Cocoa: Do mouse move and cursor update handling separate from view

We are using tracking areas for mouse move, enter/leave and cursor
update events, so we should keep handling of that out of the
"normal" event chain.

If we handle mouse moved events in the views' mouseMoved method,
we need to pass the event up the responder chain if we didn't handle it,
or we would break for example hover behavior in native WebViews,
because these do not handle mouse moved events directly in their
mouseMoved:, but only if the event wasn't handled otherwise
(arguably a bug in Web(HTML)View).
But passing the event up the responder chain is not good either, because
the QNSViews in the parent hierarchy get the event from their tracking
areas already.

Change-Id: I636a84ab1b7ef73070f81a8e33b5fa734ff4a42c
Task-number: QTBUG-26593
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/platforms/cocoa/qnsview.h

@@ -54,6 +54,8 @@ class QCocoaBackingStore;
 class QCocoaGLContext;
 QT_END_NAMESPACE
 
+Q_FORWARD_DECLARE_OBJC_CLASS(QNSViewMouseMoveHelper);
+
 @interface QNSView : NSView <NSTextInputClient> {
     QCocoaBackingStore* m_backingStore;
     QPoint m_backingStoreOffset;
@@ -72,6 +74,7 @@ QT_END_NAMESPACE
     QCocoaGLContext *m_glContext;
     bool m_shouldSetGLContextinDrawRect;
     NSString *m_inputSource;
+    QNSViewMouseMoveHelper *m_mouseMoveHelper;
 }
 
 - (id)init;
@@ -102,9 +105,10 @@ QT_END_NAMESPACE
 - (void)mouseDown:(NSEvent *)theEvent;
 - (void)mouseDragged:(NSEvent *)theEvent;
 - (void)mouseUp:(NSEvent *)theEvent;
-- (void)mouseMoved:(NSEvent *)theEvent;
-- (void)mouseEntered:(NSEvent *)theEvent;
-- (void)mouseExited:(NSEvent *)theEvent;
+- (void)mouseMovedImpl:(NSEvent *)theEvent;
+- (void)mouseEnteredImpl:(NSEvent *)theEvent;
+- (void)mouseExitedImpl:(NSEvent *)theEvent;
+- (void)cursorUpdateImpl:(NSEvent *)theEvent;
 - (void)rightMouseDown:(NSEvent *)theEvent;
 - (void)rightMouseDragged:(NSEvent *)theEvent;
 - (void)rightMouseUp:(NSEvent *)theEvent;

src/plugins/platforms/cocoa/qnsview.mm

@@ -75,6 +75,53 @@ static NSString *_q_NSWindowDidChangeOcclusionStateNotification = nil;
   - (CGFloat)deviceDeltaZ;
 @end
 
+@interface QNSViewMouseMoveHelper : NSObject
+{
+    QNSView *view;
+}
+
+- (id)initWithView:(QNSView *)theView;
+
+- (void)mouseMoved:(NSEvent *)theEvent;
+- (void)mouseEntered:(NSEvent *)theEvent;
+- (void)mouseExited:(NSEvent *)theEvent;
+- (void)cursorUpdate:(NSEvent *)theEvent;
+
+@end
+
+@implementation QNSViewMouseMoveHelper
+
+- (id)initWithView:(QNSView *)theView
+{
+    self = [super init];
+    if (self) {
+        view = theView;
+    }
+    return self;
+}
+
+- (void)mouseMoved:(NSEvent *)theEvent
+{
+    [view mouseMovedImpl:theEvent];
+}
+
+- (void)mouseEntered:(NSEvent *)theEvent
+{
+    [view mouseEnteredImpl:theEvent];
+}
+
+- (void)mouseExited:(NSEvent *)theEvent
+{
+    [view mouseExitedImpl:theEvent];
+}
+
+- (void)cursorUpdate:(NSEvent *)theEvent
+{
+    [view cursorUpdateImpl:theEvent];
+}
+
+@end
+
 @implementation QNSView
 
 + (void)initialize
@@ -100,6 +147,7 @@ static NSString *_q_NSWindowDidChangeOcclusionStateNotification = nil;
         currentCustomDragTypes = 0;
         m_sendUpAsRightButton = false;
         m_inputSource = 0;
+        m_mouseMoveHelper = [[QNSViewMouseMoveHelper alloc] initWithView:self];
 
         if (!touchDevice) {
             touchDevice = new QTouchDevice;
@@ -119,6 +167,7 @@ static NSString *_q_NSWindowDidChangeOcclusionStateNotification = nil;
     m_subscribesForGlobalFrameNotifications = false;
     [m_inputSource release];
     [[NSNotificationCenter defaultCenter] removeObserver:self];
+    [m_mouseMoveHelper release];
 
     delete currentCustomDragTypes;
 
@@ -753,13 +802,13 @@ static NSString *_q_NSWindowDidChangeOcclusionStateNotification = nil;
                                  | NSTrackingInVisibleRect | NSTrackingMouseMoved | NSTrackingCursorUpdate;
     NSTrackingArea *ta = [[[NSTrackingArea alloc] initWithRect:[self frame]
                                                       options:trackingOptions
-                                                        owner:self
+                                                        owner:m_mouseMoveHelper
                                                      userInfo:nil]
                                                                 autorelease];
     [self addTrackingArea:ta];
 }
 
--(void)cursorUpdate:(NSEvent *)theEvent
+-(void)cursorUpdateImpl:(NSEvent *)theEvent
 {
     Q_UNUSED(theEvent)
     // Set the cursor manually if there is no NSWindow.
@@ -776,10 +825,10 @@ static NSString *_q_NSWindowDidChangeOcclusionStateNotification = nil;
         [self addCursorRect:[self visibleRect] cursor:m_platformWindow->m_windowCursor];
 }
 
-- (void)mouseMoved:(NSEvent *)theEvent
+- (void)mouseMovedImpl:(NSEvent *)theEvent
 {
     if (m_window->flags() & Qt::WindowTransparentForInput)
-        return [super mouseMoved:theEvent];
+        return;
 
     QPointF windowPoint;
     QPointF screenPoint;
@@ -806,12 +855,13 @@ static NSString *_q_NSWindowDidChangeOcclusionStateNotification = nil;
     [self handleMouseEvent: theEvent];
 }
 
-- (void)mouseEntered:(NSEvent *)theEvent
+- (void)mouseEnteredImpl:(NSEvent *)theEvent
 {
+    Q_UNUSED(theEvent)
     m_platformWindow->m_windowUnderMouse = true;
 
     if (m_window->flags() & Qt::WindowTransparentForInput)
-        return [super mouseEntered:theEvent];
+        return;
 
     // Top-level windows generate enter events for sub-windows.
     if (!m_platformWindow->m_nsWindow)
@@ -824,13 +874,13 @@ static NSString *_q_NSWindowDidChangeOcclusionStateNotification = nil;
     QWindowSystemInterface::handleEnterEvent(m_platformWindow->m_enterLeaveTargetWindow, windowPoint, screenPoint);
 }
 
-- (void)mouseExited:(NSEvent *)theEvent
+- (void)mouseExitedImpl:(NSEvent *)theEvent
 {
+    Q_UNUSED(theEvent);
     m_platformWindow->m_windowUnderMouse = false;
 
     if (m_window->flags() & Qt::WindowTransparentForInput)
-        return [super mouseExited:theEvent];
-    Q_UNUSED(theEvent);
+        return;
 
     // Top-level windows generate leave events for sub-windows.
     if (!m_platformWindow->m_nsWindow)