Fix crash-on-exit when embedding QNView

The QWindow and QCocoaWindow may be deleted
before the QNSView (which Cocoa keeps a reference
to).

Clear pointers to the Qt windows on QCocoaWindow
destruction and add null-pointer check to QNView::isOpaque.

Change-Id: I71764886c27bf1d14fb4e684c15e7c72e1c0a17c
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@theqtcompany.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoawindow.mm b/src/plugins/platforms/cocoa/qcocoawindow.mm
index c7a57d5776..bbf487c309 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.mm
+++ b/src/plugins/platforms/cocoa/qcocoawindow.mm
@@ -446,6 +446,14 @@ QCocoaWindow::~QCocoaWindow()
                                               name:nil object:m_nsWindow];
     }
 
+    // The QNSView object may outlive the corresponding QCocoaWindow object,
+    // for example during app shutdown when the QNSView is embedded in a
+    // foregin NSView hiearchy. Clear the pointers to the QWindow/QCocoaWindow
+    // here to make sure QNSView does not dereference stale pointers.
+    if (m_qtView) {
+        [m_qtView clearQWindowPointers];
+    }
+
     foreach (QCocoaWindow *child, m_childWindows) {
        [m_nsWindow removeChildWindow:child->m_nsWindow];
         child->m_parentCocoaWindow = 0;