func disableRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DPMS"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 5 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}
+
+// EnableCookie is a cookie used only for Enable requests.
+type EnableCookie struct {
+	*xgb.Cookie
+}
+
+// Enable sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func Enable(c *xgb.Conn) EnableCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'Enable' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(enableRequest(c), cookie)
+	return EnableCookie{cookie}
+}
+
+// EnableChecked sends a checked request.
+// If an error occurs, it can be retrieved using EnableCookie.Check.
+func EnableChecked(c *xgb.Conn) EnableCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'Enable' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(enableRequest(c), cookie)
+	return EnableCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook EnableCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// enableRequest writes a Enable request to a byte slice for transfer.
+func enableRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DPMS"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 4 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}
+
+// ForceLevelCookie is a cookie used only for ForceLevel requests.
+type ForceLevelCookie struct {
+	*xgb.Cookie
+}
+
+// ForceLevel sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func ForceLevel(c *xgb.Conn, PowerLevel uint16) ForceLevelCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'ForceLevel' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(forceLevelRequest(c, PowerLevel), cookie)
+	return ForceLevelCookie{cookie}
+}
+
+// ForceLevelChecked sends a checked request.
+// If an error occurs, it can be retrieved using ForceLevelCookie.Check.
+func ForceLevelChecked(c *xgb.Conn, PowerLevel uint16) ForceLevelCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'ForceLevel' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(forceLevelRequest(c, PowerLevel), cookie)
+	return ForceLevelCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook ForceLevelCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// forceLevelRequest writes a ForceLevel request to a byte slice for transfer.
+func forceLevelRequest(c *xgb.Conn, PowerLevel uint16) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DPMS"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 6 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put16(buf[b:], PowerLevel)
+	b += 2
+
+	return buf
+}
+
+// GetTimeoutsCookie is a cookie used only for GetTimeouts requests.
+type GetTimeoutsCookie struct {
+	*xgb.Cookie
+}
+
+// GetTimeouts sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetTimeoutsCookie.Reply.
+func GetTimeouts(c *xgb.Conn) GetTimeoutsCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'GetTimeouts' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getTimeoutsRequest(c), cookie)
+	return GetTimeoutsCookie{cookie}
+}
+
+// GetTimeoutsUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetTimeoutsUnchecked(c *xgb.Conn) GetTimeoutsCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'GetTimeouts' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getTimeoutsRequest(c), cookie)
+	return GetTimeoutsCookie{cookie}
+}
+
+// GetTimeoutsReply represents the data returned from a GetTimeouts request.
+type GetTimeoutsReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	StandbyTimeout uint16
+	SuspendTimeout uint16
+	OffTimeout     uint16
+	// padding: 18 bytes
+}
+
+// Reply blocks and returns the reply data for a GetTimeouts request.
+func (cook GetTimeoutsCookie) Reply() (*GetTimeoutsReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getTimeoutsReply(buf), nil
+}
+
+// getTimeoutsReply reads a byte slice into a GetTimeoutsReply value.
+func getTimeoutsReply(buf []byte) *GetTimeoutsReply {
+	v := new(GetTimeoutsReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.StandbyTimeout = xgb.Get16(buf[b:])
+	b += 2
+
+	v.SuspendTimeout = xgb.Get16(buf[b:])
+	b += 2
+
+	v.OffTimeout = xgb.Get16(buf[b:])
+	b += 2
+
+	b += 18 // padding
+
+	return v
+}
+
+// getTimeoutsRequest writes a GetTimeouts request to a byte slice for transfer.
+func getTimeoutsRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DPMS"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 2 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}
+
+// GetVersionCookie is a cookie used only for GetVersion requests.
+type GetVersionCookie struct {
+	*xgb.Cookie
+}
+
+// GetVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetVersionCookie.Reply.
+func GetVersion(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) GetVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'GetVersion' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return GetVersionCookie{cookie}
+}
+
+// GetVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetVersionUnchecked(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) GetVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'GetVersion' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return GetVersionCookie{cookie}
+}
+
+// GetVersionReply represents the data returned from a GetVersion request.
+type GetVersionReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	ServerMajorVersion uint16
+	ServerMinorVersion uint16
+}
+
+// Reply blocks and returns the reply data for a GetVersion request.
+func (cook GetVersionCookie) Reply() (*GetVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getVersionReply(buf), nil
+}
+
+// getVersionReply reads a byte slice into a GetVersionReply value.
+func getVersionReply(buf []byte) *GetVersionReply {
+	v := new(GetVersionReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.ServerMajorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	v.ServerMinorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	return v
+}
+
+// getVersionRequest writes a GetVersion request to a byte slice for transfer.
+func getVersionRequest(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DPMS"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put16(buf[b:], ClientMajorVersion)
+	b += 2
+
+	xgb.Put16(buf[b:], ClientMinorVersion)
+	b += 2
+
+	return buf
+}
+
+// InfoCookie is a cookie used only for Info requests.
+type InfoCookie struct {
+	*xgb.Cookie
+}
+
+// Info sends a checked request.
+// If an error occurs, it will be returned with the reply by calling InfoCookie.Reply.
+func Info(c *xgb.Conn) InfoCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'Info' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(infoRequest(c), cookie)
+	return InfoCookie{cookie}
+}
+
+// InfoUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func InfoUnchecked(c *xgb.Conn) InfoCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'Info' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(infoRequest(c), cookie)
+	return InfoCookie{cookie}
+}
+
+// InfoReply represents the data returned from a Info request.
+type InfoReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	PowerLevel uint16
+	State      bool
+	// padding: 21 bytes
+}
+
+// Reply blocks and returns the reply data for a Info request.
+func (cook InfoCookie) Reply() (*InfoReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return infoReply(buf), nil
+}
+
+// infoReply reads a byte slice into a InfoReply value.
+func infoReply(buf []byte) *InfoReply {
+	v := new(InfoReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.PowerLevel = xgb.Get16(buf[b:])
+	b += 2
+
+	if buf[b] == 1 {
+		v.State = true
+	} else {
+		v.State = false
+	}
+	b += 1
+
+	b += 21 // padding
+
+	return v
+}
+
+// infoRequest writes a Info request to a byte slice for transfer.
+func infoRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DPMS"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 7 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}
+
+// SetTimeoutsCookie is a cookie used only for SetTimeouts requests.
+type SetTimeoutsCookie struct {
+	*xgb.Cookie
+}
+
+// SetTimeouts sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func SetTimeouts(c *xgb.Conn, StandbyTimeout, SuspendTimeout, OffTimeout uint16) SetTimeoutsCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'SetTimeouts' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(setTimeoutsRequest(c, StandbyTimeout, SuspendTimeout, OffTimeout), cookie)
+	return SetTimeoutsCookie{cookie}
+}
+
+// SetTimeoutsChecked sends a checked request.
+// If an error occurs, it can be retrieved using SetTimeoutsCookie.Check.
+func SetTimeoutsChecked(c *xgb.Conn, StandbyTimeout, SuspendTimeout, OffTimeout uint16) SetTimeoutsCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["DPMS"]; !ok {
+		panic("Cannot issue request 'SetTimeouts' using the uninitialized extension 'DPMS'. dpms.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(setTimeoutsRequest(c, StandbyTimeout, SuspendTimeout, OffTimeout), cookie)
+	return SetTimeoutsCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook SetTimeoutsCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// setTimeoutsRequest writes a SetTimeouts request to a byte slice for transfer.
+func setTimeoutsRequest(c *xgb.Conn, StandbyTimeout, SuspendTimeout, OffTimeout uint16) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["DPMS"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 3 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put16(buf[b:], StandbyTimeout)
+	b += 2
+
+	xgb.Put16(buf[b:], SuspendTimeout)
+	b += 2
+
+	xgb.Put16(buf[b:], OffTimeout)
+	b += 2
+
+	return buf
+}

nexgb/examples/atoms/.gitignore

@@ -0,0 +1,3 @@
+atoms
+*.info
+*.prof

nexgb/examples/atoms/Makefile

@@ -0,0 +1,12 @@
+atoms:
+	go build
+
+test: atoms
+	./atoms --requests 500000 --cpu 1 \
+		--cpuprof cpu1.prof --memprof mem1.prof > atoms1.info 2>&1
+	./atoms --requests 500000 --cpu 2 \
+		--cpuprof cpu2.prof --memprof mem2.prof > atoms2.info 2>&1
+	./atoms --requests 500000 --cpu 3 \
+		--cpuprof cpu3.prof --memprof mem3.prof > atoms3.info 2>&1
+	./atoms --requests 500000 --cpu 6 \
+		--cpuprof cpu6.prof --memprof mem6.prof > atoms6.info 2>&1

nexgb/examples/atoms/main.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"runtime"
+	"runtime/pprof"
+	"time"
+
+	xgb "janouch.name/haven/nexgb"
+	"janouch.name/haven/nexgb/xproto"
+)
+
+var (
+	flagRequests    int
+	flagGOMAXPROCS  int
+	flagCpuProfName string
+	flagMemProfName string
+)
+
+func init() {
+	flag.IntVar(&flagRequests, "requests", 100000, "Number of atoms to intern.")
+	flag.IntVar(&flagGOMAXPROCS, "cpu", 1, "Value of GOMAXPROCS.")
+	flag.StringVar(&flagCpuProfName, "cpuprof", "cpu.prof",
+		"Name of CPU profile file.")
+	flag.StringVar(&flagMemProfName, "memprof", "mem.prof",
+		"Name of memory profile file.")
+
+	flag.Parse()
+
+	runtime.GOMAXPROCS(flagGOMAXPROCS)
+}
+
+func seqNames(n int) []string {
+	names := make([]string, n)
+	for i := range names {
+		names[i] = fmt.Sprintf("NAME%d", i)
+	}
+	return names
+}
+
+func main() {
+	X, err := xgb.NewConn()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	names := seqNames(flagRequests)
+
+	fcpu, err := os.Create(flagCpuProfName)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer fcpu.Close()
+	pprof.StartCPUProfile(fcpu)
+	defer pprof.StopCPUProfile()
+
+	start := time.Now()
+	cookies := make([]xproto.InternAtomCookie, flagRequests)
+	for i := 0; i < flagRequests; i++ {
+		cookies[i] = xproto.InternAtom(X,
+			false, uint16(len(names[i])), names[i])
+	}
+	for _, cookie := range cookies {
+		cookie.Reply()
+	}
+	fmt.Printf("Exec time: %s\n\n", time.Since(start))
+
+	fmem, err := os.Create(flagMemProfName)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer fmem.Close()
+	pprof.WriteHeapProfile(fmem)
+
+	memStats := &runtime.MemStats{}
+	runtime.ReadMemStats(memStats)
+
+	// This isn't right. I'm not sure what's wrong.
+	lastGcTime := time.Unix(int64(memStats.LastGC/1000000000),
+		int64(memStats.LastGC-memStats.LastGC/1000000000))
+
+	fmt.Printf("Alloc: %d\n", memStats.Alloc)
+	fmt.Printf("TotalAlloc: %d\n", memStats.TotalAlloc)
+	fmt.Printf("LastGC: %s\n", lastGcTime)
+	fmt.Printf("PauseTotalNs: %d\n", memStats.PauseTotalNs)
+	fmt.Printf("PauseNs: %d\n", memStats.PauseNs)
+	fmt.Printf("NumGC: %d\n", memStats.NumGC)
+}

nexgb/examples/create-window/main.go

@@ -0,0 +1,107 @@
+// Example create-window shows how to create a window, map it, resize it,
+// and listen to structure and key events (i.e., when the window is resized
+// by the window manager, or when key presses/releases are made when the
+// window has focus). The events are printed to stdout.
+package main
+
+import (
+	"fmt"
+
+	xgb "janouch.name/haven/nexgb"
+	"janouch.name/haven/nexgb/xproto"
+)
+
+func main() {
+	X, err := xgb.NewConn()
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	// xproto.Setup retrieves the Setup information from the setup bytes
+	// gathered during connection.
+	setup := xproto.Setup(X)
+
+	// This is the default screen with all its associated info.
+	screen := setup.DefaultScreen(X)
+
+	// Any time a new resource (i.e., a window, pixmap, graphics context, etc.)
+	// is created, we need to generate a resource identifier.
+	// If the resource is a window, then use xproto.NewWindowId. If it's for
+	// a pixmap, then use xproto.NewPixmapId. And so on...
+	wid, _ := xproto.NewWindowId(X)
+
+	// CreateWindow takes a boatload of parameters.
+	xproto.CreateWindow(X, screen.RootDepth, wid, screen.Root,
+		0, 0, 500, 500, 0,
+		xproto.WindowClassInputOutput, screen.RootVisual, 0, []uint32{})
+
+	// This call to ChangeWindowAttributes could be factored out and
+	// included with the above CreateWindow call, but it is left here for
+	// instructive purposes. It tells X to send us events when the 'structure'
+	// of the window is changed (i.e., when it is resized, mapped, unmapped,
+	// etc.) and when a key press or a key release has been made when the
+	// window has focus.
+	// We also set the 'BackPixel' to white so that the window isn't butt ugly.
+	xproto.ChangeWindowAttributes(X, wid,
+		xproto.CwBackPixel|xproto.CwEventMask,
+		[]uint32{ // values must be in the order defined by the protocol
+			0xffffffff,
+			xproto.EventMaskStructureNotify |
+				xproto.EventMaskKeyPress |
+				xproto.EventMaskKeyRelease})
+
+	// MapWindow makes the window we've created appear on the screen.
+	// We demonstrated the use of a 'checked' request here.
+	// A checked request is a fancy way of saying, "do error handling
+	// synchronously." Namely, if there is a problem with the MapWindow request,
+	// we'll get the error *here*. If we were to do a normal unchecked
+	// request (like the above CreateWindow and ChangeWindowAttributes
+	// requests), then we would only see the error arrive in the main event
+	// loop.
+	//
+	// Typically, checked requests are useful when you need to make sure they
+	// succeed. Since they are synchronous, they incur a round trip cost before
+	// the program can continue, but this is only going to be noticeable if
+	// you're issuing tons of requests in succession.
+	//
+	// Note that requests without replies are by default unchecked while
+	// requests *with* replies are checked by default.
+	err = xproto.MapWindowChecked(X, wid).Check()
+	if err != nil {
+		fmt.Printf("Checked Error for mapping window %d: %s\n", wid, err)
+	} else {
+		fmt.Printf("Map window %d successful!\n", wid)
+	}
+
+	// This is an example of an invalid MapWindow request and what an error
+	// looks like.
+	err = xproto.MapWindowChecked(X, 0).Check()
+	if err != nil {
+		fmt.Printf("Checked Error for mapping window 0x1: %s\n", err)
+	} else { // neva
+		fmt.Printf("Map window 0x1 successful!\n")
+	}
+
+	// Start the main event loop.
+	for {
+		// WaitForEvent either returns an event or an error and never both.
+		// If both are nil, then something went wrong and the loop should be
+		// halted.
+		//
+		// An error can only be seen here as a response to an unchecked
+		// request.
+		ev, xerr := X.WaitForEvent()
+		if ev == nil && xerr == nil {
+			fmt.Println("Both event and error are nil. Exiting...")
+			return
+		}
+
+		if ev != nil {
+			fmt.Printf("Event: %s\n", ev)
+		}
+		if xerr != nil {
+			fmt.Printf("Error: %s\n", xerr)
+		}
+	}
+}

nexgb/examples/doc.go

@@ -0,0 +1,21 @@
+/*
+Package examples contains a few different use cases of XGB, like creating
+a window, reading properties, and querying for information about multiple
+heads using the Xinerama or RandR extensions.
+
+If you're looking to get started quickly, I recommend checking out the
+create-window example first. It is the most documented and probably covers
+some of the more common bare bones cases of creating windows and responding
+to events.
+
+If you're looking to query information about your window manager,
+get-active-window is a start. However, to do anything extensive requires
+a lot of boiler plate. To that end, I'd recommend use of my higher level
+library, xgbutil: https://janouch.name/haven/nexgbutil
+
+There are also examples of using the Xinerama and RandR extensions, if you're
+interested in querying information about your active heads. In RandR's case,
+you can also reconfigure your heads, but the example doesn't cover that.
+
+*/
+package documentation

nexgb/examples/get-active-window/main.go

@@ -0,0 +1,61 @@
+// Example get-active-window reads the _NET_ACTIVE_WINDOW property of the root
+// window and uses the result (a window id) to get the name of the window.
+package main
+
+import (
+	"fmt"
+	"log"
+
+	xgb "janouch.name/haven/nexgb"
+	"janouch.name/haven/nexgb/xproto"
+)
+
+func main() {
+	X, err := xgb.NewConn()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Get the window id of the root window.
+	setup := xproto.Setup(X)
+	root := setup.DefaultScreen(X).Root
+
+	// Get the atom id (i.e., intern an atom) of "_NET_ACTIVE_WINDOW".
+	aname := "_NET_ACTIVE_WINDOW"
+	activeAtom, err := xproto.InternAtom(X, true, uint16(len(aname)),
+		aname).Reply()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Get the atom id (i.e., intern an atom) of "_NET_WM_NAME".
+	aname = "_NET_WM_NAME"
+	nameAtom, err := xproto.InternAtom(X, true, uint16(len(aname)),
+		aname).Reply()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Get the actual value of _NET_ACTIVE_WINDOW.
+	// Note that 'reply.Value' is just a slice of bytes, so we use an
+	// XGB helper function, 'Get32', to pull an unsigned 32-bit integer out
+	// of the byte slice. We then convert it to an X resource id so it can
+	// be used to get the name of the window in the next GetProperty request.
+	reply, err := xproto.GetProperty(X, false, root, activeAtom.Atom,
+		xproto.GetPropertyTypeAny, 0, (1<<32)-1).Reply()
+	if err != nil {
+		log.Fatal(err)
+	}
+	windowId := xproto.Window(xgb.Get32(reply.Value))
+	fmt.Printf("Active window id: %X\n", windowId)
+
+	// Now get the value of _NET_WM_NAME for the active window.
+	// Note that this time, we simply convert the resulting byte slice,
+	// reply.Value, to a string.
+	reply, err = xproto.GetProperty(X, false, windowId, nameAtom.Atom,
+		xproto.GetPropertyTypeAny, 0, (1<<32)-1).Reply()
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("Active window name: %s\n", string(reply.Value))
+}

nexgb/examples/randr/main.go

@@ -0,0 +1,92 @@
+// Example randr uses the randr protocol to get information about the active
+// heads. It also listens for events that are sent when the head configuration
+// changes. Since it listens to events, you'll have to manually kill this
+// process when you're done (i.e., ctrl+c.)
+//
+// While this program is running, if you use 'xrandr' to reconfigure your
+// heads, you should see event information dumped to standard out.
+//
+// For more information, please see the RandR protocol spec:
+// http://www.x.org/releases/X11R7.6/doc/randrproto/randrproto.txt
+package main
+
+import (
+	"fmt"
+	"log"
+
+	xgb "janouch.name/haven/nexgb"
+	"janouch.name/haven/nexgb/randr"
+	"janouch.name/haven/nexgb/xproto"
+)
+
+func main() {
+	X, _ := xgb.NewConn()
+
+	// Every extension must be initialized before it can be used.
+	err := randr.Init(X)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Get the root window on the default screen.
+	root := xproto.Setup(X).DefaultScreen(X).Root
+
+	// Gets the current screen resources. Screen resources contains a list
+	// of names, crtcs, outputs and modes, among other things.
+	resources, err := randr.GetScreenResources(X, root).Reply()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Iterate through all of the outputs and show some of their info.
+	for _, output := range resources.Outputs {
+		info, err := randr.GetOutputInfo(X, output, 0).Reply()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		if info.Connection == randr.ConnectionConnected {
+			bestMode := info.Modes[0]
+			for _, mode := range resources.Modes {
+				if mode.Id == uint32(bestMode) {
+					fmt.Printf("Width: %d, Height: %d\n",
+						mode.Width, mode.Height)
+				}
+			}
+		}
+	}
+
+	fmt.Println("\n")
+
+	// Iterate through all of the crtcs and show some of their info.
+	for _, crtc := range resources.Crtcs {
+		info, err := randr.GetCrtcInfo(X, crtc, 0).Reply()
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf("X: %d, Y: %d, Width: %d, Height: %d\n",
+			info.X, info.Y, info.Width, info.Height)
+	}
+
+	// Tell RandR to send us events. (I think these are all of them, as of 1.3.)
+	err = randr.SelectInputChecked(X, root,
+		randr.NotifyMaskScreenChange|
+			randr.NotifyMaskCrtcChange|
+			randr.NotifyMaskOutputChange|
+			randr.NotifyMaskOutputProperty).Check()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Listen to events and just dump them to standard out.
+	// A more involved approach will have to read the 'U' field of
+	// RandrNotifyEvent, which is a union (really a struct) of type
+	// RanrNotifyDataUnion.
+	for {
+		ev, err := X.WaitForEvent()
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Println(ev)
+	}
+}

nexgb/examples/xinerama/main.go

@@ -0,0 +1,40 @@
+// Example xinerama shows how to query the geometry of all active heads.
+package main
+
+import (
+	"fmt"
+	"log"
+
+	xgb "janouch.name/haven/nexgb"
+	"janouch.name/haven/nexgb/xinerama"
+)
+
+func main() {
+	X, err := xgb.NewConn()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Initialize the Xinerama extension.
+	// The appropriate 'Init' function must be run for *every*
+	// extension before any of its requests can be used.
+	err = xinerama.Init(X)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Issue a request to get the screen information.
+	reply, err := xinerama.QueryScreens(X).Reply()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// reply.Number is the number of active heads, while reply.ScreenInfo
+	// is a slice of XineramaScreenInfo containing the rectangle geometry
+	// of each head.
+	fmt.Printf("Number of heads: %d\n", reply.Number)
+	for i, screen := range reply.ScreenInfo {
+		fmt.Printf("%d :: X: %d, Y: %d, Width: %d, Height: %d\n",
+			i, screen.XOrg, screen.YOrg, screen.Width, screen.Height)
+	}
+}

nexgb/ge/ge.go

@@ -0,0 +1,169 @@
+// Package ge is the X client API for the Generic Event Extension extension.
+package ge
+
+// This file is automatically generated from ge.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 1
+	MinorVersion = 0
+)
+
+// Init must be called before using the Generic Event Extension extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 23, "Generic Event Extension").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named Generic Event Extension could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["Generic Event Extension"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["Generic Event Extension"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["Generic Event Extension"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["Generic Event Extension"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["Generic Event Extension"] = make(map[int]xgb.NewErrorFun)
+}
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// QueryVersionCookie is a cookie used only for QueryVersion requests.
+type QueryVersionCookie struct {
+	*xgb.Cookie
+}
+
+// QueryVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling QueryVersionCookie.Reply.
+func QueryVersion(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Generic Event Extension"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'Generic Event Extension'. ge.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func QueryVersionUnchecked(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["Generic Event Extension"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'Generic Event Extension'. ge.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionReply represents the data returned from a QueryVersion request.
+type QueryVersionReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	MajorVersion uint16
+	MinorVersion uint16
+	// padding: 20 bytes
+}
+
+// Reply blocks and returns the reply data for a QueryVersion request.
+func (cook QueryVersionCookie) Reply() (*QueryVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return queryVersionReply(buf), nil
+}
+
+// queryVersionReply reads a byte slice into a QueryVersionReply value.
+func queryVersionReply(buf []byte) *QueryVersionReply {
+	v := new(QueryVersionReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.MajorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	v.MinorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	b += 20 // padding
+
+	return v
+}
+
+// queryVersionRequest writes a QueryVersion request to a byte slice for transfer.
+func queryVersionRequest(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["Generic Event Extension"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put16(buf[b:], ClientMajorVersion)
+	b += 2
+
+	xgb.Put16(buf[b:], ClientMinorVersion)
+	b += 2
+
+	return buf
+}

nexgb/help.go

@@ -0,0 +1,105 @@
+package nexgb
+
+/*
+help.go is meant to contain a rough hodge podge of functions that are mainly
+used in the auto generated code. Indeed, several functions here are simple
+wrappers so that the sub-packages don't need to be smart about which stdlib
+packages to import.
+
+Also, the 'Get..' and 'Put..' functions are used through the core xgb package
+too. (xgbutil uses them too.)
+*/
+
+import (
+	"fmt"
+	"strings"
+)
+
+// StringsJoin is an alias to strings.Join. It allows us to avoid having to
+// import 'strings' in each of the generated Go files.
+func StringsJoin(ss []string, sep string) string {
+	return strings.Join(ss, sep)
+}
+
+// Sprintf is so we don't need to import 'fmt' in the generated Go files.
+func Sprintf(format string, v ...interface{}) string {
+	return fmt.Sprintf(format, v...)
+}
+
+// Errorf is just a wrapper for fmt.Errorf. Exists for the same reason
+// that 'stringsJoin' and 'sprintf' exists.
+func Errorf(format string, v ...interface{}) error {
+	return fmt.Errorf(format, v...)
+}
+
+// Pad a length to align on 4 bytes.
+func Pad(n int) int {
+	return (n + 3) & ^3
+}
+
+// PopCount counts the number of bits set in a value list mask.
+func PopCount(mask0 int) int {
+	mask := uint32(mask0)
+	n := 0
+	for i := uint32(0); i < 32; i++ {
+		if mask&(1<<i) != 0 {
+			n++
+		}
+	}
+	return n
+}
+
+// Put16 takes a 16 bit integer and copies it into a byte slice.
+func Put16(buf []byte, v uint16) {
+	buf[0] = byte(v)
+	buf[1] = byte(v >> 8)
+}
+
+// Put32 takes a 32 bit integer and copies it into a byte slice.
+func Put32(buf []byte, v uint32) {
+	buf[0] = byte(v)
+	buf[1] = byte(v >> 8)
+	buf[2] = byte(v >> 16)
+	buf[3] = byte(v >> 24)
+}
+
+// Put64 takes a 64 bit integer and copies it into a byte slice.
+func Put64(buf []byte, v uint64) {
+	buf[0] = byte(v)
+	buf[1] = byte(v >> 8)
+	buf[2] = byte(v >> 16)
+	buf[3] = byte(v >> 24)
+	buf[4] = byte(v >> 32)
+	buf[5] = byte(v >> 40)
+	buf[6] = byte(v >> 48)
+	buf[7] = byte(v >> 56)
+}
+
+// Get16 constructs a 16 bit integer from the beginning of a byte slice.
+func Get16(buf []byte) uint16 {
+	v := uint16(buf[0])
+	v |= uint16(buf[1]) << 8
+	return v
+}
+
+// Get32 constructs a 32 bit integer from the beginning of a byte slice.
+func Get32(buf []byte) uint32 {
+	v := uint32(buf[0])
+	v |= uint32(buf[1]) << 8
+	v |= uint32(buf[2]) << 16
+	v |= uint32(buf[3]) << 24
+	return v
+}
+
+// Get64 constructs a 64 bit integer from the beginning of a byte slice.
+func Get64(buf []byte) uint64 {
+	v := uint64(buf[0])
+	v |= uint64(buf[1]) << 8
+	v |= uint64(buf[2]) << 16
+	v |= uint64(buf[3]) << 24
+	v |= uint64(buf[4]) << 32
+	v |= uint64(buf[5]) << 40
+	v |= uint64(buf[6]) << 48
+	v |= uint64(buf[7]) << 56
+	return v
+}

nexgb/screensaver/screensaver.go

@@ -0,0 +1,695 @@
+// Package screensaver is the X client API for the MIT-SCREEN-SAVER extension.
+package screensaver
+
+// This file is automatically generated from screensaver.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 1
+	MinorVersion = 1
+)
+
+// Init must be called before using the MIT-SCREEN-SAVER extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 16, "MIT-SCREEN-SAVER").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named MIT-SCREEN-SAVER could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["MIT-SCREEN-SAVER"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["MIT-SCREEN-SAVER"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["MIT-SCREEN-SAVER"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["MIT-SCREEN-SAVER"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["MIT-SCREEN-SAVER"] = make(map[int]xgb.NewErrorFun)
+}
+
+const (
+	EventNotifyMask = 1
+	EventCycleMask  = 2
+)
+
+const (
+	KindBlanked  = 0
+	KindInternal = 1
+	KindExternal = 2
+)
+
+// Notify is the event number for a NotifyEvent.
+const Notify = 0
+
+type NotifyEvent struct {
+	Sequence uint16
+	State    byte
+	Time     xproto.Timestamp
+	Root     xproto.Window
+	Window   xproto.Window
+	Kind     byte
+	Forced   bool
+	// padding: 14 bytes
+}
+
+// NotifyEventNew constructs a NotifyEvent value that implements xgb.Event from a byte slice.
+func NotifyEventNew(buf []byte) xgb.Event {
+	v := NotifyEvent{}
+	b := 1 // don't read event number
+
+	v.State = buf[b]
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Time = xproto.Timestamp(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.Root = xproto.Window(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.Window = xproto.Window(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.Kind = buf[b]
+	b += 1
+
+	if buf[b] == 1 {
+		v.Forced = true
+	} else {
+		v.Forced = false
+	}
+	b += 1
+
+	b += 14 // padding
+
+	return v
+}
+
+// Bytes writes a NotifyEvent value to a byte slice.
+func (v NotifyEvent) Bytes() []byte {
+	buf := make([]byte, 32)
+	b := 0
+
+	// write event number
+	buf[b] = 0
+	b += 1
+
+	buf[b] = v.State
+	b += 1
+
+	b += 2 // skip sequence number
+
+	xgb.Put32(buf[b:], uint32(v.Time))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(v.Root))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(v.Window))
+	b += 4
+
+	buf[b] = v.Kind
+	b += 1
+
+	if v.Forced {
+		buf[b] = 1
+	} else {
+		buf[b] = 0
+	}
+	b += 1
+
+	b += 14 // padding
+
+	return buf
+}
+
+// SequenceId returns the sequence id attached to the Notify event.
+// Events without a sequence number (KeymapNotify) return 0.
+// This is mostly used internally.
+func (v NotifyEvent) SequenceId() uint16 {
+	return v.Sequence
+}
+
+// String is a rudimentary string representation of NotifyEvent.
+func (v NotifyEvent) String() string {
+	fieldVals := make([]string, 0, 7)
+	fieldVals = append(fieldVals, xgb.Sprintf("Sequence: %d", v.Sequence))
+	fieldVals = append(fieldVals, xgb.Sprintf("State: %d", v.State))
+	fieldVals = append(fieldVals, xgb.Sprintf("Time: %d", v.Time))
+	fieldVals = append(fieldVals, xgb.Sprintf("Root: %d", v.Root))
+	fieldVals = append(fieldVals, xgb.Sprintf("Window: %d", v.Window))
+	fieldVals = append(fieldVals, xgb.Sprintf("Kind: %d", v.Kind))
+	fieldVals = append(fieldVals, xgb.Sprintf("Forced: %t", v.Forced))
+	return "Notify {" + xgb.StringsJoin(fieldVals, ", ") + "}"
+}
+
+func init() {
+	xgb.NewExtEventFuncs["MIT-SCREEN-SAVER"][0] = NotifyEventNew
+}
+
+const (
+	StateOff      = 0
+	StateOn       = 1
+	StateCycle    = 2
+	StateDisabled = 3
+)
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// QueryInfoCookie is a cookie used only for QueryInfo requests.
+type QueryInfoCookie struct {
+	*xgb.Cookie
+}
+
+// QueryInfo sends a checked request.
+// If an error occurs, it will be returned with the reply by calling QueryInfoCookie.Reply.
+func QueryInfo(c *xgb.Conn, Drawable xproto.Drawable) QueryInfoCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'QueryInfo' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(queryInfoRequest(c, Drawable), cookie)
+	return QueryInfoCookie{cookie}
+}
+
+// QueryInfoUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func QueryInfoUnchecked(c *xgb.Conn, Drawable xproto.Drawable) QueryInfoCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'QueryInfo' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(queryInfoRequest(c, Drawable), cookie)
+	return QueryInfoCookie{cookie}
+}
+
+// QueryInfoReply represents the data returned from a QueryInfo request.
+type QueryInfoReply struct {
+	Sequence         uint16 // sequence number of the request for this reply
+	Length           uint32 // number of bytes in this reply
+	State            byte
+	SaverWindow      xproto.Window
+	MsUntilServer    uint32
+	MsSinceUserInput uint32
+	EventMask        uint32
+	Kind             byte
+	// padding: 7 bytes
+}
+
+// Reply blocks and returns the reply data for a QueryInfo request.
+func (cook QueryInfoCookie) Reply() (*QueryInfoReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return queryInfoReply(buf), nil
+}
+
+// queryInfoReply reads a byte slice into a QueryInfoReply value.
+func queryInfoReply(buf []byte) *QueryInfoReply {
+	v := new(QueryInfoReply)
+	b := 1 // skip reply determinant
+
+	v.State = buf[b]
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.SaverWindow = xproto.Window(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.MsUntilServer = xgb.Get32(buf[b:])
+	b += 4
+
+	v.MsSinceUserInput = xgb.Get32(buf[b:])
+	b += 4
+
+	v.EventMask = xgb.Get32(buf[b:])
+	b += 4
+
+	v.Kind = buf[b]
+	b += 1
+
+	b += 7 // padding
+
+	return v
+}
+
+// queryInfoRequest writes a QueryInfo request to a byte slice for transfer.
+func queryInfoRequest(c *xgb.Conn, Drawable xproto.Drawable) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SCREEN-SAVER"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 1 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Drawable))
+	b += 4
+
+	return buf
+}
+
+// QueryVersionCookie is a cookie used only for QueryVersion requests.
+type QueryVersionCookie struct {
+	*xgb.Cookie
+}
+
+// QueryVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling QueryVersionCookie.Reply.
+func QueryVersion(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion byte) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func QueryVersionUnchecked(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion byte) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionReply represents the data returned from a QueryVersion request.
+type QueryVersionReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	ServerMajorVersion uint16
+	ServerMinorVersion uint16
+	// padding: 20 bytes
+}
+
+// Reply blocks and returns the reply data for a QueryVersion request.
+func (cook QueryVersionCookie) Reply() (*QueryVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return queryVersionReply(buf), nil
+}
+
+// queryVersionReply reads a byte slice into a QueryVersionReply value.
+func queryVersionReply(buf []byte) *QueryVersionReply {
+	v := new(QueryVersionReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.ServerMajorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	v.ServerMinorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	b += 20 // padding
+
+	return v
+}
+
+// queryVersionRequest writes a QueryVersion request to a byte slice for transfer.
+func queryVersionRequest(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion byte) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SCREEN-SAVER"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	buf[b] = ClientMajorVersion
+	b += 1
+
+	buf[b] = ClientMinorVersion
+	b += 1
+
+	b += 2 // padding
+
+	return buf
+}
+
+// SelectInputCookie is a cookie used only for SelectInput requests.
+type SelectInputCookie struct {
+	*xgb.Cookie
+}
+
+// SelectInput sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func SelectInput(c *xgb.Conn, Drawable xproto.Drawable, EventMask uint32) SelectInputCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'SelectInput' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(selectInputRequest(c, Drawable, EventMask), cookie)
+	return SelectInputCookie{cookie}
+}
+
+// SelectInputChecked sends a checked request.
+// If an error occurs, it can be retrieved using SelectInputCookie.Check.
+func SelectInputChecked(c *xgb.Conn, Drawable xproto.Drawable, EventMask uint32) SelectInputCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'SelectInput' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(selectInputRequest(c, Drawable, EventMask), cookie)
+	return SelectInputCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook SelectInputCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// selectInputRequest writes a SelectInput request to a byte slice for transfer.
+func selectInputRequest(c *xgb.Conn, Drawable xproto.Drawable, EventMask uint32) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SCREEN-SAVER"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 2 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Drawable))
+	b += 4
+
+	xgb.Put32(buf[b:], EventMask)
+	b += 4
+
+	return buf
+}
+
+// SetAttributesCookie is a cookie used only for SetAttributes requests.
+type SetAttributesCookie struct {
+	*xgb.Cookie
+}
+
+// SetAttributes sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func SetAttributes(c *xgb.Conn, Drawable xproto.Drawable, X, Y int16, Width, Height, BorderWidth uint16, Class, Depth byte, Visual xproto.Visualid, ValueMask uint32, ValueList []uint32) SetAttributesCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'SetAttributes' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(setAttributesRequest(c, Drawable, X, Y, Width, Height, BorderWidth, Class, Depth, Visual, ValueMask, ValueList), cookie)
+	return SetAttributesCookie{cookie}
+}
+
+// SetAttributesChecked sends a checked request.
+// If an error occurs, it can be retrieved using SetAttributesCookie.Check.
+func SetAttributesChecked(c *xgb.Conn, Drawable xproto.Drawable, X, Y int16, Width, Height, BorderWidth uint16, Class, Depth byte, Visual xproto.Visualid, ValueMask uint32, ValueList []uint32) SetAttributesCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'SetAttributes' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(setAttributesRequest(c, Drawable, X, Y, Width, Height, BorderWidth, Class, Depth, Visual, ValueMask, ValueList), cookie)
+	return SetAttributesCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook SetAttributesCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// setAttributesRequest writes a SetAttributes request to a byte slice for transfer.
+func setAttributesRequest(c *xgb.Conn, Drawable xproto.Drawable, X, Y int16, Width, Height, BorderWidth uint16, Class, Depth byte, Visual xproto.Visualid, ValueMask uint32, ValueList []uint32) []byte {
+	size := xgb.Pad((28 + xgb.Pad((4 * xgb.PopCount(int(ValueMask))))))
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SCREEN-SAVER"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 3 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Drawable))
+	b += 4
+
+	xgb.Put16(buf[b:], uint16(X))
+	b += 2
+
+	xgb.Put16(buf[b:], uint16(Y))
+	b += 2
+
+	xgb.Put16(buf[b:], Width)
+	b += 2
+
+	xgb.Put16(buf[b:], Height)
+	b += 2
+
+	xgb.Put16(buf[b:], BorderWidth)
+	b += 2
+
+	buf[b] = Class
+	b += 1
+
+	buf[b] = Depth
+	b += 1
+
+	xgb.Put32(buf[b:], uint32(Visual))
+	b += 4
+
+	xgb.Put32(buf[b:], ValueMask)
+	b += 4
+
+	for i := 0; i < xgb.PopCount(int(ValueMask)); i++ {
+		xgb.Put32(buf[b:], ValueList[i])
+		b += 4
+	}
+	b = xgb.Pad(b)
+
+	return buf
+}
+
+// SuspendCookie is a cookie used only for Suspend requests.
+type SuspendCookie struct {
+	*xgb.Cookie
+}
+
+// Suspend sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func Suspend(c *xgb.Conn, Suspend bool) SuspendCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'Suspend' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(suspendRequest(c, Suspend), cookie)
+	return SuspendCookie{cookie}
+}
+
+// SuspendChecked sends a checked request.
+// If an error occurs, it can be retrieved using SuspendCookie.Check.
+func SuspendChecked(c *xgb.Conn, Suspend bool) SuspendCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'Suspend' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(suspendRequest(c, Suspend), cookie)
+	return SuspendCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook SuspendCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// suspendRequest writes a Suspend request to a byte slice for transfer.
+func suspendRequest(c *xgb.Conn, Suspend bool) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SCREEN-SAVER"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 5 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	if Suspend {
+		buf[b] = 1
+	} else {
+		buf[b] = 0
+	}
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}
+
+// UnsetAttributesCookie is a cookie used only for UnsetAttributes requests.
+type UnsetAttributesCookie struct {
+	*xgb.Cookie
+}
+
+// UnsetAttributes sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func UnsetAttributes(c *xgb.Conn, Drawable xproto.Drawable) UnsetAttributesCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'UnsetAttributes' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(unsetAttributesRequest(c, Drawable), cookie)
+	return UnsetAttributesCookie{cookie}
+}
+
+// UnsetAttributesChecked sends a checked request.
+// If an error occurs, it can be retrieved using UnsetAttributesCookie.Check.
+func UnsetAttributesChecked(c *xgb.Conn, Drawable xproto.Drawable) UnsetAttributesCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SCREEN-SAVER"]; !ok {
+		panic("Cannot issue request 'UnsetAttributes' using the uninitialized extension 'MIT-SCREEN-SAVER'. screensaver.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(unsetAttributesRequest(c, Drawable), cookie)
+	return UnsetAttributesCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook UnsetAttributesCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// unsetAttributesRequest writes a UnsetAttributes request to a byte slice for transfer.
+func unsetAttributesRequest(c *xgb.Conn, Drawable xproto.Drawable) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SCREEN-SAVER"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 4 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Drawable))
+	b += 4
+
+	return buf
+}

