io/input: [API] execute commands immediately

Change the semantics of commands to execute immediately. In cases where
execution of a command introduces a inconsistency, freeze event routing
and defer the command as well as queued events to the next frame.

Rename Source.Queue to Source.Execute to better fit the new command
semantics.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

gesture/gesture.go

@@ -315,7 +315,7 @@ func (s *Scroll) Update(cfg unit.Metric, q input.Source, t time.Time, axis Axis,
 			if e.Priority < pointer.Grabbed {
 				slop := cfg.Dp(touchSlop)
 				if dist := dist; dist >= slop || -slop >= dist {
-					q.Queue(pointer.GrabCmd{Tag: s, ID: e.PointerID})
+					q.Execute(pointer.GrabCmd{Tag: s, ID: e.PointerID})
 				}
 			} else {
 				s.last = v
@@ -389,7 +389,7 @@ func (d *Drag) Update(cfg unit.Metric, q input.Source, axis Axis) []pointer.Even
 				diff := e.Position.Sub(d.start)
 				slop := cfg.Dp(touchSlop)
 				if diff.X*diff.X+diff.Y*diff.Y > float32(slop*slop) {
-					q.Queue(pointer.GrabCmd{Tag: d, ID: e.PointerID})
+					q.Execute(pointer.GrabCmd{Tag: d, ID: e.PointerID})
 				}
 			}
 		case pointer.Release, pointer.Cancel:

io/input/clipboard_test.go

@@ -17,8 +17,8 @@ func TestClipboardDuplicateEvent(t *testing.T) {
 	ops, router, handler := new(op.Ops), new(Router), make([]int, 2)
 
 	// Both must receive the event once
-	router.Source().Queue(clipboard.ReadCmd{Tag: &handler[0]})
+	router.Source().Execute(clipboard.ReadCmd{Tag: &handler[0]})
-	router.Source().Queue(clipboard.ReadCmd{Tag: &handler[1]})
+	router.Source().Execute(clipboard.ReadCmd{Tag: &handler[1]})
 
 	router.Frame(ops)
 	event := transfer.DataEvent{
@@ -41,7 +41,7 @@ func TestClipboardDuplicateEvent(t *testing.T) {
 	assertClipboardEvent(t, router.Events(&handler[1]), false)
 	ops.Reset()
 
-	router.Source().Queue(clipboard.ReadCmd{Tag: &handler[0]})
+	router.Source().Execute(clipboard.ReadCmd{Tag: &handler[0]})
 
 	router.Frame(ops)
 	// No ClipboardEvent sent
@@ -56,7 +56,7 @@ func TestQueueProcessReadClipboard(t *testing.T) {
 	ops.Reset()
 
 	// Request read
-	router.Source().Queue(clipboard.ReadCmd{Tag: &handler[0]})
+	router.Source().Execute(clipboard.ReadCmd{Tag: &handler[0]})
 
 	router.Frame(ops)
 	assertClipboardReadCmd(t, router, 1)
@@ -94,28 +94,18 @@ func TestQueueProcessReadClipboard(t *testing.T) {
 }
 
 func TestQueueProcessWriteClipboard(t *testing.T) {
-	ops, router := new(op.Ops), new(Router)
+	router := new(Router)
-	ops.Reset()
 
 	const mime = "application/text"
-	router.Source().Queue(clipboard.WriteCmd{Type: mime, Data: io.NopCloser(strings.NewReader("Write 1"))})
+	router.Source().Execute(clipboard.WriteCmd{Type: mime, Data: io.NopCloser(strings.NewReader("Write 1"))})
 
-	router.Frame(ops)
 	assertClipboardWriteCmd(t, router, mime, "Write 1")
-	ops.Reset()
-
-	// No WriteCmd
-
-	router.Frame(ops)
 	assertClipboardWriteCmd(t, router, "", "")
-	ops.Reset()
 
-	router.Source().Queue(clipboard.WriteCmd{Type: mime, Data: io.NopCloser(strings.NewReader("Write 2"))})
+	router.Source().Execute(clipboard.WriteCmd{Type: mime, Data: io.NopCloser(strings.NewReader("Write 2"))})
 
