// compressMotionNotify takes a MotionNotify event, and inspects the event
// queue for any future MotionNotify events that can be received without
// blocking. The most recent MotionNotify event is then returned.
// Note that we need to make sure that the Event, Child, Detail, State, Root
// and SameScreen fields are the same to ensure the same window/action is
// generating events. That is, we are only compressing the RootX, RootY,
// EventX and EventY fields.
// This function is not thread safe, since Peek returns a *copy* of the
// event queue---which could be out of date by the time we dequeue events.
func compressMotionNotify(X *xgbutil.XUtil,
ev xevent.MotionNotifyEvent) xevent.MotionNotifyEvent {
// We force a round trip request so that we make sure to read all
// available events.
X.Sync()
xevent.Read(X, false)
// The most recent MotionNotify event that we'll end up returning.
laste := ev
// Look through each event in the queue. If it's an event and it matches
// all the fields in 'ev' that are detailed above, then set it to 'laste'.
// In which case, we'll also dequeue the event, otherwise it will be
// processed twice!
// N.B. If our only goal was to find the most recent relevant MotionNotify
// event, we could traverse the event queue backwards and simply use
// the first MotionNotify we see. However, this could potentially leave
// other MotionNotify events in the queue, which we *don't* want to be
// processed. So we stride along and just pick off MotionNotify events
// until we don't see any more.
for i, ee := range xevent.Peek(X) {
if ee.Err != nil { // This is an error, skip it.
continue
}
// Use type assertion to make sure this is a MotionNotify event.
if mn, ok := ee.Event.(xproto.MotionNotifyEvent); ok {
// Now make sure all appropriate fields are equivalent.
if ev.Event == mn.Event && ev.Child == mn.Child &&
ev.Detail == mn.Detail && ev.State == mn.State &&
ev.Root == mn.Root && ev.SameScreen == mn.SameScreen {
// Set the most recent/valid motion notify event.
laste = xevent.MotionNotifyEvent{&mn}
// We cheat and use the stack semantics of defer to dequeue
// most recent motion notify events first, so that the indices
// don't become invalid. (If we dequeued oldest first, we'd
// have to account for all future events shifting to the left
// by one.)
defer func(i int) { xevent.DequeueAt(X, i) }(i)
}
}
}
// This isn't strictly necessary, but is correct. We should update
// xgbutil's sense of time with the most recent event processed.
// This is typically done in the main event loop, but since we are
// subverting the main event loop, we should take care of it.
X.TimeSet(laste.Time)
return laste
}
// dragStep executes the "step" function registered for the current drag.
// It also compresses the MotionNotify events.
func dragStep(xu *xgbutil.XUtil, ev xevent.MotionNotifyEvent) {
// If for whatever reason we don't have any *piece* of a grab,
// we've gotta back out.
if !mouseDrag(xu) || mouseDragStep(xu) == nil || mouseDragEnd(xu) == nil {
dragUngrab(xu)
mouseDragStepSet(xu, nil)
mouseDragEndSet(xu, nil)
return
}
// The most recent MotionNotify event that we'll end up returning.
laste := ev
// We force a round trip request so that we make sure to read all
// available events.
xu.Sync()
xevent.Read(xu, false)
// Compress MotionNotify events.
for i, ee := range xevent.Peek(xu) {
if ee.Err != nil { // This is an error, skip it.
continue
}
// Use type assertion to make sure this is a MotionNotify event.
if mn, ok := ee.Event.(xproto.MotionNotifyEvent); ok {
// Now make sure all appropriate fields are equivalent.
if ev.Event == mn.Event && ev.Child == mn.Child &&
ev.Detail == mn.Detail && ev.State == mn.State &&
ev.Root == mn.Root && ev.SameScreen == mn.SameScreen {
// Set the most recent/valid motion notify event.
laste = xevent.MotionNotifyEvent{&mn}
// We cheat and use the stack semantics of defer to dequeue
// most recent motion notify events first, so that the indices
// don't become invalid. (If we dequeued oldest first, we'd
// have to account for all future events shifting to the left
// by one.)
defer func(i int) { xevent.DequeueAt(xu, i) }(i)
}
}
}
xu.TimeSet(laste.Time)
// now actually run the step
mouseDragStep(xu)(xu, int(laste.RootX), int(laste.RootY),
int(laste.EventX), int(laste.EventY))
}
// processEventQueue processes every item in the event/error queue.
func processEventQueue(xu *xgbutil.XUtil, pingBefore, pingAfter chan struct{}) {
for !Empty(xu) {
if Quitting(xu) {
return
}
// We send the ping *before* the next event is dequeued.
// This is so the queue doesn't present a misrepresentation of which
// events haven't been processed yet.
if pingBefore != nil && pingAfter != nil {
pingBefore <- struct{}{}
}
ev, err := Dequeue(xu)
// If we gobbled up an error, send it to the error event handler
// and move on the next event/error.
if err != nil {
ErrorHandlerGet(xu)(err)
if pingBefore != nil && pingAfter != nil {
pingAfter <- struct{}{}
}
continue
}
// We know there isn't an error. If there isn't an event either,
// then there's a bug somewhere.
if ev == nil {
xgbutil.Logger.Fatal("BUG: Expected an event but got nil.")
