Drag and drop examples not working correctly in Cocoa

In the updated examples, the drag operation is changed in the drop-event
handler, which was not handled correctly in the Cocoa. This is now
supported for drag and drop from same application. If the drop was to
another application, the drag will return the result from the last
drag-move event.

Task-number: 252103
Reviewed-by: nrc

3 files changed, 62 insertions, 27 deletions

diff --git a/src/gui/kernel/qcocoaview_mac.mm b/src/gui/kernel/qcocoaview_mac.mm
index e84af90..fae4821 100644
--- a/src/gui/kernel/qcocoaview_mac.mm
+++ b/src/gui/kernel/qcocoaview_mac.mm
@@ -292,9 +292,18 @@ extern "C" {
     QPoint posDrag(localPoint.x, localPoint.y);
     NSDragOperation nsActions = [sender draggingSourceOperationMask]; 
     Qt::DropActions qtAllowed = qt_mac_mapNSDragOperations(nsActions);
+    QT_PREPEND_NAMESPACE(qt_mac_dnd_answer_rec.lastOperation) = nsActions;
+    Qt::KeyboardModifiers modifiers  = Qt::NoModifier;
+    if ([sender draggingSource] != nil) {
+        // modifier flags might have changed, update it here since we don't send any input events.
+        QApplicationPrivate::modifier_buttons = qt_cocoaModifiers2QtModifiers([[NSApp currentEvent] modifierFlags]);
+        modifiers = QApplication::keyboardModifiers();
+    } else {
+        // when the source is from another application the above technique will not work.
+        modifiers = qt_cocoaDragOperation2QtModifiers(nsActions);
+    }
     // send the drag enter event to the widget.
-    QDragEnterEvent qDEEvent(posDrag, qtAllowed, mimeData,
-            QApplication::mouseButtons(), QApplication::keyboardModifiers());
+    QDragEnterEvent qDEEvent(posDrag, qtAllowed, mimeData, QApplication::mouseButtons(), modifiers);
     QApplication::sendEvent(qwidget, &qDEEvent);
     if (!qDEEvent.isAccepted()) {
         // widget is not interested in this drag, so ignore this drop data.
@@ -302,24 +311,23 @@ extern "C" {
         return NSDragOperationNone;
     } else {
         // send a drag move event immediately after a drag enter event (as per documentation).
-        QDragMoveEvent qDMEvent(posDrag, qtAllowed, mimeData,
-                QApplication::mouseButtons(), QApplication::keyboardModifiers());
+        QDragMoveEvent qDMEvent(posDrag, qtAllowed, mimeData, QApplication::mouseButtons(), modifiers);
         qDMEvent.setDropAction(qDEEvent.dropAction());
         qDMEvent.accept(); // accept by default, since enter event was accepted.
         QApplication::sendEvent(qwidget, &qDMEvent);
         if (!qDMEvent.isAccepted() || qDMEvent.dropAction() == Qt::IgnoreAction) {
             // since we accepted the drag enter event, the widget expects 
             // future drage move events.  
-	    // ### check if we need to treat this like the drag enter event.
+            // ### check if we need to treat this like the drag enter event.
             nsActions = QT_PREPEND_NAMESPACE(qt_mac_mapDropAction)(qDEEvent.dropAction());
         } else {
             nsActions = QT_PREPEND_NAMESPACE(qt_mac_mapDropAction)(qDMEvent.dropAction());
-	}
+        }
         QT_PREPEND_NAMESPACE(qt_mac_copy_answer_rect)(qDMEvent);
-	return nsActions;
+        return nsActions;
     } 
  }
- 
+
 - (NSDragOperation)draggingUpdated:(id < NSDraggingInfo >)sender
 {
     // drag enter event was rejected, so ignore the move event. 
@@ -337,11 +345,19 @@ extern "C" {
     // send drag move event to the widget    
     QT_PREPEND_NAMESPACE(qt_mac_dnd_answer_rec.lastOperation) = nsActions;
     Qt::DropActions qtAllowed = QT_PREPEND_NAMESPACE(qt_mac_mapNSDragOperations)(nsActions);
+    Qt::KeyboardModifiers modifiers  = Qt::NoModifier;
+    if ([sender draggingSource] != nil) {
+        // modifier flags might have changed, update it here since we don't send any input events.
+        QApplicationPrivate::modifier_buttons = qt_cocoaModifiers2QtModifiers([[NSApp currentEvent] modifierFlags]);
+        modifiers = QApplication::keyboardModifiers();
+    } else {
+        // when the source is from another application the above technique will not work.
+        modifiers = qt_cocoaDragOperation2QtModifiers(nsActions);
+    }
     QMimeData *mimeData = dropData;
     if (QDragManager::self()->source())
         mimeData = QDragManager::self()->dragPrivate()->data;
-    QDragMoveEvent qDMEvent(posDrag, qtAllowed, mimeData,
