ui: add package input for merged input

To avoid passing a queue type for each kind of input (pointer, key),
introduce package input for mapping a handler key to all input events.

Future input sources can be added without changes to programs, and
as an added bonus, event ordering is preserved across input sources.

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

ui/key/key.go

@@ -16,14 +16,6 @@ type OpHideInput struct{}
 
 type Key interface{}
 
-type Events interface {
-	For(k Key) []Event
-}
-
-type Event interface {
-	isKeyEvent()
-}
-
 type Focus struct {
 	Focus bool
 }
@@ -93,9 +85,9 @@ func (h OpHideInput) Add(o *ui.Ops) {
 	o.Write(data)
 }
 
-func (Edit) ImplementsEvent()  {}
-func (Chord) ImplementsEvent() {}
-func (Focus) ImplementsEvent() {}
-func (Edit) isKeyEvent()       {}
-func (Chord) isKeyEvent()      {}
-func (Focus) isKeyEvent()      {}
+func (Edit) ImplementsEvent()       {}
+func (Chord) ImplementsEvent()      {}
+func (Focus) ImplementsEvent()      {}
+func (Edit) ImplementsInputEvent()  {}
+func (Chord) ImplementsInputEvent() {}
+func (Focus) ImplementsInputEvent() {}

ui/key/queue.go

@@ -1,145 +0,0 @@
-// SPDX-License-Identifier: Unlicense OR MIT
-
-package key
-
-import (
-	"gioui.org/ui"
-	"gioui.org/ui/internal/ops"
-)
-
-type Queue struct {
-	focus    Key
-	handlers map[Key]*handler
-	reader   ui.OpsReader
-	state    TextInputState
-}
-
-type handler struct {
-	active bool
-	events []Event
-}
-
-type listenerPriority uint8
-
-const (
-	priNone listenerPriority = iota
-	priDefault
-	priCurrentFocus
-	priNewFocus
-)
-
-// InputState returns the last text input state as
-// determined in Frame.
-func (q *Queue) InputState() TextInputState {
-	return q.state
-}
-
-func (q *Queue) Frame(root *ui.Ops) {
-	if q.handlers == nil {
-		q.handlers = make(map[Key]*handler)
-	}
-	for _, h := range q.handlers {
-		h.active = false
-		h.events = h.events[:0]
-	}
-	q.reader.Reset(root)
-	focus, pri, hide := q.resolveFocus()
-	for k, h := range q.handlers {
-		if !h.active {
-			delete(q.handlers, k)
-			if q.focus == k {
-				q.focus = nil
-			}
-		}
-	}
-	changed := focus != nil && focus != q.focus
-	if focus != q.focus {
-		if q.focus != nil {
-			if h, ok := q.handlers[q.focus]; ok {
-				h.events = append(h.events, Focus{Focus: false})
-			}
-		}
-		q.focus = focus
-		if q.focus != nil {
-			// A new focus always exists in the handler map.
-			h := q.handlers[q.focus]
-			h.events = append(h.events, Focus{Focus: true})
-		}
-	}
-	switch {
-	case pri == priNewFocus:
-		q.state = TextInputOpen
-	case hide:
-		q.state = TextInputClosed
-	case changed:
-		q.state = TextInputFocus
-	default:
-		q.state = TextInputKeep
-	}
-}
-
-func (q *Queue) Push(e Event) {
-	if q.focus == nil {
-		return
-	}
-	h := q.handlers[q.focus]
-	h.events = append(h.events, e)
-}
-
-func (q *Queue) For(k Key) []Event {
-	h := q.handlers[k]
-	if h == nil {
-		return nil
-	}
-	return h.events
-}
-
-func (q *Queue) resolveFocus() (Key, listenerPriority, bool) {
-	var k Key
-	var pri listenerPriority
-	var hide bool
-loop:
-	for {
-		encOp, ok := q.reader.Decode()
-		if !ok {
-			break
-		}
-		switch ops.OpType(encOp.Data[0]) {
-		case ops.TypeKeyHandler:
-			var op OpHandler
-			op.Decode(encOp.Data, encOp.Refs)
-			var newPri listenerPriority
-			switch {
-			case op.Focus:
-				newPri = priNewFocus
-			case op.Key == q.focus:
-				newPri = priCurrentFocus
-			default:
-				newPri = priDefault
-			}
-			if newPri >= pri {
-				k, pri = op.Key, newPri
-			}
-			h, ok := q.handlers[op.Key]
-			if !ok {
-				h = &handler{
-					// Reset the handler on (each) first appearance.
-					events: []Event{Focus{Focus: false}},
-				}
-				q.handlers[op.Key] = h
-			}
-			h.active = true
-		case ops.TypeHideInput:
-			hide = true
-		case ops.TypePush:
-			newK, newPri, h := q.resolveFocus()
-			hide = hide || h
-			if newPri >= pri {
-				k, pri = newK, newPri
-			}
-		case ops.TypePop:
-			break loop
-		}
-	}
-	return k, pri, hide
-}