-	router.Frame(ops)
 	assertClipboardReadCmd(t, router, 0)
 	assertClipboardWriteCmd(t, router, mime, "Write 2")
-	ops.Reset()
 }
 
 func assertClipboardEvent(t *testing.T, events []event.Event, expected bool) {

io/input/key_test.go

@@ -37,9 +37,8 @@ func TestKeyMultiples(t *testing.T) {
 	ops := new(op.Ops)
 	r := new(Router)
 
-	r.Source().Queue(key.SoftKeyboardCmd{Show: true})
+	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
 	event.InputOp(ops, &handlers[0])
-	r.Source().Queue(key.FocusCmd{Tag: &handlers[2]})
 	event.InputOp(ops, &handlers[1])
 
 	// The last one must be focused:
@@ -51,6 +50,7 @@ func TestKeyMultiples(t *testing.T) {
 
 	r.Frame(ops)
 
+	r.Source().Execute(key.FocusCmd{Tag: &handlers[2]})
 	assertKeyEvent(t, r.Events(&handlers[2], key.FocusFilter{}), true)
 	assertFocus(t, r, &handlers[2])
 
@@ -63,12 +63,12 @@ func TestKeyStacked(t *testing.T) {
 	r := new(Router)
 
 	event.InputOp(ops, &handlers[0])
-	r.Source().Queue(key.FocusCmd{})
+	r.Source().Execute(key.FocusCmd{})
-	r.Source().Queue(key.SoftKeyboardCmd{Show: false})
+	r.Source().Execute(key.SoftKeyboardCmd{Show: false})
 	event.InputOp(ops, &handlers[1])
-	r.Source().Queue(key.FocusCmd{Tag: &handlers[1]})
+	r.Source().Execute(key.FocusCmd{Tag: &handlers[1]})
 	event.InputOp(ops, &handlers[2])
-	r.Source().Queue(key.SoftKeyboardCmd{Show: true})
+	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
 	event.InputOp(ops, &handlers[3])
 
 	for i := range handlers {
@@ -88,7 +88,7 @@ func TestKeySoftKeyboardNoFocus(t *testing.T) {
 
 	// It's possible to open the keyboard
 	// without any active focus:
-	r.Source().Queue(key.SoftKeyboardCmd{Show: true})
+	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
 
 	r.Frame(ops)
 
@@ -103,8 +103,8 @@ func TestKeyRemoveFocus(t *testing.T) {
 
 	// New InputOp with Focus and Keyboard:
 	event.InputOp(ops, &handlers[0])
-	r.Source().Queue(key.FocusCmd{Tag: &handlers[0]})
+	r.Source().Execute(key.FocusCmd{Tag: &handlers[0]})
-	r.Source().Queue(key.SoftKeyboardCmd{Show: true})
+	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
 
 	// New InputOp without any focus:
 	event.InputOp(ops, &handlers[1])
@@ -136,7 +136,7 @@ func TestKeyRemoveFocus(t *testing.T) {
 	event.InputOp(ops, &handlers[1])
 
 	// Remove focus by focusing on a tag that don't exist.
-	r.Source().Queue(key.FocusCmd{Tag: new(int)})
+	r.Source().Execute(key.FocusCmd{Tag: new(int)})
 
 	r.Frame(ops)
 
@@ -149,26 +149,26 @@ func TestKeyRemoveFocus(t *testing.T) {
 	event.InputOp(ops, &handlers[0])
 	event.InputOp(ops, &handlers[1])
 
-	r.Frame(ops)
-
 	assertKeyEventUnexpected(t, r.Events(&handlers[0], key.FocusFilter{}))
 	assertKeyEventUnexpected(t, r.Events(&handlers[1], key.FocusFilter{}))
 	assertFocus(t, r, nil)
 	assertKeyboard(t, r, TextInputClose)
 
+	r.Frame(ops)
 	ops.Reset()
 
 	// Set focus to InputOp which already
 	// exists in the previous frame:
-	r.Source().Queue(key.FocusCmd{Tag: &handlers[0]})
+	r.Source().Execute(key.FocusCmd{Tag: &handlers[0]})
 	event.InputOp(ops, &handlers[0])
-	r.Source().Queue(key.SoftKeyboardCmd{Show: true})
+	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
+	assertFocus(t, r, &handlers[0])
+
+	ops.Reset()
 