-            QApplication::mouseButtons(), QApplication::keyboardModifiers());
+    QDragMoveEvent qDMEvent(posDrag, qtAllowed, mimeData, QApplication::mouseButtons(), modifiers);
     qDMEvent.setDropAction(QT_PREPEND_NAMESPACE(qt_mac_dnd_answer_rec).lastAction);
     qDMEvent.accept();
     QApplication::sendEvent(qwidget, &qDMEvent);
@@ -370,12 +386,12 @@ extern "C" {
 - (BOOL)performDragOperation:(id <NSDraggingInfo>)sender
 {
     [self addDropData:sender];
-    
+
     NSPoint windowPoint = [sender draggingLocation];
     NSPoint globalPoint = [[sender draggingDestinationWindow] convertBaseToScreen:windowPoint];
     NSPoint localPoint = [self convertPoint:windowPoint fromView:nil];
     QPoint posDrop(localPoint.x, localPoint.y);
-    
+
     NSDragOperation nsActions = [sender draggingSourceOperationMask]; 
     Qt::DropActions qtAllowed = qt_mac_mapNSDragOperations(nsActions);
     QMimeData *mimeData = dropData;
@@ -387,6 +403,8 @@ extern "C" {
     if (QDragManager::self()->object)
         QDragManager::self()->dragPrivate()->target = qwidget;
     QApplication::sendEvent(qwidget, &de);
+    if (QDragManager::self()->object)
+        QDragManager::self()->dragPrivate()->executed_action = de.dropAction();
     if (!de.isAccepted())
         return NO;
     else
@@ -417,10 +435,9 @@ extern "C" {
 - (void) setFrameSize:(NSSize)newSize
 {
     [super setFrameSize:newSize];
- 
+
     // A change in size has required the view to be invalidated.
-    if ([self inLiveResize])
-    {
+    if ([self inLiveResize]) {
         NSRect rects[4];
         NSInteger count;
         [self getRectsExposedDuringLiveResize:rects count:&count];
@@ -428,9 +445,7 @@ extern "C" {
         {
             [self setNeedsDisplayInRect:rects[count]];
         }
-    }
-    else
-    {
+    } else {
         [self setNeedsDisplay:YES];
     }
 }
@@ -565,7 +580,7 @@ extern "C" {
     if (!qAppInstance()->activeModalWidget() || QApplicationPrivate::tryModalHelper(qwidget, 0)) {
         QApplication::sendEvent(qwidget, &enterEvent);
         qt_mouseover = qwidget;
-        
+
         // Update cursor and dispatch hover events.
         qt_mac_update_cursor_at_global_pos(flipPoint(globalPoint).toPoint());
         if (qwidget->testAttribute(Qt::WA_Hover) &&
@@ -620,7 +635,7 @@ extern "C" {
         [viewsToLookAt addObject:qt_mac_nativeview_for(parentWidget)];
         parentWidget = parentWidget->parentWidget();
     }
-    
+
     // Now walk through the subviews of each view and determine which subview should
     // get the event. We look through all the subviews at a given level with
     // the assumption that the last item to be found the candidate has a higher z-order.
@@ -756,7 +771,7 @@ extern "C" {
     if (currentIManager && [currentIManager wantsToHandleMouseEvents]) {
         [currentIManager handleMouseEvent:theEvent];
     }
-    
+
     NSPoint windowPoint = [theEvent locationInWindow];
     NSPoint globalPoint = [[theEvent window] convertBaseToScreen:windowPoint];
     NSPoint localPoint = [self convertPoint:windowPoint fromView:nil];
@@ -765,7 +780,7 @@ extern "C" {
     Qt::MouseButton buttons = cocoaButton2QtButton([theEvent buttonNumber]);
     bool wheelOK = false;
     Qt::KeyboardModifiers keyMods = qt_cocoaModifiers2QtModifiers([theEvent modifierFlags]);
-    
+
     // Mouse wheel deltas seem to tick in at increments of 0.1. Qt widgets
     // expect the delta to be a multiple of 120. 
     const int ScrollFactor = 10 * 120;
@@ -787,7 +802,7 @@ extern "C" {
             wheelOK = qwe2.isAccepted();
         }
     }
-    
+
     if (deltaY) {
         QWheelEvent qwe(qlocal, qglobal, deltaY, buttons, keyMods, Qt::Vertical);
         qt_sendSpontaneousEvent(qwidget, &qwe);
@@ -800,7 +815,7 @@ extern "C" {
             wheelOK = qwe2.isAccepted();
         }
     }
-    
+
     if (deltaZ) {
         // Qt doesn't explicitly support wheels with a Z component. In a misguided attempt to
         // try to be ahead of the pack, I'm adding this extra value.
@@ -889,6 +904,11 @@ extern "C" {
     Q_UNUSED(anImage);
     Q_UNUSED(aPoint);
     qMacDnDParams()->performedAction = operation;
+    if (QDragManager::self()->object
+        && QDragManager::self()->dragPrivate()->executed_action != Qt::ActionMask) {
+        qMacDnDParams()->performedAction =
+                qt_mac_mapDropAction(QDragManager::self()->dragPrivate()->executed_action);
+    }
 }
 
