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hpcu: add a selection unifier

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So far not supporting large selections.
This commit is contained in:
Přemysl Eric Janouch 2018-09-24 13:11:11 +02:00
parent f198f9f6ac
commit 7d51aaa9a4
Signed by: p
GPG Key ID: A0420B94F92B9493
2 changed files with 368 additions and 4 deletions
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21
README
View File

@ -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.

351
hpcu/main.go Normal file
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@ -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)
}
}
}