nexgb/shm/shm.go

@@ -0,0 +1,942 @@
+// Package shm is the X client API for the MIT-SHM extension.
+package shm
+
+// This file is automatically generated from shm.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 1
+	MinorVersion = 2
+)
+
+// Init must be called before using the MIT-SHM extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 7, "MIT-SHM").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named MIT-SHM could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["MIT-SHM"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["MIT-SHM"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["MIT-SHM"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["MIT-SHM"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["MIT-SHM"] = make(map[int]xgb.NewErrorFun)
+}
+
+// BadBadSeg is the error number for a BadBadSeg.
+const BadBadSeg = 0
+
+type BadSegError xproto.ValueError
+
+// BadSegErrorNew constructs a BadSegError value that implements xgb.Error from a byte slice.
+func BadSegErrorNew(buf []byte) xgb.Error {
+	v := BadSegError(xproto.ValueErrorNew(buf).(xproto.ValueError))
+	v.NiceName = "BadSeg"
+	return v
+}
+
+// SequenceId returns the sequence id attached to the BadBadSeg error.
+// This is mostly used internally.
+func (err BadSegError) SequenceId() uint16 {
+	return err.Sequence
+}
+
+// BadId returns the 'BadValue' number if one exists for the BadBadSeg error. If no bad value exists, 0 is returned.
+func (err BadSegError) BadId() uint32 {
+	return 0
+}
+
+// Error returns a rudimentary string representation of the BadBadSeg error.
+func (err BadSegError) Error() string {
+	fieldVals := make([]string, 0, 4)
+	fieldVals = append(fieldVals, "NiceName: "+err.NiceName)
+	fieldVals = append(fieldVals, xgb.Sprintf("Sequence: %d", err.Sequence))
+	fieldVals = append(fieldVals, xgb.Sprintf("BadValue: %d", err.BadValue))
+	fieldVals = append(fieldVals, xgb.Sprintf("MinorOpcode: %d", err.MinorOpcode))
+	fieldVals = append(fieldVals, xgb.Sprintf("MajorOpcode: %d", err.MajorOpcode))
+	return "BadBadSeg {" + xgb.StringsJoin(fieldVals, ", ") + "}"
+}
+
+func init() {
+	xgb.NewExtErrorFuncs["MIT-SHM"][0] = BadSegErrorNew
+}
+
+// Completion is the event number for a CompletionEvent.
+const Completion = 0
+
+type CompletionEvent struct {
+	Sequence uint16
+	// padding: 1 bytes
+	Drawable   xproto.Drawable
+	MinorEvent uint16
+	MajorEvent byte
+	// padding: 1 bytes
+	Shmseg Seg
+	Offset uint32
+}
+
+// CompletionEventNew constructs a CompletionEvent value that implements xgb.Event from a byte slice.
+func CompletionEventNew(buf []byte) xgb.Event {
+	v := CompletionEvent{}
+	b := 1 // don't read event number
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Drawable = xproto.Drawable(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.MinorEvent = xgb.Get16(buf[b:])
+	b += 2
+
+	v.MajorEvent = buf[b]
+	b += 1
+
+	b += 1 // padding
+
+	v.Shmseg = Seg(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.Offset = xgb.Get32(buf[b:])
+	b += 4
+
+	return v
+}
+
+// Bytes writes a CompletionEvent value to a byte slice.
+func (v CompletionEvent) Bytes() []byte {
+	buf := make([]byte, 32)
+	b := 0
+
+	// write event number
+	buf[b] = 0
+	b += 1
+
+	b += 1 // padding
+
+	b += 2 // skip sequence number
+
+	xgb.Put32(buf[b:], uint32(v.Drawable))
+	b += 4
+
+	xgb.Put16(buf[b:], v.MinorEvent)
+	b += 2
+
+	buf[b] = v.MajorEvent
+	b += 1
+
+	b += 1 // padding
+
+	xgb.Put32(buf[b:], uint32(v.Shmseg))
+	b += 4
+
+	xgb.Put32(buf[b:], v.Offset)
+	b += 4
+
+	return buf
+}
+
+// SequenceId returns the sequence id attached to the Completion event.
+// Events without a sequence number (KeymapNotify) return 0.
+// This is mostly used internally.
+func (v CompletionEvent) SequenceId() uint16 {
+	return v.Sequence
+}
+
+// String is a rudimentary string representation of CompletionEvent.
+func (v CompletionEvent) String() string {
+	fieldVals := make([]string, 0, 7)
+	fieldVals = append(fieldVals, xgb.Sprintf("Sequence: %d", v.Sequence))
+	fieldVals = append(fieldVals, xgb.Sprintf("Drawable: %d", v.Drawable))
+	fieldVals = append(fieldVals, xgb.Sprintf("MinorEvent: %d", v.MinorEvent))
+	fieldVals = append(fieldVals, xgb.Sprintf("MajorEvent: %d", v.MajorEvent))
+	fieldVals = append(fieldVals, xgb.Sprintf("Shmseg: %d", v.Shmseg))
+	fieldVals = append(fieldVals, xgb.Sprintf("Offset: %d", v.Offset))
+	return "Completion {" + xgb.StringsJoin(fieldVals, ", ") + "}"
+}
+
+func init() {
+	xgb.NewExtEventFuncs["MIT-SHM"][0] = CompletionEventNew
+}
+
+type Seg uint32
+
+func NewSegId(c *xgb.Conn) (Seg, error) {
+	id, err := c.NewId()
+	if err != nil {
+		return 0, err
+	}
+	return Seg(id), nil
+}
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// AttachCookie is a cookie used only for Attach requests.
+type AttachCookie struct {
+	*xgb.Cookie
+}
+
+// Attach sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func Attach(c *xgb.Conn, Shmseg Seg, Shmid uint32, ReadOnly bool) AttachCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'Attach' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(attachRequest(c, Shmseg, Shmid, ReadOnly), cookie)
+	return AttachCookie{cookie}
+}
+
+// AttachChecked sends a checked request.
+// If an error occurs, it can be retrieved using AttachCookie.Check.
+func AttachChecked(c *xgb.Conn, Shmseg Seg, Shmid uint32, ReadOnly bool) AttachCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'Attach' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(attachRequest(c, Shmseg, Shmid, ReadOnly), cookie)
+	return AttachCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook AttachCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// attachRequest writes a Attach request to a byte slice for transfer.
+func attachRequest(c *xgb.Conn, Shmseg Seg, Shmid uint32, ReadOnly bool) []byte {
+	size := 16
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SHM"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 1 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Shmseg))
+	b += 4
+
+	xgb.Put32(buf[b:], Shmid)
+	b += 4
+
+	if ReadOnly {
+		buf[b] = 1
+	} else {
+		buf[b] = 0
+	}
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}
+
+// AttachFdCookie is a cookie used only for AttachFd requests.
+type AttachFdCookie struct {
+	*xgb.Cookie
+}
+
+// AttachFd sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func AttachFd(c *xgb.Conn, Shmseg Seg, ReadOnly bool) AttachFdCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'AttachFd' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(attachFdRequest(c, Shmseg, ReadOnly), cookie)
+	return AttachFdCookie{cookie}
+}
+
+// AttachFdChecked sends a checked request.
+// If an error occurs, it can be retrieved using AttachFdCookie.Check.
+func AttachFdChecked(c *xgb.Conn, Shmseg Seg, ReadOnly bool) AttachFdCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'AttachFd' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(attachFdRequest(c, Shmseg, ReadOnly), cookie)
+	return AttachFdCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook AttachFdCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// attachFdRequest writes a AttachFd request to a byte slice for transfer.
+func attachFdRequest(c *xgb.Conn, Shmseg Seg, ReadOnly bool) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SHM"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 6 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Shmseg))
+	b += 4
+
+	if ReadOnly {
+		buf[b] = 1
+	} else {
+		buf[b] = 0
+	}
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}
+
+// CreatePixmapCookie is a cookie used only for CreatePixmap requests.
+type CreatePixmapCookie struct {
+	*xgb.Cookie
+}
+
+// CreatePixmap sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func CreatePixmap(c *xgb.Conn, Pid xproto.Pixmap, Drawable xproto.Drawable, Width, Height uint16, Depth byte, Shmseg Seg, Offset uint32) CreatePixmapCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'CreatePixmap' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(createPixmapRequest(c, Pid, Drawable, Width, Height, Depth, Shmseg, Offset), cookie)
+	return CreatePixmapCookie{cookie}
+}
+
+// CreatePixmapChecked sends a checked request.
+// If an error occurs, it can be retrieved using CreatePixmapCookie.Check.
+func CreatePixmapChecked(c *xgb.Conn, Pid xproto.Pixmap, Drawable xproto.Drawable, Width, Height uint16, Depth byte, Shmseg Seg, Offset uint32) CreatePixmapCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'CreatePixmap' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(createPixmapRequest(c, Pid, Drawable, Width, Height, Depth, Shmseg, Offset), cookie)
+	return CreatePixmapCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook CreatePixmapCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// createPixmapRequest writes a CreatePixmap request to a byte slice for transfer.
+func createPixmapRequest(c *xgb.Conn, Pid xproto.Pixmap, Drawable xproto.Drawable, Width, Height uint16, Depth byte, Shmseg Seg, Offset uint32) []byte {
+	size := 28
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SHM"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 5 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Pid))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Drawable))
+	b += 4
+
+	xgb.Put16(buf[b:], Width)
+	b += 2
+
+	xgb.Put16(buf[b:], Height)
+	b += 2
+
+	buf[b] = Depth
+	b += 1
+
+	b += 3 // padding
+
+	xgb.Put32(buf[b:], uint32(Shmseg))
+	b += 4
+
+	xgb.Put32(buf[b:], Offset)
+	b += 4
+
+	return buf
+}
+
+// CreateSegmentCookie is a cookie used only for CreateSegment requests.
+type CreateSegmentCookie struct {
+	*xgb.Cookie
+}
+
+// CreateSegment sends a checked request.
+// If an error occurs, it will be returned with the reply by calling CreateSegmentCookie.Reply.
+func CreateSegment(c *xgb.Conn, Shmseg Seg, Size uint32, ReadOnly bool) CreateSegmentCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'CreateSegment' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(createSegmentRequest(c, Shmseg, Size, ReadOnly), cookie)
+	return CreateSegmentCookie{cookie}
+}
+
+// CreateSegmentUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func CreateSegmentUnchecked(c *xgb.Conn, Shmseg Seg, Size uint32, ReadOnly bool) CreateSegmentCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'CreateSegment' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(createSegmentRequest(c, Shmseg, Size, ReadOnly), cookie)
+	return CreateSegmentCookie{cookie}
+}
+
+// CreateSegmentReply represents the data returned from a CreateSegment request.
+type CreateSegmentReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	Nfd      byte
+	// padding: 24 bytes
+}
+
+// Reply blocks and returns the reply data for a CreateSegment request.
+func (cook CreateSegmentCookie) Reply() (*CreateSegmentReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return createSegmentReply(buf), nil
+}
+
+// createSegmentReply reads a byte slice into a CreateSegmentReply value.
+func createSegmentReply(buf []byte) *CreateSegmentReply {
+	v := new(CreateSegmentReply)
+	b := 1 // skip reply determinant
+
+	v.Nfd = buf[b]
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	b += 24 // padding
+
+	return v
+}
+
+// createSegmentRequest writes a CreateSegment request to a byte slice for transfer.
+func createSegmentRequest(c *xgb.Conn, Shmseg Seg, Size uint32, ReadOnly bool) []byte {
+	size := 16
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SHM"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 7 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Shmseg))
+	b += 4
+
+	xgb.Put32(buf[b:], Size)
+	b += 4
+
+	if ReadOnly {
+		buf[b] = 1
+	} else {
+		buf[b] = 0
+	}
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}
+
+// DetachCookie is a cookie used only for Detach requests.
+type DetachCookie struct {
+	*xgb.Cookie
+}
+
+// Detach sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func Detach(c *xgb.Conn, Shmseg Seg) DetachCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'Detach' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(detachRequest(c, Shmseg), cookie)
+	return DetachCookie{cookie}
+}
+
+// DetachChecked sends a checked request.
+// If an error occurs, it can be retrieved using DetachCookie.Check.
+func DetachChecked(c *xgb.Conn, Shmseg Seg) DetachCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'Detach' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(detachRequest(c, Shmseg), cookie)
+	return DetachCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook DetachCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// detachRequest writes a Detach request to a byte slice for transfer.
+func detachRequest(c *xgb.Conn, Shmseg Seg) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SHM"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 2 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Shmseg))
+	b += 4
+
+	return buf
+}
+
+// GetImageCookie is a cookie used only for GetImage requests.
+type GetImageCookie struct {
+	*xgb.Cookie
+}
+
+// GetImage sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetImageCookie.Reply.
+func GetImage(c *xgb.Conn, Drawable xproto.Drawable, X, Y int16, Width, Height uint16, PlaneMask uint32, Format byte, Shmseg Seg, Offset uint32) GetImageCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'GetImage' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getImageRequest(c, Drawable, X, Y, Width, Height, PlaneMask, Format, Shmseg, Offset), cookie)
+	return GetImageCookie{cookie}
+}
+
+// GetImageUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetImageUnchecked(c *xgb.Conn, Drawable xproto.Drawable, X, Y int16, Width, Height uint16, PlaneMask uint32, Format byte, Shmseg Seg, Offset uint32) GetImageCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'GetImage' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getImageRequest(c, Drawable, X, Y, Width, Height, PlaneMask, Format, Shmseg, Offset), cookie)
+	return GetImageCookie{cookie}
+}
+
+// GetImageReply represents the data returned from a GetImage request.
+type GetImageReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	Depth    byte
+	Visual   xproto.Visualid
+	Size     uint32
+}
+
+// Reply blocks and returns the reply data for a GetImage request.
+func (cook GetImageCookie) Reply() (*GetImageReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getImageReply(buf), nil
+}
+
+// getImageReply reads a byte slice into a GetImageReply value.
+func getImageReply(buf []byte) *GetImageReply {
+	v := new(GetImageReply)
+	b := 1 // skip reply determinant
+
+	v.Depth = buf[b]
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.Visual = xproto.Visualid(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.Size = xgb.Get32(buf[b:])
+	b += 4
+
+	return v
+}
+
+// getImageRequest writes a GetImage request to a byte slice for transfer.
+func getImageRequest(c *xgb.Conn, Drawable xproto.Drawable, X, Y int16, Width, Height uint16, PlaneMask uint32, Format byte, Shmseg Seg, Offset uint32) []byte {
+	size := 32
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SHM"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 4 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Drawable))
+	b += 4
+
+	xgb.Put16(buf[b:], uint16(X))
+	b += 2
+
+	xgb.Put16(buf[b:], uint16(Y))
+	b += 2
+
+	xgb.Put16(buf[b:], Width)
+	b += 2
+
+	xgb.Put16(buf[b:], Height)
+	b += 2
+
+	xgb.Put32(buf[b:], PlaneMask)
+	b += 4
+
+	buf[b] = Format
+	b += 1
+
+	b += 3 // padding
+
+	xgb.Put32(buf[b:], uint32(Shmseg))
+	b += 4
+
+	xgb.Put32(buf[b:], Offset)
+	b += 4
+
+	return buf
+}
+
+// PutImageCookie is a cookie used only for PutImage requests.
+type PutImageCookie struct {
+	*xgb.Cookie
+}
+
+// PutImage sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func PutImage(c *xgb.Conn, Drawable xproto.Drawable, Gc xproto.Gcontext, TotalWidth, TotalHeight, SrcX, SrcY, SrcWidth, SrcHeight uint16, DstX, DstY int16, Depth, Format, SendEvent byte, Shmseg Seg, Offset uint32) PutImageCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'PutImage' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(putImageRequest(c, Drawable, Gc, TotalWidth, TotalHeight, SrcX, SrcY, SrcWidth, SrcHeight, DstX, DstY, Depth, Format, SendEvent, Shmseg, Offset), cookie)
+	return PutImageCookie{cookie}
+}
+
+// PutImageChecked sends a checked request.
+// If an error occurs, it can be retrieved using PutImageCookie.Check.
+func PutImageChecked(c *xgb.Conn, Drawable xproto.Drawable, Gc xproto.Gcontext, TotalWidth, TotalHeight, SrcX, SrcY, SrcWidth, SrcHeight uint16, DstX, DstY int16, Depth, Format, SendEvent byte, Shmseg Seg, Offset uint32) PutImageCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'PutImage' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(putImageRequest(c, Drawable, Gc, TotalWidth, TotalHeight, SrcX, SrcY, SrcWidth, SrcHeight, DstX, DstY, Depth, Format, SendEvent, Shmseg, Offset), cookie)
+	return PutImageCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook PutImageCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// putImageRequest writes a PutImage request to a byte slice for transfer.
+func putImageRequest(c *xgb.Conn, Drawable xproto.Drawable, Gc xproto.Gcontext, TotalWidth, TotalHeight, SrcX, SrcY, SrcWidth, SrcHeight uint16, DstX, DstY int16, Depth, Format, SendEvent byte, Shmseg Seg, Offset uint32) []byte {
+	size := 40
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SHM"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 3 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Drawable))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Gc))
+	b += 4
+
+	xgb.Put16(buf[b:], TotalWidth)
+	b += 2
+
+	xgb.Put16(buf[b:], TotalHeight)
+	b += 2
+
+	xgb.Put16(buf[b:], SrcX)
+	b += 2
+
+	xgb.Put16(buf[b:], SrcY)
+	b += 2
+
+	xgb.Put16(buf[b:], SrcWidth)
+	b += 2
+
+	xgb.Put16(buf[b:], SrcHeight)
+	b += 2
+
+	xgb.Put16(buf[b:], uint16(DstX))
+	b += 2
+
+	xgb.Put16(buf[b:], uint16(DstY))
+	b += 2
+
+	buf[b] = Depth
+	b += 1
+
+	buf[b] = Format
+	b += 1
+
+	buf[b] = SendEvent
+	b += 1
+
+	b += 1 // padding
+
+	xgb.Put32(buf[b:], uint32(Shmseg))
+	b += 4
+
+	xgb.Put32(buf[b:], Offset)
+	b += 4
+
+	return buf
+}
+
+// QueryVersionCookie is a cookie used only for QueryVersion requests.
+type QueryVersionCookie struct {
+	*xgb.Cookie
+}
+
+// QueryVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling QueryVersionCookie.Reply.
+func QueryVersion(c *xgb.Conn) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(queryVersionRequest(c), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func QueryVersionUnchecked(c *xgb.Conn) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["MIT-SHM"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'MIT-SHM'. shm.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(queryVersionRequest(c), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionReply represents the data returned from a QueryVersion request.
+type QueryVersionReply struct {
+	Sequence      uint16 // sequence number of the request for this reply
+	Length        uint32 // number of bytes in this reply
+	SharedPixmaps bool
+	MajorVersion  uint16
+	MinorVersion  uint16
+	Uid           uint16
+	Gid           uint16
+	PixmapFormat  byte
+	// padding: 15 bytes
+}
+
+// Reply blocks and returns the reply data for a QueryVersion request.
+func (cook QueryVersionCookie) Reply() (*QueryVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return queryVersionReply(buf), nil
+}
+
+// queryVersionReply reads a byte slice into a QueryVersionReply value.
+func queryVersionReply(buf []byte) *QueryVersionReply {
+	v := new(QueryVersionReply)
+	b := 1 // skip reply determinant
+
+	if buf[b] == 1 {
+		v.SharedPixmaps = true
+	} else {
+		v.SharedPixmaps = false
+	}
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.MajorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	v.MinorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Uid = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Gid = xgb.Get16(buf[b:])
+	b += 2
+
+	v.PixmapFormat = buf[b]
+	b += 1
+
+	b += 15 // padding
+
+	return v
+}
+
+// queryVersionRequest writes a QueryVersion request to a byte slice for transfer.
+func queryVersionRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["MIT-SHM"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}

nexgb/sync.go

@@ -0,0 +1,29 @@
+package nexgb
+
+// Sync sends a round trip request and waits for the response.
+// This forces all pending cookies to be dealt with.
+// You actually shouldn't need to use this like you might with Xlib. Namely,
+// buffers are automatically flushed using Go's channels and round trip requests
+// are forced where appropriate automatically.
+func (c *Conn) Sync() {
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(c.getInputFocusRequest(), cookie)
+	cookie.Reply() // wait for the buffer to clear
+}
+
+// getInputFocusRequest writes the raw bytes to a buffer.
+// It is duplicated from xproto/xproto.go.
+func (c *Conn) getInputFocusRequest() []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	buf[b] = 43 // request opcode
+	b += 1
+
+	b += 1                         // padding
+	Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}

nexgb/xcmisc/xcmisc.go

@@ -0,0 +1,363 @@
+// Package xcmisc is the X client API for the XC-MISC extension.
+package xcmisc
+
+// This file is automatically generated from xc_misc.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 1
+	MinorVersion = 1
+)
+
+// Init must be called before using the XC-MISC extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 7, "XC-MISC").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named XC-MISC could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["XC-MISC"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["XC-MISC"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["XC-MISC"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["XC-MISC"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["XC-MISC"] = make(map[int]xgb.NewErrorFun)
+}
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// GetVersionCookie is a cookie used only for GetVersion requests.
+type GetVersionCookie struct {
+	*xgb.Cookie
+}
+
+// GetVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetVersionCookie.Reply.
+func GetVersion(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) GetVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XC-MISC"]; !ok {
+		panic("Cannot issue request 'GetVersion' using the uninitialized extension 'XC-MISC'. xcmisc.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return GetVersionCookie{cookie}
+}
+
+// GetVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetVersionUnchecked(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) GetVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XC-MISC"]; !ok {
+		panic("Cannot issue request 'GetVersion' using the uninitialized extension 'XC-MISC'. xcmisc.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return GetVersionCookie{cookie}
+}
+
+// GetVersionReply represents the data returned from a GetVersion request.
+type GetVersionReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	ServerMajorVersion uint16
+	ServerMinorVersion uint16
+}
+
+// Reply blocks and returns the reply data for a GetVersion request.
+func (cook GetVersionCookie) Reply() (*GetVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getVersionReply(buf), nil
+}
+
+// getVersionReply reads a byte slice into a GetVersionReply value.
+func getVersionReply(buf []byte) *GetVersionReply {
+	v := new(GetVersionReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.ServerMajorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	v.ServerMinorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	return v
+}
+
+// getVersionRequest writes a GetVersion request to a byte slice for transfer.
+func getVersionRequest(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XC-MISC"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put16(buf[b:], ClientMajorVersion)
+	b += 2
+
+	xgb.Put16(buf[b:], ClientMinorVersion)
+	b += 2
+
+	return buf
+}
+
+// GetXIDListCookie is a cookie used only for GetXIDList requests.
+type GetXIDListCookie struct {
+	*xgb.Cookie
+}
+
+// GetXIDList sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetXIDListCookie.Reply.
+func GetXIDList(c *xgb.Conn, Count uint32) GetXIDListCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XC-MISC"]; !ok {
+		panic("Cannot issue request 'GetXIDList' using the uninitialized extension 'XC-MISC'. xcmisc.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getXIDListRequest(c, Count), cookie)
+	return GetXIDListCookie{cookie}
+}
+
+// GetXIDListUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetXIDListUnchecked(c *xgb.Conn, Count uint32) GetXIDListCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XC-MISC"]; !ok {
+		panic("Cannot issue request 'GetXIDList' using the uninitialized extension 'XC-MISC'. xcmisc.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getXIDListRequest(c, Count), cookie)
+	return GetXIDListCookie{cookie}
+}
+
+// GetXIDListReply represents the data returned from a GetXIDList request.
+type GetXIDListReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	IdsLen uint32
+	// padding: 20 bytes
+	Ids []uint32 // size: xgb.Pad((int(IdsLen) * 4))
+}
+
+// Reply blocks and returns the reply data for a GetXIDList request.
+func (cook GetXIDListCookie) Reply() (*GetXIDListReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getXIDListReply(buf), nil
+}
+
+// getXIDListReply reads a byte slice into a GetXIDListReply value.
+func getXIDListReply(buf []byte) *GetXIDListReply {
+	v := new(GetXIDListReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.IdsLen = xgb.Get32(buf[b:])
+	b += 4
+
+	b += 20 // padding
+
+	v.Ids = make([]uint32, v.IdsLen)
+	for i := 0; i < int(v.IdsLen); i++ {
+		v.Ids[i] = xgb.Get32(buf[b:])
+		b += 4
+	}
+
+	return v
+}
+
+// getXIDListRequest writes a GetXIDList request to a byte slice for transfer.
+func getXIDListRequest(c *xgb.Conn, Count uint32) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XC-MISC"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 2 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], Count)
+	b += 4
+
+	return buf
+}
+
+// GetXIDRangeCookie is a cookie used only for GetXIDRange requests.
+type GetXIDRangeCookie struct {
+	*xgb.Cookie
+}
+
+// GetXIDRange sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetXIDRangeCookie.Reply.
+func GetXIDRange(c *xgb.Conn) GetXIDRangeCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XC-MISC"]; !ok {
+		panic("Cannot issue request 'GetXIDRange' using the uninitialized extension 'XC-MISC'. xcmisc.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getXIDRangeRequest(c), cookie)
+	return GetXIDRangeCookie{cookie}
+}
+
+// GetXIDRangeUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetXIDRangeUnchecked(c *xgb.Conn) GetXIDRangeCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XC-MISC"]; !ok {
+		panic("Cannot issue request 'GetXIDRange' using the uninitialized extension 'XC-MISC'. xcmisc.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getXIDRangeRequest(c), cookie)
+	return GetXIDRangeCookie{cookie}
+}
+
+// GetXIDRangeReply represents the data returned from a GetXIDRange request.
+type GetXIDRangeReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	StartId uint32
+	Count   uint32
+}
+
+// Reply blocks and returns the reply data for a GetXIDRange request.
+func (cook GetXIDRangeCookie) Reply() (*GetXIDRangeReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getXIDRangeReply(buf), nil
+}
+
+// getXIDRangeReply reads a byte slice into a GetXIDRangeReply value.
+func getXIDRangeReply(buf []byte) *GetXIDRangeReply {
+	v := new(GetXIDRangeReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.StartId = xgb.Get32(buf[b:])
+	b += 4
+
+	v.Count = xgb.Get32(buf[b:])
+	b += 4
+
+	return v
+}
+
+// getXIDRangeRequest writes a GetXIDRange request to a byte slice for transfer.
+func getXIDRangeRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XC-MISC"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 1 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}

