macOS: Improve QDebug output for QNSView and QCocoaWindow

By printing the corresponding QPlatformWindow and QWindow for a given
QNSView we make it easier to track issues regardless of which of the
views/windows are being logged.

Change-Id: I4a42eff7f87cf3c8e722cd6ad8baccd4eeab8eb3
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

src/plugins/platforms/cocoa/qcocoawindow.h

@@ -54,6 +54,11 @@
 #include "qt_mac_p.h"
 
 QT_BEGIN_NAMESPACE
+
+#ifndef QT_NO_DEBUG_STREAM
+class QDebug;
+#endif
+
 // QCocoaWindow
 //
 // QCocoaWindow is an NSView (not an NSWindow!) in the sense
@@ -287,6 +292,10 @@ public: // for QNSView
     bool m_hasWindowFilePath;
 };
 
+#ifndef QT_NO_DEBUG_STREAM
+QDebug operator<<(QDebug debug, const QCocoaWindow *window);
+#endif
+
 QT_END_NAMESPACE
 
 #endif // QCOCOAWINDOW_H

src/plugins/platforms/cocoa/qcocoawindow.mm

@@ -62,6 +62,8 @@
 
 #include <vector>
 
+QT_BEGIN_NAMESPACE
+
 enum {
     defaultWindowWidth = 160,
     defaultWindowHeight = 160
@@ -1776,4 +1778,19 @@ void QCocoaWindow::setFrameStrutEventsEnabled(bool enabled)
     m_frameStrutEventsEnabled = enabled;
 }
 
+#ifndef QT_NO_DEBUG_STREAM
+QDebug operator<<(QDebug debug, const QCocoaWindow *window)
+{
+    QDebugStateSaver saver(debug);
+    debug.nospace();
+    debug << "QCocoaWindow(" << (const void *)window;
+    if (window)
+        debug << ", window=" << window->window();
+    debug << ')';
+    return debug;
+}
+#endif // !QT_NO_DEBUG_STREAM
+
 #include "moc_qcocoawindow.cpp"
+
+QT_END_NAMESPACE

src/plugins/platforms/cocoa/qnsview.mm

@@ -221,6 +221,22 @@ static QTouchDevice *touchDevice = 0;
     return self;
 }
 
+- (NSString *)description
+{
+    NSMutableString *description = [NSMutableString stringWithString:[super description]];
+
+#ifndef QT_NO_DEBUG_STREAM
+    QString platformWindowDescription;
+    QDebug debug(&platformWindowDescription);
+    debug.nospace() << "; " << m_platformWindow << ">";
+
+    NSRange lastCharacter = [description rangeOfComposedCharacterSequenceAtIndex:description.length - 1];
+    [description replaceCharactersInRange:lastCharacter withString:platformWindowDescription.toNSString()];
+#endif
+
+    return description;
+}
+
 #ifndef QT_NO_OPENGL
 - (void) setQCocoaGLContext:(QCocoaGLContext *)context
 {