 	// Remove focus.
 	event.InputOp(ops, &handlers[1])
-	r.Source().Queue(key.FocusCmd{})
+	r.Source().Execute(key.FocusCmd{})
-
-	r.Frame(ops)
 
 	assertKeyEventUnexpected(t, r.Events(&handlers[1], key.FocusFilter{}))
 	assertFocus(t, r, nil)
@@ -181,9 +181,9 @@ func TestKeyFocusedInvisible(t *testing.T) {
 	r := new(Router)
 
 	// Set new InputOp with focus:
-	r.Source().Queue(key.FocusCmd{Tag: &handlers[0]})
+	r.Source().Execute(key.FocusCmd{Tag: &handlers[0]})
 	event.InputOp(ops, &handlers[0])
-	r.Source().Queue(key.SoftKeyboardCmd{Show: true})
+	r.Source().Execute(key.SoftKeyboardCmd{Show: true})
 
 	// Set new InputOp without focus:
 	event.InputOp(ops, &handlers[1])
@@ -403,7 +403,7 @@ func TestKeyRouting(t *testing.T) {
 	r2.Events(&handlers[3], key.FocusFilter{})
 	r2.Events(&handlers[4], fa...)
 
-	r2.Source().Queue(key.FocusCmd{Tag: &handlers[3]})
+	r2.Source().Execute(key.FocusCmd{Tag: &handlers[3]})
 	r2.Frame(ops)
 
 	r2.Queue(A, B)

io/input/pointer_test.go

@@ -99,10 +99,10 @@ func TestPointerGrab(t *testing.T) {
 			Position: f32.Pt(50, 50),
 		},
 	)
-	r.Source().Queue(pointer.GrabCmd{Tag: handler1})
 	assertEventPointerTypeSequence(t, r.Events(handler1, filter), pointer.Press)
 	assertEventPointerTypeSequence(t, r.Events(handler2, filter), pointer.Press)
 	assertEventPointerTypeSequence(t, r.Events(handler3, filter), pointer.Press)
+	r.Source().Execute(pointer.GrabCmd{Tag: handler1})
 	r.Frame(&ops)
 	r.Queue(
 		pointer.Event{
@@ -136,9 +136,9 @@ func TestPointerGrabSameHandlerTwice(t *testing.T) {
 			Position: f32.Pt(50, 50),
 		},
 	)
-	r.Source().Queue(pointer.GrabCmd{Tag: handler1})
 	assertEventPointerTypeSequence(t, r.Events(handler1, filter), pointer.Press)
 	assertEventPointerTypeSequence(t, r.Events(handler2, filter), pointer.Press)
+	r.Source().Execute(pointer.GrabCmd{Tag: handler1})
 	r.Frame(&ops)
 	r.Queue(
 		pointer.Event{
@@ -941,7 +941,7 @@ func TestTransfer(t *testing.T) {
 
 		// Offer valid type and data.
 		ofr := &offer{data: "hello"}
-		r.Source().Queue(transfer.OfferCmd{Tag: src, Type: "file", Data: ofr})
+		r.Source().Execute(transfer.OfferCmd{Tag: src, Type: "file", Data: ofr})
 		r.Frame(ops)
 		assertEventSequence(t, r.Events(src, transfer.SourceFilter{Type: "file"}), transfer.CancelEvent{})
 		evs := r.Events(tgt, transfer.TargetFilter{Type: "file"})
@@ -989,9 +989,9 @@ func TestTransfer(t *testing.T) {
 			},
 		)
 		ofr := &offer{data: "hello"}
-		r.Source().Queue(transfer.OfferCmd{Tag: src, Type: "file", Data: ofr})
 		r.Events(src, transfer.SourceFilter{Type: "file"})
 		r.Events(tgt, transfer.TargetFilter{Type: "file"})
+		r.Source().Execute(transfer.OfferCmd{Tag: src, Type: "file", Data: ofr})
 		r.Frame(ops)
 		assertEventSequence(t, r.Events(src, transfer.SourceFilter{Type: "file"}), transfer.CancelEvent{})
 		// Ignore DataEvent and verify that the next frame closes it as unused.

io/input/router.go

@@ -38,8 +38,8 @@ type Router struct {
 	cqueue clipboardQueue
 
 	// states is the list of pending state changes resulting from
-	// incoming events. The first element is the current state,
+	// incoming events. The first element, if present, contains the state
-	// if any.
+	// and events for the current frame.
 	changes []stateChange
 
 	reader ops.Reader
@@ -54,6 +54,10 @@ type Router struct {
 	// transfers is the pending transfer.DataEvent.Open functions.
 	transfers []io.ReadCloser
 