nexgb/xevie/xevie.go

@@ -0,0 +1,595 @@
+// Package xevie is the X client API for the XEVIE extension.
+package xevie
+
+// This file is automatically generated from xevie.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 1
+	MinorVersion = 0
+)
+
+// Init must be called before using the XEVIE extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 5, "XEVIE").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named XEVIE could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["XEVIE"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["XEVIE"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["XEVIE"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["XEVIE"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["XEVIE"] = make(map[int]xgb.NewErrorFun)
+}
+
+const (
+	DatatypeUnmodified = 0
+	DatatypeModified   = 1
+)
+
+type Event struct {
+	// padding: 32 bytes
+}
+
+// EventRead reads a byte slice into a Event value.
+func EventRead(buf []byte, v *Event) int {
+	b := 0
+
+	b += 32 // padding
+
+	return b
+}
+
+// EventReadList reads a byte slice into a list of Event values.
+func EventReadList(buf []byte, dest []Event) int {
+	b := 0
+	for i := 0; i < len(dest); i++ {
+		dest[i] = Event{}
+		b += EventRead(buf[b:], &dest[i])
+	}
+	return xgb.Pad(b)
+}
+
+// Bytes writes a Event value to a byte slice.
+func (v Event) Bytes() []byte {
+	buf := make([]byte, 32)
+	b := 0
+
+	b += 32 // padding
+
+	return buf[:b]
+}
+
+// EventListBytes writes a list of Event values to a byte slice.
+func EventListBytes(buf []byte, list []Event) int {
+	b := 0
+	var structBytes []byte
+	for _, item := range list {
+		structBytes = item.Bytes()
+		copy(buf[b:], structBytes)
+		b += len(structBytes)
+	}
+	return xgb.Pad(b)
+}
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// EndCookie is a cookie used only for End requests.
+type EndCookie struct {
+	*xgb.Cookie
+}
+
+// End sends a checked request.
+// If an error occurs, it will be returned with the reply by calling EndCookie.Reply.
+func End(c *xgb.Conn, Cmap uint32) EndCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'End' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(endRequest(c, Cmap), cookie)
+	return EndCookie{cookie}
+}
+
+// EndUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func EndUnchecked(c *xgb.Conn, Cmap uint32) EndCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'End' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(endRequest(c, Cmap), cookie)
+	return EndCookie{cookie}
+}
+
+// EndReply represents the data returned from a End request.
+type EndReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	// padding: 24 bytes
+}
+
+// Reply blocks and returns the reply data for a End request.
+func (cook EndCookie) Reply() (*EndReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return endReply(buf), nil
+}
+
+// endReply reads a byte slice into a EndReply value.
+func endReply(buf []byte) *EndReply {
+	v := new(EndReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	b += 24 // padding
+
+	return v
+}
+
+// endRequest writes a End request to a byte slice for transfer.
+func endRequest(c *xgb.Conn, Cmap uint32) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XEVIE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 2 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], Cmap)
+	b += 4
+
+	return buf
+}
+
+// QueryVersionCookie is a cookie used only for QueryVersion requests.
+type QueryVersionCookie struct {
+	*xgb.Cookie
+}
+
+// QueryVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling QueryVersionCookie.Reply.
+func QueryVersion(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func QueryVersionUnchecked(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(queryVersionRequest(c, ClientMajorVersion, ClientMinorVersion), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionReply represents the data returned from a QueryVersion request.
+type QueryVersionReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	ServerMajorVersion uint16
+	ServerMinorVersion uint16
+	// padding: 20 bytes
+}
+
+// Reply blocks and returns the reply data for a QueryVersion request.
+func (cook QueryVersionCookie) Reply() (*QueryVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return queryVersionReply(buf), nil
+}
+
+// queryVersionReply reads a byte slice into a QueryVersionReply value.
+func queryVersionReply(buf []byte) *QueryVersionReply {
+	v := new(QueryVersionReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.ServerMajorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	v.ServerMinorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	b += 20 // padding
+
+	return v
+}
+
+// queryVersionRequest writes a QueryVersion request to a byte slice for transfer.
+func queryVersionRequest(c *xgb.Conn, ClientMajorVersion, ClientMinorVersion uint16) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XEVIE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put16(buf[b:], ClientMajorVersion)
+	b += 2
+
+	xgb.Put16(buf[b:], ClientMinorVersion)
+	b += 2
+
+	return buf
+}
+
+// SelectInputCookie is a cookie used only for SelectInput requests.
+type SelectInputCookie struct {
+	*xgb.Cookie
+}
+
+// SelectInput sends a checked request.
+// If an error occurs, it will be returned with the reply by calling SelectInputCookie.Reply.
+func SelectInput(c *xgb.Conn, EventMask uint32) SelectInputCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'SelectInput' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(selectInputRequest(c, EventMask), cookie)
+	return SelectInputCookie{cookie}
+}
+
+// SelectInputUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func SelectInputUnchecked(c *xgb.Conn, EventMask uint32) SelectInputCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'SelectInput' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(selectInputRequest(c, EventMask), cookie)
+	return SelectInputCookie{cookie}
+}
+
+// SelectInputReply represents the data returned from a SelectInput request.
+type SelectInputReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	// padding: 24 bytes
+}
+
+// Reply blocks and returns the reply data for a SelectInput request.
+func (cook SelectInputCookie) Reply() (*SelectInputReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return selectInputReply(buf), nil
+}
+
+// selectInputReply reads a byte slice into a SelectInputReply value.
+func selectInputReply(buf []byte) *SelectInputReply {
+	v := new(SelectInputReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	b += 24 // padding
+
+	return v
+}
+
+// selectInputRequest writes a SelectInput request to a byte slice for transfer.
+func selectInputRequest(c *xgb.Conn, EventMask uint32) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XEVIE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 4 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], EventMask)
+	b += 4
+
+	return buf
+}
+
+// SendCookie is a cookie used only for Send requests.
+type SendCookie struct {
+	*xgb.Cookie
+}
+
+// Send sends a checked request.
+// If an error occurs, it will be returned with the reply by calling SendCookie.Reply.
+func Send(c *xgb.Conn, Event Event, DataType uint32) SendCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'Send' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(sendRequest(c, Event, DataType), cookie)
+	return SendCookie{cookie}
+}
+
+// SendUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func SendUnchecked(c *xgb.Conn, Event Event, DataType uint32) SendCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'Send' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(sendRequest(c, Event, DataType), cookie)
+	return SendCookie{cookie}
+}
+
+// SendReply represents the data returned from a Send request.
+type SendReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	// padding: 24 bytes
+}
+
+// Reply blocks and returns the reply data for a Send request.
+func (cook SendCookie) Reply() (*SendReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return sendReply(buf), nil
+}
+
+// sendReply reads a byte slice into a SendReply value.
+func sendReply(buf []byte) *SendReply {
+	v := new(SendReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	b += 24 // padding
+
+	return v
+}
+
+// sendRequest writes a Send request to a byte slice for transfer.
+func sendRequest(c *xgb.Conn, Event Event, DataType uint32) []byte {
+	size := 104
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XEVIE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 3 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	{
+		structBytes := Event.Bytes()
+		copy(buf[b:], structBytes)
+		b += len(structBytes)
+	}
+
+	xgb.Put32(buf[b:], DataType)
+	b += 4
+
+	b += 64 // padding
+
+	return buf
+}
+
+// StartCookie is a cookie used only for Start requests.
+type StartCookie struct {
+	*xgb.Cookie
+}
+
+// Start sends a checked request.
+// If an error occurs, it will be returned with the reply by calling StartCookie.Reply.
+func Start(c *xgb.Conn, Screen uint32) StartCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'Start' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(startRequest(c, Screen), cookie)
+	return StartCookie{cookie}
+}
+
+// StartUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func StartUnchecked(c *xgb.Conn, Screen uint32) StartCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XEVIE"]; !ok {
+		panic("Cannot issue request 'Start' using the uninitialized extension 'XEVIE'. xevie.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(startRequest(c, Screen), cookie)
+	return StartCookie{cookie}
+}
+
+// StartReply represents the data returned from a Start request.
+type StartReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	// padding: 24 bytes
+}
+
+// Reply blocks and returns the reply data for a Start request.
+func (cook StartCookie) Reply() (*StartReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return startReply(buf), nil
+}
+
+// startReply reads a byte slice into a StartReply value.
+func startReply(buf []byte) *StartReply {
+	v := new(StartReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	b += 24 // padding
+
+	return v
+}
+
+// startRequest writes a Start request to a byte slice for transfer.
+func startRequest(c *xgb.Conn, Screen uint32) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XEVIE"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 1 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], Screen)
+	b += 4
+
+	return buf
+}

nexgb/xgb.go

@@ -0,0 +1,554 @@
+package nexgb
+
+import (
+	"errors"
+	"io"
+	"log"
+	"net"
+	"os"
+	"sync"
+)
+
+var (
+	// Where to log error-messages. Defaults to stderr.
+	// To disable logging, just set this to log.New(ioutil.Discard, "", 0)
+	Logger = log.New(os.Stderr, "XGB: ", log.Lshortfile)
+)
+
+const (
+	// cookieBuffer represents the queue size of cookies existing at any
+	// point in time. The size of the buffer is really only important when
+	// there are many requests without replies made in sequence. Once the
+	// buffer fills, a round trip request is made to clear the buffer.
+	cookieBuffer = 1000
+
+	// xidBuffer represents the queue size of the xid channel.
+	// I don't think this value matters much, since xid generation is not
+	// that expensive.
+	xidBuffer = 5
+
+	// seqBuffer represents the queue size of the sequence number channel.
+	// I don't think this value matters much, since sequence number generation
+	// is not that expensive.
+	seqBuffer = 5
+
+	// reqBuffer represents the queue size of the number of requests that
+	// can be made until new ones block. This value seems OK.
+	reqBuffer = 100
+
+	// eventBuffer represents the queue size of the number of events or errors
+	// that can be loaded off the wire and not grabbed with WaitForEvent
+	// until reading an event blocks. This value should be big enough to handle
+	// bursts of events.
+	eventBuffer = 5000
+)
+
+// A Conn represents a connection to an X server.
+type Conn struct {
+	host          string
+	conn          net.Conn
+	display       string
+	DisplayNumber int
+	DefaultScreen int
+	SetupBytes    []byte
+
+	setupResourceIdBase uint32
+	setupResourceIdMask uint32
+
+	eventChan  chan eventOrError
+	cookieChan chan *Cookie
+	xidChan    chan xid
+	seqChan    chan uint16
+	reqChan    chan *request
+	closing    chan chan struct{}
+
+	// ExtLock is a lock used whenever new extensions are initialized.
+	// It should not be used. It is exported for use in the extension
+	// sub-packages.
+	ExtLock sync.RWMutex
+
+	// Extensions is a map from extension name to major opcode. It should
+	// not be used. It is exported for use in the extension sub-packages.
+	Extensions map[string]byte
+}
+
+// NewConn creates a new connection instance. It initializes locks, data
+// structures, and performs the initial handshake. (The code for the handshake
+// has been relegated to conn.go.)
+func NewConn() (*Conn, error) {
+	return NewConnDisplay("")
+}
+
+// NewConnDisplay is just like NewConn, but allows a specific DISPLAY
+// string to be used.
+// If 'display' is empty it will be taken from os.Getenv("DISPLAY").
+//
+// Examples:
+//	NewConn(":1") -> net.Dial("unix", "", "/tmp/.X11-unix/X1")
+//	NewConn("/tmp/launch-12/:0") -> net.Dial("unix", "", "/tmp/launch-12/:0")
+//	NewConn("hostname:2.1") -> net.Dial("tcp", "", "hostname:6002")
+//	NewConn("tcp/hostname:1.0") -> net.Dial("tcp", "", "hostname:6001")
+func NewConnDisplay(display string) (*Conn, error) {
+	conn := &Conn{}
+
+	// First connect. This reads authority, checks DISPLAY environment
+	// variable, and loads the initial Setup info.
+	err := conn.connect(display)
+	if err != nil {
+		return nil, err
+	}
+
+	return postNewConn(conn)
+}
+
+// NewConnDisplay is just like NewConn, but allows a specific net.Conn
+// to be used.
+func NewConnNet(netConn net.Conn) (*Conn, error) {
+	conn := &Conn{}
+
+	// First connect. This reads authority, checks DISPLAY environment
+	// variable, and loads the initial Setup info.
+	err := conn.connectNet(netConn)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return postNewConn(conn)
+}
+
+func postNewConn(conn *Conn) (*Conn, error) {
+	conn.Extensions = make(map[string]byte)
+
+	conn.cookieChan = make(chan *Cookie, cookieBuffer)
+	conn.xidChan = make(chan xid, xidBuffer)
+	conn.seqChan = make(chan uint16, seqBuffer)
+	conn.reqChan = make(chan *request, reqBuffer)
+	conn.eventChan = make(chan eventOrError, eventBuffer)
+	conn.closing = make(chan chan struct{}, 1)
+
+	go conn.generateXIds()
+	go conn.generateSeqIds()
+	go conn.sendRequests()
+	go conn.readResponses()
+
+	return conn, nil
+}
+
+// Close gracefully closes the connection to the X server.
+func (c *Conn) Close() {
+	close(c.reqChan)
+}
+
+// Event is an interface that can contain any of the events returned by the
+// server. Use a type assertion switch to extract the Event structs.
+type Event interface {
+	Bytes() []byte
+	String() string
+}
+
+// NewEventFun is the type of function use to construct events from raw bytes.
+// It should not be used. It is exported for use in the extension sub-packages.
+type NewEventFun func(buf []byte) Event
+
+// NewEventFuncs is a map from event numbers to functions that create
+// the corresponding event. It should not be used. It is exported for use
+// in the extension sub-packages.
+var NewEventFuncs = make(map[int]NewEventFun)
+
+// NewExtEventFuncs is a temporary map that stores event constructor functions
+// for each extension. When an extension is initialized, each event for that
+// extension is added to the 'NewEventFuncs' map. It should not be used. It is
+// exported for use in the extension sub-packages.
+var NewExtEventFuncs = make(map[string]map[int]NewEventFun)
+
+// Error is an interface that can contain any of the errors returned by
+// the server. Use a type assertion switch to extract the Error structs.
+type Error interface {
+	SequenceId() uint16
+	BadId() uint32
+	Error() string
+}
+
+// NewErrorFun is the type of function use to construct errors from raw bytes.
+// It should not be used. It is exported for use in the extension sub-packages.
+type NewErrorFun func(buf []byte) Error
+
+// NewErrorFuncs is a map from error numbers to functions that create
+// the corresponding error. It should not be used. It is exported for use in
+// the extension sub-packages.
+var NewErrorFuncs = make(map[int]NewErrorFun)
+
+// NewExtErrorFuncs is a temporary map that stores error constructor functions
+// for each extension. When an extension is initialized, each error for that
+// extension is added to the 'NewErrorFuncs' map. It should not be used. It is
+// exported for use in the extension sub-packages.
+var NewExtErrorFuncs = make(map[string]map[int]NewErrorFun)
+
+// eventOrError corresponds to values that can be either an event or an
+// error.
+type eventOrError interface{}
+
+// NewId generates a new unused ID for use with requests like CreateWindow.
+// If no new ids can be generated, the id returned is 0 and error is non-nil.
+// This shouldn't be used directly, and is exported for use in the extension
+// sub-packages.
+// If you need identifiers, use the appropriate constructor.
+// e.g., For a window id, use xproto.NewWindowId. For
+// a new pixmap id, use xproto.NewPixmapId. And so on.
+func (c *Conn) NewId() (uint32, error) {
+	xid := <-c.xidChan
+	if xid.err != nil {
+		return 0, xid.err
+	}
+	return xid.id, nil
+}
+
+// xid encapsulates a resource identifier being sent over the Conn.xidChan
+// channel. If no new resource id can be generated, id is set to 0 and a
+// non-nil error is set in xid.err.
+type xid struct {
+	id  uint32
+	err error
+}
+
+// generateXids sends new Ids down the channel for NewId to use.
+// generateXids should be run in its own goroutine.
+// This needs to be updated to use the XC Misc extension once we run out of
+// new ids.
+// Thanks to libxcb/src/xcb_xid.c. This code is greatly inspired by it.
+func (conn *Conn) generateXIds() {
+	defer close(conn.xidChan)
+
+	// This requires some explanation. From the horse's mouth:
+	// "The resource-id-mask contains a single contiguous set of bits (at least
+	// 18).  The client allocates resource IDs for types WINDOW, PIXMAP,
+	// CURSOR, FONT, GCONTEXT, and COLORMAP by choosing a value with only some
+	// subset of these bits set and ORing it with resource-id-base. Only values
+	// constructed in this way can be used to name newly created resources over
+	// this connection."
+	// So for example (using 8 bit integers), the mask might look like:
+	// 00111000
+	// So that valid values would be 00101000, 00110000, 00001000, and so on.
+	// Thus, the idea is to increment it by the place of the last least
+	// significant '1'. In this case, that value would be 00001000. To get
+	// that value, we can AND the original mask with its two's complement:
+	// 00111000 & 11001000 = 00001000.
+	// And we use that value to increment the last resource id to get a new one.
+	// (And then, of course, we OR it with resource-id-base.)
+	inc := conn.setupResourceIdMask & -conn.setupResourceIdMask
+	max := conn.setupResourceIdMask
+	last := uint32(0)
+	for {
+		// TODO: Use the XC Misc extension to look for released ids.
+		if last > 0 && last >= max-inc+1 {
+			conn.xidChan <- xid{
+				id: 0,
+				err: errors.New("There are no more available resource" +
+					"identifiers."),
+			}
+		}
+
+		last += inc
+		conn.xidChan <- xid{
+			id:  last | conn.setupResourceIdBase,
+			err: nil,
+		}
+	}
+}
+
+// newSeqId fetches the next sequence id from the Conn.seqChan channel.
+func (c *Conn) newSequenceId() uint16 {
+	return <-c.seqChan
+}
+
+// generateSeqIds returns new sequence ids. It is meant to be run in its
+// own goroutine.
+// A sequence id is generated for *every* request. It's the identifier used
+// to match up replies with requests.
+// Since sequence ids can only be 16 bit integers we start over at zero when it
+// comes time to wrap.
+// N.B. As long as the cookie buffer is less than 2^16, there are no limitations
+// on the number (or kind) of requests made in sequence.
+func (c *Conn) generateSeqIds() {
+	defer close(c.seqChan)
+
+	seqid := uint16(1)
+	for {
+		c.seqChan <- seqid
+		if seqid == uint16((1<<16)-1) {
+			seqid = 0
+		} else {
+			seqid++
+		}
+	}
+}
+
+// request encapsulates a buffer of raw bytes (containing the request data)
+// and a cookie, which when combined represents a single request.
+// The cookie is used to match up the reply/error.
+type request struct {
+	buf    []byte
+	cookie *Cookie
+
+	// seq is closed when the request (cookie) has been sequenced by the Conn.
+	seq chan struct{}
+}
+
+// NewRequest takes the bytes and a cookie of a particular request, constructs
+// a request type, and sends it over the Conn.reqChan channel.
+// Note that the sequence number is added to the cookie after it is sent
+// over the request channel, but before it is sent to X.
+//
+// Note that you may safely use NewRequest to send arbitrary byte requests
+// to X. The resulting cookie can be used just like any normal cookie and
+// abides by the same rules, except that for replies, you'll get back the
+// raw byte data. This may be useful for performance critical sections where
+// every allocation counts, since all X requests in XGB allocate a new byte
+// slice. In contrast, NewRequest allocates one small request struct and
+// nothing else. (Except when the cookie buffer is full and has to be flushed.)
+//
+// If you're using NewRequest manually, you'll need to use NewCookie to create
+// a new cookie.
+//
+// In all likelihood, you should be able to copy and paste with some minor
+// edits the generated code for the request you want to issue.
+func (c *Conn) NewRequest(buf []byte, cookie *Cookie) {
+	seq := make(chan struct{})
+	c.reqChan <- &request{buf: buf, cookie: cookie, seq: seq}
+	<-seq
+}
+
+// sendRequests is run as a single goroutine that takes requests and writes
+// the bytes to the wire and adds the cookie to the cookie queue.
+// It is meant to be run as its own goroutine.
+func (c *Conn) sendRequests() {
+	defer close(c.cookieChan)
+
+	for req := range c.reqChan {
+		// ho there! if the cookie channel is nearly full, force a round
+		// trip to clear out the cookie buffer.
+		// Note that we circumvent the request channel, because we're *in*
+		// the request channel.
+		if len(c.cookieChan) == cookieBuffer-1 {
+			if err := c.noop(); err != nil {
+				// Shut everything down.
+				break
+			}
+		}
+		req.cookie.Sequence = c.newSequenceId()
+		c.cookieChan <- req.cookie
+		c.writeBuffer(req.buf)
+		close(req.seq)
+	}
+	response := make(chan struct{})
+	c.closing <- response
+	c.noop() // Flush the response reading goroutine, ignore error.
+	<-response
+	c.conn.Close()
+}
+
+// noop circumvents the usual request sending goroutines and forces a round
+// trip request manually.
+func (c *Conn) noop() error {
+	cookie := c.NewCookie(true, true)
+	cookie.Sequence = c.newSequenceId()
+	c.cookieChan <- cookie
+	if err := c.writeBuffer(c.getInputFocusRequest()); err != nil {
+		return err
+	}
+	cookie.Reply() // wait for the buffer to clear
+	return nil
+}
+
+// writeBuffer is a convenience function for writing a byte slice to the wire.
+func (c *Conn) writeBuffer(buf []byte) error {
+	if _, err := c.conn.Write(buf); err != nil {
+		Logger.Printf("A write error is unrecoverable: %s", err)
+		return err
+	} else {
+		return nil
+	}
+}
+
+// readResponses is a goroutine that reads events, errors and
+// replies off the wire.
+// When an event is read, it is always added to the event channel.
+// When an error is read, if it corresponds to an existing checked cookie,
+// it is sent to that cookie's error channel. Otherwise it is added to the
+// event channel.
+// When a reply is read, it is added to the corresponding cookie's reply
+// channel. (It is an error if no such cookie exists in this case.)
+// Finally, cookies that came "before" this reply are always cleaned up.
+func (c *Conn) readResponses() {
+	defer close(c.eventChan)
+
+	var (
+		err        Error
+		seq        uint16
+		replyBytes []byte
+	)
+
+	for {
+		select {
+		case respond := <-c.closing:
+			respond <- struct{}{}
+			return
+		default:
+		}
+
+		buf := make([]byte, 32)
+		err, seq = nil, 0
+		if _, err := io.ReadFull(c.conn, buf); err != nil {
+			Logger.Printf("A read error is unrecoverable: %s", err)
+			c.eventChan <- err
+			c.Close()
+			continue
+		}
+		switch buf[0] {
+		case 0: // This is an error
+			// Use the constructor function for this error (that is auto
+			// generated) by looking it up by the error number.
+			newErrFun, ok := NewErrorFuncs[int(buf[1])]
+			if !ok {
+				Logger.Printf("BUG: Could not find error constructor function "+
+					"for error with number %d.", buf[1])
+				continue
+			}
+			err = newErrFun(buf)
+			seq = err.SequenceId()
+
+			// This error is either sent to the event channel or a specific
+			// cookie's error channel below.
+		case 1: // This is a reply
+			seq = Get16(buf[2:])
+
+			// check to see if this reply has more bytes to be read
+			size := Get32(buf[4:])
+			if size > 0 {
+				byteCount := 32 + size*4
+				biggerBuf := make([]byte, byteCount)
+				copy(biggerBuf[:32], buf)
+				if _, err := io.ReadFull(c.conn, biggerBuf[32:]); err != nil {
+					Logger.Printf("A read error is unrecoverable: %s", err)
+					c.eventChan <- err
+					c.Close()
+					continue
+				}
+				replyBytes = biggerBuf
+			} else {
+				replyBytes = buf
+			}
+
+			// This reply is sent to its corresponding cookie below.
+		default: // This is an event
+			// Use the constructor function for this event (like for errors,
+			// and is also auto generated) by looking it up by the event number.
+			// Note that we AND the event number with 127 so that we ignore
+			// the most significant bit (which is set when it was sent from
+			// a SendEvent request).
+			evNum := int(buf[0] & 127)
+			newEventFun, ok := NewEventFuncs[evNum]
+			if !ok {
+				Logger.Printf("BUG: Could not find event construct function "+
+					"for event with number %d.", evNum)
+				continue
+			}
+			c.eventChan <- newEventFun(buf)
+			continue
+		}
+
+		// At this point, we have a sequence number and we're either
+		// processing an error or a reply, which are both responses to
+		// requests. So all we have to do is find the cookie corresponding
+		// to this error/reply, and send the appropriate data to it.
+		// In doing so, we make sure that any cookies that came before it
+		// are marked as successful if they are void and checked.
+		// If there's a cookie that requires a reply that is before this
+		// reply, then something is wrong.
+		for cookie := range c.cookieChan {
+			// This is the cookie we're looking for. Process and break.
+			if cookie.Sequence == seq {
+				if err != nil { // this is an error to a request
+					// synchronous processing
+					if cookie.errorChan != nil {
+						cookie.errorChan <- err
+					} else { // asynchronous processing
+						c.eventChan <- err
+						// if this is an unchecked reply, ping the cookie too
+						if cookie.pingChan != nil {
+							cookie.pingChan <- true
+						}
+					}
+				} else { // this is a reply
+					if cookie.replyChan == nil {
+						Logger.Printf("Reply with sequence id %d does not "+
+							"have a cookie with a valid reply channel.", seq)
+						continue
+					} else {
+						cookie.replyChan <- replyBytes
+					}
+				}
+				break
+			}
+
+			switch {
+			// Checked requests with replies
+			case cookie.replyChan != nil && cookie.errorChan != nil:
+				Logger.Printf("Found cookie with sequence id %d that is "+
+					"expecting a reply but will never get it. Currently "+
+					"on sequence number %d", cookie.Sequence, seq)
+			// Unchecked requests with replies
+			case cookie.replyChan != nil && cookie.pingChan != nil:
+				Logger.Printf("Found cookie with sequence id %d that is "+
+					"expecting a reply (and not an error) but will never "+
+					"get it. Currently on sequence number %d",
+					cookie.Sequence, seq)
+			// Checked requests without replies
+			case cookie.pingChan != nil && cookie.errorChan != nil:
+				cookie.pingChan <- true
+				// Unchecked requests without replies don't have any channels,
+				// so we can't do anything with them except let them pass by.
+			}
+		}
+	}
+}
+
+// processEventOrError takes an eventOrError, type switches on it,
+// and returns it in Go idiomatic style.
+func processEventOrError(everr eventOrError) (Event, Error) {
+	switch ee := everr.(type) {
+	case Event:
+		return ee, nil
+	case Error:
+		return nil, ee
+	default:
+		Logger.Printf("Invalid event/error type: %T", everr)
+		return nil, nil
+	}
+}
+
+// WaitForEvent returns the next event from the server.
+// It will block until an event is available.
+// WaitForEvent returns either an Event or an Error. (Returning both
+// is a bug.) Note than an Error here is an X error and not an XGB error. That
+// is, X errors are sometimes completely expected (and you may want to ignore
+// them in some cases).
+//
+// If both the event and error are nil, then the connection has been closed.
+func (c *Conn) WaitForEvent() (Event, Error) {
+	return processEventOrError(<-c.eventChan)
+}
+
+// PollForEvent returns the next event from the server if one is available in
+// the internal queue without blocking. Note that unlike WaitForEvent, both
+// Event and Error could be nil. Indeed, they are both nil when the event queue
+// is empty.
+func (c *Conn) PollForEvent() (Event, Error) {
+	select {
+	case everr := <-c.eventChan:
+		return processEventOrError(everr)
+	default:
+		return nil, nil
+	}
+}

nexgb/xgbgen/LICENSE

@@ -0,0 +1,13 @@
+Copyright (c) 2012 - 2016, Andrew Gallant <jamslam@gmail.com>
+Copyright (c) 2018, Přemysl Janouch <p@janouch.name>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

nexgb/xgbgen/context.go

@@ -0,0 +1,182 @@
+package main
+
+import (
+	"bytes"
+	"encoding/xml"
+	"fmt"
+	"log"
+	"sort"
+	"strings"
+)
+
+// Context represents the protocol we're converting to Go, and a writer
+// buffer to write the Go source to.
+type Context struct {
+	protocol *Protocol
+	out      *bytes.Buffer
+}
+
+func newContext() *Context {
+	return &Context{
+		out: bytes.NewBuffer([]byte{}),
+	}
+}
+
+// Putln calls put and adds a new line to the end of 'format'.
+func (c *Context) Putln(format string, v ...interface{}) {
+	c.Put(format+"\n", v...)
+}
+
+// Put is a short alias to write to 'out'.
+func (c *Context) Put(format string, v ...interface{}) {
+	_, err := c.out.WriteString(fmt.Sprintf(format, v...))
+	if err != nil {
+		log.Fatalf("There was an error writing to context buffer: %s", err)
+	}
+}
+
+// PutComment writes each line of comment commented out to 'out'.
+func (c *Context) PutComment(comment string) {
+	for _, line := range strings.Split(comment, "\n") {
+		c.Putln("// %s", line)
+	}
+}
+
+// Morph is the big daddy of them all. It takes in an XML byte slice,
+// parse it, transforms the XML types into more usable types,
+// and writes Go code to the 'out' buffer.
+func (c *Context) Morph(xmlBytes []byte) {
+	parsedXml := &XML{}
+	err := xml.Unmarshal(xmlBytes, parsedXml)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Parse all imports
+	parsedXml.Imports.Eval()
+
+	// Translate XML types to nice types
+	c.protocol = parsedXml.Translate(nil)
+
+	// For backwards compatibility we patch the type of the send_event field of
+	// PutImage to be byte
+	if c.protocol.Name == "shm" {
+		for _, req := range c.protocol.Requests {
+			if req.xmlName != "PutImage" {
+				continue
+			}
+			for _, ifield := range req.Fields {
+				field, ok := ifield.(*SingleField)
+				if !ok || field.xmlName != "send_event" {
+					continue
+				}
+				field.Type = &Base{srcName: "byte", xmlName: "CARD8", size: newFixedSize(1, true)}
+			}
+		}
+	}
+
+	// Start with Go header.
+	c.Putln("// Package %s is the X client API for the %s extension.",
+		c.protocol.PkgName(), c.protocol.ExtXName)
+	c.Putln("package %s", c.protocol.PkgName())
+	c.Putln("")
+	c.Putln("// This file is automatically generated from %s.xml. "+
+		"Edit at your peril!", c.protocol.Name)
+	c.Putln("")
+
+	// Write imports. We always need to import at least xgb.
+	// We also need to import xproto if it's an extension.
+	c.Putln("import (")
+	c.Putln("xgb \"janouch.name/haven/nexgb\"")
+	c.Putln("")
+	if c.protocol.isExt() {
+		c.Putln("\"janouch.name/haven/nexgb/xproto\"")
+	}
+
+	sort.Sort(Protocols(c.protocol.Imports))
+	for _, imp := range c.protocol.Imports {
+		// We always import xproto, so skip it if it's explicitly imported
+		if imp.Name == "xproto" {
+			continue
+		}
+		c.Putln("\"janouch.name/haven/nexgb/%s\"", imp.Name)
+	}
+	c.Putln(")")
+	c.Putln("")
+
+	// If this is an extension, create a function to initialize the extension
+	// before it can be used.
+	if c.protocol.isExt() {
+		xname := c.protocol.ExtXName
+
+		c.Putln("const (")
+		c.Putln("MajorVersion = %s", c.protocol.MajorVersion)
+		c.Putln("MinorVersion = %s", c.protocol.MinorVersion)
+		c.Putln(")")
+		c.Putln("")
+
+		c.Putln("// Init must be called before using the %s extension.",
+			xname)
+		c.Putln("func Init(c *xgb.Conn) error {")
+		c.Putln("reply, err := xproto.QueryExtension(c, %d, \"%s\").Reply()",
+			len(xname), xname)
+		c.Putln("switch {")
+		c.Putln("case err != nil:")
+		c.Putln("return err")
+		c.Putln("case !reply.Present:")
+		c.Putln("return xgb.Errorf(\"No extension named %s could be found on "+
+			"on the server.\")", xname)
+		c.Putln("}")
+		c.Putln("")
+		c.Putln("c.ExtLock.Lock()")
+		c.Putln("c.Extensions[\"%s\"] = reply.MajorOpcode", xname)
+		c.Putln("c.ExtLock.Unlock()")
+		c.Putln("for evNum, fun := range xgb.NewExtEventFuncs[\"%s\"] {",
+			xname)
+		c.Putln("xgb.NewEventFuncs[int(reply.FirstEvent) + evNum] = fun")
+		c.Putln("}")
+		c.Putln("for errNum, fun := range xgb.NewExtErrorFuncs[\"%s\"] {",
+			xname)
+		c.Putln("xgb.NewErrorFuncs[int(reply.FirstError) + errNum] = fun")
+		c.Putln("}")
+		c.Putln("return nil")
+		c.Putln("}")
+		c.Putln("")
+
+		// Make sure newExtEventFuncs["EXT_NAME"] map is initialized.
+		// Same deal for newExtErrorFuncs["EXT_NAME"]
+		c.Putln("func init() {")
+		c.Putln("xgb.NewExtEventFuncs[\"%s\"] = make(map[int]xgb.NewEventFun)",
+			xname)
+		c.Putln("xgb.NewExtErrorFuncs[\"%s\"] = make(map[int]xgb.NewErrorFun)",
+			xname)
+		c.Putln("}")
+		c.Putln("")
+	} else {
+		// In the xproto package, we must provide a Setup function that uses
+		// SetupBytes in xgb.Conn to return a SetupInfo structure.
+		c.Putln("// Setup parses the setup bytes retrieved when")
+		c.Putln("// connecting into a SetupInfo struct.")
+		c.Putln("func Setup(c *xgb.Conn) *SetupInfo {")
+		c.Putln("setup := new(SetupInfo)")
+		c.Putln("SetupInfoRead(c.SetupBytes, setup)")
+		c.Putln("return setup")
+		c.Putln("}")
+		c.Putln("")
+		c.Putln("// DefaultScreen gets the default screen info from SetupInfo.")
+		c.Putln("func (s *SetupInfo) DefaultScreen(c *xgb.Conn) *ScreenInfo {")
+		c.Putln("return &s.Roots[c.DefaultScreen]")
+		c.Putln("}")
+		c.Putln("")
+	}
+
+	// Now write Go source code
+	sort.Sort(Types(c.protocol.Types))
+	sort.Sort(Requests(c.protocol.Requests))
+	for _, typ := range c.protocol.Types {
+		typ.Define(c)
+	}
+	for _, req := range c.protocol.Requests {
+		req.Define(c)
+	}
+}

