ui/input: move Router and input queues to internal package

Now that only app.Window needs the Router, make it unavailable for
clients.

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

ui/app/internal/input/router.go

@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package input
+
+import (
+	"gioui.org/ui"
+	"gioui.org/ui/input"
+	"gioui.org/ui/key"
+	"gioui.org/ui/pointer"
+)
+
+// Router is a Queue implementation that routes events from
+// all available input sources to registered handlers.
+type Router struct {
+	pqueue pointerQueue
+	kqueue keyQueue
+
+	handlers handlerEvents
+}
+
+type handlerEvents map[input.Key][]input.Event
+
+func (q *Router) Events(k input.Key) []input.Event {
+	events := q.handlers[k]
+	delete(q.handlers, k)
+	return events
+}
+
+func (q *Router) Frame(ops *ui.Ops) {
+	q.init()
+	for k := range q.handlers {
+		delete(q.handlers, k)
+	}
+	q.pqueue.Frame(ops, q.handlers)
+	q.kqueue.Frame(ops, q.handlers)
+}
+
+func (q *Router) Add(e input.Event) {
+	q.init()
+	switch e := e.(type) {
+	case pointer.Event:
+		q.pqueue.Push(e, q.handlers)
+	case key.EditEvent, key.ChordEvent, key.FocusEvent:
+		q.kqueue.Push(e, q.handlers)
+	}
+}
+
+func (q *Router) InputState() key.TextInputState {
+	return q.kqueue.InputState()
+}
+
+func (q *Router) init() {
+	if q.handlers == nil {
+		q.handlers = make(handlerEvents)
+	}
+}