+	// deferring is set if command execution and event delivery is deferred
+	// to the next frame.
+	deferring bool
+
 	// scratchFilter is for garbage-free construction of ephemeral filters.
 	scratchFilter filter
 }
@@ -109,7 +113,9 @@ type SemanticID uint
 type handler struct {
 	// active tracks whether the handler was active in the current
 	// frame. Router deletes state belonging to inactive handlers during Frame.
-	active  bool
+	active bool
+	// old is true iff the handler was aded in a previous frame.
+	old     bool
 	pointer pointerHandler
 	key     keyHandler
 	// filter the handler has asked for through event handling
@@ -129,6 +135,8 @@ type filter struct {
 // stateChange represents the new state and outgoing events
 // resulting from an incoming event.
 type stateChange struct {
+	// event, if set, is the trigger for the change.
+	event  event.Event
 	state  inputState
 	events []taggedEvent
 }
@@ -152,13 +160,12 @@ func (q *Router) Source() Source {
 	return Source{r: q}
 }
 
-// Queue a command to be executed after the current frame
+// Execute a command.
-// has completed.
+func (s Source) Execute(c Command) {
-func (s Source) Queue(c Command) {
 	if !s.Enabled() {
 		return
 	}
-	s.r.queue(c)
+	s.r.execute(c)
 }
 
 // Enabled reports whether the source is enabled. Only enabled
@@ -195,6 +202,9 @@ func (q *Router) Events(k event.Tag, filters ...event.Filter) []event.Event {
 		}
 	}
 	h.nextFilter.Merge(q.scratchFilter)
+	if q.deferring {
+		return events
+	}
 	// Accumulate events from state changes until there are no more
 	// matching events.
 	matchedIdx := 0
@@ -234,6 +244,20 @@ func (q *Router) collapseState(idx int) {
 // operation list. The text input state, wakeup time and whether
 // there are active profile handlers is also saved.
 func (q *Router) Frame(frame *op.Ops) {
+	var remaining []event.Event
+	if n := len(q.changes); n > 0 {
+		if q.deferring {
+			// Collect events for replay.
+			for _, ch := range q.changes[1:] {
+				remaining = append(remaining, ch.event)
+			}
+			q.changes = append(q.changes[:0], stateChange{state: q.changes[0].state})
+		} else {
+			// Collapse state.
+			state := q.changes[n-1].state
+			q.changes = append(q.changes[:0], stateChange{state: state})
+		}
+	}
 	for _, rc := range q.transfers {
 		if rc != nil {
 			rc.Close()
@@ -241,11 +265,7 @@ func (q *Router) Frame(frame *op.Ops) {
 	}
 	q.transfers = nil
 	q.wakeup = false
-	// Collapse state and clear events.
+	q.deferring = false
-	if n := len(q.changes); n > 1 {
-		state := q.changes[n-1].state
-		q.changes = append(q.changes[:0], stateChange{state: state})
-	}
 	for _, h := range q.handlers {
 		h.filter, h.nextFilter = h.nextFilter, h.filter
 		h.nextFilter.Reset()
@@ -263,12 +283,17 @@ func (q *Router) Frame(frame *op.Ops) {
 			delete(q.handlers, k)
 		} else {
 			h.active = false
+			h.old = true
 		}
 	}
 	q.executeCommands()
-	q.changePointerState(q.pointer.queue.Frame(q.handlers, q.lastState().pointerState))
+	q.Queue(remaining...)
-	kstate := q.key.queue.Frame(q.handlers, q.lastState().keyState)
+	st := q.lastState()
-	q.changeKeyState(kstate, nil)
+	pst, evts := q.pointer.queue.Frame(q.handlers, st.pointerState)
+	st.pointerState = pst
+	st.keyState = q.key.queue.Frame(q.handlers, q.lastState().keyState)
+	q.changeState(nil, st, evts)
+
 	// Collapse state and events.
 	q.collapseState(len(q.changes) - 1)
 