nexgb/xgbgen/doc.go

@@ -0,0 +1,74 @@
+/*
+xgbgen constructs Go source files from xproto XML description files. xgbgen
+accomplishes the same task as the Python code generator for XCB and xpyb.
+
+Usage:
+	xgbgen [flags] some-protocol.xml
+
+The flags are:
+	--proto-path path
+		The path to a directory containing xproto XML description files.
+		This is only necessary when 'some-protocol.xml' imports other
+		protocol files.
+	--gofmt=true
+		When false, the outputted Go code will not be gofmt'd. And it won't
+		be very pretty at all. This is typically useful if there are syntax
+		errors that need to be debugged in code generation. gofmt will hiccup;
+		this will allow you to see the raw code.
+
+How it works
+
+xgbgen works by parsing the input XML file using Go's encoding/xml package.
+The majority of this work is done in xml.go and xml_fields.go, where the
+appropriate types are declared.
+
+Due to the nature of the XML in the protocol description files, the types
+required to parse the XML are not well suited to reasoning about code
+generation. Because of this, all data parsed in the XML types is translated
+into more reasonable types. This translation is done in translation.go,
+and is mainly grunt work. (The only interesting tidbits are the translation
+of XML names to Go source names, and connecting fields with their
+appropriate types.)
+
+The organization of these types is greatly
+inspired by the description of the XML found here:
+http://cgit.freedesktop.org/xcb/proto/tree/doc/xml-xcb.txt
+
+These types come with a lot of supporting methods to make their use in
+code generation easier. They can be found in expression.go, field.go,
+protocol.go, request_reply.go and type.go. Of particular interest are
+expression evaluation and size calculation (in bytes).
+
+These types also come with supporting methods that convert their
+representation into Go source code. I've quartered such methods in
+go.go, go_error.go, go_event.go, go_list.go, go_request_reply.go,
+go_single_field.go, go_struct.go and go_union.go. The idea is to keep
+as much of the Go specific code generation in one area as possible. Namely,
+while not *all* Go related code is found in the 'go*.go' files, *most*
+of it is. (If there's any interest in using xgbgen for other languages,
+I'd be happy to try and make xgbgen a little more friendly in this regard.
+I did, however, design xgbgen with this in mind, so it shouldn't involve
+anything as serious as a re-design.)
+
+Why
+
+I wrote xgbgen because I found the existing code generator that was written in
+Python to be unwieldy. In particular, static and strong typing greatly helped
+me reason better about the code generation task.
+
+What does not work
+
+The core X protocol should be completely working. As far as I know, most
+extensions should work too, although I've only tested (and not much) the
+Xinerama and RandR extensions.
+
+XKB does not work. I don't have any real plans of working on this unless there
+is demand and I have some test cases to work with. (i.e., even if I could get
+something generated for XKB, I don't have the inclination to understand it
+enough to verify that it works.) XKB poses several extremely difficult
+problems that XCB also has trouble with. More info on that can be found at
+http://cgit.freedesktop.org/xcb/libxcb/tree/doc/xkb_issues and
+http://cgit.freedesktop.org/xcb/libxcb/tree/doc/xkb_internals.
+
+*/
+package main

nexgb/xgbgen/expression.go

@@ -0,0 +1,436 @@
+package main
+
+import (
+	"fmt"
+	"log"
+)
+
+// Expression represents all the different forms of expressions possible in
+// side an XML protocol description file. It's also received a few custom
+// addendums to make applying special functions (like padding) easier.
+type Expression interface {
+	// Concrete determines whether this particular expression can be computed
+	// to some constant value inside xgbgen. (The alternative is that the
+	// expression can only be computed with values at run time of the
+	// generated code.)
+	Concrete() bool
+
+	// Eval evaluates a concrete expression. It is an error to call Eval
+	// on any expression that is not concrete (or contains any sub-expression
+	// that is not concrete).
+	Eval() int
+
+	// Reduce attempts to evaluate any concrete sub-expressions.
+	// i.e., (1 + 2 * (5 + 1 + someSizeOfStruct) reduces to
+	// (3 * (6 + someSizeOfStruct)).
+	// 'prefix' is used preprended to any field reference name.
+	Reduce(prefix string) string
+
+	// String is an alias for Reduce("")
+	String() string
+
+	// Initialize makes sure all names in this expression and any subexpressions
+	// have been translated to Go source names.
+	Initialize(p *Protocol)
+
+	// Makes all field references relative to path
+	Specialize(path string) Expression
+}
+
+// Function is a custom expression not found in the XML. It's simply used
+// to apply a function named in 'Name' to the Expr expression.
+type Function struct {
+	Name string
+	Expr Expression
+}
+
+func (e *Function) Concrete() bool {
+	return false
+}
+
+func (e *Function) Eval() int {
+	log.Fatalf("Cannot evaluate a 'Function'. It is not concrete.")
+	panic("unreachable")
+}
+
+func (e *Function) Reduce(prefix string) string {
+	return fmt.Sprintf("%s(%s)", e.Name, e.Expr.Reduce(prefix))
+}
+
+func (e *Function) String() string {
+	return e.Reduce("")
+}
+
+func (e *Function) Initialize(p *Protocol) {
+	e.Expr.Initialize(p)
+}
+
+func (e *Function) Specialize(path string) Expression {
+	r := *e
+	r.Expr = r.Expr.Specialize(path)
+	return &r
+}
+
+// BinaryOp is an expression that performs some operation (defined in the XML
+// file) with Expr1 and Expr2 as operands.
+type BinaryOp struct {
+	Op    string
+	Expr1 Expression
+	Expr2 Expression
+}
+
+// newBinaryOp constructs a new binary expression when both expr1 and expr2
+// are not nil. If one or both are nil, then the non-nil expression is
+// returned unchanged or nil is returned.
+func newBinaryOp(op string, expr1, expr2 Expression) Expression {
+	switch {
+	case expr1 != nil && expr2 != nil:
+		return &BinaryOp{
+			Op:    op,
+			Expr1: expr1,
+			Expr2: expr2,
+		}
+	case expr1 != nil && expr2 == nil:
+		return expr1
+	case expr1 == nil && expr2 != nil:
+		return expr2
+	case expr1 == nil && expr2 == nil:
+		return nil
+	}
+	panic("unreachable")
+}
+
+func (e *BinaryOp) Concrete() bool {
+	return e.Expr1.Concrete() && e.Expr2.Concrete()
+}
+
+func (e *BinaryOp) Eval() int {
+	switch e.Op {
+	case "+":
+		return e.Expr1.Eval() + e.Expr2.Eval()
+	case "-":
+		return e.Expr1.Eval() - e.Expr2.Eval()
+	case "*":
+		return e.Expr1.Eval() * e.Expr2.Eval()
+	case "/":
+		return e.Expr1.Eval() / e.Expr2.Eval()
+	case "&":
+		return e.Expr1.Eval() & e.Expr2.Eval()
+	case "<<":
+		return int(uint(e.Expr1.Eval()) << uint(e.Expr2.Eval()))
+	}
+
+	log.Fatalf("Invalid binary operator '%s' for expression.", e.Op)
+	panic("unreachable")
+}
+
+func (e *BinaryOp) Reduce(prefix string) string {
+	if e.Concrete() {
+		return fmt.Sprintf("%d", e.Eval())
+	}
+
+	// An incredibly dirty hack to make sure any time we perform an operation
+	// on a field, we're dealing with ints...
+	expr1, expr2 := e.Expr1, e.Expr2
+	switch expr1.(type) {
+	case *FieldRef:
+		expr1 = &Function{
+			Name: "int",
+			Expr: expr1,
+		}
+	}
+	switch expr2.(type) {
+	case *FieldRef:
+		expr2 = &Function{
+			Name: "int",
+			Expr: expr2,
+		}
+	}
+	return fmt.Sprintf("(%s %s %s)",
+		expr1.Reduce(prefix), e.Op, expr2.Reduce(prefix))
+}
+
+func (e *BinaryOp) String() string {
+	return e.Reduce("")
+}
+
+func (e *BinaryOp) Initialize(p *Protocol) {
+	e.Expr1.Initialize(p)
+	e.Expr2.Initialize(p)
+}
+
+func (e *BinaryOp) Specialize(path string) Expression {
+	r := *e
+	r.Expr1 = r.Expr1.Specialize(path)
+	r.Expr2 = r.Expr2.Specialize(path)
+	return &r
+}
+
+// UnaryOp is the same as BinaryOp, except it's a unary operator with only
+// one sub-expression.
+type UnaryOp struct {
+	Op   string
+	Expr Expression
+}
+
+func (e *UnaryOp) Concrete() bool {
+	return e.Expr.Concrete()
+}
+
+func (e *UnaryOp) Eval() int {
+	switch e.Op {
+	case "~":
+		return ^e.Expr.Eval()
+	}
+
+	log.Fatalf("Invalid unary operator '%s' for expression.", e.Op)
+	panic("unreachable")
+}
+
+func (e *UnaryOp) Reduce(prefix string) string {
+	if e.Concrete() {
+		return fmt.Sprintf("%d", e.Eval())
+	}
+	return fmt.Sprintf("(%s (%s))", e.Op, e.Expr.Reduce(prefix))
+}
+
+func (e *UnaryOp) String() string {
+	return e.Reduce("")
+}
+
+func (e *UnaryOp) Initialize(p *Protocol) {
+	e.Expr.Initialize(p)
+}
+
+func (e *UnaryOp) Specialize(path string) Expression {
+	r := *e
+	r.Expr = r.Expr.Specialize(path)
+	return &r
+}
+
+// Padding represents the application of the 'pad' function to some
+// sub-expression.
+type Padding struct {
+	Expr Expression
+}
+
+func (e *Padding) Concrete() bool {
+	return e.Expr.Concrete()
+}
+
+func (e *Padding) Eval() int {
+	return pad(e.Expr.Eval())
+}
+
+func (e *Padding) Reduce(prefix string) string {
+	if e.Concrete() {
+		return fmt.Sprintf("%d", e.Eval())
+	}
+	return fmt.Sprintf("xgb.Pad(%s)", e.Expr.Reduce(prefix))
+}
+
+func (e *Padding) String() string {
+	return e.Reduce("")
+}
+
+func (e *Padding) Initialize(p *Protocol) {
+	e.Expr.Initialize(p)
+}
+
+func (e *Padding) Specialize(path string) Expression {
+	r := *e
+	r.Expr = r.Expr.Specialize(path)
+	return &r
+}
+
+// PopCount represents the application of the 'PopCount' function to
+// some sub-expression.
+type PopCount struct {
+	Expr Expression
+}
+
+func (e *PopCount) Concrete() bool {
+	return e.Expr.Concrete()
+}
+
+func (e *PopCount) Eval() int {
+	return int(popCount(uint(e.Expr.Eval())))
+}
+
+func (e *PopCount) Reduce(prefix string) string {
+	if e.Concrete() {
+		return fmt.Sprintf("%d", e.Eval())
+	}
+	return fmt.Sprintf("xgb.PopCount(%s)", e.Expr.Reduce(prefix))
+}
+
+func (e *PopCount) String() string {
+	return e.Reduce("")
+}
+
+func (e *PopCount) Initialize(p *Protocol) {
+	e.Expr.Initialize(p)
+}
+
+func (e *PopCount) Specialize(path string) Expression {
+	r := *e
+	r.Expr = r.Expr.Specialize(path)
+	return &r
+}
+
+// Value represents some constant integer.
+type Value struct {
+	v int
+}
+
+func (e *Value) Concrete() bool {
+	return true
+}
+
+func (e *Value) Eval() int {
+	return e.v
+}
+
+func (e *Value) Reduce(prefix string) string {
+	return fmt.Sprintf("%d", e.v)
+}
+
+func (e *Value) String() string {
+	return e.Reduce("")
+}
+
+func (e *Value) Initialize(p *Protocol) {}
+
+func (e *Value) Specialize(path string) Expression {
+	return e
+}
+
+// Bit represents some bit whose value is computed by '1 << bit'.
+type Bit struct {
+	b int
+}
+
+func (e *Bit) Concrete() bool {
+	return true
+}
+
+func (e *Bit) Eval() int {
+	return int(1 << uint(e.b))
+}
+
+func (e *Bit) Reduce(prefix string) string {
+	return fmt.Sprintf("%d", e.Eval())
+}
+
+func (e *Bit) String() string {
+	return e.Reduce("")
+}
+
+func (e *Bit) Initialize(p *Protocol) {}
+
+func (e *Bit) Specialize(path string) Expression {
+	return e
+}
+
+// FieldRef represents a reference to some variable in the generated code
+// with name Name.
+type FieldRef struct {
+	Name string
+}
+
+func (e *FieldRef) Concrete() bool {
+	return false
+}
+
+func (e *FieldRef) Eval() int {
+	log.Fatalf("Cannot evaluate a 'FieldRef'. It is not concrete.")
+	panic("unreachable")
+}
+
+func (e *FieldRef) Reduce(prefix string) string {
+	val := e.Name
+	if len(prefix) > 0 {
+		val = fmt.Sprintf("%s%s", prefix, val)
+	}
+	return val
+}
+
+func (e *FieldRef) String() string {
+	return e.Reduce("")
+}
+
+func (e *FieldRef) Initialize(p *Protocol) {
+	e.Name = SrcName(p, e.Name)
+}
+
+func (e *FieldRef) Specialize(path string) Expression {
+	return &FieldRef{Name: path + "." + e.Name}
+}
+
+// EnumRef represents a reference to some enumeration field.
+// EnumKind is the "group" an EnumItem is the name of the specific enumeration
+// value inside that group.
+type EnumRef struct {
+	EnumKind Type
+	EnumItem string
+}
+
+func (e *EnumRef) Concrete() bool {
+	return false
+}
+
+func (e *EnumRef) Eval() int {
+	log.Fatalf("Cannot evaluate an 'EnumRef'. It is not concrete.")
+	panic("unreachable")
+}
+
+func (e *EnumRef) Reduce(prefix string) string {
+	return fmt.Sprintf("%s%s", e.EnumKind, e.EnumItem)
+}
+
+func (e *EnumRef) String() string {
+	return e.Reduce("")
+}
+
+func (e *EnumRef) Initialize(p *Protocol) {
+	e.EnumKind = e.EnumKind.(*Translation).RealType(p)
+	e.EnumItem = SrcName(p, e.EnumItem)
+}
+
+func (e *EnumRef) Specialize(path string) Expression {
+	return e
+}
+
+// SumOf represents a summation of the variable in the generated code named by
+// Name. It is not currently used. (It's XKB voodoo.)
+type SumOf struct {
+	Name string
+}
+
+func (e *SumOf) Concrete() bool {
+	return false
+}
+
+func (e *SumOf) Eval() int {
+	log.Fatalf("Cannot evaluate a 'SumOf'. It is not concrete.")
+	panic("unreachable")
+}
+
+func (e *SumOf) Reduce(prefix string) string {
+	if len(prefix) > 0 {
+		return fmt.Sprintf("sum(%s%s)", prefix, e.Name)
+	}
+	return fmt.Sprintf("sum(%s)", e.Name)
+}
+
+func (e *SumOf) String() string {
+	return e.Reduce("")
+}
+
+func (e *SumOf) Initialize(p *Protocol) {
+	e.Name = SrcName(p, e.Name)
+}
+
+func (e *SumOf) Specialize(path string) Expression {
+	return e
+}

nexgb/xgbgen/field.go

@@ -0,0 +1,402 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"strings"
+)
+
+// Field corresponds to any field described in an XML protocol description
+// file. This includes struct fields, union fields, request fields,
+// reply fields and so on.
+// To make code generation easier, fields that have types are also stored.
+// Note that not all fields support all methods defined in this interface.
+// For instance, a padding field does not have a source name.
+type Field interface {
+	// Initialize sets up the source name of this field.
+	Initialize(p *Protocol)
+
+	// SrcName is the Go source name of this field.
+	SrcName() string
+
+	// XmlName is the name of this field from the XML file.
+	XmlName() string
+
+	// SrcType is the Go source type name of this field.
+	SrcType() string
+
+	// Size returns an expression that computes the size (in bytes)
+	// of this field.
+	Size() Size
+
+	// Define writes the Go code to declare this field (in a struct definition).
+	Define(c *Context)
+
+	// Read writes the Go code to convert a byte slice to a Go value
+	// of this field.
+	// 'prefix' is the prefix of the name of the Go value.
+	Read(c *Context, prefix string)
+
+	// Write writes the Go code to convert a Go value to a byte slice of
+	// this field.
+	// 'prefix' is the prefix of the name of the Go value.
+	Write(c *Context, prefix string)
+}
+
+func (pad *PadField) Initialize(p *Protocol) {}
+
+// PadField represents any type of padding. It is omitted from
+// definitions, but is used in Read/Write to increment the buffer index.
+// It is also used in size calculation.
+type PadField struct {
+	Bytes uint
+	Align uint16
+}
+
+func (p *PadField) SrcName() string {
+	panic("illegal to take source name of a pad field")
+}
+
+func (p *PadField) XmlName() string {
+	panic("illegal to take XML name of a pad field")
+}
+
+func (f *PadField) SrcType() string {
+	panic("it is illegal to call SrcType on a PadField field")
+}
+
+func (p *PadField) Size() Size {
+	if p.Align > 0 {
+		return newFixedSize(uint(p.Align), false)
+	} else {
+		return newFixedSize(p.Bytes, true)
+	}
+}
+
+type RequiredStartAlign struct {
+}
+
+func (f *RequiredStartAlign) Initialize(p *Protocol) {}
+
+func (f *RequiredStartAlign) SrcName() string {
+	panic("illegal to take source name of a required_start_align field")
+}
+
+func (f *RequiredStartAlign) XmlName() string {
+	panic("illegal to take XML name of a required_start_align field")
+}
+
+func (f *RequiredStartAlign) SrcType() string {
+	panic("it is illegal to call SrcType on a required_start_align field")
+}
+
+func (f *RequiredStartAlign) Size() Size {
+	return newFixedSize(0, true)
+}
+
+func (f *RequiredStartAlign) Define(c *Context) {}
+
+func (f *RequiredStartAlign) Read(c *Context, prefix string)  {}
+func (f *RequiredStartAlign) Write(c *Context, prefix string) {}
+
+// SingleField represents most of the fields in an XML protocol description.
+// It corresponds to any single value.
+type SingleField struct {
+	srcName string
+	xmlName string
+	Type    Type
+	Comment string
+}
+
+func (f *SingleField) Initialize(p *Protocol) {
+	f.srcName = SrcName(p, f.XmlName())
+	f.Type = f.Type.(*Translation).RealType(p)
+}
+
+func (f *SingleField) SrcName() string {
+	if f.srcName == "Bytes" {
+		return "Bytes_"
+	}
+	return f.srcName
+}
+
+func (f *SingleField) XmlName() string {
+	return f.xmlName
+}
+
+func (f *SingleField) SrcType() string {
+	return f.Type.SrcName()
+}
+
+func (f *SingleField) Size() Size {
+	return f.Type.Size()
+}
+
+// ListField represents a list of values.
+type ListField struct {
+	srcName    string
+	xmlName    string
+	Type       Type
+	LengthExpr Expression
+}
+
+func (f *ListField) SrcName() string {
+	return f.srcName
+}
+
+func (f *ListField) XmlName() string {
+	return f.xmlName
+}
+
+func (f *ListField) SrcType() string {
+	if strings.ToLower(f.Type.XmlName()) == "char" {
+		return fmt.Sprintf("string")
+	}
+	return fmt.Sprintf("[]%s", f.Type.SrcName())
+}
+
+// Length computes the *number* of values in a list.
+// If this ListField does not have any length expression, we throw our hands
+// up and simply compute the 'len' of the field name of this list.
+func (f *ListField) Length() Size {
+	if f.LengthExpr == nil {
+		return newExpressionSize(&Function{
+			Name: "len",
+			Expr: &FieldRef{
+				Name: f.SrcName(),
+			},
+		}, true)
+	}
+	return newExpressionSize(f.LengthExpr, true)
+}
+
+// Size computes the *size* of a list (in bytes).
+// It it typically a simple matter of multiplying the length of the list by
+// the size of the type of the list.
+// But if it's a list of struct where the struct has a list field, we use a
+// special function written in go_struct.go to compute the size (since the
+// size in this case can only be computed recursively).
+func (f *ListField) Size() Size {
+	elsz := f.Type.Size()
+	simpleLen := &Padding{
+		Expr: newBinaryOp("*", f.Length().Expression, elsz.Expression),
+	}
+
+	switch field := f.Type.(type) {
+	case *Struct:
+		if field.HasList() {
+			sizeFun := &Function{
+				Name: fmt.Sprintf("%sListSize", f.Type.SrcName()),
+				Expr: &FieldRef{Name: f.SrcName()},
+			}
+			return newExpressionSize(sizeFun, elsz.exact)
+		} else {
+			return newExpressionSize(simpleLen, elsz.exact)
+		}
+	case *Union:
+		return newExpressionSize(simpleLen, elsz.exact)
+	case *Base:
+		return newExpressionSize(simpleLen, elsz.exact)
+	case *Resource:
+		return newExpressionSize(simpleLen, elsz.exact)
+	case *TypeDef:
+		return newExpressionSize(simpleLen, elsz.exact)
+	default:
+		log.Panicf("Cannot compute list size with type '%T'.", f.Type)
+	}
+	panic("unreachable")
+}
+
+func (f *ListField) Initialize(p *Protocol) {
+	f.srcName = SrcName(p, f.XmlName())
+	f.Type = f.Type.(*Translation).RealType(p)
+	if f.LengthExpr != nil {
+		f.LengthExpr.Initialize(p)
+	}
+}
+
+// LocalField is exactly the same as a regular SingleField, except it isn't
+// sent over the wire. (i.e., it's probably used to compute an ExprField).
+type LocalField struct {
+	*SingleField
+}
+
+// ExprField is a field that is not parameterized, but is computed from values
+// of other fields.
+type ExprField struct {
+	srcName string
+	xmlName string
+	Type    Type
+	Expr    Expression
+}
+
+func (f *ExprField) SrcName() string {
+	return f.srcName
+}
+
+func (f *ExprField) XmlName() string {
+	return f.xmlName
+}
+
+func (f *ExprField) SrcType() string {
+	return f.Type.SrcName()
+}
+
+func (f *ExprField) Size() Size {
+	return f.Type.Size()
+}
+
+func (f *ExprField) Initialize(p *Protocol) {
+	f.srcName = SrcName(p, f.XmlName())
+	f.Type = f.Type.(*Translation).RealType(p)
+	f.Expr.Initialize(p)
+}
+
+// ValueField represents two fields in one: a mask and a list of 4-byte
+// integers. The mask specifies which kinds of values are in the list.
+// (i.e., See ConfigureWindow, CreateWindow, ChangeWindowAttributes, etc.)
+type ValueField struct {
+	Parent      interface{}
+	MaskType    Type
+	MaskName    string
+	ListName    string
+	MaskComment string
+	ListComment string
+}
+
+func (f *ValueField) SrcName() string {
+	panic("it is illegal to call SrcName on a ValueField field")
+}
+
+func (f *ValueField) XmlName() string {
+	panic("it is illegal to call XmlName on a ValueField field")
+}
+
+func (f *ValueField) SrcType() string {
+	return f.MaskType.SrcName()
+}
+
+// Size computes the size in bytes of the combination of the mask and list
+// in this value field.
+// The expression to compute this looks complicated, but it's really just
+// the number of bits set in the mask multiplied 4 (and padded of course).
+func (f *ValueField) Size() Size {
+	maskSize := f.MaskType.Size()
+	listSize := newExpressionSize(&Function{
+		Name: "xgb.Pad",
+		Expr: &BinaryOp{
+			Op:    "*",
+			Expr1: &Value{v: 4},
+			Expr2: &PopCount{
+				Expr: &Function{
+					Name: "int",
+					Expr: &FieldRef{
+						Name: f.MaskName,
+					},
+				},
+			},
+		},
+	}, true)
+	return maskSize.Add(listSize)
+}
+
+func (f *ValueField) ListLength() Size {
+	return newExpressionSize(&PopCount{
+		Expr: &Function{
+			Name: "int",
+			Expr: &FieldRef{
+				Name: f.MaskName,
+			},
+		},
+	}, true)
+}
+
+func (f *ValueField) Initialize(p *Protocol) {
+	f.MaskType = f.MaskType.(*Translation).RealType(p)
+	f.MaskName = SrcName(p, f.MaskName)
+	f.ListName = SrcName(p, f.ListName)
+}
+
+// SwitchField represents a 'switch' element in the XML protocol description
+// file.
+// Currently we translate this to a slice of uint32 and let the user sort
+// through it.
+type SwitchField struct {
+	xmlName  string
+	Name     string
+	MaskName string
+	Expr     Expression
+	Bitcases []*Bitcase
+	Comment  string
+}
+
+func (f *SwitchField) SrcName() string {
+	return f.Name
+}
+
+func (f *SwitchField) XmlName() string {
+	return f.xmlName
+}
+
+func (f *SwitchField) SrcType() string {
+	return "[]uint32"
+}
+
+func (f *SwitchField) Size() Size {
+	// TODO: size expression used here is not correct unless every element of
+	// the switch is 32 bit long. This assumption holds for xproto but may not
+	// hold for other protocols (xkb?)
+
+	listSize := newExpressionSize(&Function{
+		Name: "xgb.Pad",
+		Expr: &BinaryOp{
+			Op:    "*",
+			Expr1: &Value{v: 4},
+			Expr2: &PopCount{
+				Expr: &Function{
+					Name: "int",
+					Expr: &FieldRef{
+						Name: f.MaskName,
+					},
+				},
+			},
+		},
+	}, true)
+
+	return listSize
+}
+
+func (f *SwitchField) ListLength() Size {
+	return newExpressionSize(&PopCount{
+		Expr: &Function{
+			Name: "int",
+			Expr: &FieldRef{
+				Name: f.MaskName,
+			},
+		},
+	}, true)
+}
+
+func (f *SwitchField) Initialize(p *Protocol) {
+	f.xmlName = f.Name
+	f.Name = SrcName(p, f.Name)
+	f.Expr.Initialize(p)
+	fieldref, ok := f.Expr.(*FieldRef)
+	if !ok {
+		panic("switch field's expression not a fieldref")
+	}
+	f.MaskName = SrcName(p, fieldref.Name)
+	for _, bitcase := range f.Bitcases {
+		bitcase.Expr.Initialize(p)
+		for _, field := range bitcase.Fields {
+			field.Initialize(p)
+		}
+	}
+}
+
+// Bitcase represents a single bitcase inside a switch expression.
+// It is not currently used. (i.e., it's XKB voodoo.)
+type Bitcase struct {
+	Fields []Field
+	Expr   Expression
+}

nexgb/xgbgen/go.go

@@ -0,0 +1,229 @@
+package main
+
+import (
+	"fmt"
+)
+
+// BaseTypeMap is a map from X base types to Go types.
+// X base types should correspond to the smallest set of X types
+// that can be used to rewrite ALL X types in terms of Go types.
+// That is, if you remove any of the following types, at least one
+// XML protocol description will produce an invalid Go program.
+// The types on the left *never* show themselves in the source.
+var BaseTypeMap = map[string]string{
+	"CARD8":  "byte",
+	"CARD16": "uint16",
+	"CARD32": "uint32",
+	"INT8":   "int8",
+	"INT16":  "int16",
+	"INT32":  "int32",
+	"BYTE":   "byte",
+	"BOOL":   "bool",
+	"float":  "float64",
+	"double": "float64",
+	"char":   "byte",
+	"void":   "byte",
+}
+
+// BaseTypeSizes should have precisely the same keys as in BaseTypeMap,
+// and the values should correspond to the size of the type in bytes.
+var BaseTypeSizes = map[string]uint{
+	"CARD8":  1,
+	"CARD16": 2,
+	"CARD32": 4,
+	"INT8":   1,
+	"INT16":  2,
+	"INT32":  4,
+	"BYTE":   1,
+	"BOOL":   1,
+	"float":  4,
+	"double": 8,
+	"char":   1,
+	"void":   1,
+
+	// Id is a special type used to determine the size of all Xid types.
+	// "Id" is not actually written in the source.
+	"Id": 4,
+}
+
+// TypeMap is a map from types in the XML to type names that is used
+// in the functions that follow. Basically, every occurrence of the key
+// type is replaced with the value type.
+var TypeMap = map[string]string{
+	"VISUALTYPE": "VisualInfo",
+	"DEPTH":      "DepthInfo",
+	"SCREEN":     "ScreenInfo",
+	"Setup":      "SetupInfo",
+}
+
+// NameMap is the same as TypeMap, but for names.
+var NameMap = map[string]string{}
+
+// Reading, writing and defining...
+
+// Base types
+func (b *Base) Define(c *Context) {
+	c.Putln("// Skipping definition for base type '%s'",
+		SrcName(c.protocol, b.XmlName()))
+	c.Putln("")
+}
+
+// Enum types
+func (enum *Enum) Define(c *Context) {
+	c.Putln("const (")
+	for _, item := range enum.Items {
+		c.Putln("%s%s = %d", enum.SrcName(), item.srcName, item.Expr.Eval())
+	}
+	c.Putln(")")
+	c.Putln("")
+}
+
+// Resource types
+func (res *Resource) Define(c *Context) {
+	c.Putln("type %s uint32", res.SrcName())
+	c.Putln("")
+	c.Putln("func New%sId(c *xgb.Conn) (%s, error) {",
+		res.SrcName(), res.SrcName())
+	c.Putln("id, err := c.NewId()")
+	c.Putln("if err != nil {")
+	c.Putln("return 0, err")
+	c.Putln("}")
+	c.Putln("return %s(id), nil", res.SrcName())
+	c.Putln("}")
+	c.Putln("")
+}
+
+// TypeDef types
+func (td *TypeDef) Define(c *Context) {
+	c.Putln("type %s %s", td.srcName, td.Old.SrcName())
+	c.Putln("")
+}
+
+// Field definitions, reads and writes.
+
+// Pad fields
+func (f *PadField) Define(c *Context) {
+	if f.Align > 0 {
+		c.Putln("// alignment gap to multiple of %d", f.Align)
+	} else {
+		c.Putln("// padding: %d bytes", f.Bytes)
+	}
+}
+
+func (f *PadField) Read(c *Context, prefix string) {
+	if f.Align > 0 {
+		c.Putln("b = (b + %d) & ^%d // alignment gap", f.Align-1, f.Align-1)
+	} else {
+		c.Putln("b += %s // padding", f.Size())
+	}
+}
+
+func (f *PadField) Write(c *Context, prefix string) {
+	if f.Align > 0 {
+		c.Putln("b = (b + %d) & ^%d // alignment gap", f.Align-1, f.Align-1)
+	} else {
+		c.Putln("b += %s // padding", f.Size())
+	}
+}
+
+// Local fields
+func (f *LocalField) Define(c *Context) {
+	c.Putln("// local field: %s %s", f.SrcName(), f.Type.SrcName())
+	panic("unreachable")
+}
+
+func (f *LocalField) Read(c *Context, prefix string) {
+	c.Putln("// reading local field: %s (%s) :: %s",
+		f.SrcName(), f.Size(), f.Type.SrcName())
+	panic("unreachable")
+}
+
+func (f *LocalField) Write(c *Context, prefix string) {
+	c.Putln("// skip writing local field: %s (%s) :: %s",
+		f.SrcName(), f.Size(), f.Type.SrcName())
+}
+
+// Expr fields
+func (f *ExprField) Define(c *Context) {
+	c.Putln("// expression field: %s %s (%s)",
+		f.SrcName(), f.Type.SrcName(), f.Expr)
+	panic("unreachable")
+}
+
+func (f *ExprField) Read(c *Context, prefix string) {
+	c.Putln("// reading expression field: %s (%s) (%s) :: %s",
+		f.SrcName(), f.Size(), f.Expr, f.Type.SrcName())
+	panic("unreachable")
+}
+
+func (f *ExprField) Write(c *Context, prefix string) {
+	// Special case for bools, grrr.
+	if f.Type.SrcName() == "bool" {
+		c.Putln("buf[b] = byte(%s)", f.Expr.Reduce(prefix))
+		c.Putln("b += 1")
+	} else {
+		WriteSimpleSingleField(c, f.Expr.Reduce(prefix), f.Type)
+	}
+}
+
+// Value field
+func (f *ValueField) Define(c *Context) {
+	if f.MaskComment != "" {
+		c.PutComment(f.MaskComment)
+	}
+	c.Putln("%s %s", f.MaskName, f.SrcType())
+	if f.ListComment != "" {
+		c.PutComment(f.ListComment)
+	}
+	c.Putln("%s []uint32", f.ListName)
+}
+
+func (f *ValueField) Read(c *Context, prefix string) {
+	ReadSimpleSingleField(c,
+		fmt.Sprintf("%s%s", prefix, f.MaskName), f.MaskType)
+	c.Putln("")
+	c.Putln("%s%s = make([]uint32, %s)",
+		prefix, f.ListName, f.ListLength().Reduce(prefix))
+	c.Putln("for i := 0; i < %s; i++ {", f.ListLength().Reduce(prefix))
+	c.Putln("%s%s[i] = xgb.Get32(buf[b:])", prefix, f.ListName)
+	c.Putln("b += 4")
+	c.Putln("}")
+	c.Putln("b = xgb.Pad(b)")
+}
+
+func (f *ValueField) Write(c *Context, prefix string) {
+	WriteSimpleSingleField(c,
+		fmt.Sprintf("%s%s", prefix, f.MaskName), f.MaskType)
+	c.Putln("for i := 0; i < %s; i++ {", f.ListLength().Reduce(prefix))
+	c.Putln("xgb.Put32(buf[b:], %s%s[i])", prefix, f.ListName)
+	c.Putln("b += 4")
+	c.Putln("}")
+	c.Putln("b = xgb.Pad(b)")
+}
+
+// Switch field
+func (f *SwitchField) Define(c *Context) {
+	if f.Comment != "" {
+		c.PutComment(f.Comment)
+	}
+	c.Putln("%s []uint32", f.Name)
+}
+
+func (f *SwitchField) Read(c *Context, prefix string) {
+	c.Putln("")
+	c.Putln("%s%s = make([]uint32, %s)",
+		prefix, f.Name, f.ListLength().Reduce(prefix))
+	c.Putln("for i := 0; i < %s; i++ {", f.ListLength().Reduce(prefix))
+	c.Putln("%s%s[i] = xgb.Get32(buf[b:])", prefix, f.Name)
+	c.Putln("b += 4")
+	c.Putln("}")
+	c.Putln("b = xgb.Pad(b)")
+}
+
+func (f *SwitchField) Write(c *Context, prefix string) {
+	c.Putln("for i := 0; i < %s; i++ {", f.ListLength().Reduce(prefix))
+	c.Putln("xgb.Put32(buf[b:], %s%s[i])", prefix, f.Name)
+	c.Putln("b += 4")
+	c.Putln("}")
+	c.Putln("b = xgb.Pad(b)")
+}

