app/internal/window: [iOS] implement clipboard

Updates gio#31

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

app/internal/window/os_ios.go

@@ -17,6 +17,8 @@ __attribute__ ((visibility ("hidden"))) void gio_addLayerToView(CFTypeRef viewRe
 __attribute__ ((visibility ("hidden"))) void gio_updateView(CFTypeRef viewRef, CFTypeRef layerRef);
 __attribute__ ((visibility ("hidden"))) void gio_removeLayer(CFTypeRef layerRef);
 __attribute__ ((visibility ("hidden"))) void gio_setAnimating(CFTypeRef viewRef, int anim);
+__attribute__ ((visibility ("hidden"))) CFTypeRef gio_readClipboard(void);
+__attribute__ ((visibility ("hidden"))) void gio_writeClipboard(unichar *chars, NSUInteger length);
 */
 import "C"
 
@@ -26,6 +28,8 @@ import (
 	"runtime/debug"
 	"sync/atomic"
 	"time"
+	"unicode/utf16"
+	"unsafe"
 
 	"gioui.org/f32"
 	"gioui.org/io/key"
@@ -199,6 +203,24 @@ func onTouch(last C.int, view, touchRef C.CFTypeRef, phase C.NSInteger, x, y C.C
 	})
 }
 
+func (w *window) ReadClipboard() {
+	runOnMain(func() {
+		content := nsstringToString(C.gio_readClipboard())
+		w.w.Event(system.ClipboardEvent{Text: content})
+	})
+}
+
+func (w *window) WriteClipboard(s string) {
+	u16 := utf16.Encode([]rune(s))
+	runOnMain(func() {
+		var chars *C.unichar
+		if len(u16) > 0 {
+			chars = (*C.unichar)(unsafe.Pointer(&u16[0]))
+		}
+		C.gio_writeClipboard(chars, C.NSUInteger(len(u16)))
+	})
+}
+
 func (w *window) SetAnimating(anim bool) {
 	v := w.view
 	if v == 0 {

app/internal/window/os_ios.m

@@ -279,6 +279,24 @@ NSArray<UIKeyCommand *> *_keyCommands;
 }
 @end
 
+void gio_writeClipboard(unichar *chars, NSUInteger length) {
+	@autoreleasepool {
+		NSString *s = [NSString string];
+		if (length > 0) {
+			s = [NSString stringWithCharacters:chars length:length];
+		}
+		UIPasteboard *p = UIPasteboard.generalPasteboard;
+		p.string = s;
+	}
+}
+
+CFTypeRef gio_readClipboard(void) {
+	@autoreleasepool {
+		UIPasteboard *p = UIPasteboard.generalPasteboard;
+		return (__bridge_retained CFTypeRef)p.string;
+	}
+}
+
 void gio_setAnimating(CFTypeRef viewRef, int anim) {
 	GioView *view = (__bridge GioView *)viewRef;
 	[view setAnimating:(anim ? YES : NO)];