@@ -324,9 +349,11 @@ func (q *Router) processEvent(e event.Event) bool {
 	state := q.lastState()
 	switch e := e.(type) {
 	case pointer.Event:
-		return q.changePointerState(q.pointer.queue.Push(q.handlers, state.pointerState, e))
+		pstate, evts := q.pointer.queue.Push(q.handlers, state.pointerState, e)
+		state.pointerState = pstate
+		return q.changeState(e, state, evts)
 	case key.Event:
-		return q.addEvents(q.queueKeyEvent(state.keyState, e))
+		return q.changeState(e, state, q.queueKeyEvent(state.keyState, e))
 	case key.SnippetEvent:
 		// Expand existing, overlapping snippet.
 		if r := state.content.Snippet.Range; rangeOverlaps(r, key.Range(e)) {
@@ -341,22 +368,58 @@ func (q *Router) processEvent(e event.Event) bool {
 		if f := state.focus; f != nil {
 			evts = append(evts, taggedEvent{tag: f, event: e})
 		}
-		return q.addEvents(evts)
+		return q.changeState(e, state, evts)
 	case key.EditEvent, key.FocusEvent, key.SelectionEvent:
 		var evts []taggedEvent
 		if f := state.focus; f != nil {
 			evts = append(evts, taggedEvent{tag: f, event: e})
 		}
-		return q.addEvents(evts)
+		return q.changeState(e, state, evts)
 	case transfer.DataEvent:
-		return q.changeClipboardState(q.cqueue.Push(state.clipboardState, e))
+		cstate, evts := q.cqueue.Push(state.clipboardState, e)
+		state.clipboardState = cstate
+		return q.changeState(e, state, evts)
 	default:
 		panic("unknown event type")
 	}
 }
 
-func (q *Router) queue(f Command) {
+func (q *Router) execute(c Command) {
-	q.commands = append(q.commands, f)
+	// The command can be executed immediately if:
+	//
+	// - event delivery is not frozen, and
+	// - the influencing tag and event receivers were all seen
+	//   in the previous frame, and
+	// - no event receiver has completed their event handling.
+	if !q.deferring {
+		tag, ch := q.executeCommand(c)
+		immediate := true
+		if tag != nil {
+			h, ok := q.handlers[tag]
+			immediate = immediate && ok && h.old
+		}
+		for _, e := range ch.events {
+			h, ok := q.handlers[e.tag]
+			immediate = immediate && ok && h.old && !h.nextFilter.Matches(e.event)
+		}
+		if immediate {
+			// Hold on to the remaining events for state replay.
+			var evts []event.Event
+			for _, ch := range q.changes {
+				if ch.event != nil {
+					evts = append(evts, ch.event)
+				}
+			}
+			if len(q.changes) > 1 {
+				q.changes = q.changes[:1]
+			}
+			q.changeState(nil, ch.state, ch.events)
+			q.Queue(evts...)
+			return
+		}
+	}
+	q.deferring = true
+	q.commands = append(q.commands, c)
 }
 
 func (q *Router) state() inputState {
@@ -373,58 +436,47 @@ func (q *Router) lastState() inputState {
 	return inputState{}
 }
 
-func (q *Router) changeClipboardState(cstate clipboardState, evts []taggedEvent) bool {
-	state := q.lastState()
-	state.clipboardState = cstate
-	return q.changeState(state, evts)
-}
-
-func (q *Router) changeKeyState(kstate keyState, evts []taggedEvent) bool {
-	state := q.lastState()
-	state.keyState = kstate
-	return q.changeState(state, evts)
-}
-
-func (q *Router) changePointerState(pstate pointerState, evts []taggedEvent) bool {
-	state := q.lastState()
-	state.pointerState = pstate
-	return q.changeState(state, evts)
-}
-
 func (q *Router) executeCommands() {
-	for _, req := range q.commands {
+	for _, c := range q.commands {
-		state := q.lastState()
+		_, ch := q.executeCommand(c)
-		switch req := req.(type) {
+		q.changeState(nil, ch.state, ch.events)
-		case key.SelectionCmd:
-			kstate := q.key.queue.setSelection(state.keyState, req)
-			q.changeKeyState(kstate, nil)
-		case key.FocusCmd:
-			q.changeKeyState(q.key.queue.Focus(q.handlers, state.keyState, req.Tag))
-		case key.SoftKeyboardCmd:
-			kstate := state.keyState.softKeyboard(req.Show)
-			q.changeKeyState(kstate, nil)
-		case key.SnippetCmd:
-			kstate := q.key.queue.setSnippet(state.keyState, req)
-			q.changeKeyState(kstate, nil)
-		case transfer.OfferCmd:
-			q.changePointerState(q.pointer.queue.offerData(q.handlers, state.pointerState, req))
-		case clipboard.WriteCmd:
-			q.cqueue.ProcessWriteClipboard(req)
-		case clipboard.ReadCmd:
-			cstate := q.cqueue.ProcessReadClipboard(state.clipboardState, req.Tag)
-			q.changeClipboardState(cstate, nil)
-		case pointer.GrabCmd:
-			q.changePointerState(q.pointer.queue.grab(state.pointerState, req))
-		}
 	}
 	q.commands = nil
 }
 