nexgb/xgbgen/go_error.go

@@ -0,0 +1,179 @@
+package main
+
+import (
+	"fmt"
+)
+
+// Error types
+func (e *Error) Define(c *Context) {
+	c.Putln("// %s is the error number for a %s.", e.ErrConst(), e.ErrConst())
+	c.Putln("const %s = %d", e.ErrConst(), e.Number)
+	c.Putln("")
+	c.Putln("type %s struct {", e.ErrType())
+	c.Putln("Sequence uint16")
+	c.Putln("NiceName string")
+	for _, field := range e.Fields {
+		field.Define(c)
+	}
+	c.Putln("}")
+	c.Putln("")
+
+	// Read defines a function that transforms a byte slice into this
+	// error struct.
+	e.Read(c)
+
+	// Makes sure this error type implements the xgb.Error interface.
+	e.ImplementsError(c)
+
+	// Let's the XGB event loop read this error.
+	c.Putln("func init() {")
+	if c.protocol.isExt() {
+		c.Putln("xgb.NewExtErrorFuncs[\"%s\"][%d] = %sNew",
+			c.protocol.ExtXName, e.Number, e.ErrType())
+	} else {
+		c.Putln("xgb.NewErrorFuncs[%d] = %sNew", e.Number, e.ErrType())
+	}
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (e *Error) Read(c *Context) {
+	c.Putln("// %sNew constructs a %s value that implements xgb.Error from "+
+		"a byte slice.", e.ErrType(), e.ErrType())
+	c.Putln("func %sNew(buf []byte) xgb.Error {", e.ErrType())
+	c.Putln("v := %s{}", e.ErrType())
+	c.Putln("v.NiceName = \"%s\"", e.SrcName())
+	c.Putln("")
+	c.Putln("b := 1 // skip error determinant")
+	c.Putln("b += 1 // don't read error number")
+	c.Putln("")
+	c.Putln("v.Sequence = xgb.Get16(buf[b:])")
+	c.Putln("b += 2")
+	c.Putln("")
+	for _, field := range e.Fields {
+		field.Read(c, "v.")
+		c.Putln("")
+	}
+	c.Putln("return v")
+	c.Putln("}")
+	c.Putln("")
+}
+
+// ImplementsError writes functions to implement the XGB Error interface.
+func (e *Error) ImplementsError(c *Context) {
+	c.Putln("// SequenceId returns the sequence id attached to the %s error.",
+		e.ErrConst())
+	c.Putln("// This is mostly used internally.")
+	c.Putln("func (err %s) SequenceId() uint16 {", e.ErrType())
+	c.Putln("return err.Sequence")
+	c.Putln("}")
+	c.Putln("")
+	c.Putln("// BadId returns the 'BadValue' number if one exists for the "+
+		"%s error. If no bad value exists, 0 is returned.", e.ErrConst())
+	c.Putln("func (err %s) BadId() uint32 {", e.ErrType())
+	if !c.protocol.isExt() {
+		c.Putln("return err.BadValue")
+	} else {
+		c.Putln("return 0")
+	}
+	c.Putln("}")
+	c.Putln("// Error returns a rudimentary string representation of the %s "+
+		"error.", e.ErrConst())
+	c.Putln("")
+	c.Putln("func (err %s) Error() string {", e.ErrType())
+	ErrorFieldString(c, e.Fields, e.ErrConst())
+	c.Putln("}")
+	c.Putln("")
+}
+
+// ErrorCopy types
+func (e *ErrorCopy) Define(c *Context) {
+	c.Putln("// %s is the error number for a %s.", e.ErrConst(), e.ErrConst())
+	c.Putln("const %s = %d", e.ErrConst(), e.Number)
+	c.Putln("")
+	c.Putln("type %s %s", e.ErrType(), e.Old.(*Error).ErrType())
+	c.Putln("")
+
+	// Read defines a function that transforms a byte slice into this
+	// error struct.
+	e.Read(c)
+
+	// Makes sure this error type implements the xgb.Error interface.
+	e.ImplementsError(c)
+
+	// Let's the XGB know how to read this error.
+	c.Putln("func init() {")
+	if c.protocol.isExt() {
+		c.Putln("xgb.NewExtErrorFuncs[\"%s\"][%d] = %sNew",
+			c.protocol.ExtXName, e.Number, e.ErrType())
+	} else {
+		c.Putln("xgb.NewErrorFuncs[%d] = %sNew", e.Number, e.ErrType())
+	}
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (e *ErrorCopy) Read(c *Context) {
+	c.Putln("// %sNew constructs a %s value that implements xgb.Error from "+
+		"a byte slice.", e.ErrType(), e.ErrType())
+	c.Putln("func %sNew(buf []byte) xgb.Error {", e.ErrType())
+	c.Putln("v := %s(%sNew(buf).(%s))",
+		e.ErrType(), e.Old.(*Error).ErrType(), e.Old.(*Error).ErrType())
+	c.Putln("v.NiceName = \"%s\"", e.SrcName())
+	c.Putln("return v")
+	c.Putln("}")
+	c.Putln("")
+}
+
+// ImplementsError writes functions to implement the XGB Error interface.
+func (e *ErrorCopy) ImplementsError(c *Context) {
+	c.Putln("// SequenceId returns the sequence id attached to the %s error.",
+		e.ErrConst())
+	c.Putln("// This is mostly used internally.")
+	c.Putln("func (err %s) SequenceId() uint16 {", e.ErrType())
+	c.Putln("return err.Sequence")
+	c.Putln("}")
+	c.Putln("")
+	c.Putln("// BadId returns the 'BadValue' number if one exists for the "+
+		"%s error. If no bad value exists, 0 is returned.", e.ErrConst())
+	c.Putln("func (err %s) BadId() uint32 {", e.ErrType())
+	if !c.protocol.isExt() {
+		c.Putln("return err.BadValue")
+	} else {
+		c.Putln("return 0")
+	}
+	c.Putln("}")
+	c.Putln("")
+	c.Putln("// Error returns a rudimentary string representation of the %s "+
+		"error.", e.ErrConst())
+	c.Putln("func (err %s) Error() string {", e.ErrType())
+	ErrorFieldString(c, e.Old.(*Error).Fields, e.ErrConst())
+	c.Putln("}")
+	c.Putln("")
+}
+
+// ErrorFieldString works for both Error and ErrorCopy. It assembles all of the
+// fields in an error and formats them into a single string.
+func ErrorFieldString(c *Context, fields []Field, errName string) {
+	c.Putln("fieldVals := make([]string, 0, %d)", len(fields))
+	c.Putln("fieldVals = append(fieldVals, \"NiceName: \" + err.NiceName)")
+	c.Putln("fieldVals = append(fieldVals, "+
+		"xgb.Sprintf(\"Sequence: %s\", err.Sequence))", "%d")
+	for _, field := range fields {
+		switch field.(type) {
+		case *PadField:
+			continue
+		default:
+			if field.SrcType() == "string" {
+				c.Putln("fieldVals = append(fieldVals, \"%s: \" + err.%s)",
+					field.SrcName(), field.SrcName())
+			} else {
+				format := fmt.Sprintf("xgb.Sprintf(\"%s: %s\", err.%s)",
+					field.SrcName(), "%d", field.SrcName())
+				c.Putln("fieldVals = append(fieldVals, %s)", format)
+			}
+		}
+	}
+	c.Putln("return \"%s {\" + xgb.StringsJoin(fieldVals, \", \") + \"}\"",
+		errName)
+}

nexgb/xgbgen/go_event.go

@@ -0,0 +1,209 @@
+package main
+
+import (
+	"fmt"
+)
+
+// Event types
+func (e *Event) Define(c *Context) {
+	c.Putln("// %s is the event number for a %s.", e.SrcName(), e.EvType())
+	c.Putln("const %s = %d", e.SrcName(), e.Number)
+	c.Putln("")
+	c.Putln("type %s struct {", e.EvType())
+	if !e.NoSequence {
+		c.Putln("Sequence uint16")
+	}
+	for _, field := range e.Fields {
+		field.Define(c)
+	}
+	c.Putln("}")
+	c.Putln("")
+
+	// Read defines a function that transforms a byte slice into this
+	// event struct.
+	e.Read(c)
+
+	// Write defines a function that transforms this event struct into
+	// a byte slice.
+	e.Write(c)
+
+	// Makes sure that this event type is an Event interface.
+	c.Putln("// SequenceId returns the sequence id attached to the %s event.",
+		e.SrcName())
+	c.Putln("// Events without a sequence number (KeymapNotify) return 0.")
+	c.Putln("// This is mostly used internally.")
+	c.Putln("func (v %s) SequenceId() uint16 {", e.EvType())
+	if e.NoSequence {
+		c.Putln("return uint16(0)")
+	} else {
+		c.Putln("return v.Sequence")
+	}
+	c.Putln("}")
+	c.Putln("")
+	c.Putln("// String is a rudimentary string representation of %s.",
+		e.EvType())
+	c.Putln("func (v %s) String() string {", e.EvType())
+	EventFieldString(c, e.Fields, e.SrcName())
+	c.Putln("}")
+	c.Putln("")
+
+	// Let's the XGB event loop read this event.
+	c.Putln("func init() {")
+	if c.protocol.isExt() {
+		c.Putln("xgb.NewExtEventFuncs[\"%s\"][%d] = %sNew",
+			c.protocol.ExtXName, e.Number, e.EvType())
+	} else {
+		c.Putln("xgb.NewEventFuncs[%d] = %sNew", e.Number, e.EvType())
+	}
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (e *Event) Read(c *Context) {
+	c.Putln("// %sNew constructs a %s value that implements xgb.Event from "+
+		"a byte slice.", e.EvType(), e.EvType())
+	c.Putln("func %sNew(buf []byte) xgb.Event {", e.EvType())
+	c.Putln("v := %s{}", e.EvType())
+	c.Putln("b := 1 // don't read event number")
+	c.Putln("")
+	for i, field := range e.Fields {
+		if i == 1 && !e.NoSequence {
+			c.Putln("v.Sequence = xgb.Get16(buf[b:])")
+			c.Putln("b += 2")
+			c.Putln("")
+		}
+		field.Read(c, "v.")
+		c.Putln("")
+	}
+	c.Putln("return v")
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (e *Event) Write(c *Context) {
+	c.Putln("// Bytes writes a %s value to a byte slice.", e.EvType())
+	c.Putln("func (v %s) Bytes() []byte {", e.EvType())
+	c.Putln("buf := make([]byte, %s)", e.Size())
+	c.Putln("b := 0")
+	c.Putln("")
+	c.Putln("// write event number")
+	c.Putln("buf[b] = %d", e.Number)
+	c.Putln("b += 1")
+	c.Putln("")
+	for i, field := range e.Fields {
+		if i == 1 && !e.NoSequence {
+			c.Putln("b += 2 // skip sequence number")
+			c.Putln("")
+		}
+		field.Write(c, "v.")
+		c.Putln("")
+	}
+	c.Putln("return buf")
+	c.Putln("}")
+	c.Putln("")
+}
+
+// EventCopy types
+func (e *EventCopy) Define(c *Context) {
+	c.Putln("// %s is the event number for a %s.", e.SrcName(), e.EvType())
+	c.Putln("const %s = %d", e.SrcName(), e.Number)
+	c.Putln("")
+	c.Putln("type %s %s", e.EvType(), e.Old.(*Event).EvType())
+	c.Putln("")
+
+	// Read defines a function that transforms a byte slice into this
+	// event struct.
+	e.Read(c)
+
+	// Write defines a function that transoforms this event struct into
+	// a byte slice.
+	e.Write(c)
+
+	// Makes sure that this event type is an Event interface.
+	c.Putln("// SequenceId returns the sequence id attached to the %s event.",
+		e.SrcName())
+	c.Putln("// Events without a sequence number (KeymapNotify) return 0.")
+	c.Putln("// This is mostly used internally.")
+	c.Putln("func (v %s) SequenceId() uint16 {", e.EvType())
+	if e.Old.(*Event).NoSequence {
+		c.Putln("return uint16(0)")
+	} else {
+		c.Putln("return v.Sequence")
+	}
+	c.Putln("}")
+	c.Putln("")
+	c.Putln("func (v %s) String() string {", e.EvType())
+	EventFieldString(c, e.Old.(*Event).Fields, e.SrcName())
+	c.Putln("}")
+	c.Putln("")
+
+	// Let's the XGB event loop read this event.
+	c.Putln("func init() {")
+	if c.protocol.isExt() {
+		c.Putln("xgb.NewExtEventFuncs[\"%s\"][%d] = %sNew",
+			c.protocol.ExtXName, e.Number, e.EvType())
+	} else {
+		c.Putln("xgb.NewEventFuncs[%d] = %sNew", e.Number, e.EvType())
+	}
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (e *EventCopy) Read(c *Context) {
+	c.Putln("// %sNew constructs a %s value that implements xgb.Event from "+
+		"a byte slice.", e.EvType(), e.EvType())
+	c.Putln("func %sNew(buf []byte) xgb.Event {", e.EvType())
+	c.Putln("return %s(%sNew(buf).(%s))",
+		e.EvType(), e.Old.(*Event).EvType(), e.Old.(*Event).EvType())
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (e *EventCopy) Write(c *Context) {
+	c.Putln("// Bytes writes a %s value to a byte slice.", e.EvType())
+	c.Putln("func (v %s) Bytes() []byte {", e.EvType())
+	c.Putln("return %s(v).Bytes()", e.Old.(*Event).EvType())
+	c.Putln("}")
+	c.Putln("")
+}
+
+// EventFieldString works for both Event and EventCopy. It assembles all of the
+// fields in an event and formats them into a single string.
+func EventFieldString(c *Context, fields []Field, evName string) {
+	c.Putln("fieldVals := make([]string, 0, %d)", len(fields))
+	if evName != "KeymapNotify" {
+		c.Putln("fieldVals = append(fieldVals, "+
+			"xgb.Sprintf(\"Sequence: %s\", v.Sequence))", "%d")
+	}
+	for _, field := range fields {
+		switch f := field.(type) {
+		case *PadField:
+			continue
+		case *SingleField:
+			switch f.Type.(type) {
+			case *Base:
+			case *Resource:
+			case *TypeDef:
+			default:
+				continue
+			}
+
+			switch field.SrcType() {
+			case "string":
+				format := fmt.Sprintf("xgb.Sprintf(\"%s: %s\", v.%s)",
+					field.SrcName(), "%s", field.SrcName())
+				c.Putln("fieldVals = append(fieldVals, %s)", format)
+			case "bool":
+				format := fmt.Sprintf("xgb.Sprintf(\"%s: %s\", v.%s)",
+					field.SrcName(), "%t", field.SrcName())
+				c.Putln("fieldVals = append(fieldVals, %s)", format)
+			default:
+				format := fmt.Sprintf("xgb.Sprintf(\"%s: %s\", v.%s)",
+					field.SrcName(), "%d", field.SrcName())
+				c.Putln("fieldVals = append(fieldVals, %s)", format)
+			}
+		}
+	}
+	c.Putln("return \"%s {\" + xgb.StringsJoin(fieldVals, \", \") + \"}\"",
+		evName)
+}

nexgb/xgbgen/go_list.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"strings"
+)
+
+// List fields
+func (f *ListField) Define(c *Context) {
+	c.Putln("%s %s // size: %s",
+		f.SrcName(), f.SrcType(), f.Size())
+}
+
+func (f *ListField) Read(c *Context, prefix string) {
+	switch t := f.Type.(type) {
+	case *Resource:
+		length := f.LengthExpr.Reduce(prefix)
+		c.Putln("%s%s = make([]%s, %s)",
+			prefix, f.SrcName(), t.SrcName(), length)
+		c.Putln("for i := 0; i < int(%s); i++ {", length)
+		ReadSimpleSingleField(c, fmt.Sprintf("%s%s[i]", prefix, f.SrcName()), t)
+		c.Putln("}")
+	case *Base:
+		length := f.LengthExpr.Reduce(prefix)
+		if strings.ToLower(t.XmlName()) == "char" {
+			c.Putln("{")
+			c.Putln("byteString := make([]%s, %s)", t.SrcName(), length)
+			c.Putln("copy(byteString[:%s], buf[b:])", length)
+			c.Putln("%s%s = string(byteString)", prefix, f.SrcName())
+			// This is apparently a special case. The "Str" type itself
+			// doesn't specify any padding. I suppose it's up to the
+			// request/reply spec that uses it to get the padding right?
+			c.Putln("b += int(%s)", length)
+			c.Putln("}")
+		} else if t.SrcName() == "byte" {
+			c.Putln("%s%s = make([]%s, %s)",
+				prefix, f.SrcName(), t.SrcName(), length)
+			c.Putln("copy(%s%s[:%s], buf[b:])", prefix, f.SrcName(), length)
+			c.Putln("b += int(%s)", length)
+		} else {
+			c.Putln("%s%s = make([]%s, %s)",
+				prefix, f.SrcName(), t.SrcName(), length)
+			c.Putln("for i := 0; i < int(%s); i++ {", length)
+			ReadSimpleSingleField(c,
+				fmt.Sprintf("%s%s[i]", prefix, f.SrcName()), t)
+			c.Putln("}")
+		}
+	case *TypeDef:
+		length := f.LengthExpr.Reduce(prefix)
+		c.Putln("%s%s = make([]%s, %s)",
+			prefix, f.SrcName(), t.SrcName(), length)
+		c.Putln("for i := 0; i < int(%s); i++ {", length)
+		ReadSimpleSingleField(c, fmt.Sprintf("%s%s[i]", prefix, f.SrcName()), t)
+		c.Putln("}")
+	case *Union:
+		c.Putln("%s%s = make([]%s, %s)",
+			prefix, f.SrcName(), t.SrcName(), f.LengthExpr.Reduce(prefix))
+		c.Putln("b += %sReadList(buf[b:], %s%s)",
+			t.SrcName(), prefix, f.SrcName())
+	case *Struct:
+		c.Putln("%s%s = make([]%s, %s)",
+			prefix, f.SrcName(), t.SrcName(), f.LengthExpr.Reduce(prefix))
+		c.Putln("b += %sReadList(buf[b:], %s%s)",
+			t.SrcName(), prefix, f.SrcName())
+	default:
+		log.Panicf("Cannot read list field '%s' with %T type.",
+			f.XmlName(), f.Type)
+	}
+}
+
+func (f *ListField) Write(c *Context, prefix string) {
+	switch t := f.Type.(type) {
+	case *Resource:
+		length := f.Length().Reduce(prefix)
+		c.Putln("for i := 0; i < int(%s); i++ {", length)
+		WriteSimpleSingleField(c,
+			fmt.Sprintf("%s%s[i]", prefix, f.SrcName()), t)
+		c.Putln("}")
+	case *Base:
+		length := f.Length().Reduce(prefix)
+		if t.SrcName() == "byte" {
+			c.Putln("copy(buf[b:], %s%s[:%s])", prefix, f.SrcName(), length)
+			c.Putln("b += int(%s)", length)
+		} else {
+			c.Putln("for i := 0; i < int(%s); i++ {", length)
+			WriteSimpleSingleField(c,
+				fmt.Sprintf("%s%s[i]", prefix, f.SrcName()), t)
+			c.Putln("}")
+		}
+	case *TypeDef:
+		length := f.Length().Reduce(prefix)
+		c.Putln("for i := 0; i < int(%s); i++ {", length)
+		WriteSimpleSingleField(c,
+			fmt.Sprintf("%s%s[i]", prefix, f.SrcName()), t)
+		c.Putln("}")
+	case *Union:
+		c.Putln("b += %sListBytes(buf[b:], %s%s)",
+			t.SrcName(), prefix, f.SrcName())
+	case *Struct:
+		c.Putln("b += %sListBytes(buf[b:], %s%s)",
+			t.SrcName(), prefix, f.SrcName())
+	default:
+		log.Panicf("Cannot write list field '%s' with %T type.",
+			f.XmlName(), f.Type)
+	}
+}

nexgb/xgbgen/go_request_reply.go

@@ -0,0 +1,288 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+func (r *Request) Define(c *Context) {
+	c.Putln("// %s is a cookie used only for %s requests.",
+		r.CookieName(), r.SrcName())
+	c.Putln("type %s struct {", r.CookieName())
+	c.Putln("*xgb.Cookie")
+	c.Putln("}")
+	c.Putln("")
+
+	if r.Doc.Description != "" {
+		c.PutComment(r.Doc.Description)
+		c.Putln("//")
+	}
+
+	allErrors := make([]string, 0, len(r.Doc.Errors))
+	for kind := range r.Doc.Errors {
+		allErrors = append(allErrors, kind)
+	}
+	sort.Strings(allErrors)
+
+	undocErrors := make([]string, 0)
+	for _, kind := range allErrors {
+		if desc := r.Doc.Errors[kind]; desc == "" {
+			undocErrors = append(undocErrors, kind)
+		} else {
+			c.PutComment(fmt.Sprintf("May return a %s error if %s%s", kind,
+				strings.ToLower(desc[:1]), desc[1:]))
+			c.Putln("//")
+		}
+	}
+	if len(undocErrors) > 0 {
+		c.Putln("// May return %s errors.", strings.Join(undocErrors, ", "))
+		c.Putln("//")
+	}
+
+	if r.Reply != nil {
+		c.Putln("// %s sends a checked request.", r.SrcName())
+		c.Putln("// If an error occurs, it will be returned with the reply "+
+			"by calling %s.Reply.", r.CookieName())
+		c.Putln("func %s(c *xgb.Conn, %s) %s {",
+			r.SrcName(), r.ParamNameTypes(), r.CookieName())
+		r.CheckExt(c)
+		c.Putln("cookie := c.NewCookie(true, true)")
+		c.Putln("c.NewRequest(%s(c, %s), cookie)", r.ReqName(), r.ParamNames())
+		c.Putln("return %s{cookie}", r.CookieName())
+		c.Putln("}")
+		c.Putln("")
+
+		c.Putln("// %sUnchecked sends an unchecked request.", r.SrcName())
+		c.Putln("// If an error occurs, it can only be retrieved using " +
+			"xgb.WaitForEvent or xgb.PollForEvent.")
+		c.Putln("func %sUnchecked(c *xgb.Conn, %s) %s {",
+			r.SrcName(), r.ParamNameTypes(), r.CookieName())
+		r.CheckExt(c)
+		c.Putln("cookie := c.NewCookie(false, true)")
+		c.Putln("c.NewRequest(%s(c, %s), cookie)", r.ReqName(), r.ParamNames())
+		c.Putln("return %s{cookie}", r.CookieName())
+		c.Putln("}")
+		c.Putln("")
+
+		r.ReadReply(c)
+	} else {
+		c.Putln("// %s sends an unchecked request.", r.SrcName())
+		c.Putln("// If an error occurs, it can only be retrieved using " +
+			"xgb.WaitForEvent or xgb.PollForEvent.")
+		c.Putln("func %s(c *xgb.Conn, %s) %s {",
+			r.SrcName(), r.ParamNameTypes(), r.CookieName())
+		r.CheckExt(c)
+		c.Putln("cookie := c.NewCookie(false, false)")
+		c.Putln("c.NewRequest(%s(c, %s), cookie)", r.ReqName(), r.ParamNames())
+		c.Putln("return %s{cookie}", r.CookieName())
+		c.Putln("}")
+		c.Putln("")
+
+		c.Putln("// %sChecked sends a checked request.", r.SrcName())
+		c.Putln("// If an error occurs, it can be retrieved using "+
+			"%s.Check.", r.CookieName())
+		c.Putln("func %sChecked(c *xgb.Conn, %s) %s {",
+			r.SrcName(), r.ParamNameTypes(), r.CookieName())
+		r.CheckExt(c)
+		c.Putln("cookie := c.NewCookie(true, false)")
+		c.Putln("c.NewRequest(%s(c, %s), cookie)", r.ReqName(), r.ParamNames())
+		c.Putln("return %s{cookie}", r.CookieName())
+		c.Putln("}")
+		c.Putln("")
+
+		c.Putln("// Check returns an error if one occurred for checked " +
+			"requests that are not expecting a reply.")
+		c.Putln("// This cannot be called for requests expecting a reply, " +
+			"nor for unchecked requests.")
+		c.Putln("func (cook %s) Check() error {", r.CookieName())
+		c.Putln("return cook.Cookie.Check()")
+		c.Putln("}")
+		c.Putln("")
+	}
+	r.WriteRequest(c)
+}
+
+func (r *Request) CheckExt(c *Context) {
+	if !c.protocol.isExt() {
+		return
+	}
+	c.Putln("c.ExtLock.RLock()")
+	c.Putln("defer c.ExtLock.RUnlock()")
+	c.Putln("if _, ok := c.Extensions[\"%s\"]; !ok {", c.protocol.ExtXName)
+	c.Putln("panic(\"Cannot issue request '%s' using the uninitialized "+
+		"extension '%s'. %s.Init(connObj) must be called first.\")",
+		r.SrcName(), c.protocol.ExtXName, c.protocol.PkgName())
+	c.Putln("}")
+}
+
+func (r *Request) ReadReply(c *Context) {
+	c.Putln("// %s represents the data returned from a %s request.",
+		r.ReplyTypeName(), r.SrcName())
+	c.Putln("type %s struct {", r.ReplyTypeName())
+	c.Putln("Sequence uint16 // sequence number of the request for this reply")
+	c.Putln("Length uint32 // number of bytes in this reply")
+	for _, field := range r.Reply.Fields {
+		field.Define(c)
+	}
+	c.Putln("}")
+	c.Putln("")
+
+	c.Putln("// Reply blocks and returns the reply data for a %s request.",
+		r.SrcName())
+	c.Putln("func (cook %s) Reply() (*%s, error) {",
+		r.CookieName(), r.ReplyTypeName())
+	c.Putln("buf, err := cook.Cookie.Reply()")
+	c.Putln("if err != nil {")
+	c.Putln("return nil, err")
+	c.Putln("}")
+	c.Putln("if buf == nil {")
+	c.Putln("return nil, nil")
+	c.Putln("}")
+	c.Putln("return %s(buf), nil", r.ReplyName())
+	c.Putln("}")
+	c.Putln("")
+
+	c.Putln("// %s reads a byte slice into a %s value.",
+		r.ReplyName(), r.ReplyTypeName())
+	c.Putln("func %s(buf []byte) *%s {",
+		r.ReplyName(), r.ReplyTypeName())
+	c.Putln("v := new(%s)", r.ReplyTypeName())
+	c.Putln("b := 1 // skip reply determinant")
+	c.Putln("")
+	for i, field := range r.Reply.Fields {
+		field.Read(c, "v.")
+		c.Putln("")
+		if i == 0 {
+			c.Putln("v.Sequence = xgb.Get16(buf[b:])")
+			c.Putln("b += 2")
+			c.Putln("")
+			c.Putln("v.Length = xgb.Get32(buf[b:]) // 4-byte units")
+			c.Putln("b += 4")
+			c.Putln("")
+		}
+	}
+	c.Putln("return v")
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (r *Request) WriteRequest(c *Context) {
+	sz := r.Size(c)
+	writeSize1 := func() {
+		if sz.exact {
+			c.Putln("xgb.Put16(buf[b:], uint16(size / 4)) " +
+				"// write request size in 4-byte units")
+		} else {
+			c.Putln("blen := b")
+		}
+		c.Putln("b += 2")
+		c.Putln("")
+	}
+	writeSize2 := func() {
+		if sz.exact {
+			c.Putln("return buf")
+			return
+		}
+		c.Putln("b = xgb.Pad(b)")
+		c.Putln("xgb.Put16(buf[blen:], uint16(b / 4)) " +
+			"// write request size in 4-byte units")
+		c.Putln("return buf[:b]")
+	}
+	c.Putln("// %s writes a %s request to a byte slice for transfer.",
+		r.ReqName(), r.SrcName())
+	c.Putln("func %s(c *xgb.Conn, %s) []byte {",
+		r.ReqName(), r.ParamNameTypes())
+	c.Putln("size := %s", sz)
+	c.Putln("b := 0")
+	c.Putln("buf := make([]byte, size)")
+	c.Putln("")
+	if c.protocol.isExt() {
+		c.Putln("c.ExtLock.RLock()")
+		c.Putln("buf[b] = c.Extensions[\"%s\"]", c.protocol.ExtXName)
+		c.Putln("c.ExtLock.RUnlock()")
+		c.Putln("b += 1")
+		c.Putln("")
+	}
+	c.Putln("buf[b] = %d // request opcode", r.Opcode)
+	c.Putln("b += 1")
+	c.Putln("")
+	if len(r.Fields) == 0 {
+		if !c.protocol.isExt() {
+			c.Putln("b += 1 // padding")
+		}
+		writeSize1()
+	} else if c.protocol.isExt() {
+		writeSize1()
+	}
+	for i, field := range r.Fields {
+		field.Write(c, "")
+		c.Putln("")
+		if i == 0 && !c.protocol.isExt() {
+			writeSize1()
+		}
+	}
+	writeSize2()
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (r *Request) ParamNames() string {
+	names := make([]string, 0, len(r.Fields))
+	for _, field := range r.Fields {
+		switch f := field.(type) {
+		case *ValueField:
+			names = append(names, f.MaskName)
+			names = append(names, f.ListName)
+		case *PadField:
+			continue
+		case *ExprField:
+			continue
+		default:
+			names = append(names, fmt.Sprintf("%s", field.SrcName()))
+		}
+	}
+	return strings.Join(names, ", ")
+}
+
+func (r *Request) ParamNameTypes() string {
+	nameTypes := make([]string, 0, len(r.Fields))
+
+	chunk := make([]string, 0)
+	chunkType := ""
+	flushChunk := func() {
+		if len(chunk) > 0 {
+			nameTypes = append(nameTypes, chunk[:len(chunk)-1]...)
+			nameTypes = append(nameTypes,
+				fmt.Sprintf("%s %s", chunk[len(chunk)-1], chunkType))
+		}
+		chunk = nil
+		chunkType = ""
+	}
+
+	for _, field := range r.Fields {
+		switch f := field.(type) {
+		case *ValueField:
+			flushChunk()
+			nameTypes = append(nameTypes,
+				fmt.Sprintf("%s %s", f.MaskName, f.MaskType.SrcName()))
+			nameTypes = append(nameTypes,
+				fmt.Sprintf("%s []uint32", f.ListName))
+		case *PadField:
+			continue
+		case *ExprField:
+			continue
+		case *RequiredStartAlign:
+			continue
+		default:
+			curType := field.SrcType()
+			if curType != chunkType {
+				flushChunk()
+			}
+			chunk = append(chunk, field.SrcName())
+			chunkType = curType
+		}
+	}
+	flushChunk()
+	return strings.Join(nameTypes, ", ")
+}

