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>

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.Queue(key.SoftKeyboardCmd{Show: true})
+	gtx.Execute(key.FocusCmd{Tag: &e.eventKey})
+	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.Queue(key.SoftKeyboardCmd{Show: true})
+	gtx.Execute(key.FocusCmd{Tag: l})
+	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":