-func (q *Router) addEvents(evts []taggedEvent) bool {
+// executeCommand the command and return the resulting state change along with the
-	return q.changeState(q.lastState(), evts)
+// tag the state change depended on, if any.
+func (q *Router) executeCommand(c Command) (event.Tag, stateChange) {
+	state := q.state()
+	var evts []taggedEvent
+	var tag event.Tag
+	switch req := c.(type) {
+	case key.SelectionCmd:
+		tag = req.Tag
+		state.keyState = q.key.queue.setSelection(state.keyState, req)
+	case key.FocusCmd:
+		tag = req.Tag
+		state.keyState, evts = q.key.queue.Focus(q.handlers, state.keyState, req.Tag)
+	case key.SoftKeyboardCmd:
+		state.keyState = state.keyState.softKeyboard(req.Show)
+	case key.SnippetCmd:
+		tag = req.Tag
+		state.keyState = q.key.queue.setSnippet(state.keyState, req)
+	case transfer.OfferCmd:
+		tag = req.Tag
+		state.pointerState, evts = q.pointer.queue.offerData(q.handlers, state.pointerState, req)
+	case clipboard.WriteCmd:
+		q.cqueue.ProcessWriteClipboard(req)
+	case clipboard.ReadCmd:
+		state.clipboardState = q.cqueue.ProcessReadClipboard(state.clipboardState, req.Tag)
+	case pointer.GrabCmd:
+		tag = req.Tag
+		state.pointerState, evts = q.pointer.queue.grab(state.pointerState, req)
+	}
+	return tag, stateChange{state: state, events: evts}
 }
 
-func (q *Router) changeState(state inputState, evts []taggedEvent) bool {
+func (q *Router) changeState(e event.Event, state inputState, evts []taggedEvent) bool {
 	// Wrap pointer.DataEvent.Open functions to detect them not being called.
 	for i := range evts {
 		e := &evts[i]
@@ -439,16 +491,18 @@ func (q *Router) changeState(state inputState, evts []taggedEvent) bool {
 			e.event = de
 		}
 	}
-	n := len(q.changes)
+	// Initialize the first change to contain the current state
-	// We must add a new state change if
+	// and events that are bound for the current frame.
-	//
+	if len(q.changes) == 0 {
-	//  - there is no first state change, or
+		q.changes = append(q.changes, stateChange{})
-	//  - the state change is not atomic from the perspective of the handlers.
+	}
-	if len(q.changes) == 0 || (len(evts) > 0 && len(q.changes[n-1].events) > 0) {
+	if e != nil && len(evts) > 0 {
-		q.changes = append(q.changes, stateChange{state: state, events: evts})
+		// An event triggered events bound for user receivers. Add a state change to be
+		// able to redo the change in case of a command execution.
+		q.changes = append(q.changes, stateChange{event: e, state: state, events: evts})
 	} else {
 		// Otherwise, merge with previous change.
-		prev := &q.changes[n-1]
+		prev := &q.changes[len(q.changes)-1]
 		prev.state = state
 		prev.events = append(prev.events, evts...)
 	}
@@ -504,8 +558,10 @@ func (q *Router) queueKeyEvent(state keyState, e key.Event) []taggedEvent {
 }
 
 func (q *Router) MoveFocus(dir key.FocusDirection) bool {
-	ks, evts := q.key.queue.MoveFocus(q.handlers, q.lastState().keyState, dir)
+	state := q.lastState()
-	return q.changeKeyState(ks, evts)
+	kstate, evts := q.key.queue.MoveFocus(q.handlers, state.keyState, dir)
+	state.keyState = kstate
+	return q.changeState(nil, state, evts)
 }
 
