app,app/internal/window: [macOS] add app.Window.Close for closing a window

Recently support was added for multiple top-level windows. Add support
for closing those windows.

macOS only; all others stubbed out.

Signed-off-by: Larry Clapp <larry@theclapp.org>

app/internal/window/os_android.go

@@ -650,6 +650,9 @@ func (w *window) ReadClipboard() {
 	})
 }
 
+// Close the window. Not implemented for Android.
+func (w *window) Close() {}
+
 // RunOnMain is the exported version of runOnMain without a JNI
 // environement.
 func RunOnMain(f func()) {

app/internal/window/os_ios.go

@@ -299,6 +299,9 @@ func (w *window) ShowTextInput(show bool) {
 	})
 }
 
+// Close the window. Not implemented for iOS.
+func (w *window) Close() {}
+
 func NewWindow(win Callbacks, opts *Options) error {
 	mainWindow.in <- windowAndOptions{win, opts}
 	return <-mainWindow.errs

app/internal/window/os_js.go

@@ -406,6 +406,9 @@ func (w *window) ShowTextInput(show bool) {
 	}()
 }
 
+// Close the window. Not implemented for js.
+func (w *window) Close() {}
+
 func (w *window) draw(sync bool) {
 	width, height, scale, cfg := w.config()
 	if cfg == (unit.Metric{}) || width == 0 || height == 0 {

app/internal/window/os_macos.go

@@ -44,6 +44,7 @@ __attribute__ ((visibility ("hidden"))) void gio_appTerminate(void);
 __attribute__ ((visibility ("hidden"))) CFTypeRef gio_createWindow(CFTypeRef viewRef, const char *title, CGFloat width, CGFloat height);
 __attribute__ ((visibility ("hidden"))) void gio_makeKeyAndOrderFront(CFTypeRef windowRef);
 __attribute__ ((visibility ("hidden"))) NSPoint gio_cascadeTopLeftFromPoint(CFTypeRef windowRef, NSPoint topLeft);
+__attribute__ ((visibility ("hidden"))) void gio_close(CFTypeRef windowRef);
 */
 import "C"
 
@@ -132,6 +133,17 @@ func (w *window) SetAnimating(anim bool) {
 	}
 }
 
+// Close the window. Only implemented for macOS.
+func (w *window) Close() {
+	runOnMain(func() {
+		// Make sure the view is still valid. The window might've been closed
+		// during the switch to the main thread.
+		if w.view != 0 {
+			C.gio_close(w.window)
+		}
+	})
+}
+
 func (w *window) setStage(stage system.Stage) {
 	if stage == w.stage {
 		return

app/internal/window/os_macos.m

@@ -153,6 +153,11 @@ void gio_appTerminate(void) {
 	}
 }
 
+void gio_close(CFTypeRef windowRef) {
+  NSWindow* window = (__bridge NSWindow *)windowRef;
+  [window performClose:nil];
+}
+
 @implementation GioAppDelegate
 - (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
 	[[NSRunningApplication currentApplication] activateWithOptions:(NSApplicationActivateAllWindows | NSApplicationActivateIgnoringOtherApps)];

app/internal/window/os_wayland.go

@@ -1426,6 +1426,9 @@ func (w *window) surface() (*C.struct_wl_surface, int, int) {
 
 func (w *window) ShowTextInput(show bool) {}
 
+// Close the window. Not implemented for Wayland.
+func (w *window) Close() {}
+
 // detectUIScale reports the system UI scale, or 1.0 if it fails.
 func detectUIScale() float32 {
 	// TODO: What about other window environments?

app/internal/window/os_windows.go

@@ -501,6 +501,9 @@ func (w *window) HWND() (syscall.Handle, int, int) {
 	return w.hwnd, w.width, w.height
 }
 
+// Close the window. Not implemented for Windows.
+func (w *window) Close() {}
+
 func convertKeyCode(code uintptr) (string, bool) {
 	if '0' <= code && code <= '9' || 'A' <= code && code <= 'Z' {
 		return string(rune(code)), true

app/internal/window/os_x11.go

@@ -110,6 +110,9 @@ func (w *x11Window) WriteClipboard(s string) {
 
 func (w *x11Window) ShowTextInput(show bool) {}
 
+// Close the window. Not implemented for X11.
+func (w *x11Window) Close() {}
+
 var x11OneByte = make([]byte, 1)
 
 func (w *x11Window) wakeup() {

app/internal/window/window.go

@@ -57,6 +57,9 @@ type Driver interface {
 	ReadClipboard()
 	// WriteClipboard requests a clipboard write.
 	WriteClipboard(s string)
+
+	// Close the window.
+	Close()
 }
 
 type windowRendezvous struct {

app/window.go

@@ -208,6 +208,17 @@ func (w *Window) WriteClipboard(s string) {
 	})
 }
 
+// Close the window. The window's event loop should exit when it receives
+// system.DestroyEvent.
+//
+// Currently, only the macOS driver implements this functionality, all others
+// are stubbed.
+func (w *Window) Close() {
+	w.driverDo(func() {
+		w.driver.Close()
+	})
+}
+
 // driverDo calls f as soon as the window has a valid driver attached,
 // or does nothing if the window is destroyed while waiting.
 func (w *Window) driverDo(f func()) {