[Mac] More defensive programming

CocoaNativeWindow now checks for and reports failures to allocate
resources in its constructor. Additionally, it no longer calls UI
methods in the finalizer thread, as those methods will crash on Cocoa.

Source/OpenTK/Platform/MacOS/CocoaNativeWindow.cs

@@ -147,8 +147,8 @@ namespace OpenTK.Platform.MacOS
         public CocoaNativeWindow(int x, int y, int width, int height, string title, GraphicsMode mode, GameWindowFlags options, DisplayDevice device)
         {
             // Create the window class
-            Interlocked.Increment(ref UniqueId);
+            int unique_id = Interlocked.Increment(ref UniqueId);
-            windowClass = Class.AllocateClass("OpenTK_GameWindow" + UniqueId, "NSWindow");
+            windowClass = Class.AllocateClass("OpenTK_GameWindow" + unique_id, "NSWindow");
             Class.RegisterMethod(windowClass, new WindowKeyDownDelegate(WindowKeyDown), "keyDown:", "v@:@");
             Class.RegisterMethod(windowClass, new WindowDidResizeDelegate(WindowDidResize), "windowDidResize:", "v@:@");
             Class.RegisterMethod(windowClass, new WindowDidMoveDelegate(WindowDidMove), "windowDidMove:", "v@:@");
@@ -164,7 +164,7 @@ namespace OpenTK.Platform.MacOS
             Class.RegisterMethod(windowClass, new CanBecomeMainWindowDelegate(CanBecomeMainWindow), "canBecomeMainWindow", "b@:");
             Class.RegisterClass(windowClass);
 
-            IntPtr viewClass = Class.AllocateClass("OpenTK_NSView" + UniqueId, "NSView");
+            IntPtr viewClass = Class.AllocateClass("OpenTK_NSView" + unique_id, "NSView");
             Class.RegisterMethod(viewClass, new ResetCursorRectsDelegate(ResetCursorRects), "resetCursorRects", "v@:");
             Class.RegisterClass(viewClass);
 
@@ -183,15 +183,34 @@ namespace OpenTK.Platform.MacOS
             var style = GetStyleMask(windowBorder);
             var bufferingType = NSBackingStore.Buffered;
 
-            IntPtr windowPtr;
+            IntPtr classPtr;
-            windowPtr = Cocoa.SendIntPtr(windowClass, Selector.Alloc);
+            classPtr = Cocoa.SendIntPtr(windowClass, Selector.Alloc);
-            windowPtr = Cocoa.SendIntPtr(windowPtr, Selector.Get("initWithContentRect:styleMask:backing:defer:"), contentRect, (int)style, (int)bufferingType, false);
+            if (classPtr == IntPtr.Zero)
+            {
+                Debug.Print("[Error] Failed to allocate window class.");
+                throw new PlatformException();
+            }
+
+            bool defer = false;
+            IntPtr windowPtr = Cocoa.SendIntPtr(classPtr, Selector.Get("initWithContentRect:styleMask:backing:defer:"), contentRect, (int)style, (int)bufferingType, defer);
+            if (windowPtr == IntPtr.Zero)
+            {
+                Debug.Print("[Error] Failed to initialize window with ({0}, {1}, {2}, {3}).",
+                    contentRect, style, bufferingType, defer);
+                throw new PlatformException();
+            }
 
             // Replace view with our custom implementation
             // that overrides resetCursorRects (maybe there is
             // a better way to implement this override?)
             // Existing view:
             IntPtr viewPtr = Cocoa.SendIntPtr(windowPtr, Selector.Get("contentView"));
+            if (viewPtr == IntPtr.Zero)
+            {
+                Debug.Print("[Error] Failed to retrieve content view for window {0}.", windowPtr);
+                throw new PlatformException();
+            }
+
             // Our custom view with the same bounds:
             viewPtr = Cocoa.SendIntPtr(
                 Cocoa.SendIntPtr(viewClass, Selector.Alloc),
@@ -201,6 +220,11 @@ namespace OpenTK.Platform.MacOS
             {
                 Cocoa.SendVoid(windowPtr, Selector.Get("setContentView:"), viewPtr);
             }
+            else
+            {
+                Debug.Print("[Error] Failed to initialize content view with frame {0}.", selBounds);
+                throw new PlatformException();
+            }
 
             windowInfo = new CocoaWindowInfo(windowPtr);
 
@@ -574,7 +598,7 @@ namespace OpenTK.Platform.MacOS
             if (shouldClose)
             {
                 shouldClose = false;
-                CloseWindow();
+                CloseWindow(false);
             }
         }
 
@@ -1020,14 +1044,14 @@ namespace OpenTK.Platform.MacOS
             Debug.Print("Disposing of CocoaNativeWindow.");
             NSApplication.Quit -= ApplicationQuit;
 
+            if (disposing)
+            {
                 CursorVisible = true;
                 if (exists)
                 {
-                CloseWindow();
+                    CloseWindow(true);
                 }
 
-            if (disposing)
-            {
                 if (trackingArea != IntPtr.Zero)
                 {
                     Cocoa.SendVoid(windowInfo.ViewHandle, selRemoveTrackingArea, trackingArea);
@@ -1038,6 +1062,10 @@ namespace OpenTK.Platform.MacOS
                 Debug.Print("[Mac] Disposing {0}", windowInfo);
                 windowInfo.Dispose();
             }
+            else
+            {
+                Debug.Print("{0} leaked, did you forget to call Dispose()?", GetType().FullName);
+            }
 
             disposed = true;
             OnDisposed(EventArgs.Empty);
@@ -1130,13 +1158,13 @@ namespace OpenTK.Platform.MacOS
             return (NSWindowStyle)Cocoa.SendUint(windowInfo.Handle, selStyleMask);
         }
 
-        void CloseWindow()
+        void CloseWindow(bool shutdown)
         {
             exists = false;
 
             // PerformClose is equivalent to pressing the close-button, which
             // does not work in a borderless window. Handle this special case.
-            if (GetStyleMask() == NSWindowStyle.Borderless)
+            if (GetStyleMask() == NSWindowStyle.Borderless || shutdown)
             {
                 if (WindowShouldClose(IntPtr.Zero, IntPtr.Zero, IntPtr.Zero))
                 {