 // RevealFocus scrolls the current focus (if any) into viewport
@@ -546,7 +602,7 @@ func (q *Router) ScrollFocus(dist image.Point) {
 	}
 	kh := &q.handlers[focus].key
 	area := q.key.queue.AreaFor(kh)
-	q.addEvents(q.pointer.queue.Deliver(q.handlers, area, pointer.Event{
+	q.changeState(nil, q.lastState(), q.pointer.queue.Deliver(q.handlers, area, pointer.Event{
 		Kind:   pointer.Scroll,
 		Source: pointer.Touch,
 		Scroll: f32internal.FPt(dist),
@@ -593,16 +649,19 @@ func (q *Router) ClickFocus() {
 	}
 	area := q.key.queue.AreaFor(kh)
 	e.Kind = pointer.Press
-	q.addEvents(q.pointer.queue.Deliver(q.handlers, area, e))
+	state := q.lastState()
+	q.changeState(nil, state, q.pointer.queue.Deliver(q.handlers, area, e))
 	e.Kind = pointer.Release
-	q.addEvents(q.pointer.queue.Deliver(q.handlers, area, e))
+	q.changeState(nil, state, q.pointer.queue.Deliver(q.handlers, area, e))
 }
 
 // TextInputState returns the input state from the most recent
 // call to Frame.
 func (q *Router) TextInputState() TextInputState {
-	kstate, s := q.state().InputState()
+	state := q.state()
-	q.changeKeyState(kstate, nil)
+	kstate, s := state.InputState()
+	state.keyState = kstate
+	q.changeState(nil, state, nil)
 	return s
 }
 
@@ -713,7 +772,7 @@ func (q *Router) collect() {
 			pc.inputOp(tag, &s.pointer)
 			a := pc.currentArea()
 			b := pc.currentAreaBounds()
-			if s.filter.focusable {
+			if s.filter.key.focusable {
 				kq.inputOp(tag, &s.key, t, a, b)
 			}
 

widget/button.go

@@ -80,7 +80,7 @@ func (b *Clickable) Pressed() bool {
 
 // Focus requests the input focus for the element.
 func (b *Clickable) Focus(gtx layout.Context) {
-	gtx.Queue(key.FocusCmd{Tag: &b.keyTag})
+	gtx.Execute(key.FocusCmd{Tag: &b.keyTag})
 }
 
 // Focused reports whether b has focus.
@@ -149,7 +149,7 @@ func (b *Clickable) Update(gtx layout.Context) []Click {
 			}
 		case gesture.KindPress:
 			if e.Source == pointer.Mouse {
-				gtx.Queue(key.FocusCmd{Tag: &b.keyTag})
+				gtx.Execute(key.FocusCmd{Tag: &b.keyTag})
 			}
 			b.history = append(b.history, Press{
 				Position: e.Position,

widget/dnd.go

@@ -76,7 +76,7 @@ func (d *Draggable) Update(gtx layout.Context) (mime string, requested bool) {
 // Offer the data ready for a drop. Must be called after being Requested.
 // The mime must be one in the requested list.
 func (d *Draggable) Offer(gtx layout.Context, mime string, data io.ReadCloser) {
-	gtx.Queue(transfer.OfferCmd{Tag: &d.handle, Type: mime, Data: data})
+	gtx.Execute(transfer.OfferCmd{Tag: &d.handle, Type: mime, Data: data})
 }
 
 // Pos returns the drag position relative to its initial click position.

widget/dnd_test.go

@@ -51,17 +51,16 @@ func TestDraggable(t *testing.T) {
 		},
 	)
 	ofr := &offer{data: "hello"}
-	drag.Offer(gtx, "file", ofr)
 	drag.Update(gtx)
 	r.Events(drag, transfer.TargetFilter{Type: drag.Type})
+	drag.Offer(gtx, "file", ofr)
 	r.Frame(gtx.Ops)
 
 	evs := r.Events(drag, transfer.TargetFilter{Type: drag.Type})
 	if len(evs) != 2 {
-		t.Fatalf("expected 2 event, got %d", len(evs))
+		t.Fatalf("expected 3 event, got %d", len(evs))
 	}
 	ev := evs[0].(transfer.DataEvent)
-	ev.Open = nil
 	if got, want := ev.Type, "file"; got != want {
 		t.Errorf("expected %v; got %v", got, want)
 	}