nexgb/xgbgen/go_single_field.go

@@ -0,0 +1,169 @@
+package main
+
+import (
+	"fmt"
+	"log"
+)
+
+func (f *SingleField) Define(c *Context) {
+	if f.Comment != "" {
+		c.PutComment(f.Comment)
+	}
+	c.Putln("%s %s", f.SrcName(), f.Type.SrcName())
+}
+
+func ReadSimpleSingleField(c *Context, name string, typ Type) {
+	switch t := typ.(type) {
+	case *Resource:
+		c.Putln("%s = %s(xgb.Get32(buf[b:]))", name, t.SrcName())
+	case *TypeDef:
+		switch t.Size().Eval() {
+		case 1:
+			c.Putln("%s = %s(buf[b])", name, t.SrcName())
+		case 2:
+			c.Putln("%s = %s(xgb.Get16(buf[b:]))", name, t.SrcName())
+		case 4:
+			c.Putln("%s = %s(xgb.Get32(buf[b:]))", name, t.SrcName())
+		case 8:
+			c.Putln("%s = %s(xgb.Get64(buf[b:]))", name, t.SrcName())
+		}
+	case *Base:
+		// If this is a bool, stop short and do something special.
+		if t.SrcName() == "bool" {
+			c.Putln("if buf[b] == 1 {")
+			c.Putln("%s = true", name)
+			c.Putln("} else {")
+			c.Putln("%s = false", name)
+			c.Putln("}")
+			break
+		}
+
+		var val string
+		switch t.Size().Eval() {
+		case 1:
+			val = fmt.Sprintf("buf[b]")
+		case 2:
+			val = fmt.Sprintf("xgb.Get16(buf[b:])")
+		case 4:
+			val = fmt.Sprintf("xgb.Get32(buf[b:])")
+		case 8:
+			val = fmt.Sprintf("xgb.Get64(buf[b:])")
+		}
+
+		// We need to convert base types if they aren't uintXX or byte
+		ty := t.SrcName()
+		if ty != "byte" && ty != "uint16" && ty != "uint32" && ty != "uint64" {
+			val = fmt.Sprintf("%s(%s)", ty, val)
+		}
+		c.Putln("%s = %s", name, val)
+	default:
+		log.Panicf("Cannot read field '%s' as a simple field with %T type.",
+			name, typ)
+	}
+
+	c.Putln("b += %s", typ.Size())
+}
+
+func (f *SingleField) Read(c *Context, prefix string) {
+	switch t := f.Type.(type) {
+	case *Resource:
+		ReadSimpleSingleField(c, fmt.Sprintf("%s%s", prefix, f.SrcName()), t)
+	case *TypeDef:
+		ReadSimpleSingleField(c, fmt.Sprintf("%s%s", prefix, f.SrcName()), t)
+	case *Base:
+		ReadSimpleSingleField(c, fmt.Sprintf("%s%s", prefix, f.SrcName()), t)
+	case *Struct:
+		c.Putln("%s%s = %s{}", prefix, f.SrcName(), t.SrcName())
+		c.Putln("b += %sRead(buf[b:], &%s%s)", t.SrcName(), prefix, f.SrcName())
+	case *Union:
+		c.Putln("%s%s = %s{}", prefix, f.SrcName(), t.SrcName())
+		c.Putln("b += %sRead(buf[b:], &%s%s)", t.SrcName(), prefix, f.SrcName())
+	default:
+		log.Panicf("Cannot read field '%s' with %T type.", f.XmlName(), f.Type)
+	}
+}
+
+func WriteSimpleSingleField(c *Context, name string, typ Type) {
+	switch t := typ.(type) {
+	case *Resource:
+		c.Putln("xgb.Put32(buf[b:], uint32(%s))", name)
+	case *TypeDef:
+		switch t.Size().Eval() {
+		case 1:
+			c.Putln("buf[b] = byte(%s)", name)
+		case 2:
+			c.Putln("xgb.Put16(buf[b:], uint16(%s))", name)
+		case 4:
+			c.Putln("xgb.Put32(buf[b:], uint32(%s))", name)
+		case 8:
+			c.Putln("xgb.Put64(buf[b:], uint64(%s))", name)
+		}
+	case *Base:
+		// If this is a bool, stop short and do something special.
+		if t.SrcName() == "bool" {
+			c.Putln("if %s {", name)
+			c.Putln("buf[b] = 1")
+			c.Putln("} else {")
+			c.Putln("buf[b] = 0")
+			c.Putln("}")
+			break
+		}
+
+		switch t.Size().Eval() {
+		case 1:
+			if t.SrcName() != "byte" {
+				c.Putln("buf[b] = byte(%s)", name)
+			} else {
+				c.Putln("buf[b] = %s", name)
+			}
+		case 2:
+			if t.SrcName() != "uint16" {
+				c.Putln("xgb.Put16(buf[b:], uint16(%s))", name)
+			} else {
+				c.Putln("xgb.Put16(buf[b:], %s)", name)
+			}
+		case 4:
+			if t.SrcName() != "uint32" {
+				c.Putln("xgb.Put32(buf[b:], uint32(%s))", name)
+			} else {
+				c.Putln("xgb.Put32(buf[b:], %s)", name)
+			}
+		case 8:
+			if t.SrcName() != "uint64" {
+				c.Putln("xgb.Put64(buf[b:], uint64(%s))", name)
+			} else {
+				c.Putln("xgb.Put64(buf[b:], %s)", name)
+			}
+		}
+	default:
+		log.Fatalf("Cannot read field '%s' as a simple field with %T type.",
+			name, typ)
+	}
+
+	c.Putln("b += %s", typ.Size())
+}
+
+func (f *SingleField) Write(c *Context, prefix string) {
+	switch t := f.Type.(type) {
+	case *Resource:
+		WriteSimpleSingleField(c, fmt.Sprintf("%s%s", prefix, f.SrcName()), t)
+	case *TypeDef:
+		WriteSimpleSingleField(c, fmt.Sprintf("%s%s", prefix, f.SrcName()), t)
+	case *Base:
+		WriteSimpleSingleField(c, fmt.Sprintf("%s%s", prefix, f.SrcName()), t)
+	case *Union:
+		c.Putln("{")
+		c.Putln("unionBytes := %s%s.Bytes()", prefix, f.SrcName())
+		c.Putln("copy(buf[b:], unionBytes)")
+		c.Putln("b += len(unionBytes)")
+		c.Putln("}")
+	case *Struct:
+		c.Putln("{")
+		c.Putln("structBytes := %s%s.Bytes()", prefix, f.SrcName())
+		c.Putln("copy(buf[b:], structBytes)")
+		c.Putln("b += len(structBytes)")
+		c.Putln("}")
+	default:
+		log.Fatalf("Cannot read field '%s' with %T type.", f.XmlName(), f.Type)
+	}
+}

nexgb/xgbgen/go_struct.go

@@ -0,0 +1,118 @@
+package main
+
+func (s *Struct) Define(c *Context) {
+	c.Putln("type %s struct {", s.SrcName())
+	for _, field := range s.Fields {
+		field.Define(c)
+	}
+	c.Putln("}")
+	c.Putln("")
+
+	// Write function that reads bytes and produces this struct.
+	s.Read(c)
+
+	// Write function that reads bytes and produces a list of this struct.
+	s.ReadList(c)
+
+	// Write function that writes bytes given this struct.
+	s.Write(c)
+
+	// Write function that writes a list of this struct.
+	s.WriteList(c)
+
+	// Write function that computes the size of a list of these structs,
+	// IF there is a list field in this struct.
+	if s.HasList() {
+		s.WriteListSize(c)
+	}
+}
+
+// Read for a struct creates a function 'ReadStructName' that takes a source
+// byte slice (i.e., the buffer) and a destination struct, and returns
+// the number of bytes read off the buffer.
+// 'ReadStructName' should only be used to read raw reply data from the wire.
+func (s *Struct) Read(c *Context) {
+	c.Putln("// %sRead reads a byte slice into a %s value.",
+		s.SrcName(), s.SrcName())
+	c.Putln("func %sRead(buf []byte, v *%s) int {", s.SrcName(), s.SrcName())
+
+	c.Putln("b := 0")
+	c.Putln("")
+	for _, field := range s.Fields {
+		field.Read(c, "v.")
+		c.Putln("")
+	}
+	c.Putln("return b")
+
+	c.Putln("}")
+	c.Putln("")
+}
+
+// ReadList for a struct creates a function 'ReadStructNameList' that takes
+// a source (i.e., the buffer) byte slice, and a destination slice and returns
+// the number of bytes read from the byte slice.
+func (s *Struct) ReadList(c *Context) {
+	c.Putln("// %sReadList reads a byte slice into a list of %s values.",
+		s.SrcName(), s.SrcName())
+	c.Putln("func %sReadList(buf []byte, dest []%s) int {",
+		s.SrcName(), s.SrcName())
+	c.Putln("b := 0")
+	c.Putln("for i := 0; i < len(dest); i++ {")
+	c.Putln("dest[i] = %s{}", s.SrcName())
+	c.Putln("b += %sRead(buf[b:], &dest[i])", s.SrcName())
+	c.Putln("}")
+
+	c.Putln("return xgb.Pad(b)")
+
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (s *Struct) Write(c *Context) {
+	c.Putln("// Bytes writes a %s value to a byte slice.", s.SrcName())
+	c.Putln("func (v %s) Bytes() []byte {", s.SrcName())
+	c.Putln("buf := make([]byte, %s)", s.Size().Reduce("v."))
+	c.Putln("b := 0")
+	c.Putln("")
+	for _, field := range s.Fields {
+		field.Write(c, "v.")
+		c.Putln("")
+	}
+	c.Putln("return buf[:b]")
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (s *Struct) WriteList(c *Context) {
+	c.Putln("// %sListBytes writes a list of %s values to a byte slice.",
+		s.SrcName(), s.SrcName())
+	c.Putln("func %sListBytes(buf []byte, list []%s) int {",
+		s.SrcName(), s.SrcName())
+	c.Putln("b := 0")
+	c.Putln("var structBytes []byte")
+	c.Putln("for _, item := range list {")
+	c.Putln("structBytes = item.Bytes()")
+	c.Putln("copy(buf[b:], structBytes)")
+	c.Putln("b += len(structBytes)")
+	c.Putln("}")
+	c.Putln("return xgb.Pad(b)")
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (s *Struct) WriteListSize(c *Context) {
+	c.Putln("// %sListSize computes the size (bytes) of a list of %s values.",
+		s.SrcName(), s.SrcName())
+	c.Putln("func %sListSize(list []%s) int {", s.SrcName(), s.SrcName())
+	c.Putln("size := 0")
+	if s.Size().Expression.Concrete() {
+		c.Putln("for _ = range list {")
+	} else {
+		c.Putln("for _, item := range list {")
+	}
+	c.Putln("size += %s", s.Size().Reduce("item."))
+	c.Putln("}")
+	c.Putln("return size")
+	c.Putln("}")
+	c.Putln("")
+}

nexgb/xgbgen/go_union.go

@@ -0,0 +1,147 @@
+package main
+
+// Union types
+func (u *Union) Define(c *Context) {
+	c.Putln("// %s is a represention of the %s union type.",
+		u.SrcName(), u.SrcName())
+	c.Putln("// Note that to *create* a Union, you should *never* create")
+	c.Putln("// this struct directly (unless you know what you're doing).")
+	c.Putln("// Instead use one of the following constructors for '%s':",
+		u.SrcName())
+	for _, field := range u.Fields {
+		c.Putln("//     %s%sNew(%s %s) %s", u.SrcName(), field.SrcName(),
+			field.SrcName(), field.SrcType(), u.SrcName())
+	}
+
+	c.Putln("type %s struct {", u.SrcName())
+	for _, field := range u.Fields {
+		field.Define(c)
+	}
+	c.Putln("}")
+	c.Putln("")
+
+	// Write functions for each field that create instances of this
+	// union using the corresponding field.
+	u.New(c)
+
+	// Write function that reads bytes and produces this union.
+	u.Read(c)
+
+	// Write function that reads bytes and produces a list of this union.
+	u.ReadList(c)
+
+	// Write function that writes bytes given this union.
+	u.Write(c)
+
+	// Write function that writes a list of this union.
+	u.WriteList(c)
+}
+
+func (u *Union) New(c *Context) {
+	for _, field := range u.Fields {
+		c.Putln("// %s%sNew constructs a new %s union type with the %s field.",
+			u.SrcName(), field.SrcName(), u.SrcName(), field.SrcName())
+		c.Putln("func %s%sNew(%s %s) %s {",
+			u.SrcName(), field.SrcName(), field.SrcName(),
+			field.SrcType(), u.SrcName())
+		c.Putln("var b int")
+		c.Putln("buf := make([]byte, %s)", u.Size())
+		c.Putln("")
+		field.Write(c, "")
+		c.Putln("")
+		c.Putln("// Create the Union type")
+		c.Putln("v := %s{}", u.SrcName())
+		c.Putln("")
+		c.Putln("// Now copy buf into all fields")
+		c.Putln("")
+		for _, field2 := range u.Fields {
+			c.Putln("b = 0 // always read the same bytes")
+			field2.Read(c, "v.")
+			c.Putln("")
+		}
+		c.Putln("return v")
+		c.Putln("}")
+		c.Putln("")
+	}
+}
+
+func (u *Union) Read(c *Context) {
+	c.Putln("// %sRead reads a byte slice into a %s value.",
+		u.SrcName(), u.SrcName())
+	c.Putln("func %sRead(buf []byte, v *%s) int {", u.SrcName(), u.SrcName())
+	c.Putln("var b int")
+	c.Putln("")
+	for _, field := range u.Fields {
+		c.Putln("b = 0 // re-read the same bytes")
+		field.Read(c, "v.")
+		c.Putln("")
+	}
+	c.Putln("return %s", u.Size())
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (u *Union) ReadList(c *Context) {
+	c.Putln("// %sReadList reads a byte slice into a list of %s values.",
+		u.SrcName(), u.SrcName())
+	c.Putln("func %sReadList(buf []byte, dest []%s) int {",
+		u.SrcName(), u.SrcName())
+	c.Putln("b := 0")
+	c.Putln("for i := 0; i < len(dest); i++ {")
+	c.Putln("dest[i] = %s{}", u.SrcName())
+	c.Putln("b += %sRead(buf[b:], &dest[i])", u.SrcName())
+	c.Putln("}")
+	c.Putln("return xgb.Pad(b)")
+	c.Putln("}")
+	c.Putln("")
+}
+
+// This is a bit tricky since writing from a Union implies that only
+// the data inside ONE of the elements is actually written.
+// However, we only currently support unions where every field has the
+// *same* *fixed* size. Thus, we make sure to always read bytes into
+// every field which allows us to simply pick the first field and write it.
+func (u *Union) Write(c *Context) {
+	c.Putln("// Bytes writes a %s value to a byte slice.", u.SrcName())
+	c.Putln("// Each field in a union must contain the same data.")
+	c.Putln("// So simply pick the first field and write that to the wire.")
+	c.Putln("func (v %s) Bytes() []byte {", u.SrcName())
+	c.Putln("buf := make([]byte, %s)", u.Size().Reduce("v."))
+	c.Putln("b := 0")
+	c.Putln("")
+	u.Fields[0].Write(c, "v.")
+	c.Putln("return buf")
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (u *Union) WriteList(c *Context) {
+	c.Putln("// %sListBytes writes a list of %s values to a byte slice.",
+		u.SrcName(), u.SrcName())
+	c.Putln("func %sListBytes(buf []byte, list []%s) int {",
+		u.SrcName(), u.SrcName())
+	c.Putln("b := 0")
+	c.Putln("var unionBytes []byte")
+	c.Putln("for _, item := range list {")
+	c.Putln("unionBytes = item.Bytes()")
+	c.Putln("copy(buf[b:], unionBytes)")
+	c.Putln("b += xgb.Pad(len(unionBytes))")
+	c.Putln("}")
+	c.Putln("return b")
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (u *Union) WriteListSize(c *Context) {
+	c.Putln("// Union list size %s", u.SrcName())
+	c.Putln("// %sListSize computes the size (bytes) of a list of %s values.",
+		u.SrcName())
+	c.Putln("func %sListSize(list []%s) int {", u.SrcName(), u.SrcName())
+	c.Putln("size := 0")
+	c.Putln("for _, item := range list {")
+	c.Putln("size += %s", u.Size().Reduce("item."))
+	c.Putln("}")
+	c.Putln("return size")
+	c.Putln("}")
+	c.Putln("")
+}

nexgb/xgbgen/main.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"flag"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+var (
+	protoPath = flag.String("proto-path",
+		"/usr/share/xcb", "path to directory of X protocol XML files")
+	gofmt = flag.Bool("gofmt", true,
+		"When disabled, gofmt will not be run before outputting Go code")
+)
+
+func usage() {
+	basename := os.Args[0]
+	if lastSlash := strings.LastIndex(basename, "/"); lastSlash > -1 {
+		basename = basename[lastSlash+1:]
+	}
+	log.Printf("Usage: %s [flags] xml-file", basename)
+	flag.PrintDefaults()
+	os.Exit(1)
+}
+
+func init() {
+	log.SetFlags(0)
+}
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+
+	if flag.NArg() != 1 {
+		log.Printf("A single XML protocol file can be processed at once.")
+		flag.Usage()
+	}
+
+	// Read the single XML file into []byte
+	xmlBytes, err := ioutil.ReadFile(flag.Arg(0))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Initialize the buffer, parse it, and filter it through gofmt.
+	c := newContext()
+	c.Morph(xmlBytes)
+
+	if !*gofmt {
+		c.out.WriteTo(os.Stdout)
+	} else {
+		cmdGofmt := exec.Command("gofmt")
+		cmdGofmt.Stdin = c.out
+		cmdGofmt.Stdout = os.Stdout
+		cmdGofmt.Stderr = os.Stderr
+		err = cmdGofmt.Run()
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+}

nexgb/xgbgen/misc.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"regexp"
+	"strings"
+)
+
+// AllCaps is a regex to test if a string identifier is made of
+// all upper case letters.
+var allCaps = regexp.MustCompile("^[A-Z0-9]+$")
+
+// popCount counts number of bits 'set' in mask.
+func popCount(mask uint) uint {
+	m := uint32(mask)
+	n := uint(0)
+	for i := uint32(0); i < 32; i++ {
+		if m&(1<<i) != 0 {
+			n++
+		}
+	}
+	return n
+}
+
+// pad makes sure 'n' aligns on 4 bytes.
+func pad(n int) int {
+	return (n + 3) & ^3
+}
+
+// splitAndTitle takes a string, splits it by underscores, capitalizes the
+// first letter of each chunk, and smushes'em back together.
+func splitAndTitle(s string) string {
+	// If the string is all caps, lower it and capitalize first letter.
+	if allCaps.MatchString(s) {
+		return strings.Title(strings.ToLower(s))
+	}
+
+	// If the string has no underscores, capitalize it and leave it be.
+	if i := strings.Index(s, "_"); i == -1 {
+		return strings.Title(s)
+	}
+
+	// Now split the name at underscores, capitalize the first
+	// letter of each chunk, and smush'em back together.
+	chunks := strings.Split(s, "_")
+	for i, chunk := range chunks {
+		chunks[i] = strings.Title(strings.ToLower(chunk))
+	}
+	return strings.Join(chunks, "")
+}

nexgb/xgbgen/protocol.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"log"
+	"strings"
+)
+
+// Protocol is a type that encapsulates all information about one
+// particular XML file. It also contains links to other protocol types
+// if this protocol imports other other extensions. The import relationship
+// is recursive.
+type Protocol struct {
+	Parent       *Protocol
+	Name         string
+	ExtXName     string
+	ExtName      string
+	MajorVersion string
+	MinorVersion string
+
+	Imports  []*Protocol
+	Types    []Type
+	Requests []*Request
+}
+
+type Protocols []*Protocol
+
+func (ps Protocols) Len() int           { return len(ps) }
+func (ps Protocols) Swap(i, j int)      { ps[i], ps[j] = ps[j], ps[i] }
+func (ps Protocols) Less(i, j int) bool { return ps[i].ExtName < ps[j].ExtName }
+
+// Initialize traverses all structures, looks for 'Translation' type,
+// and looks up the real type in the namespace. It also sets the source
+// name for all relevant fields/structures.
+// This is necessary because we don't traverse the XML in order initially.
+func (p *Protocol) Initialize() {
+	for _, typ := range p.Types {
+		typ.Initialize(p)
+	}
+	for _, req := range p.Requests {
+		req.Initialize(p)
+	}
+}
+
+// PkgName returns the name of this package.
+// i.e., 'xproto' for the core X protocol, 'randr' for the RandR extension, etc.
+func (p *Protocol) PkgName() string {
+	return strings.Replace(p.Name, "_", "", -1)
+}
+
+// ProtocolGet searches the current context for the protocol with the given
+// name. (i.e., the current protocol and its imports.)
+// It is an error if one is not found.
+func (p *Protocol) ProtocolFind(name string) *Protocol {
+	if p.Name == name {
+		return p // that was easy
+	}
+	for _, imp := range p.Imports {
+		if imp.Name == name {
+			return imp
+		}
+	}
+	log.Panicf("Could not find protocol with name '%s'.", name)
+	panic("unreachable")
+}
+
+// isExt returns true if this protocol is an extension.
+// i.e., it's name isn't "xproto".
+func (p *Protocol) isExt() bool {
+	return strings.ToLower(p.Name) != "xproto"
+}

nexgb/xgbgen/request_reply.go

@@ -0,0 +1,170 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"unicode"
+)
+
+// Doc contains any documentation, if present. Example C code is excluded.
+type Doc struct {
+	Brief       string            // short description
+	Description string            // long description
+	Fields      map[string]string // from field name to description
+	Errors      map[string]string // from error type to description
+}
+
+// DescribeField is an accessor that supports nil receivers.
+func (d *Doc) DescribeField(name string) string {
+	if d == nil {
+		return ""
+	}
+	return d.Fields[name]
+}
+
+// Request represents all XML 'request' nodes.
+// If the request doesn't have a reply, Reply is nil.
+type Request struct {
+	srcName string // The Go name of this request.
+	xmlName string // The XML name of this request.
+	Opcode  int
+	Combine bool    // Not currently used.
+	Fields  []Field // All fields in the request.
+	Reply   *Reply  // A reply, if one exists for this request.
+	Doc     Doc     // Documentation.
+}
+
+type Requests []*Request
+
+func (rs Requests) Len() int           { return len(rs) }
+func (rs Requests) Swap(i, j int)      { rs[i], rs[j] = rs[j], rs[i] }
+func (rs Requests) Less(i, j int) bool { return rs[i].xmlName < rs[j].xmlName }
+
+// Initialize creates the proper Go source name for this request.
+// It also initializes the reply if one exists, and all fields in this request.
+func (r *Request) Initialize(p *Protocol) {
+	r.srcName = SrcName(p, r.xmlName)
+	if p.isExt() {
+		r.srcName = r.srcName
+	}
+
+	if r.Reply != nil {
+		r.Reply.Initialize(p)
+	}
+	for _, field := range r.Fields {
+		field.Initialize(p)
+	}
+}
+
+func (r *Request) SrcName() string {
+	return r.srcName
+}
+
+func (r *Request) XmlName() string {
+	return r.xmlName
+}
+
+// ReplyName gets the Go source name of the function that generates a
+// reply type from a slice of bytes.
+// The generated function is not currently exported.
+func (r *Request) ReplyName() string {
+	if r.Reply == nil {
+		log.Panicf("Cannot call 'ReplyName' on request %s, which has no reply.",
+			r.SrcName())
+	}
+	name := r.SrcName()
+	lower := string(unicode.ToLower(rune(name[0]))) + name[1:]
+	return fmt.Sprintf("%sReply", lower)
+}
+
+// ReplyTypeName gets the Go source name of the type holding all reply data
+// for this request.
+func (r *Request) ReplyTypeName() string {
+	if r.Reply == nil {
+		log.Panicf("Cannot call 'ReplyName' on request %s, which has no reply.",
+			r.SrcName())
+	}
+	return fmt.Sprintf("%sReply", r.SrcName())
+}
+
+// ReqName gets the Go source name of the function that generates a byte
+// slice from a list of parameters.
+// The generated function is not currently exported.
+func (r *Request) ReqName() string {
+	name := r.SrcName()
+	lower := string(unicode.ToLower(rune(name[0]))) + name[1:]
+	return fmt.Sprintf("%sRequest", lower)
+}
+
+// CookieName gets the Go source name of the type that holds cookies for
+// this request.
+func (r *Request) CookieName() string {
+	return fmt.Sprintf("%sCookie", r.SrcName())
+}
+
+// Size for Request needs a context.
+// Namely, if this is an extension, we need to account for *four* bytes
+// of a header (extension opcode, request opcode, and the sequence number).
+// If it's a core protocol request, then we only account for *three*
+// bytes of the header (remove the extension opcode).
+func (r *Request) Size(c *Context) Size {
+	size := newFixedSize(0, true)
+
+	// If this is a core protocol request, we squeeze in an extra byte of
+	// data (from the fields below) between the opcode and the size of the
+	// request. In an extension request, this byte is always occupied
+	// by the opcode of the request (while the first byte is always occupied
+	// by the opcode of the extension).
+	if !c.protocol.isExt() {
+		size = size.Add(newFixedSize(3, true))
+	} else {
+		size = size.Add(newFixedSize(4, true))
+	}
+
+	for _, field := range r.Fields {
+		switch field := field.(type) {
+		case *LocalField: // local fields don't go over the wire
+			continue
+		case *SingleField:
+			fsz := field.Size()
+			if _, isstruct := field.Type.(*Struct); isstruct {
+				fsz.Expression = fsz.Expression.Specialize(field.SrcName())
+			}
+			size = size.Add(fsz)
+		default:
+			size = size.Add(field.Size())
+		}
+	}
+	return newExpressionSize(&Padding{
+		Expr: size.Expression,
+	}, size.exact)
+}
+
+// Reply encapsulates the fields associated with a 'reply' element.
+type Reply struct {
+	Fields []Field
+	Doc    Doc
+}
+
+// Size gets the number of bytes in this request's reply.
+// A reply always has at least 7 bytes:
+// 1 byte: A reply discriminant (first byte set to 1)
+// 2 bytes: A sequence number
+// 4 bytes: Number of additional bytes in 4-byte units past initial 32 bytes.
+func (r *Reply) Size() Size {
+	size := newFixedSize(0, true)
+
+	// Account for reply discriminant, sequence number and reply length
+	size = size.Add(newFixedSize(7, true))
+
+	for _, field := range r.Fields {
+		size = size.Add(field.Size())
+	}
+	return size
+}
+
+func (r *Reply) Initialize(p *Protocol) {
+	for _, field := range r.Fields {
+		field.Initialize(p)
+	}
+}

nexgb/xgbgen/size.go

@@ -0,0 +1,31 @@
+package main
+
+// Size corresponds to an expression that represents the number of bytes
+// in some *thing*. Generally, sizes are used to allocate buffers and to
+// inform X how big requests are.
+// Size is basically a thin layer over an Expression that yields easy methods
+// for adding and multiplying sizes.
+type Size struct {
+	Expression
+	exact bool
+}
+
+// newFixedSize creates a new Size with some fixed and known value.
+func newFixedSize(fixed uint, exact bool) Size {
+	return Size{&Value{v: int(fixed)}, exact}
+}
+
+// newExpressionSize creates a new Size with some expression.
+func newExpressionSize(variable Expression, exact bool) Size {
+	return Size{variable, exact}
+}
+
+// Add adds s1 and s2 and returns a new Size.
+func (s1 Size) Add(s2 Size) Size {
+	return Size{newBinaryOp("+", s1, s2), s1.exact && s2.exact}
+}
+
+// Multiply mupltiplies s1 and s2 and returns a new Size.
+func (s1 Size) Multiply(s2 Size) Size {
+	return Size{newBinaryOp("*", s1, s2), s1.exact && s2.exact}
+}

nexgb/xgbgen/translation.go

@@ -0,0 +1,498 @@
+package main
+
+/*
+translation.go provides a 'Translate' method on every XML type that converts
+the XML type into our "better" representation.
+
+i.e., the representation of Fields and Expressions is just too general.
+We end up losing a lot of the advantages of static typing if we keep
+the types that encoding/xml forces us into.
+*/
+
+import (
+	"log"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+func (xml *XML) Translate(parent *Protocol) *Protocol {
+	protocol := &Protocol{
+		Parent:       parent,
+		Name:         xml.Header,
+		ExtXName:     xml.ExtensionXName,
+		ExtName:      xml.ExtensionName,
+		MajorVersion: xml.MajorVersion,
+		MinorVersion: xml.MinorVersion,
+
+		Imports:  make([]*Protocol, 0),
+		Types:    make([]Type, 0),
+		Requests: make([]*Request, len(xml.Requests)),
+	}
+
+	for _, imp := range xml.Imports {
+		if imp.xml != nil {
+			protocol.Imports = append(protocol.Imports,
+				imp.xml.Translate(protocol))
+		}
+	}
+
+	for xmlName, srcName := range BaseTypeMap {
+		newBaseType := &Base{
+			srcName: srcName,
+			xmlName: xmlName,
+			size:    newFixedSize(BaseTypeSizes[xmlName], true),
+		}
+		protocol.Types = append(protocol.Types, newBaseType)
+	}
+	for _, enum := range xml.Enums {
+		protocol.Types = append(protocol.Types, enum.Translate())
+	}
+	for _, xid := range xml.Xids {
+		protocol.Types = append(protocol.Types, xid.Translate())
+	}
+	for _, xidunion := range xml.XidUnions {
+		protocol.Types = append(protocol.Types, xidunion.Translate())
+	}
+	for _, typedef := range xml.TypeDefs {
+		protocol.Types = append(protocol.Types, typedef.Translate())
+	}
+	for _, s := range xml.Structs {
+		protocol.Types = append(protocol.Types, s.Translate())
+	}
+	for _, union := range xml.Unions {
+		protocol.Types = append(protocol.Types, union.Translate())
+	}
+	for _, ev := range xml.Events {
+		protocol.Types = append(protocol.Types, ev.Translate())
+	}
+	for _, evcopy := range xml.EventCopies {
+		protocol.Types = append(protocol.Types, evcopy.Translate())
+	}
+	for _, err := range xml.Errors {
+		protocol.Types = append(protocol.Types, err.Translate())
+	}
+	for _, errcopy := range xml.ErrorCopies {
+		protocol.Types = append(protocol.Types, errcopy.Translate())
+	}
+
+	for i, request := range xml.Requests {
+		protocol.Requests[i] = request.Translate()
+	}
+
+	// Now load all of the type and source name information.
+	protocol.Initialize()
+
+	// Make sure all enums have concrete values.
+	for _, typ := range protocol.Types {
+		enum, ok := typ.(*Enum)
+		if !ok {
+			continue
+		}
+		nextValue := 0
+		for _, item := range enum.Items {
+			if item.Expr == nil {
+				item.Expr = &Value{v: nextValue}
+				nextValue++
+			} else {
+				nextValue = item.Expr.Eval() + 1
+			}
+		}
+	}
+
+	return protocol
+}
+
+func (x *XMLEnum) Translate() *Enum {
+	enum := &Enum{
+		xmlName: x.Name,
+		Items:   make([]*EnumItem, len(x.Items)),
+	}
+	for i, item := range x.Items {
+		enum.Items[i] = &EnumItem{
+			xmlName: item.Name,
+			Expr:    item.Expr.Translate(),
+		}
+	}
+	return enum
+}
+
+func (x *XMLXid) Translate() *Resource {
+	return &Resource{
+		xmlName: x.Name,
+	}
+}
+
+func (x *XMLTypeDef) Translate() *TypeDef {
+	return &TypeDef{
+		xmlName: x.New,
+		Old:     newTranslation(x.Old),
+	}
+}
+
+func (x *XMLEvent) Translate() *Event {
+	ev := &Event{
+		xmlName:    x.Name,
+		Number:     x.Number,
+		NoSequence: x.NoSequence,
+		Fields:     make([]Field, 0, len(x.Fields)),
+		Doc:        x.Doc.Translate(),
+	}
+	for _, field := range x.Fields {
+		ev.Fields = append(ev.Fields, field.Translate(ev, &ev.Doc))
+	}
+	return ev
+}
+
+func (x *XMLEventCopy) Translate() *EventCopy {
+	return &EventCopy{
+		xmlName: x.Name,
+		Number:  x.Number,
+		Old:     newTranslation(x.Ref),
+	}
+}
+
+func (x *XMLError) Translate() *Error {
+	err := &Error{
+		xmlName: x.Name,
+		Number:  x.Number,
+		Fields:  make([]Field, len(x.Fields)),
+	}
+	for i, field := range x.Fields {
+		err.Fields[i] = field.Translate(err, nil)
+	}
+	return err
+}
+
+func (x *XMLErrorCopy) Translate() *ErrorCopy {
+	return &ErrorCopy{
+		xmlName: x.Name,
+		Number:  x.Number,
+		Old:     newTranslation(x.Ref),
+	}
+}
+
+// XCB documentation is positively stuffed with TODOs. We'd like to make it
+// look a bit less shitty, so remove those as they don't convey information.
+//
+//  ^TODO
+//  ^TODO:
+//  ^TODO: question?
+//  ^TODO: Some words
+//  ^TODO: some words
+//  ^TODO: some words with full stop.
+//  ^TODO: some words with full stop. and a question?
+//  ... (TODO),
+//  ... (TODO).
+//  ... (TODO: a question?).
+//  ... TODO: a question?
+//  ... (word TODO) ...
+var todoRE = regexp.MustCompile(`(?m:^TODO.*| \([^)]*TODO[^)]*\)| TODO:.*)`)
+var paraRE = regexp.MustCompile(`\n{3,}`)
+
+var backticksRE = regexp.MustCompile("`(?:xcb_|XCB_)?(.*?)(?:_t)?`")
+
+// fixDocumentation tries to translate XCB documentation to match XGB.
+// Note that <doc> blocks only appear in xproto, so this doesn't have that much
+// of a value--users still need to read Xlib or X11 protocol docs.
+// Despite that, it's better to have something than nothing.
+//
+// We don't attempt to add proper prefixes to enum values or guess at
+// specific XCB_NONE types (the latter is undecidable).
+//
+// We can't decide whether `fields_len` should be converted to len(Fields)
+// or FieldsLen because e.g. StringLen is retained in ImageText8/16 but
+// PointsLen is implied by the length of the Points slice in PolyLine.
+func fixDocumentation(xcb string) string {
+	last, result := 0, make([]byte, 0, len(xcb))
+	for _, m := range backticksRE.FindAllStringSubmatchIndex(xcb, -1) {
+		result = append(result, xcb[last:m[0]]...)
+		inner := xcb[m[2]:m[3]]
+		last = m[1]
+
+		// Do not convert atom names to identifiers, mainly _NET_WM_*.
+		if strings.Contains(inner, "WM_") {
+			result = append(result, inner...)
+		} else {
+			result = append(result, splitAndTitle(inner)...)
+		}
+	}
+	result = todoRE.ReplaceAllLiteral(append(result, xcb[last:]...), nil)
+	result = paraRE.ReplaceAllLiteral(result, []byte("\n\n"))
+	return strings.TrimSpace(string(result))
+}
+
+func (x *XMLDoc) Translate() Doc {
+	if x == nil {
+		return Doc{}
+	}
+	d := Doc{
+		Brief:       fixDocumentation(x.Brief),
+		Description: fixDocumentation(x.Description),
+		Fields:      make(map[string]string),
+		Errors:      make(map[string]string),
+	}
+	for _, x := range x.Fields {
+		d.Fields[x.Name] = fixDocumentation(x.Description)
+	}
+	for _, x := range x.Errors {
+		d.Errors[x.Type] = fixDocumentation(x.Description)
+	}
+	return d
+}
+
+func (x *XMLStruct) Translate() *Struct {
+	s := &Struct{
+		xmlName: x.Name,
+		Fields:  make([]Field, len(x.Fields)),
+	}
+	for i, field := range x.Fields {
+		s.Fields[i] = field.Translate(s, nil)
+	}
+	return s
+}
+
+func (x *XMLUnion) Translate() *Union {
+	u := &Union{
+		xmlName: x.Name,
+		Fields:  make([]Field, len(x.Fields)),
+	}
+	for i, field := range x.Fields {
+		u.Fields[i] = field.Translate(u, nil)
+	}
+	return u
+}
+
+func (x *XMLRequest) Translate() *Request {
+	r := &Request{
+		xmlName: x.Name,
+		Opcode:  x.Opcode,
+		Combine: x.Combine,
+		Fields:  make([]Field, 0, len(x.Fields)),
+		Reply:   x.Reply.Translate(),
+		Doc:     x.Doc.Translate(),
+	}
+	for _, field := range x.Fields {
+		if field.XMLName.Local == "fd" {
+			continue
+		}
+		r.Fields = append(r.Fields, field.Translate(r, &r.Doc))
+	}
+
+	// Address bug (or legacy code) in QueryTextExtents.
+	// The XML protocol description references 'string_len' in the
+	// computation of the 'odd_length' field. However, 'string_len' is not
+	// defined. Therefore, let's forcefully add it as a 'local field'.
+	// (i.e., a parameter in the caller but does not get sent over the wire.)
+	if x.Name == "QueryTextExtents" {
+		stringLenLocal := &LocalField{&SingleField{
+			xmlName: "string_len",
+			Type:    newTranslation("CARD16"),
+		}}
+		r.Fields = append(r.Fields, stringLenLocal)
+	}
+
+	return r
+}
+
+func (x *XMLReply) Translate() *Reply {
+	if x == nil {
+		return nil
+	}
+
+	r := &Reply{
+		Fields: make([]Field, 0, len(x.Fields)),
+		Doc:    x.Doc.Translate(),
+	}
+	for _, field := range x.Fields {
+		if field.XMLName.Local == "fd" {
+			continue
+		}
+		r.Fields = append(r.Fields, field.Translate(r, &r.Doc))
+	}
+	return r
+}
+
+func (x *XMLExpression) Translate() Expression {
+	if x == nil {
+		return nil
+	}
+
+	switch x.XMLName.Local {
+	case "op":
+		if len(x.Exprs) != 2 {
+			log.Panicf("'op' found %d expressions; expected 2.", len(x.Exprs))
+		}
+		return &BinaryOp{
+			Op:    x.Op,
+			Expr1: x.Exprs[0].Translate(),
+			Expr2: x.Exprs[1].Translate(),
+		}
+	case "unop":
+		if len(x.Exprs) != 1 {
+			log.Panicf("'unop' found %d expressions; expected 1.", len(x.Exprs))
+		}
+		return &UnaryOp{
+			Op:   x.Op,
+			Expr: x.Exprs[0].Translate(),
+		}
+	case "popcount":
+		if len(x.Exprs) != 1 {
+			log.Panicf("'popcount' found %d expressions; expected 1.",
+				len(x.Exprs))
+		}
+		return &PopCount{
+			Expr: x.Exprs[0].Translate(),
+		}
+	case "value":
+		val, err := strconv.Atoi(strings.TrimSpace(x.Data))
+		if err != nil {
+			log.Panicf("Could not convert '%s' in 'value' expression to int.",
+				x.Data)
+		}
+		return &Value{
+			v: val,
+		}
+	case "bit":
+		bit, err := strconv.Atoi(strings.TrimSpace(x.Data))
+		if err != nil {
+			log.Panicf("Could not convert '%s' in 'bit' expression to int.",
+				x.Data)
+		}
+		if bit < 0 || bit > 31 {
+			log.Panicf("A 'bit' literal must be in the range [0, 31], but "+
+				" is %d", bit)
+		}
+		return &Bit{
+			b: bit,
+		}
+	case "fieldref":
+		return &FieldRef{
+			Name: x.Data,
+		}
+	case "enumref":
+		return &EnumRef{
+			EnumKind: newTranslation(x.Ref),
+			EnumItem: x.Data,
+		}
+	case "sumof":
+		return &SumOf{
+			Name: x.Ref,
+		}
+	}
+
+	log.Panicf("Unrecognized tag '%s' in expression context. Expected one of "+
+		"op, fieldref, value, bit, enumref, unop, sumof or popcount.",
+		x.XMLName.Local)
+	panic("unreachable")
+}
+
+func (x *XMLField) Translate(parent interface{}, doc *Doc) Field {
+	switch x.XMLName.Local {
+	case "pad":
+		return &PadField{
+			Bytes: x.Bytes,
+			Align: x.Align,
+		}
+	case "field":
+		s := &SingleField{
+			xmlName: x.Name,
+			Type:    newTranslation(x.Type),
+			Comment: doc.DescribeField(x.Name),
+		}
+		return s
+	case "list":
+		return &ListField{
+			xmlName:    x.Name,
+			Type:       newTranslation(x.Type),
+			LengthExpr: x.Expr.Translate(),
+		}
+	case "localfield":
+		return &LocalField{&SingleField{
+			xmlName: x.Name,
+			Type:    newTranslation(x.Type),
+		}}
+	case "exprfield":
+		return &ExprField{
+			xmlName: x.Name,
+			Type:    newTranslation(x.Type),
+			Expr:    x.Expr.Translate(),
+		}
+	case "valueparam":
+		return &ValueField{
+			Parent:      parent,
+			MaskType:    newTranslation(x.ValueMaskType),
+			MaskName:    x.ValueMaskName,
+			ListName:    x.ValueListName,
+			MaskComment: doc.DescribeField(x.ValueMaskName),
+			ListComment: doc.DescribeField(x.ValueListName),
+		}
+	case "switch":
+		swtch := &SwitchField{
+			Name:     x.Name,
+			Expr:     x.Expr.Translate(),
+			Bitcases: make([]*Bitcase, len(x.Bitcases)),
+			Comment:  doc.DescribeField(x.Name),
+		}
+		for i, bitcase := range x.Bitcases {
+			swtch.Bitcases[i] = bitcase.Translate()
+		}
+		return swtch
+	case "required_start_align":
+		return &RequiredStartAlign{}
+	}
+
+	log.Panicf("Unrecognized field element: %s", x.XMLName.Local)
+	panic("unreachable")
+}
+
+func (x *XMLBitcase) Translate() *Bitcase {
+	b := &Bitcase{
+		Expr:   x.Expr().Translate(),
+		Fields: make([]Field, len(x.Fields)),
+	}
+	for i, field := range x.Fields {
+		b.Fields[i] = field.Translate(b, nil)
+	}
+	return b
+}
+
+// SrcName is used to translate any identifier into a Go name.
+// Mostly used for fields, but used in a couple other places too (enum items).
+func SrcName(p *Protocol, name string) string {
+	// If it's in the name map, use that translation.
+	if newn, ok := NameMap[name]; ok {
+		return newn
+	}
+	return splitAndTitle(name)
+}
+
+func TypeSrcName(p *Protocol, typ Type) string {
+	t := typ.XmlName()
+
+	// If this is a base type, then write the raw Go type.
+	if baseType, ok := typ.(*Base); ok {
+		return baseType.SrcName()
+	}
+
+	// If it's in the type map, use that translation.
+	if newt, ok := TypeMap[t]; ok {
+		return newt
+	}
+
+	// If there's a namespace to this type, just use it and be done.
+	if colon := strings.Index(t, ":"); colon > -1 {
+		namespace := t[:colon]
+		rest := t[colon+1:]
+		return p.ProtocolFind(namespace).PkgName() + "." + splitAndTitle(rest)
+	}
+
+	// Since there's no namespace, we're left with the raw type name.
+	// If the type is part of the source we're generating (i.e., there is
+	// no parent protocol), then just return that type name.
+	// Otherwise, we must qualify it with a package name.
+	if p.Parent == nil {
+		return splitAndTitle(t)
+	}
+	return p.PkgName() + "." + splitAndTitle(t)
+}

