app/internal/window: [wasm] implement clipboard

Update gio#31

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

app/internal/window/os_js.go

@@ -19,10 +19,12 @@ import (
 
 type window struct {
 	window                js.Value
+	clipboard             js.Value
 	cnv                   js.Value
 	tarea                 js.Value
 	w                     Callbacks
 	redraw                js.Func
+	clipboardCallback     js.Func
 	requestAnimationFrame js.Value
 	cleanfuncs            []func()
 	touches               []js.Value
@@ -43,15 +45,21 @@ func NewWindow(win Callbacks, opts *Options) error {
 	tarea := createTextArea(doc)
 	cont.Call("appendChild", tarea)
 	w := &window{
-		cnv:    cnv,
-		tarea:  tarea,
-		window: js.Global().Get("window"),
+		cnv:       cnv,
+		tarea:     tarea,
+		window:    js.Global().Get("window"),
+		clipboard: js.Global().Get("navigator").Get("clipboard"),
 	}
 	w.requestAnimationFrame = w.window.Get("requestAnimationFrame")
 	w.redraw = w.funcOf(func(this js.Value, args []js.Value) interface{} {
 		w.animCallback()
 		return nil
 	})
+	w.clipboardCallback = w.funcOf(func(this js.Value, args []js.Value) interface{} {
+		content := args[0].String()
+		win.Event(system.ClipboardEvent{Text: content})
+		return nil
+	})
 	w.addEventListeners()
 	w.w = win
 	go func() {
@@ -343,6 +351,26 @@ func (w *window) SetAnimating(anim bool) {
 	w.animating = anim
 }
 
+func (w *window) ReadClipboard() {
+	if w.clipboard.IsUndefined() {
+		return
+	}
+	if w.clipboard.Get("readText").IsUndefined() {
+		return
+	}
+	w.clipboard.Call("readText", w.clipboard).Call("then", w.clipboardCallback)
+}
+
+func (w *window) WriteClipboard(s string) {
+	if w.clipboard.IsUndefined() {
+		return
+	}
+	if w.clipboard.Get("writeText").IsUndefined() {
+		return
+	}
+	w.clipboard.Call("writeText", s)
+}
+
 func (w *window) ShowTextInput(show bool) {
 	// Run in a goroutine to avoid a deadlock if the
 	// focus change result in an event.