}
switch event := ev.(type) {
case xproto.KeyPressEvent:
e := KeyPressEvent{&event}
// If we're redirecting key events, this is the place to do it!
if wid := RedirectKeyGet(xu); wid > 0 {
e.Event = wid
}
xu.TimeSet(e.Time)
runCallbacks(xu, e, KeyPress, e.Event)
case xproto.KeyReleaseEvent:
e := KeyReleaseEvent{&event}
// If we're redirecting key events, this is the place to do it!
if wid := RedirectKeyGet(xu); wid > 0 {
e.Event = wid
}
xu.TimeSet(e.Time)
runCallbacks(xu, e, KeyRelease, e.Event)
case xproto.ButtonPressEvent:
e := ButtonPressEvent{&event}
xu.TimeSet(e.Time)
runCallbacks(xu, e, ButtonPress, e.Event)
case xproto.ButtonReleaseEvent:
e := ButtonReleaseEvent{&event}
xu.TimeSet(e.Time)
runCallbacks(xu, e, ButtonRelease, e.Event)
case xproto.MotionNotifyEvent:
e := MotionNotifyEvent{&event}
xu.TimeSet(e.Time)
runCallbacks(xu, e, MotionNotify, e.Event)
case xproto.EnterNotifyEvent:
e := EnterNotifyEvent{&event}
xu.TimeSet(e.Time)
runCallbacks(xu, e, EnterNotify, e.Event)
case xproto.LeaveNotifyEvent:
e := LeaveNotifyEvent{&event}
xu.TimeSet(e.Time)
runCallbacks(xu, e, LeaveNotify, e.Event)
case xproto.FocusInEvent:
e := FocusInEvent{&event}
runCallbacks(xu, e, FocusIn, e.Event)
case xproto.FocusOutEvent:
e := FocusOutEvent{&event}
runCallbacks(xu, e, FocusOut, e.Event)
case xproto.KeymapNotifyEvent:
e := KeymapNotifyEvent{&event}
runCallbacks(xu, e, KeymapNotify, NoWindow)
case xproto.ExposeEvent:
e := ExposeEvent{&event}
runCallbacks(xu, e, Expose, e.Window)
case xproto.GraphicsExposureEvent:
e := GraphicsExposureEvent{&event}
runCallbacks(xu, e, GraphicsExposure, xproto.Window(e.Drawable))
case xproto.NoExposureEvent:
e := NoExposureEvent{&event}
runCallbacks(xu, e, NoExposure, xproto.Window(e.Drawable))
case xproto.VisibilityNotifyEvent:
e := VisibilityNotifyEvent{&event}
runCallbacks(xu, e, VisibilityNotify, e.Window)
case xproto.CreateNotifyEvent:
e := CreateNotifyEvent{&event}
runCallbacks(xu, e, CreateNotify, e.Parent)
case xproto.DestroyNotifyEvent:
e := DestroyNotifyEvent{&event}
runCallbacks(xu, e, DestroyNotify, e.Window)
case xproto.UnmapNotifyEvent:
e := UnmapNotifyEvent{&event}
runCallbacks(xu, e, UnmapNotify, e.Window)
case xproto.MapNotifyEvent:
e := MapNotifyEvent{&event}
runCallbacks(xu, e, MapNotify, e.Event)
case xproto.MapRequestEvent:
e := MapRequestEvent{&event}
runCallbacks(xu, e, MapRequest, e.Window)
runCallbacks(xu, e, MapRequest, e.Parent)
case xproto.ReparentNotifyEvent:
e := ReparentNotifyEvent{&event}
runCallbacks(xu, e, ReparentNotify, e.Window)
case xproto.ConfigureNotifyEvent:
e := ConfigureNotifyEvent{&event}
runCallbacks(xu, e, ConfigureNotify, e.Window)
case xproto.ConfigureRequestEvent:
e := ConfigureRequestEvent{&event}
runCallbacks(xu, e, ConfigureRequest, e.Window)
runCallbacks(xu, e, ConfigureRequest, e.Parent)
case xproto.GravityNotifyEvent:
e := GravityNotifyEvent{&event}
runCallbacks(xu, e, GravityNotify, e.Window)
case xproto.ResizeRequestEvent:
e := ResizeRequestEvent{&event}
runCallbacks(xu, e, ResizeRequest, e.Window)
case xproto.CirculateNotifyEvent:
e := CirculateNotifyEvent{&event}
runCallbacks(xu, e, CirculateNotify, e.Window)
case xproto.CirculateRequestEvent:
e := CirculateRequestEvent{&event}
runCallbacks(xu, e, CirculateRequest, e.Window)
case xproto.PropertyNotifyEvent:
e := PropertyNotifyEvent{&event}
xu.TimeSet(e.Time)
runCallbacks(xu, e, PropertyNotify, e.Window)
case xproto.SelectionClearEvent:
e := SelectionClearEvent{&event}
xu.TimeSet(e.Time)
runCallbacks(xu, e, SelectionClear, e.Owner)
case xproto.SelectionRequestEvent:
e := SelectionRequestEvent{&event}
xu.TimeSet(e.Time)
runCallbacks(xu, e, SelectionRequest, e.Requestor)
case xproto.SelectionNotifyEvent:
e := SelectionNotifyEvent{&event}
xu.TimeSet(e.Time)
runCallbacks(xu, e, SelectionNotify, e.Requestor)
case xproto.ColormapNotifyEvent:
e := ColormapNotifyEvent{&event}
runCallbacks(xu, e, ColormapNotify, e.Window)
case xproto.ClientMessageEvent:
e := ClientMessageEvent{&event}
runCallbacks(xu, e, ClientMessage, e.Window)
case xproto.MappingNotifyEvent:
e := MappingNotifyEvent{&event}
runCallbacks(xu, e, MappingNotify, NoWindow)
case shape.NotifyEvent:
e := ShapeNotifyEvent{&event}
runCallbacks(xu, e, ShapeNotify, e.AffectedWindow)
default:
if event != nil {
xgbutil.Logger.Printf("ERROR: UNSUPPORTED EVENT TYPE: %T",
event)
}
}
if pingBefore != nil && pingAfter != nil {
pingAfter <- struct{}{}
}
}
}