nexgb/xgbgen/type.go

@@ -0,0 +1,391 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Type interface {
+	Initialize(p *Protocol)
+	SrcName() string
+	XmlName() string
+	Size() Size
+
+	Define(c *Context)
+}
+
+type Types []Type
+
+func (ts Types) Len() int      { return len(ts) }
+func (ts Types) Swap(i, j int) { ts[i], ts[j] = ts[j], ts[i] }
+func (ts Types) Less(i, j int) bool {
+	x1, x2 := ts[i].XmlName(), ts[j].XmlName()
+	s1, s2 := ts[i].SrcName(), ts[j].SrcName()
+	return (s1 == s2 && x1 < x2) || s1 < s2
+}
+
+// Translation is used *only* when transitioning from XML types to
+// our better representation. They are placeholders for the real types (below)
+// that will replace them.
+type Translation struct {
+	xmlName string
+}
+
+func newTranslation(name string) *Translation {
+	return &Translation{xmlName: name}
+}
+
+// RealType takes 'XmlName' and finds its real concrete type in our Protocol.
+// It is an error if we can't find such a type.
+func (t *Translation) RealType(p *Protocol) Type {
+	// Check to see if there is a namespace. If so, strip it and use it to
+	// make sure we only look for a type in that protocol.
+	namespace, typeName := "", t.XmlName()
+	if ni := strings.Index(t.XmlName(), ":"); ni > -1 {
+		namespace, typeName = strings.ToLower(typeName[:ni]), typeName[ni+1:]
+	}
+
+	if len(namespace) == 0 || namespace == strings.ToLower(p.Name) {
+		for _, typ := range p.Types {
+			if typeName == typ.XmlName() {
+				return typ
+			}
+		}
+	}
+	for _, imp := range p.Imports {
+		if len(namespace) == 0 || namespace == strings.ToLower(imp.Name) {
+			for _, typ := range imp.Types {
+				if typeName == typ.XmlName() {
+					return typ
+				}
+			}
+		}
+	}
+	panic("Could not find real type for translation type: " + t.XmlName())
+}
+
+func (t *Translation) SrcName() string {
+	panic("it is illegal to call SrcName on a translation type")
+}
+
+func (t *Translation) XmlName() string {
+	return t.xmlName
+}
+
+func (t *Translation) Size() Size {
+	panic("it is illegal to call Size on a translation type")
+}
+
+func (t *Translation) Define(c *Context) {
+	panic("it is illegal to call Define on a translation type")
+}
+
+func (t *Translation) Initialize(p *Protocol) {
+	panic("it is illegal to call Initialize on a translation type")
+}
+
+type Base struct {
+	srcName string
+	xmlName string
+	size    Size
+}
+
+func (b *Base) SrcName() string {
+	return b.srcName
+}
+
+func (b *Base) XmlName() string {
+	return b.xmlName
+}
+
+func (b *Base) Size() Size {
+	return b.size
+}
+
+func (b *Base) Initialize(p *Protocol) {
+	b.srcName = TypeSrcName(p, b)
+}
+
+type Enum struct {
+	srcName string
+	xmlName string
+	Items   []*EnumItem
+}
+
+type EnumItem struct {
+	srcName string
+	xmlName string
+	Expr    Expression
+}
+
+func (enum *Enum) SrcName() string {
+	return enum.srcName
+}
+
+func (enum *Enum) XmlName() string {
+	return enum.xmlName
+}
+
+func (enum *Enum) Size() Size {
+	panic("Cannot take size of enum")
+}
+
+func (enum *Enum) Initialize(p *Protocol) {
+	enum.srcName = TypeSrcName(p, enum)
+	for _, item := range enum.Items {
+		item.srcName = SrcName(p, item.xmlName)
+		if item.Expr != nil {
+			item.Expr.Initialize(p)
+		}
+	}
+}
+
+type Resource struct {
+	srcName string
+	xmlName string
+}
+
+func (r *Resource) SrcName() string {
+	return r.srcName
+}
+
+func (r *Resource) XmlName() string {
+	return r.xmlName
+}
+
+func (r *Resource) Size() Size {
+	return newFixedSize(BaseTypeSizes["Id"], true)
+}
+
+func (r *Resource) Initialize(p *Protocol) {
+	r.srcName = TypeSrcName(p, r)
+}
+
+type TypeDef struct {
+	srcName string
+	xmlName string
+	Old     Type
+}
+
+func (t *TypeDef) SrcName() string {
+	return t.srcName
+}
+
+func (t *TypeDef) XmlName() string {
+	return t.xmlName
+}
+
+func (t *TypeDef) Size() Size {
+	return t.Old.Size()
+}
+
+func (t *TypeDef) Initialize(p *Protocol) {
+	t.Old = t.Old.(*Translation).RealType(p)
+	t.srcName = TypeSrcName(p, t)
+}
+
+type Event struct {
+	srcName    string
+	xmlName    string
+	Number     int
+	NoSequence bool
+	Fields     []Field
+	Doc        Doc
+}
+
+func (e *Event) SrcName() string {
+	return e.srcName
+}
+
+func (e *Event) XmlName() string {
+	return e.xmlName
+}
+
+func (e *Event) Size() Size {
+	return newExpressionSize(&Value{v: 32}, true)
+}
+
+func (e *Event) Initialize(p *Protocol) {
+	e.srcName = TypeSrcName(p, e)
+	for _, field := range e.Fields {
+		field.Initialize(p)
+	}
+}
+
+func (e *Event) EvType() string {
+	return fmt.Sprintf("%sEvent", e.srcName)
+}
+
+type EventCopy struct {
+	srcName string
+	xmlName string
+	Old     Type
+	Number  int
+}
+
+func (e *EventCopy) SrcName() string {
+	return e.srcName
+}
+
+func (e *EventCopy) XmlName() string {
+	return e.xmlName
+}
+
+func (e *EventCopy) Size() Size {
+	return newExpressionSize(&Value{v: 32}, true)
+}
+
+func (e *EventCopy) Initialize(p *Protocol) {
+	e.srcName = TypeSrcName(p, e)
+	e.Old = e.Old.(*Translation).RealType(p)
+	if _, ok := e.Old.(*Event); !ok {
+		panic("an EventCopy's old type *must* be *Event")
+	}
+}
+
+func (e *EventCopy) EvType() string {
+	return fmt.Sprintf("%sEvent", e.srcName)
+}
+
+type Error struct {
+	srcName string
+	xmlName string
+	Number  int
+	Fields  []Field
+}
+
+func (e *Error) SrcName() string {
+	return e.srcName
+}
+
+func (e *Error) XmlName() string {
+	return e.xmlName
+}
+
+func (e *Error) Size() Size {
+	return newExpressionSize(&Value{v: 32}, true)
+}
+
+func (e *Error) Initialize(p *Protocol) {
+	e.srcName = TypeSrcName(p, e)
+	for _, field := range e.Fields {
+		field.Initialize(p)
+	}
+}
+
+func (e *Error) ErrConst() string {
+	return fmt.Sprintf("Bad%s", e.srcName)
+}
+
+func (e *Error) ErrType() string {
+	return fmt.Sprintf("%sError", e.srcName)
+}
+
+type ErrorCopy struct {
+	srcName string
+	xmlName string
+	Old     Type
+	Number  int
+}
+
+func (e *ErrorCopy) SrcName() string {
+	return e.srcName
+}
+
+func (e *ErrorCopy) XmlName() string {
+	return e.xmlName
+}
+
+func (e *ErrorCopy) Size() Size {
+	return newExpressionSize(&Value{v: 32}, true)
+}
+
+func (e *ErrorCopy) Initialize(p *Protocol) {
+	e.srcName = TypeSrcName(p, e)
+	e.Old = e.Old.(*Translation).RealType(p)
+	if _, ok := e.Old.(*Error); !ok {
+		panic("an ErrorCopy's old type *must* be *Event")
+	}
+}
+
+func (e *ErrorCopy) ErrConst() string {
+	return fmt.Sprintf("Bad%s", e.srcName)
+}
+
+func (e *ErrorCopy) ErrType() string {
+	return fmt.Sprintf("%sError", e.srcName)
+}
+
+type Struct struct {
+	srcName string
+	xmlName string
+	Fields  []Field
+}
+
+func (s *Struct) SrcName() string {
+	return s.srcName
+}
+
+func (s *Struct) XmlName() string {
+	return s.xmlName
+}
+
+func (s *Struct) Size() Size {
+	size := newFixedSize(0, true)
+	for _, field := range s.Fields {
+		size = size.Add(field.Size())
+	}
+	return size
+}
+
+func (s *Struct) Initialize(p *Protocol) {
+	s.srcName = TypeSrcName(p, s)
+	for _, field := range s.Fields {
+		field.Initialize(p)
+	}
+}
+
+// HasList returns whether there is a field in this struct that is a list.
+// When true, a more involved calculation is necessary to compute this struct's
+// size.
+func (s *Struct) HasList() bool {
+	for _, field := range s.Fields {
+		if _, ok := field.(*ListField); ok {
+			return true
+		}
+	}
+	return false
+}
+
+type Union struct {
+	srcName string
+	xmlName string
+	Fields  []Field
+}
+
+func (u *Union) SrcName() string {
+	return u.srcName
+}
+
+func (u *Union) XmlName() string {
+	return u.xmlName
+}
+
+// Size for Union is broken. At least, it's broken for XKB.
+// It *looks* like the protocol inherently relies on some amount of
+// memory unsafety, since some members of unions in XKB are *variable* in
+// length! The only thing I can come up with, maybe, is when a union has
+// variable size, simply return the raw bytes. Then it's up to the user to
+// pass those raw bytes into the appropriate New* constructor. GROSS!
+// As of now, just pluck out the first field and return that size. This
+// should work for union elements in randr.xml and xproto.xml.
+func (u *Union) Size() Size {
+	return u.Fields[0].Size()
+}
+
+func (u *Union) Initialize(p *Protocol) {
+	u.srcName = fmt.Sprintf("%sUnion", TypeSrcName(p, u))
+	for _, field := range u.Fields {
+		field.Initialize(p)
+	}
+}

nexgb/xgbgen/xml.go

@@ -0,0 +1,159 @@
+package main
+
+import (
+	"encoding/xml"
+	"io/ioutil"
+	"log"
+)
+
+type XML struct {
+	// Root 'xcb' element properties.
+	XMLName        xml.Name `xml:"xcb"`
+	Header         string   `xml:"header,attr"`
+	ExtensionXName string   `xml:"extension-xname,attr"`
+	ExtensionName  string   `xml:"extension-name,attr"`
+	MajorVersion   string   `xml:"major-version,attr"`
+	MinorVersion   string   `xml:"minor-version,attr"`
+
+	// Types for all top-level elements.
+	// First are the simple ones.
+	Imports     XMLImports      `xml:"import"`
+	Enums       []*XMLEnum      `xml:"enum"`
+	Xids        []*XMLXid       `xml:"xidtype"`
+	XidUnions   []*XMLXid       `xml:"xidunion"`
+	TypeDefs    []*XMLTypeDef   `xml:"typedef"`
+	EventCopies []*XMLEventCopy `xml:"eventcopy"`
+	ErrorCopies []*XMLErrorCopy `xml:"errorcopy"`
+
+	// Here are the complex ones, i.e., anything with "structure contents"
+	Structs  []*XMLStruct  `xml:"struct"`
+	Unions   []*XMLUnion   `xml:"union"`
+	Requests []*XMLRequest `xml:"request"`
+	Events   []*XMLEvent   `xml:"event"`
+	Errors   []*XMLError   `xml:"error"`
+}
+
+type XMLImports []*XMLImport
+
+func (imports XMLImports) Eval() {
+	for _, imp := range imports {
+		xmlBytes, err := ioutil.ReadFile(*protoPath + "/" + imp.Name + ".xml")
+		if err != nil {
+			log.Fatalf("Could not read X protocol description for import "+
+				"'%s' because: %s", imp.Name, err)
+		}
+
+		imp.xml = &XML{}
+		err = xml.Unmarshal(xmlBytes, imp.xml)
+		if err != nil {
+			log.Fatal("Could not parse X protocol description for import "+
+				"'%s' because: %s", imp.Name, err)
+		}
+
+		// recursive imports...
+		imp.xml.Imports.Eval()
+	}
+}
+
+type XMLImport struct {
+	Name string `xml:",chardata"`
+	xml  *XML   `xml:"-"`
+}
+
+type XMLEnum struct {
+	Name  string         `xml:"name,attr"`
+	Items []*XMLEnumItem `xml:"item"`
+}
+
+type XMLEnumItem struct {
+	Name string         `xml:"name,attr"`
+	Expr *XMLExpression `xml:",any"`
+}
+
+type XMLXid struct {
+	XMLName xml.Name
+	Name    string `xml:"name,attr"`
+}
+
+type XMLTypeDef struct {
+	Old string `xml:"oldname,attr"`
+	New string `xml:"newname,attr"`
+}
+
+type XMLEventCopy struct {
+	Name   string `xml:"name,attr"`
+	Number int    `xml:"number,attr"`
+	Ref    string `xml:"ref,attr"`
+}
+
+type XMLErrorCopy struct {
+	Name   string `xml:"name,attr"`
+	Number int    `xml:"number,attr"`
+	Ref    string `xml:"ref,attr"`
+}
+
+type XMLDocField struct {
+	Name        string `xml:"name,attr"`
+	Description string `xml:",chardata"`
+}
+
+type XMLDocError struct {
+	Type        string `xml:"type,attr"`
+	Description string `xml:",chardata"`
+}
+
+type XMLDoc struct {
+	Brief       string         `xml:"brief"`
+	Description string         `xml:"description"`
+	Example     string         `xml:"example"`
+	Fields      []*XMLDocField `xml:"field"`
+	Errors      []*XMLDocError `xml:"error"`
+}
+
+type XMLStruct struct {
+	Name   string      `xml:"name,attr"`
+	Fields []*XMLField `xml:",any"`
+}
+
+type XMLUnion struct {
+	Name   string      `xml:"name,attr"`
+	Fields []*XMLField `xml:",any"`
+}
+
+type XMLRequest struct {
+	Name    string      `xml:"name,attr"`
+	Opcode  int         `xml:"opcode,attr"`
+	Combine bool        `xml:"combine-adjacent,attr"`
+	Fields  []*XMLField `xml:",any"`
+	Reply   *XMLReply   `xml:"reply"`
+	Doc     *XMLDoc     `xml:"doc"`
+}
+
+type XMLReply struct {
+	Fields []*XMLField `xml:",any"`
+	Doc    *XMLDoc     `xml:"doc"`
+}
+
+type XMLEvent struct {
+	Name       string      `xml:"name,attr"`
+	Number     int         `xml:"number,attr"`
+	NoSequence bool        `xml:"no-sequence-number,attr"`
+	Fields     []*XMLField `xml:",any"`
+	Doc        *XMLDoc     `xml:"doc"`
+}
+
+type XMLError struct {
+	Name   string      `xml:"name,attr"`
+	Number int         `xml:"number,attr"`
+	Fields []*XMLField `xml:",any"`
+}
+
+type XMLExpression struct {
+	XMLName xml.Name
+
+	Exprs []*XMLExpression `xml:",any"`
+
+	Data string `xml:",chardata"`
+	Op   string `xml:"op,attr"`
+	Ref  string `xml:"ref,attr"`
+}

nexgb/xgbgen/xml_fields.go

@@ -0,0 +1,86 @@
+package main
+
+import (
+	"encoding/xml"
+	"log"
+)
+
+type XMLField struct {
+	XMLName xml.Name
+
+	// For 'pad' element
+	Bytes uint   `xml:"bytes,attr"`
+	Align uint16 `xml:"align,attr"`
+
+	// For 'field', 'list', 'localfield', 'exprfield' and 'switch' elements.
+	Name string `xml:"name,attr"`
+
+	// For 'field', 'list', 'localfield', and 'exprfield' elements.
+	Type string `xml:"type,attr"`
+
+	// For 'list', 'exprfield' and 'switch' elements.
+	Expr *XMLExpression `xml:",any"`
+
+	// For 'valueparm' element.
+	ValueMaskType string `xml:"value-mask-type,attr"`
+	ValueMaskName string `xml:"value-mask-name,attr"`
+	ValueListName string `xml:"value-list-name,attr"`
+
+	// For 'switch' element.
+	Bitcases []*XMLBitcase `xml:"bitcase"`
+
+	// I don't know which elements these are for. The documentation is vague.
+	// They also seem to be completely optional.
+	OptEnum    string `xml:"enum,attr"`
+	OptMask    string `xml:"mask,attr"`
+	OptAltEnum string `xml:"altenum,attr"`
+}
+
+// Bitcase represents a single expression followed by any number of fields.
+// Namely, if the switch's expression (all bitcases are inside a switch),
+// and'd with the bitcase's expression is equal to the bitcase expression,
+// then the fields should be included in its parent structure.
+// Note that since a bitcase is unique in that expressions and fields are
+// siblings, we must exhaustively search for one of them. Essentially,
+// it's the closest thing to a Union I can get to in Go without interfaces.
+// Would an '<expression>' tag have been too much to ask? :-(
+type XMLBitcase struct {
+	Fields []*XMLField `xml:",any"`
+
+	// All the different expressions.
+	// When it comes time to choose one, use the 'Expr' method.
+	ExprOp    *XMLExpression `xml:"op"`
+	ExprUnOp  *XMLExpression `xml:"unop"`
+	ExprField *XMLExpression `xml:"fieldref"`
+	ExprValue *XMLExpression `xml:"value"`
+	ExprBit   *XMLExpression `xml:"bit"`
+	ExprEnum  *XMLExpression `xml:"enumref"`
+	ExprSum   *XMLExpression `xml:"sumof"`
+	ExprPop   *XMLExpression `xml:"popcount"`
+}
+
+// Expr chooses the only non-nil Expr* field from Bitcase.
+// Panic if there is more than one non-nil expression.
+func (b *XMLBitcase) Expr() *XMLExpression {
+	choices := []*XMLExpression{
+		b.ExprOp, b.ExprUnOp, b.ExprField, b.ExprValue,
+		b.ExprBit, b.ExprEnum, b.ExprSum, b.ExprPop,
+	}
+
+	var choice *XMLExpression = nil
+	numNonNil := 0
+	for _, c := range choices {
+		if c != nil {
+			numNonNil++
+			choice = c
+		}
+	}
+
+	if choice == nil {
+		log.Panicf("No top level expression found in a bitcase.")
+	}
+	if numNonNil > 1 {
+		log.Panicf("More than one top-level expression was found in a bitcase.")
+	}
+	return choice
+}

nexgb/xinerama/xinerama.go

@@ -0,0 +1,717 @@
+// Package xinerama is the X client API for the XINERAMA extension.
+package xinerama
+
+// This file is automatically generated from xinerama.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 1
+	MinorVersion = 1
+)
+
+// Init must be called before using the XINERAMA extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 8, "XINERAMA").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named XINERAMA could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["XINERAMA"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["XINERAMA"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["XINERAMA"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["XINERAMA"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["XINERAMA"] = make(map[int]xgb.NewErrorFun)
+}
+
+type ScreenInfo struct {
+	XOrg   int16
+	YOrg   int16
+	Width  uint16
+	Height uint16
+}
+
+// ScreenInfoRead reads a byte slice into a ScreenInfo value.
+func ScreenInfoRead(buf []byte, v *ScreenInfo) int {
+	b := 0
+
+	v.XOrg = int16(xgb.Get16(buf[b:]))
+	b += 2
+
+	v.YOrg = int16(xgb.Get16(buf[b:]))
+	b += 2
+
+	v.Width = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Height = xgb.Get16(buf[b:])
+	b += 2
+
+	return b
+}
+
+// ScreenInfoReadList reads a byte slice into a list of ScreenInfo values.
+func ScreenInfoReadList(buf []byte, dest []ScreenInfo) int {
+	b := 0
+	for i := 0; i < len(dest); i++ {
+		dest[i] = ScreenInfo{}
+		b += ScreenInfoRead(buf[b:], &dest[i])
+	}
+	return xgb.Pad(b)
+}
+
+// Bytes writes a ScreenInfo value to a byte slice.
+func (v ScreenInfo) Bytes() []byte {
+	buf := make([]byte, 8)
+	b := 0
+
+	xgb.Put16(buf[b:], uint16(v.XOrg))
+	b += 2
+
+	xgb.Put16(buf[b:], uint16(v.YOrg))
+	b += 2
+
+	xgb.Put16(buf[b:], v.Width)
+	b += 2
+
+	xgb.Put16(buf[b:], v.Height)
+	b += 2
+
+	return buf[:b]
+}
+
+// ScreenInfoListBytes writes a list of ScreenInfo values to a byte slice.
+func ScreenInfoListBytes(buf []byte, list []ScreenInfo) int {
+	b := 0
+	var structBytes []byte
+	for _, item := range list {
+		structBytes = item.Bytes()
+		copy(buf[b:], structBytes)
+		b += len(structBytes)
+	}
+	return xgb.Pad(b)
+}
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// GetScreenCountCookie is a cookie used only for GetScreenCount requests.
+type GetScreenCountCookie struct {
+	*xgb.Cookie
+}
+
+// GetScreenCount sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetScreenCountCookie.Reply.
+func GetScreenCount(c *xgb.Conn, Window xproto.Window) GetScreenCountCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'GetScreenCount' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getScreenCountRequest(c, Window), cookie)
+	return GetScreenCountCookie{cookie}
+}
+
+// GetScreenCountUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetScreenCountUnchecked(c *xgb.Conn, Window xproto.Window) GetScreenCountCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'GetScreenCount' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getScreenCountRequest(c, Window), cookie)
+	return GetScreenCountCookie{cookie}
+}
+
+// GetScreenCountReply represents the data returned from a GetScreenCount request.
+type GetScreenCountReply struct {
+	Sequence    uint16 // sequence number of the request for this reply
+	Length      uint32 // number of bytes in this reply
+	ScreenCount byte
+	Window      xproto.Window
+}
+
+// Reply blocks and returns the reply data for a GetScreenCount request.
+func (cook GetScreenCountCookie) Reply() (*GetScreenCountReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getScreenCountReply(buf), nil
+}
+
+// getScreenCountReply reads a byte slice into a GetScreenCountReply value.
+func getScreenCountReply(buf []byte) *GetScreenCountReply {
+	v := new(GetScreenCountReply)
+	b := 1 // skip reply determinant
+
+	v.ScreenCount = buf[b]
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.Window = xproto.Window(xgb.Get32(buf[b:]))
+	b += 4
+
+	return v
+}
+
+// getScreenCountRequest writes a GetScreenCount request to a byte slice for transfer.
+func getScreenCountRequest(c *xgb.Conn, Window xproto.Window) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XINERAMA"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 2 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	return buf
+}
+
+// GetScreenSizeCookie is a cookie used only for GetScreenSize requests.
+type GetScreenSizeCookie struct {
+	*xgb.Cookie
+}
+
+// GetScreenSize sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetScreenSizeCookie.Reply.
+func GetScreenSize(c *xgb.Conn, Window xproto.Window, Screen uint32) GetScreenSizeCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'GetScreenSize' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getScreenSizeRequest(c, Window, Screen), cookie)
+	return GetScreenSizeCookie{cookie}
+}
+
+// GetScreenSizeUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetScreenSizeUnchecked(c *xgb.Conn, Window xproto.Window, Screen uint32) GetScreenSizeCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'GetScreenSize' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getScreenSizeRequest(c, Window, Screen), cookie)
+	return GetScreenSizeCookie{cookie}
+}
+
+// GetScreenSizeReply represents the data returned from a GetScreenSize request.
+type GetScreenSizeReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	Width  uint32
+	Height uint32
+	Window xproto.Window
+	Screen uint32
+}
+
+// Reply blocks and returns the reply data for a GetScreenSize request.
+func (cook GetScreenSizeCookie) Reply() (*GetScreenSizeReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getScreenSizeReply(buf), nil
+}
+
+// getScreenSizeReply reads a byte slice into a GetScreenSizeReply value.
+func getScreenSizeReply(buf []byte) *GetScreenSizeReply {
+	v := new(GetScreenSizeReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.Width = xgb.Get32(buf[b:])
+	b += 4
+
+	v.Height = xgb.Get32(buf[b:])
+	b += 4
+
+	v.Window = xproto.Window(xgb.Get32(buf[b:]))
+	b += 4
+
+	v.Screen = xgb.Get32(buf[b:])
+	b += 4
+
+	return v
+}
+
+// getScreenSizeRequest writes a GetScreenSize request to a byte slice for transfer.
+func getScreenSizeRequest(c *xgb.Conn, Window xproto.Window, Screen uint32) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XINERAMA"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 3 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	xgb.Put32(buf[b:], Screen)
+	b += 4
+
+	return buf
+}
+
+// GetStateCookie is a cookie used only for GetState requests.
+type GetStateCookie struct {
+	*xgb.Cookie
+}
+
+// GetState sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetStateCookie.Reply.
+func GetState(c *xgb.Conn, Window xproto.Window) GetStateCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'GetState' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getStateRequest(c, Window), cookie)
+	return GetStateCookie{cookie}
+}
+
+// GetStateUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetStateUnchecked(c *xgb.Conn, Window xproto.Window) GetStateCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'GetState' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getStateRequest(c, Window), cookie)
+	return GetStateCookie{cookie}
+}
+
+// GetStateReply represents the data returned from a GetState request.
+type GetStateReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	State    byte
+	Window   xproto.Window
+}
+
+// Reply blocks and returns the reply data for a GetState request.
+func (cook GetStateCookie) Reply() (*GetStateReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getStateReply(buf), nil
+}
+
+// getStateReply reads a byte slice into a GetStateReply value.
+func getStateReply(buf []byte) *GetStateReply {
+	v := new(GetStateReply)
+	b := 1 // skip reply determinant
+
+	v.State = buf[b]
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.Window = xproto.Window(xgb.Get32(buf[b:]))
+	b += 4
+
+	return v
+}
+
+// getStateRequest writes a GetState request to a byte slice for transfer.
+func getStateRequest(c *xgb.Conn, Window xproto.Window) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XINERAMA"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 1 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	return buf
+}
+
+// IsActiveCookie is a cookie used only for IsActive requests.
+type IsActiveCookie struct {
+	*xgb.Cookie
+}
+
+// IsActive sends a checked request.
+// If an error occurs, it will be returned with the reply by calling IsActiveCookie.Reply.
+func IsActive(c *xgb.Conn) IsActiveCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'IsActive' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(isActiveRequest(c), cookie)
+	return IsActiveCookie{cookie}
+}
+
+// IsActiveUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func IsActiveUnchecked(c *xgb.Conn) IsActiveCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'IsActive' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(isActiveRequest(c), cookie)
+	return IsActiveCookie{cookie}
+}
+
+// IsActiveReply represents the data returned from a IsActive request.
+type IsActiveReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	State uint32
+}
+
+// Reply blocks and returns the reply data for a IsActive request.
+func (cook IsActiveCookie) Reply() (*IsActiveReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return isActiveReply(buf), nil
+}
+
+// isActiveReply reads a byte slice into a IsActiveReply value.
+func isActiveReply(buf []byte) *IsActiveReply {
+	v := new(IsActiveReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.State = xgb.Get32(buf[b:])
+	b += 4
+
+	return v
+}
+
+// isActiveRequest writes a IsActive request to a byte slice for transfer.
+func isActiveRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XINERAMA"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 4 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}
+
+// QueryScreensCookie is a cookie used only for QueryScreens requests.
+type QueryScreensCookie struct {
+	*xgb.Cookie
+}
+
+// QueryScreens sends a checked request.
+// If an error occurs, it will be returned with the reply by calling QueryScreensCookie.Reply.
+func QueryScreens(c *xgb.Conn) QueryScreensCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'QueryScreens' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(queryScreensRequest(c), cookie)
+	return QueryScreensCookie{cookie}
+}
+
+// QueryScreensUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func QueryScreensUnchecked(c *xgb.Conn) QueryScreensCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'QueryScreens' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(queryScreensRequest(c), cookie)
+	return QueryScreensCookie{cookie}
+}
+
+// QueryScreensReply represents the data returned from a QueryScreens request.
+type QueryScreensReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	Number uint32
+	// padding: 20 bytes
+	ScreenInfo []ScreenInfo // size: xgb.Pad((int(Number) * 8))
+}
+
+// Reply blocks and returns the reply data for a QueryScreens request.
+func (cook QueryScreensCookie) Reply() (*QueryScreensReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return queryScreensReply(buf), nil
+}
+
+// queryScreensReply reads a byte slice into a QueryScreensReply value.
+func queryScreensReply(buf []byte) *QueryScreensReply {
+	v := new(QueryScreensReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.Number = xgb.Get32(buf[b:])
+	b += 4
+
+	b += 20 // padding
+
+	v.ScreenInfo = make([]ScreenInfo, v.Number)
+	b += ScreenInfoReadList(buf[b:], v.ScreenInfo)
+
+	return v
+}
+
+// queryScreensRequest writes a QueryScreens request to a byte slice for transfer.
+func queryScreensRequest(c *xgb.Conn) []byte {
+	size := 4
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XINERAMA"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 5 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	return buf
+}
+
+// QueryVersionCookie is a cookie used only for QueryVersion requests.
+type QueryVersionCookie struct {
+	*xgb.Cookie
+}
+
+// QueryVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling QueryVersionCookie.Reply.
+func QueryVersion(c *xgb.Conn, Major, Minor byte) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(queryVersionRequest(c, Major, Minor), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func QueryVersionUnchecked(c *xgb.Conn, Major, Minor byte) QueryVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XINERAMA"]; !ok {
+		panic("Cannot issue request 'QueryVersion' using the uninitialized extension 'XINERAMA'. xinerama.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(queryVersionRequest(c, Major, Minor), cookie)
+	return QueryVersionCookie{cookie}
+}
+
+// QueryVersionReply represents the data returned from a QueryVersion request.
+type QueryVersionReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	// padding: 1 bytes
+	Major uint16
+	Minor uint16
+}
+
+// Reply blocks and returns the reply data for a QueryVersion request.
+func (cook QueryVersionCookie) Reply() (*QueryVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return queryVersionReply(buf), nil
+}
+
+// queryVersionReply reads a byte slice into a QueryVersionReply value.
+func queryVersionReply(buf []byte) *QueryVersionReply {
+	v := new(QueryVersionReply)
+	b := 1 // skip reply determinant
+
+	b += 1 // padding
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.Major = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Minor = xgb.Get16(buf[b:])
+	b += 2
+
+	return v
+}
+
+// queryVersionRequest writes a QueryVersion request to a byte slice for transfer.
+func queryVersionRequest(c *xgb.Conn, Major, Minor byte) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XINERAMA"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	buf[b] = Major
+	b += 1
+
+	buf[b] = Minor
+	b += 1
+
+	return buf
+}

