internal/ui: use RegisterClass API (#2442)

Updates #1162

This change uses purego's new RegisterClass API to clean up the
EbitengineWindowDelegate ObjC class. Doing so makes the code
easier to read and more efficient since it directly get the origResizable
and origDelegate fields.

internal/ui/ui_glfw_darwin.go

@@ -31,90 +31,128 @@ import (
 
 var class_EbitengineWindowDelegate objc.Class
 
-func init() {
+type windowDelgate struct {
-	class_EbitengineWindowDelegate = objc.AllocateClassPair(objc.GetClass("NSObject"), "EbitengineWindowDelegate", 0)
+	isa           objc.Class `objc:"EbitengineWindowDelegate : NSObject <NSWindowDelegate>"`
-	protocol := objc.GetProtocol("NSWindowDelegate")
+	origDelegate  objc.ID
-	class_EbitengineWindowDelegate.AddProtocol(protocol)
+	origResizable bool
-	// TODO: remove these Ivars and place them in Go since there is only ever one instance of this class
+}
-	class_EbitengineWindowDelegate.AddIvar("origDelegate", objc.ID(0), "@")
+
-	class_EbitengineWindowDelegate.AddIvar("origResizable", false, "B")
+func (w *windowDelgate) pushResizableState(win objc.ID) {
-	origDelegateOffset := class_EbitengineWindowDelegate.InstanceVariable("origDelegate").Offset()
+	window := cocoa.NSWindow{ID: win}
-	origResizableOffset := class_EbitengineWindowDelegate.InstanceVariable("origResizable").Offset()
+	w.origResizable = window.StyleMask()&cocoa.NSWindowStyleMaskResizable != 0
-	getOrigDelegate := func(self objc.ID) objc.ID {
+	if !w.origResizable {
-		selfPtr := *(**uintptr)(unsafe.Pointer(&self))
-		return *(*objc.ID)(unsafe.Pointer(uintptr(unsafe.Pointer(selfPtr)) + origDelegateOffset))
-	}
-	getResizable := func(self objc.ID) bool {
-		selfPtr := *(**uintptr)(unsafe.Pointer(&self))
-		return *(*bool)(unsafe.Pointer(uintptr(unsafe.Pointer(selfPtr)) + origResizableOffset))
-	}
-	setResizable := func(self objc.ID, resizable bool) {
-		selfPtr := *(**uintptr)(unsafe.Pointer(&self))
-		*(*bool)(unsafe.Pointer(uintptr(unsafe.Pointer(selfPtr)) + origResizableOffset)) = resizable
-	}
-	pushResizableState := func(self, w objc.ID) {
-		window := cocoa.NSWindow{ID: w}
-		setResizable(self, window.StyleMask()&cocoa.NSWindowStyleMaskResizable != 0)
-		if !getResizable(self) {
 		window.SetStyleMask(window.StyleMask() | cocoa.NSWindowStyleMaskResizable)
 	}
-	}
+}
-	popResizableState := func(self, w objc.ID) {
+
-		window := cocoa.NSWindow{ID: w}
+func (w *windowDelgate) popResizableState(win objc.ID) {
-		if !getResizable(self) {
+	if !w.origResizable {
+		window := cocoa.NSWindow{ID: win}
 		window.SetStyleMask(window.StyleMask() & ^uint(cocoa.NSWindowStyleMaskResizable))
 	}
-		setResizable(self, false)
+	w.origResizable = false
-	}
+}
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("initWithOrigDelegate:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, origDelegate objc.ID) objc.ID {
+
-		self = self.SendSuper(objc.RegisterName("init"))
+func (w *windowDelgate) InitWithOrigDelegate(cmd objc.SEL, origDelegate objc.ID) objc.ID {
+	self := objc.ID(unsafe.Pointer(w)).SendSuper(objc.RegisterName("init"))
 	if self != 0 {
-			selfPtr := *(**uintptr)(unsafe.Pointer(&self))
+		w = *(**windowDelgate)(unsafe.Pointer(&self))
-			*(*objc.ID)(unsafe.Pointer(uintptr(unsafe.Pointer(selfPtr)) + origDelegateOffset)) = origDelegate
+		w.origDelegate = origDelegate
 	}
 	return self
-	}), "@@:B")
+}
-	// The method set of origDelegate_ must sync with GLFWWindowDelegate's implementation.
-	// See cocoa_window.m in GLFW.
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowShouldClose:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) int {
-		return int(getOrigDelegate(self).Send(objc.RegisterName("windowShouldClose:"), notification))
-	}), "B@:@")
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowDidResize:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
-		getOrigDelegate(self).Send(cmd, notification)
-	}), "v@:@")
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowDidMove:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
-		getOrigDelegate(self).Send(cmd, notification)
-	}), "v@:@")
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowDidMiniaturize:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
-		getOrigDelegate(self).Send(cmd, notification)
-	}), "v@:@")
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowDidDeminiaturize:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
-		getOrigDelegate(self).Send(cmd, notification)
-	}), "v@:@")
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowDidBecomeKey:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
-		getOrigDelegate(self).Send(cmd, notification)
-	}), "v@:@")
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowDidResignKey:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
-		getOrigDelegate(self).Send(cmd, notification)
-	}), "v@:@")
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowDidChangeOcclusionState:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
-		getOrigDelegate(self).Send(cmd, notification)
-	}), "v@:@")
 
