xgb-selection: add a demo to track X11 selections

This commit is contained in:
Přemysl Eric Janouch 2018-09-23 16:59:18 +02:00
parent 106e9b82b8
commit f198f9f6ac
Signed by: p
GPG Key ID: A0420B94F92B9493

199
prototypes/xgb-selection.go Normal file
View File

@ -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)
}
}
}