 - (QWidget *)qt_qwidget
@@ -1202,13 +1222,13 @@ Qt::DropAction QDragManager::drag(QDrag *o)
      so we just bail early to prevent it */
     if(!(GetCurrentEventButtonState() & kEventMouseButtonPrimary))
         return Qt::IgnoreAction;
-    
+
     if(object) {
         dragPrivate()->source->removeEventFilter(this);
         cancel();
         beingCancelled = false;
     }
-    
+
     object = o;
     dragPrivate()->target = 0;
 
@@ -1220,7 +1240,7 @@ Qt::DropAction QDragManager::drag(QDrag *o)
     QMacPasteboard dragBoard((CFStringRef) NSDragPboard, QMacPasteboardMime::MIME_DND);
     dragPrivate()->data->setData(QLatin1String("application/x-qt-mime-type-name"), QByteArray());
     dragBoard.setMimeData(dragPrivate()->data);
-    
+
     // create the image
     QPoint hotspot;
     QPixmap pix = dragPrivate()->pixmap;
@@ -1266,6 +1286,7 @@ Qt::DropAction QDragManager::drag(QDrag *o)
     NSSize mouseOffset = {0.0, 0.0};
     NSPasteboard *pboard = [NSPasteboard pasteboardWithName:NSDragPboard];
     NSPoint windowPoint = [dndParams->theEvent locationInWindow];
+    dragPrivate()->executed_action = Qt::ActionMask;
     // do the drag
     [dndParams->view retain];
     [dndParams->view dragImage:image
@@ -1277,6 +1298,7 @@ Qt::DropAction QDragManager::drag(QDrag *o)
                      slideBack:YES];
     [dndParams->view release];
     [image release];
+    dragPrivate()->executed_action = Qt::IgnoreAction;
     object = 0;
     Qt::DropAction performedAction(qt_mac_mapNSDragOperation(dndParams->performedAction));
     // do post drag processing, if required.
diff --git a/src/gui/kernel/qt_cocoa_helpers_mac.mm b/src/gui/kernel/qt_cocoa_helpers_mac.mm
index 52e76d8..f000292 100644
--- a/src/gui/kernel/qt_cocoa_helpers_mac.mm
+++ b/src/gui/kernel/qt_cocoa_helpers_mac.mm
@@ -515,6 +515,18 @@ Qt::KeyboardModifiers qt_cocoaModifiers2QtModifiers(ulong modifierFlags)
     return qtMods;
 }
 
+Qt::KeyboardModifiers qt_cocoaDragOperation2QtModifiers(uint dragOperations)
+{
+    Qt::KeyboardModifiers qtMods =Qt::NoModifier;
+    if (dragOperations &  NSDragOperationLink)
+        qtMods |= Qt::MetaModifier;
+    if (dragOperations & NSDragOperationGeneric)
+        qtMods |= Qt::ControlModifier;
+    if (dragOperations & NSDragOperationCopy)
+        qtMods |= Qt::AltModifier;
+    return qtMods;
+}
+
 static inline QEvent::Type cocoaEvent2QtEvent(NSUInteger eventType)
 {
     // Handle the trivial cases that can be determined from the type.
diff --git a/src/gui/kernel/qt_cocoa_helpers_mac_p.h b/src/gui/kernel/qt_cocoa_helpers_mac_p.h
index ef55aa4..63a301c 100644
--- a/src/gui/kernel/qt_cocoa_helpers_mac_p.h
+++ b/src/gui/kernel/qt_cocoa_helpers_mac_p.h
@@ -141,6 +141,7 @@ inline QApplication *qAppInstance() { return static_cast<QApplication *>(QCoreAp
 struct ::TabletProximityRec;
 void qt_dispatchTabletProximityEvent(const ::TabletProximityRec &proxRec);
 Qt::KeyboardModifiers qt_cocoaModifiers2QtModifiers(ulong modifierFlags);
+Qt::KeyboardModifiers qt_cocoaDragOperation2QtModifiers(uint dragOperations);
 inline int flipYCoordinate(int y)
 {
     return QApplication::desktop()->screenGeometry(0).height() - y;