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowWillEnterFullScreen:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
+// The method set of origDelegate_ must sync with GLFWWindowDelegate's implementation.
-		pushResizableState(self, cocoa.NSNotification{ID: notification}.Object())
+// See cocoa_window.m in GLFW.
-	}), "v@:@")
+
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowDidEnterFullScreen:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
+func (w *windowDelgate) WindowShouldClose(cmd objc.SEL, notification objc.ID) bool {
-		popResizableState(self, cocoa.NSNotification{ID: notification}.Object())
+	return w.origDelegate.Send(cmd, notification) != 0
-	}), "v@:@")
+}
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowWillExitFullScreen:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
+
-		pushResizableState(self, cocoa.NSNotification{ID: notification}.Object())
+func (w *windowDelgate) WindowDidResize(cmd objc.SEL, notification objc.ID) {
-	}), "v@:@")
+	w.origDelegate.Send(cmd, notification)
-	class_EbitengineWindowDelegate.AddMethod(objc.RegisterName("windowDidExitFullScreen:"), objc.NewIMP(func(self objc.ID, cmd objc.SEL, notification objc.ID) {
+}
-		popResizableState(self, cocoa.NSNotification{ID: notification}.Object())
+
+func (w *windowDelgate) WindowDidMove(cmd objc.SEL, notification objc.ID) {
+	w.origDelegate.Send(cmd, notification)
+}
+
+func (w *windowDelgate) WindowDidMiniaturize(cmd objc.SEL, notification objc.ID) {
+	w.origDelegate.Send(cmd, notification)
+}
+
+func (w *windowDelgate) WindowDidDeminiaturize(cmd objc.SEL, notification objc.ID) {
+	w.origDelegate.Send(cmd, notification)
+}
+
+func (w *windowDelgate) WindowDidBecomeKey(cmd objc.SEL, notification objc.ID) {
+	w.origDelegate.Send(cmd, notification)
+}
+
+func (w *windowDelgate) WindowDidResignKey(cmd objc.SEL, notification objc.ID) {
+	w.origDelegate.Send(cmd, notification)
+}
+
+func (w *windowDelgate) WindowDidChangeOcclusionState(cmd objc.SEL, notification objc.ID) {
+	w.origDelegate.Send(cmd, notification)
+}
+
+func (w *windowDelgate) WindowWillEnterFullScreen(cmd objc.SEL, notification objc.ID) {
+	w.pushResizableState(cocoa.NSNotification{ID: notification}.Object())
+}
+
+func (w *windowDelgate) WindowDidEnterFullScreen(cmd objc.SEL, notification objc.ID) {
+	w.popResizableState(cocoa.NSNotification{ID: notification}.Object())
+}
+
+func (w *windowDelgate) WindowWillExitFullScreen(cmd objc.SEL, notification objc.ID) {
+	w.pushResizableState(cocoa.NSNotification{ID: notification}.Object())
+}
+
+func (w *windowDelgate) WindowDidExitFullScreen(cmd objc.SEL, notification objc.ID) {
+	w.popResizableState(cocoa.NSNotification{ID: notification}.Object())
 	// Do not call setFrame here (#2295). setFrame here causes unexpected results.
-	}), "v@:@")
+}
-	class_EbitengineWindowDelegate.Register()
+
+func (w *windowDelgate) Selector(cmd string) objc.SEL {
+	switch cmd {
+	case "InitWithOrigDelegate":
+		return objc.RegisterName("initWithOrigDelegate:")
+	case "WindowShouldClose":
+		return objc.RegisterName("windowShouldClose:")
+	case "WindowDidResize":
+		return objc.RegisterName("windowDidResize:")
+	case "WindowDidMove":
+		return objc.RegisterName("windowDidMove:")
+	case "WindowDidMiniaturize":
+		return objc.RegisterName("windowDidMiniaturize:")
+	case "WindowDidDeminiaturize":
+		return objc.RegisterName("windowDidDeminiaturize:")
+	case "WindowDidBecomeKey":
+		return objc.RegisterName("windowDidBecomeKey:")
+	case "WindowDidResignKey":
+		return objc.RegisterName("windowDidResignKey:")
+	case "WindowDidChangeOcclusionState":
+		return objc.RegisterName("windowDidChangeOcclusionState:")
+	case "WindowWillEnterFullScreen":
+		return objc.RegisterName("windowWillEnterFullScreen:")
+	case "WindowDidEnterFullScreen":
+		return objc.RegisterName("windowDidEnterFullScreen:")
+	case "WindowWillExitFullScreen":
+		return objc.RegisterName("windowWillExitFullScreen:")
+	case "WindowDidExitFullScreen":
+		return objc.RegisterName("windowDidExitFullScreen:")
+	default:
+		return 0
+	}
+}
+
+func init() {
+	var err error
+	class_EbitengineWindowDelegate, err = objc.RegisterClass(&windowDelgate{})
+	if err != nil {
+		panic(err)
+	}
 }
 
 type graphicsDriverCreatorImpl struct {