Cocoa: Use helper class for event handling in native windows

QNSWindow and QNSPanel duplicate some code when it comes to event
handling, which can be refactored. Also, it's currently not
possible to keep an NSWindow derived instance temporarily alive
as QCocoaWindow is not designed to keep track of more than one
NSWindow. Finally, we can reduce the size of (and eventually remove)
the QCocoaWindowCategory which polutes the NSWindow namespace.

We move QNSWindow and QNSPanel specific API into QNSWindowProtocol,
and define QCocoaNSWindow as NSWindow extended by that protocol.
This gives us a type we can refer to any of the native windows
QCocoaWindow instanciates.

We introduce QNSWindowHelper which gathers the common code between
QNSWindow and QNSPanel. This is a one-to-one mapping that keeps a
weak (non-retaining) reference to the NSWindow and a weak reference
to the QCocoaWindow. It has the same life span as its associated
NSWindow.

Task-number: QTBUG-33082
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
Change-Id: I38d001bf13f64a1ba4f1439291c5103c3f755183
Reviewed-by: Liang Qi <liang.qi@digia.com>

1 files changed, 39 insertions, 11 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoawindow.h b/src/plugins/platforms/cocoa/qcocoawindow.h
index 748280af6a..0f08cd18fb 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.h
+++ b/src/plugins/platforms/cocoa/qcocoawindow.h
@@ -52,27 +52,57 @@
 
 QT_FORWARD_DECLARE_CLASS(QCocoaWindow)
 
-@interface QNSWindow : NSWindow
+@class QNSWindowHelper;
+
+@protocol QNSWindowProtocol
+
+@property (nonatomic, readonly) QNSWindowHelper *helper;
+
+- (void)superSendEvent:(NSEvent *)theEvent;
+- (void)closeAndRelease;
+
+@end
+
+typedef NSWindow<QNSWindowProtocol> QCocoaNSWindow;
+
+@interface QNSWindowHelper : NSObject
 {
-    @public QCocoaWindow *m_cocoaPlatformWindow;
+    QCocoaNSWindow *_window;
+    QCocoaWindow *_platformWindow;
 }
+
+@property (nonatomic, readonly) QCocoaNSWindow *window;
+@property (nonatomic, readonly) QCocoaWindow *platformWindow;
+
+- (id)initWithNSWindow:(QCocoaNSWindow *)window platformWindow:(QCocoaWindow *)platformWindow;
+- (void)handleWindowEvent:(NSEvent *)theEvent;
+
+@end
+
+@interface QNSWindow : NSWindow<QNSWindowProtocol>
+{
+    QNSWindowHelper *_helper;
+}
+
+@property (nonatomic, readonly) QNSWindowHelper *helper;
+
 - (id)initWithContentRect:(NSRect)contentRect
       styleMask:(NSUInteger)windowStyle
       qPlatformWindow:(QCocoaWindow *)qpw;
 
-- (void)clearPlatformWindow;
 @end
 
-@interface QNSPanel : NSPanel
+@interface QNSPanel : NSPanel<QNSWindowProtocol>
 {
-    @public QCocoaWindow *m_cocoaPlatformWindow;
+    QNSWindowHelper *_helper;
 }
 
+@property (nonatomic, readonly) QNSWindowHelper *helper;
+
 - (id)initWithContentRect:(NSRect)contentRect
       styleMask:(NSUInteger)windowStyle
       qPlatformWindow:(QCocoaWindow *)qpw;
 
-- (void)clearPlatformWindow;
 @end
 
 @class QNSWindowDelegate;
@@ -183,9 +213,8 @@ public:
     QWindow *childWindowAt(QPoint windowPoint);
 protected:
     void recreateWindow(const QPlatformWindow *parentWindow);
-    NSWindow *createNSWindow();
-    void setNSWindow(NSWindow *window);
-    void clearNSWindow(NSWindow *window);
+    QCocoaNSWindow *createNSWindow();
+    void setNSWindow(QCocoaNSWindow *window);
 
     bool shouldUseNSPanel();
 
@@ -202,7 +231,7 @@ public: // for QNSView
 
     NSView *m_contentView;
     QNSView *m_qtView;
-    NSWindow *m_nsWindow;
+    QCocoaNSWindow *m_nsWindow;
     QCocoaWindow *m_forwardWindow;
 
     // TODO merge to one variable if possible
@@ -213,7 +242,6 @@ public: // for QNSView
     bool m_isNSWindowChild; // this window is a non-top level QWindow with a NSWindow.
     QList<QCocoaWindow *> m_childWindows;
 
-    QNSWindowDelegate *m_nsWindowDelegate;
     Qt::WindowFlags m_windowFlags;
     Qt::WindowState m_synchedWindowState;
     Qt::WindowModality m_windowModality;