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