widget/editor.go

@@ -475,13 +475,13 @@ func (e *Editor) command(gtx layout.Context, k key.Event) {
 		// half is in Editor.processKey() under clipboard.Event.
 		case "V":
 			if !e.ReadOnly {
-				gtx.Queue(clipboard.ReadCmd{Tag: &e.eventKey})
+				gtx.Execute(clipboard.ReadCmd{Tag: &e.eventKey})
 			}
 		// Copy or Cut selection -- ignored if nothing selected.
 		case "C", "X":
 			e.scratch = e.text.SelectedText(e.scratch)
 			if text := string(e.scratch); text != "" {
-				gtx.Queue(clipboard.WriteCmd{Type: "application/text", Data: io.NopCloser(strings.NewReader(text))})
+				gtx.Execute(clipboard.WriteCmd{Type: "application/text", Data: io.NopCloser(strings.NewReader(text))})
 				if k.Name == "X" && !e.ReadOnly {
 					e.Delete(1)
 				}
@@ -556,8 +556,8 @@ func (e *Editor) command(gtx layout.Context, k key.Event) {
 
 // Focus requests the input focus for the Editor.
 func (e *Editor) Focus(gtx layout.Context) {
-	gtx.Queue(key.FocusCmd{Tag: &e.eventKey})
+	gtx.Execute(key.FocusCmd{Tag: &e.eventKey})
-	gtx.Queue(key.SoftKeyboardCmd{Show: true})
+	gtx.Execute(key.SoftKeyboardCmd{Show: true})
 }
 
 // Focused returns whether the editor is focused or not.
@@ -601,7 +601,7 @@ func (e *Editor) Update(gtx layout.Context) {
 		}
 		if newSel != e.ime.selection {
 			e.ime.selection = newSel
-			gtx.Queue(key.SelectionCmd{Tag: &e.eventKey, Range: newSel.rng, Caret: newSel.caret})
+			gtx.Execute(key.SelectionCmd{Tag: &e.eventKey, Range: newSel.rng, Caret: newSel.caret})
 		}
 
 		e.updateSnippet(gtx, e.ime.start, e.ime.end)
@@ -658,7 +658,7 @@ func (e *Editor) updateSnippet(gtx layout.Context, start, end int) {
 		return
 	}
 	e.ime.snippet = newSnip
-	gtx.Queue(key.SnippetCmd{Tag: &e.eventKey, Snippet: newSnip})
+	gtx.Execute(key.SnippetCmd{Tag: &e.eventKey, Snippet: newSnip})
 }
 
 func (e *Editor) layout(gtx layout.Context, textMaterial, selectMaterial op.CallOp) layout.Dimensions {

widget/enum.go

@@ -51,7 +51,7 @@ func (e *Enum) Update(gtx layout.Context) bool {
 			switch ev.Kind {
 			case gesture.KindPress:
 				if ev.Source == pointer.Mouse {
-					gtx.Queue(key.FocusCmd{Tag: &state.tag})
+					gtx.Execute(key.FocusCmd{Tag: &state.tag})
 				}
 			case gesture.KindClick:
 				if state.key != e.Value {

widget/selectable.go

@@ -100,8 +100,8 @@ func (l *Selectable) initialize() {
 
 // Focus requests the input focus for the label.
 func (l *Selectable) Focus(gtx layout.Context) {
-	gtx.Queue(key.FocusCmd{Tag: l})
+	gtx.Execute(key.FocusCmd{Tag: l})
-	gtx.Queue(key.SoftKeyboardCmd{Show: true})
+	gtx.Execute(key.SoftKeyboardCmd{Show: true})
 }
 
 // Focused returns whether the label is focused or not.
@@ -348,7 +348,7 @@ func (e *Selectable) command(gtx layout.Context, k key.Event) {
 		case "C", "X":
 			e.scratch = e.text.SelectedText(e.scratch)
 			if text := string(e.scratch); text != "" {
-				gtx.Queue(clipboard.WriteCmd{Type: "application/text", Data: io.NopCloser(strings.NewReader(text))})
+				gtx.Execute(clipboard.WriteCmd{Type: "application/text", Data: io.NopCloser(strings.NewReader(text))})
 			}
 		// Select all
 		case "A":