nexgb/xproto/xproto_test.go

@@ -0,0 +1,384 @@
+package xproto
+
+/*
+	Tests for XGB.
+
+	These tests only test the core X protocol at the moment. It isn't even
+	close to complete coverage (and probably never will be), but it does test
+	a number of different corners: requests with no replies, requests without
+	replies, checked (i.e., synchronous) errors, unchecked (i.e., asynchronous)
+	errors, and sequence number wrapping.
+
+	There are also a couple of benchmarks that show the difference between
+	correctly issuing lots of requests and gathering replies and
+	incorrectly doing the same. (This particular difference is one of the
+	claimed advantages of the XCB, and therefore XGB, family.)
+
+	In sum, these tests are more focused on testing the core xgb package itself,
+	rather than whether xproto has properly implemented the core X client
+	protocol.
+*/
+
+import (
+	"fmt"
+	"log"
+	"math/rand"
+	"testing"
+	"time"
+
+	xgb "janouch.name/haven/nexgb"
+)
+
+// The X connection used throughout testing.
+var X *xgb.Conn
+
+// init initializes the X connection, seeds the RNG and starts waiting
+// for events.
+func init() {
+	var err error
+
+	X, err = xgb.NewConn()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	rand.Seed(time.Now().UnixNano())
+
+	go grabEvents()
+}
+
+/******************************************************************************/
+// Tests
+/******************************************************************************/
+
+// TestSynchronousError purposefully causes a BadWindow error in a
+// MapWindow request, and checks it synchronously.
+func TestSynchronousError(t *testing.T) {
+	err := MapWindowChecked(X, 0).Check() // resource 0 is always invalid
+	if err == nil {
+		t.Fatalf("MapWindow: A MapWindow request that should return an " +
+			"error has returned a nil error.")
+	}
+	verifyMapWindowError(t, err)
+}
+
+// TestAsynchronousError does the same thing as TestSynchronousError, but
+// grabs the error asynchronously instead.
+func TestAsynchronousError(t *testing.T) {
+	MapWindow(X, 0) // resource id 0 is always invalid
+
+	evOrErr := waitForEvent(t, 5)
+	if evOrErr.ev != nil {
+		t.Fatalf("After issuing an erroneous MapWindow request, we have "+
+			"received an event rather than an error: %s", evOrErr.ev)
+	}
+	verifyMapWindowError(t, evOrErr.err)
+}
+
+// TestCookieBuffer issues (2^16) + n requets *without* replies to guarantee
+// that the sequence number wraps and that the cookie buffer will have to
+// flush itself (since there are no replies coming in to flush it).
+// And just like TestSequenceWrap, we issue another request with a reply
+// at the end to make sure XGB is still working properly.
+func TestCookieBuffer(t *testing.T) {
+	n := (1 << 16) + 10
+	for i := 0; i < n; i++ {
+		NoOperation(X)
+	}
+	TestProperty(t)
+}
+
+// TestSequenceWrap issues (2^16) + n requests w/ replies to guarantee that the
+// sequence number (which is a 16 bit integer) will wrap. It then issues one
+// final request to ensure things still work properly.
+func TestSequenceWrap(t *testing.T) {
+	n := (1 << 16) + 10
+	for i := 0; i < n; i++ {
+		_, err := InternAtom(X, false, 5, "RANDO").Reply()
+		if err != nil {
+			t.Fatalf("InternAtom: %s", err)
+		}
+	}
+	TestProperty(t)
+}
+
+// TestProperty tests whether a random value can be set and read.
+func TestProperty(t *testing.T) {
+	propName := randString(20) // whatevs
+	writeVal := randString(20)
+	readVal, err := changeAndGetProp(propName, writeVal)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if readVal != writeVal {
+		t.Errorf("The value written, '%s', is not the same as the "+
+			"value read '%s'.", writeVal, readVal)
+	}
+}
+
+// TestWindowEvents creates a window, maps it, listens for configure notify
+// events, issues a configure request, and checks for the appropriate
+// configure notify event.
+// This probably violates the notion of "test one thing and test it well,"
+// but testing X stuff is unique since it involves so much state.
+// Each request is checked to make sure there are no errors returned. If there
+// is an error, the test is failed.
+// You may see a window appear quickly and then disappear. Do not be alarmed :P
+// It's possible that this test will yield a false negative because we cannot
+// control our environment. That is, the window manager could override the
+// placement set. However, we set override redirect on the window, so the
+// window manager *shouldn't* touch our window if it is well-behaved.
+func TestWindowEvents(t *testing.T) {
+	// The geometry to set the window.
+	gx, gy, gw, gh := 200, 400, 1000, 300
+
+	wid, err := NewWindowId(X)
+	if err != nil {
+		t.Fatalf("NewId: %s", err)
+	}
+
+	screen := Setup(X).DefaultScreen(X) // alias
+	err = CreateWindowChecked(X, screen.RootDepth, wid, screen.Root,
+		0, 0, 500, 500, 0,
+		WindowClassInputOutput, screen.RootVisual,
+		CwBackPixel|CwOverrideRedirect, []uint32{0xffffffff, 1}).Check()
+	if err != nil {
+		t.Fatalf("CreateWindow: %s", err)
+	}
+
+	err = MapWindowChecked(X, wid).Check()
+	if err != nil {
+		t.Fatalf("MapWindow: %s", err)
+	}
+
+	// We don't listen in the CreateWindow request so that we don't get
+	// a MapNotify event.
+	err = ChangeWindowAttributesChecked(X, wid,
+		CwEventMask, []uint32{EventMaskStructureNotify}).Check()
+	if err != nil {
+		t.Fatalf("ChangeWindowAttributes: %s", err)
+	}
+
+	err = ConfigureWindowChecked(X, wid,
+		ConfigWindowX|ConfigWindowY|
+			ConfigWindowWidth|ConfigWindowHeight,
+		[]uint32{uint32(gx), uint32(gy), uint32(gw), uint32(gh)}).Check()
+	if err != nil {
+		t.Fatalf("ConfigureWindow: %s", err)
+	}
+
+	evOrErr := waitForEvent(t, 5)
+	switch event := evOrErr.ev.(type) {
+	case ConfigureNotifyEvent:
+		if event.X != int16(gx) {
+			t.Fatalf("x was set to %d but ConfigureNotify reports %d",
+				gx, event.X)
+		}
+		if event.Y != int16(gy) {
+			t.Fatalf("y was set to %d but ConfigureNotify reports %d",
+				gy, event.Y)
+		}
+		if event.Width != uint16(gw) {
+			t.Fatalf("width was set to %d but ConfigureNotify reports %d",
+				gw, event.Width)
+		}
+		if event.Height != uint16(gh) {
+			t.Fatalf("height was set to %d but ConfigureNotify reports %d",
+				gh, event.Height)
+		}
+	default:
+		t.Fatalf("Expected a ConfigureNotifyEvent but got %T instead.", event)
+	}
+
+	// Okay, clean up!
+	err = ChangeWindowAttributesChecked(X, wid,
+		CwEventMask, []uint32{0}).Check()
+	if err != nil {
+		t.Fatalf("ChangeWindowAttributes: %s", err)
+	}
+
+	err = DestroyWindowChecked(X, wid).Check()
+	if err != nil {
+		t.Fatalf("DestroyWindow: %s", err)
+	}
+}
+
+// Calls GetFontPath function, Issue #12
+func TestGetFontPath(t *testing.T) {
+	fontPathReply, err := GetFontPath(X).Reply()
+	if err != nil {
+		t.Fatalf("GetFontPath: %v", err)
+	}
+	_ = fontPathReply
+}
+
+func TestListFonts(t *testing.T) {
+	listFontsReply, err := ListFonts(X, 10, 1, "*").Reply()
+	if err != nil {
+		t.Fatalf("ListFonts: %v", err)
+	}
+	_ = listFontsReply
+}
+
+/******************************************************************************/
+// Benchmarks
+/******************************************************************************/
+
+// BenchmarkInternAtomsGood shows how many requests with replies
+// *should* be sent and gathered from the server. Namely, send as many
+// requests as you can at once, then go back and gather up all the replies.
+// More importantly, this approach can exploit parallelism when
+// GOMAXPROCS > 1.
+// Run with `go test -run 'nomatch' -bench '.*' -cpu 1,2,6` if you have
+// multiple cores to see the improvement that parallelism brings.
+func BenchmarkInternAtomsGood(b *testing.B) {
+	b.StopTimer()
+	names := seqNames(b.N)
+
+	b.StartTimer()
+	cookies := make([]InternAtomCookie, b.N)
+	for i := 0; i < b.N; i++ {
+		cookies[i] = InternAtom(X, false, uint16(len(names[i])), names[i])
+	}
+	for _, cookie := range cookies {
+		cookie.Reply()
+	}
+}
+
+// BenchmarkInternAtomsBad shows how *not* to issue a lot of requests with
+// replies. Namely, each subsequent request isn't issued *until* the last
+// reply is made. This implies a round trip to the X server for every
+// iteration.
+func BenchmarkInternAtomsPoor(b *testing.B) {
+	b.StopTimer()
+	names := seqNames(b.N)
+
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		InternAtom(X, false, uint16(len(names[i])), names[i]).Reply()
+	}
+}
+
+/******************************************************************************/
+// Helper functions
+/******************************************************************************/
+
+// changeAndGetProp sets property 'prop' with value 'val'.
+// It then gets the value of that property and returns it.
+// (It's used to check that the 'val' going in is the same 'val' going out.)
+// It tests both requests with and without replies (GetProperty and
+// ChangeProperty respectively.)
+func changeAndGetProp(prop, val string) (string, error) {
+	setup := Setup(X)
+	root := setup.DefaultScreen(X).Root
+
+	propAtom, err := InternAtom(X, false, uint16(len(prop)), prop).Reply()
+	if err != nil {
+		return "", fmt.Errorf("InternAtom: %s", err)
+	}
+
+	typName := "UTF8_STRING"
+	typAtom, err := InternAtom(X, false, uint16(len(typName)), typName).Reply()
+	if err != nil {
+		return "", fmt.Errorf("InternAtom: %s", err)
+	}
+
+	err = ChangePropertyChecked(X, PropModeReplace, root, propAtom.Atom,
+		typAtom.Atom, 8, uint32(len(val)), []byte(val)).Check()
+	if err != nil {
+		return "", fmt.Errorf("ChangeProperty: %s", err)
+	}
+
+	reply, err := GetProperty(X, false, root, propAtom.Atom,
+		GetPropertyTypeAny, 0, (1<<32)-1).Reply()
+	if err != nil {
+		return "", fmt.Errorf("GetProperty: %s", err)
+	}
+	if reply.Format != 8 {
+		return "", fmt.Errorf("Property reply format is %d but it should be 8.",
+			reply.Format)
+	}
+
+	return string(reply.Value), nil
+}
+
+// verifyMapWindowError takes an error that is returned with an invalid
+// MapWindow request with a window Id of 0 and makes sure the error is the
+// right type and contains the correct values.
+func verifyMapWindowError(t *testing.T, err error) {
+	switch e := err.(type) {
+	case WindowError:
+		if e.BadValue != 0 {
+			t.Fatalf("WindowError should report a bad value of 0 but "+
+				"it reports %d instead.", e.BadValue)
+		}
+		if e.MajorOpcode != 8 {
+			t.Fatalf("WindowError should report a major opcode of 8 "+
+				"(which is a MapWindow request), but it reports %d instead.",
+				e.MajorOpcode)
+		}
+	default:
+		t.Fatalf("Expected a WindowError but got %T instead.", e)
+	}
+}
+
+// randString generates a random string of length n.
+func randString(n int) string {
+	byts := make([]byte, n)
+	for i := 0; i < n; i++ {
+		rando := rand.Intn(53)
+		switch {
+		case rando <= 25:
+			byts[i] = byte(65 + rando)
+		case rando <= 51:
+			byts[i] = byte(97 + rando - 26)
+		default:
+			byts[i] = ' '
+		}
+	}
+	return string(byts)
+}
+
+// seqNames creates a slice of NAME0, NAME1, ..., NAMEN.
+func seqNames(n int) []string {
+	names := make([]string, n)
+	for i := range names {
+		names[i] = fmt.Sprintf("NAME%d", i)
+	}
+	return names
+}
+
+// evErr represents a value that is either an event or an error.
+type evErr struct {
+	ev  xgb.Event
+	err xgb.Error
+}
+
+// channel used to pass evErrs.
+var evOrErrChan = make(chan evErr, 0)
+
+// grabEvents is a goroutine that reads events off the wire.
+// We used this instead of WaitForEvent directly in our tests so that
+// we can timeout and fail a test.
+func grabEvents() {
+	for {
+		ev, err := X.WaitForEvent()
+		evOrErrChan <- evErr{ev, err}
+	}
+}
+
+// waitForEvent asks the evOrErrChan channel for an event.
+// If it doesn't get an event in 'n' seconds, the current test is failed.
+func waitForEvent(t *testing.T, n int) evErr {
+	var evOrErr evErr
+
+	select {
+	case evOrErr = <-evOrErrChan:
+	case <-time.After(time.Second * 5):
+		t.Fatalf("After waiting 5 seconds for an event or an error, " +
+			"we have timed out.")
+	}
+
+	return evOrErr
+}

nexgb/xtest/xtest.go

@@ -0,0 +1,417 @@
+// Package xtest is the X client API for the XTEST extension.
+package xtest
+
+// This file is automatically generated from xtest.xml. Edit at your peril!
+
+import (
+	xgb "janouch.name/haven/nexgb"
+
+	"janouch.name/haven/nexgb/xproto"
+)
+
+const (
+	MajorVersion = 2
+	MinorVersion = 2
+)
+
+// Init must be called before using the XTEST extension.
+func Init(c *xgb.Conn) error {
+	reply, err := xproto.QueryExtension(c, 5, "XTEST").Reply()
+	switch {
+	case err != nil:
+		return err
+	case !reply.Present:
+		return xgb.Errorf("No extension named XTEST could be found on on the server.")
+	}
+
+	c.ExtLock.Lock()
+	c.Extensions["XTEST"] = reply.MajorOpcode
+	c.ExtLock.Unlock()
+	for evNum, fun := range xgb.NewExtEventFuncs["XTEST"] {
+		xgb.NewEventFuncs[int(reply.FirstEvent)+evNum] = fun
+	}
+	for errNum, fun := range xgb.NewExtErrorFuncs["XTEST"] {
+		xgb.NewErrorFuncs[int(reply.FirstError)+errNum] = fun
+	}
+	return nil
+}
+
+func init() {
+	xgb.NewExtEventFuncs["XTEST"] = make(map[int]xgb.NewEventFun)
+	xgb.NewExtErrorFuncs["XTEST"] = make(map[int]xgb.NewErrorFun)
+}
+
+const (
+	CursorNone    = 0
+	CursorCurrent = 1
+)
+
+// Skipping definition for base type 'Bool'
+
+// Skipping definition for base type 'Byte'
+
+// Skipping definition for base type 'Card8'
+
+// Skipping definition for base type 'Char'
+
+// Skipping definition for base type 'Void'
+
+// Skipping definition for base type 'Double'
+
+// Skipping definition for base type 'Float'
+
+// Skipping definition for base type 'Int16'
+
+// Skipping definition for base type 'Int32'
+
+// Skipping definition for base type 'Int8'
+
+// Skipping definition for base type 'Card16'
+
+// Skipping definition for base type 'Card32'
+
+// CompareCursorCookie is a cookie used only for CompareCursor requests.
+type CompareCursorCookie struct {
+	*xgb.Cookie
+}
+
+// CompareCursor sends a checked request.
+// If an error occurs, it will be returned with the reply by calling CompareCursorCookie.Reply.
+func CompareCursor(c *xgb.Conn, Window xproto.Window, Cursor xproto.Cursor) CompareCursorCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XTEST"]; !ok {
+		panic("Cannot issue request 'CompareCursor' using the uninitialized extension 'XTEST'. xtest.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(compareCursorRequest(c, Window, Cursor), cookie)
+	return CompareCursorCookie{cookie}
+}
+
+// CompareCursorUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func CompareCursorUnchecked(c *xgb.Conn, Window xproto.Window, Cursor xproto.Cursor) CompareCursorCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XTEST"]; !ok {
+		panic("Cannot issue request 'CompareCursor' using the uninitialized extension 'XTEST'. xtest.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(compareCursorRequest(c, Window, Cursor), cookie)
+	return CompareCursorCookie{cookie}
+}
+
+// CompareCursorReply represents the data returned from a CompareCursor request.
+type CompareCursorReply struct {
+	Sequence uint16 // sequence number of the request for this reply
+	Length   uint32 // number of bytes in this reply
+	Same     bool
+}
+
+// Reply blocks and returns the reply data for a CompareCursor request.
+func (cook CompareCursorCookie) Reply() (*CompareCursorReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return compareCursorReply(buf), nil
+}
+
+// compareCursorReply reads a byte slice into a CompareCursorReply value.
+func compareCursorReply(buf []byte) *CompareCursorReply {
+	v := new(CompareCursorReply)
+	b := 1 // skip reply determinant
+
+	if buf[b] == 1 {
+		v.Same = true
+	} else {
+		v.Same = false
+	}
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	return v
+}
+
+// compareCursorRequest writes a CompareCursor request to a byte slice for transfer.
+func compareCursorRequest(c *xgb.Conn, Window xproto.Window, Cursor xproto.Cursor) []byte {
+	size := 12
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XTEST"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 1 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	xgb.Put32(buf[b:], uint32(Window))
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Cursor))
+	b += 4
+
+	return buf
+}
+
+// FakeInputCookie is a cookie used only for FakeInput requests.
+type FakeInputCookie struct {
+	*xgb.Cookie
+}
+
+// FakeInput sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func FakeInput(c *xgb.Conn, Type, Detail byte, Time uint32, Root xproto.Window, RootX, RootY int16, Deviceid byte) FakeInputCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XTEST"]; !ok {
+		panic("Cannot issue request 'FakeInput' using the uninitialized extension 'XTEST'. xtest.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(fakeInputRequest(c, Type, Detail, Time, Root, RootX, RootY, Deviceid), cookie)
+	return FakeInputCookie{cookie}
+}
+
+// FakeInputChecked sends a checked request.
+// If an error occurs, it can be retrieved using FakeInputCookie.Check.
+func FakeInputChecked(c *xgb.Conn, Type, Detail byte, Time uint32, Root xproto.Window, RootX, RootY int16, Deviceid byte) FakeInputCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XTEST"]; !ok {
+		panic("Cannot issue request 'FakeInput' using the uninitialized extension 'XTEST'. xtest.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(fakeInputRequest(c, Type, Detail, Time, Root, RootX, RootY, Deviceid), cookie)
+	return FakeInputCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook FakeInputCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// fakeInputRequest writes a FakeInput request to a byte slice for transfer.
+func fakeInputRequest(c *xgb.Conn, Type, Detail byte, Time uint32, Root xproto.Window, RootX, RootY int16, Deviceid byte) []byte {
+	size := 36
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XTEST"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 2 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	buf[b] = Type
+	b += 1
+
+	buf[b] = Detail
+	b += 1
+
+	b += 2 // padding
+
+	xgb.Put32(buf[b:], Time)
+	b += 4
+
+	xgb.Put32(buf[b:], uint32(Root))
+	b += 4
+
+	b += 8 // padding
+
+	xgb.Put16(buf[b:], uint16(RootX))
+	b += 2
+
+	xgb.Put16(buf[b:], uint16(RootY))
+	b += 2
+
+	b += 7 // padding
+
+	buf[b] = Deviceid
+	b += 1
+
+	return buf
+}
+
+// GetVersionCookie is a cookie used only for GetVersion requests.
+type GetVersionCookie struct {
+	*xgb.Cookie
+}
+
+// GetVersion sends a checked request.
+// If an error occurs, it will be returned with the reply by calling GetVersionCookie.Reply.
+func GetVersion(c *xgb.Conn, MajorVersion byte, MinorVersion uint16) GetVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XTEST"]; !ok {
+		panic("Cannot issue request 'GetVersion' using the uninitialized extension 'XTEST'. xtest.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, true)
+	c.NewRequest(getVersionRequest(c, MajorVersion, MinorVersion), cookie)
+	return GetVersionCookie{cookie}
+}
+
+// GetVersionUnchecked sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GetVersionUnchecked(c *xgb.Conn, MajorVersion byte, MinorVersion uint16) GetVersionCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XTEST"]; !ok {
+		panic("Cannot issue request 'GetVersion' using the uninitialized extension 'XTEST'. xtest.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, true)
+	c.NewRequest(getVersionRequest(c, MajorVersion, MinorVersion), cookie)
+	return GetVersionCookie{cookie}
+}
+
+// GetVersionReply represents the data returned from a GetVersion request.
+type GetVersionReply struct {
+	Sequence     uint16 // sequence number of the request for this reply
+	Length       uint32 // number of bytes in this reply
+	MajorVersion byte
+	MinorVersion uint16
+}
+
+// Reply blocks and returns the reply data for a GetVersion request.
+func (cook GetVersionCookie) Reply() (*GetVersionReply, error) {
+	buf, err := cook.Cookie.Reply()
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	return getVersionReply(buf), nil
+}
+
+// getVersionReply reads a byte slice into a GetVersionReply value.
+func getVersionReply(buf []byte) *GetVersionReply {
+	v := new(GetVersionReply)
+	b := 1 // skip reply determinant
+
+	v.MajorVersion = buf[b]
+	b += 1
+
+	v.Sequence = xgb.Get16(buf[b:])
+	b += 2
+
+	v.Length = xgb.Get32(buf[b:]) // 4-byte units
+	b += 4
+
+	v.MinorVersion = xgb.Get16(buf[b:])
+	b += 2
+
+	return v
+}
+
+// getVersionRequest writes a GetVersion request to a byte slice for transfer.
+func getVersionRequest(c *xgb.Conn, MajorVersion byte, MinorVersion uint16) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XTEST"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 0 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	buf[b] = MajorVersion
+	b += 1
+
+	b += 1 // padding
+
+	xgb.Put16(buf[b:], MinorVersion)
+	b += 2
+
+	return buf
+}
+
+// GrabControlCookie is a cookie used only for GrabControl requests.
+type GrabControlCookie struct {
+	*xgb.Cookie
+}
+
+// GrabControl sends an unchecked request.
+// If an error occurs, it can only be retrieved using xgb.WaitForEvent or xgb.PollForEvent.
+func GrabControl(c *xgb.Conn, Impervious bool) GrabControlCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XTEST"]; !ok {
+		panic("Cannot issue request 'GrabControl' using the uninitialized extension 'XTEST'. xtest.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(false, false)
+	c.NewRequest(grabControlRequest(c, Impervious), cookie)
+	return GrabControlCookie{cookie}
+}
+
+// GrabControlChecked sends a checked request.
+// If an error occurs, it can be retrieved using GrabControlCookie.Check.
+func GrabControlChecked(c *xgb.Conn, Impervious bool) GrabControlCookie {
+	c.ExtLock.RLock()
+	defer c.ExtLock.RUnlock()
+	if _, ok := c.Extensions["XTEST"]; !ok {
+		panic("Cannot issue request 'GrabControl' using the uninitialized extension 'XTEST'. xtest.Init(connObj) must be called first.")
+	}
+	cookie := c.NewCookie(true, false)
+	c.NewRequest(grabControlRequest(c, Impervious), cookie)
+	return GrabControlCookie{cookie}
+}
+
+// Check returns an error if one occurred for checked requests that are not expecting a reply.
+// This cannot be called for requests expecting a reply, nor for unchecked requests.
+func (cook GrabControlCookie) Check() error {
+	return cook.Cookie.Check()
+}
+
+// grabControlRequest writes a GrabControl request to a byte slice for transfer.
+func grabControlRequest(c *xgb.Conn, Impervious bool) []byte {
+	size := 8
+	b := 0
+	buf := make([]byte, size)
+
+	c.ExtLock.RLock()
+	buf[b] = c.Extensions["XTEST"]
+	c.ExtLock.RUnlock()
+	b += 1
+
+	buf[b] = 3 // request opcode
+	b += 1
+
+	xgb.Put16(buf[b:], uint16(size/4)) // write request size in 4-byte units
+	b += 2
+
+	if Impervious {
+		buf[b] = 1
+	} else {
+		buf[b] = 0
+	}
+	b += 1
+
+	b += 3 // padding
+
+	return buf
+}

prototypes/xgb-selection.go

@@ -0,0 +1,199 @@
+// Follow X11 selection contents as they are being changed.
+package main
+
+import (
+	"janouch.name/haven/nexgb"
+	"janouch.name/haven/nexgb/xfixes"
+	"janouch.name/haven/nexgb/xproto"
+	"log"
+)
+
+func main() {
+	X, err := nexgb.NewConn()
+	if err != nil {
+		log.Fatalln(err)
+	}
+	if err := xfixes.Init(X); err != nil {
+		log.Fatalln(err)
+	}
+
+	setup := xproto.Setup(X)
+	screen := setup.DefaultScreen(X)
+
+	// Resolve a few required atoms that are not static in the core protocol.
+	const (
+		clipboard  = "CLIPBOARD"
+		utf8String = "UTF8_STRING"
+		incr       = "INCR"
+	)
+
+	atomCLIPBOARD, err := xproto.InternAtom(X, false,
+		uint16(len(clipboard)), clipboard).Reply()
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	atomUTF8String, err := xproto.InternAtom(X, false,
+		uint16(len(utf8String)), utf8String).Reply()
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	atomINCR, err := xproto.InternAtom(X, false,
+		uint16(len(incr)), incr).Reply()
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	// Create a window.
+	wid, err := xproto.NewWindowId(X)
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	_ = xproto.CreateWindow(X, screen.RootDepth, wid, screen.Root, 0, 0, 1, 1,
+		0, xproto.WindowClassInputOutput, screen.RootVisual, xproto.CwEventMask,
+		[]uint32{xproto.EventMaskPropertyChange})
+
+	// Select for update events of each selection.
+	_ = xfixes.QueryVersion(X, xfixes.MajorVersion, xfixes.MinorVersion)
+
+	_ = xfixes.SelectSelectionInput(X, wid,
+		xproto.AtomPrimary, xfixes.SelectionEventMaskSetSelectionOwner|
+			xfixes.SelectionEventMaskSelectionWindowDestroy|
+			xfixes.SelectionEventMaskSelectionClientClose)
+
+	_ = xfixes.SelectSelectionInput(X, wid,
+		atomCLIPBOARD.Atom, xfixes.SelectionEventMaskSetSelectionOwner|
+			xfixes.SelectionEventMaskSelectionWindowDestroy|
+			xfixes.SelectionEventMaskSelectionClientClose)
+
+	type selectionState struct {
+		name       string           // name of the selection
+		inProgress xproto.Timestamp // timestamp of retrieved selection
+		buffer     []byte           // UTF-8 text buffer
+		incr       bool             // INCR running
+		incrFailed bool             // INCR failure indicator
+	}
+	states := map[xproto.Atom]*selectionState{
+		xproto.AtomPrimary: {name: "PRIMARY"},
+		atomCLIPBOARD.Atom: {name: "CLIPBOARD"},
+	}
+
+	for {
+		ev, xerr := X.WaitForEvent()
+		if xerr != nil {
+			log.Printf("Error: %s\n", xerr)
+			return
+		}
+		if ev == nil {
+			return
+		}
+
+		switch e := ev.(type) {
+		case xfixes.SelectionNotifyEvent:
+			state, ok := states[e.Selection]
+			if !ok {
+				break
+			}
+
+			// Not checking whether we should give up when our current retrieval
+			// attempt is interrupted--the timeout mostly solves this.
+			if e.Owner == xproto.WindowNone {
+				// This may potentially log before a request for past data
+				// finishes, if only because of INCR. Just saying.
+				log.Printf("%s: -\n", state.name)
+				break
+			}
+
+			// Don't try to process two things at once.  Each request gets a few
+			// seconds to finish, then we move on, hoping that a property race
+			// doesn't commence.  Ideally we'd set up a separate queue for these
+			// skipped requests and process them later.
+			if state.inProgress != 0 && e.Timestamp-state.inProgress < 5000 {
+				break
+			}
+
+			// ICCCM says we should ensure the named property doesn't exist.
+			_ = xproto.DeleteProperty(X, e.Window, e.Selection)
+
+			_ = xproto.ConvertSelection(X, e.Window, e.Selection,
+				atomUTF8String.Atom, e.Selection, e.Timestamp)
+
+			state.inProgress = e.Timestamp
+			state.incr = false
+
+		case xproto.SelectionNotifyEvent:
+			state, ok := states[e.Selection]
+			if e.Requestor != wid || !ok || e.Time != state.inProgress {
+				break
+			}
+
+			state.inProgress = 0
+			if e.Property == xproto.AtomNone {
+				break
+			}
+
+			// XXX: This is simplified and doesn't necessarily read it all.
+			// Maybe we could use setup.MaximumRequestLength.
+			// Though xorg-xserver doesn't seem to limit the length of replies
+			// or even the length of properties in the first place.
+			// It only has a huge (0xffffffff - sizeof(xChangePropertyReq))/4
+			// limit for ChangeProperty requests, which is way more than
+			// max-request-len (normally 0xffff), even though I can't
+			// XChangeProperty more than 0xffffe0 bytes at a time.
+			reply, err := xproto.GetProperty(X, false, /* delete */
+				e.Requestor, e.Property, xproto.GetPropertyTypeAny,
+				0, 0x8000).Reply()
+			if err != nil {
+				break
+			}
+
+			state.buffer = nil
+
+			// When you select a lot of text in VIM, it starts the ICCCM
+			// INCR mechanism, from which there is no opt-out.
+			if reply.Type == atomINCR.Atom {
+				state.inProgress = e.Time
+				state.incr = true
+				state.incrFailed = false
+			} else if reply.Type == atomUTF8String.Atom && reply.Format == 8 {
+				log.Printf("%s: '%s'\n", state.name, string(reply.Value))
+			}
+
+			_ = xproto.DeleteProperty(X, e.Requestor, e.Property)
+
+		case xproto.PropertyNotifyEvent:
+			state, ok := states[e.Atom]
+			if e.Window != wid || e.State != xproto.PropertyNewValue ||
+				!ok || !state.incr {
+				break
+			}
+
+			reply, err := xproto.GetProperty(X, false, /* delete */
+				e.Window, e.Atom, xproto.GetPropertyTypeAny, 0, 0x8000).Reply()
+			if err != nil {
+				state.incrFailed = true
+				break
+			}
+
+			if reply.Type == atomUTF8String.Atom && reply.Format == 8 {
+				state.buffer = append(state.buffer, reply.Value...)
+			} else {
+				// We need to keep deleting the property.
+				state.incrFailed = true
+			}
+
+			if reply.ValueLen == 0 {
+				if !state.incrFailed {
+					log.Printf("%s: '%s'\n",
+						state.name, string(state.buffer))
+				}
+				state.inProgress = 0
+				state.incr = false
+			}
+
+			_ = xproto.DeleteProperty(X, e.Window, e.Atom)
+		}
+	}
+}