b=751429 handle modifier changes in periodic synthetic mouse events for drag sources r=roc

--HG--
extra : rebase_source : 08c12b5e4e2acb7e65ff29168356312eb9185d97

widget/gtk2/nsDragService.cpp

@@ -100,7 +100,12 @@ FuncToGpointer(T aFunction)
 }
 
 static PRLogModuleInfo *sDragLm = NULL;
+
+// data used for synthetic periodic motion events sent to the source widget
+// grabbing real events for the drag.
 static guint sMotionEventTimerID;
+static GdkEvent *sMotionEvent;
+static GtkWidget *sGrabWidget;
 
 static const char gMimeListType[] = "application/x-moz-internal-item-list";
 static const char gMozUrlType[] = "_NETSCAPE_URL";
@@ -167,7 +172,6 @@ nsDragService::nsDragService()
     if (!sDragLm)
         sDragLm = PR_NewLogModule("nsDragService");
     PR_LOG(sDragLm, PR_LOG_DEBUG, ("nsDragService::nsDragService"));
-    mGrabWidget = 0;
     mCanDrop = false;
     mTargetDragDataReceived = false;
     mTargetDragData = 0;
@@ -232,42 +236,21 @@ nsDragService::Observe(nsISupports *aSubject, const char *aTopic,
 // change its feedback re whether it could accept the drop, and so the
 // source's behavior on drop will not be consistent.)
 
-struct MotionEventData {
-    MotionEventData(GtkWidget *aWidget, GdkEvent *aEvent)
-        : mWidget(aWidget), mEvent(gdk_event_copy(aEvent))
-    {
-        MOZ_COUNT_CTOR(MotionEventData);
-        g_object_ref(mWidget);
-    }
-    ~MotionEventData()
-    {
-        MOZ_COUNT_DTOR(MotionEventData);
-        g_object_unref(mWidget);
-        gdk_event_free(mEvent);
-    }
-    GtkWidget *mWidget;
-    GdkEvent *mEvent;
-};
-
-static void
-DestroyMotionEventData(gpointer data)
-{
-    delete static_cast<MotionEventData*>(data);
-}
-
 static gboolean
 DispatchMotionEventCopy(gpointer aData)
 {
-    MotionEventData *data = static_cast<MotionEventData*>(aData);
-
-    // Clear the timer id before OnSourceGrabEventAfter is called during event dispatch.
+    // Clear the timer id before OnSourceGrabEventAfter is called during event
+    // dispatch.
     sMotionEventTimerID = 0;
 
+    GdkEvent *event = sMotionEvent;
+    sMotionEvent = NULL;
     // If there is no longer a grab on the widget, then the drag is over and
     // there is no need to continue drag motion.
-    if (gtk_widget_has_grab(data->mWidget)) {
-        gtk_propagate_event(data->mWidget, data->mEvent);
+    if (gtk_widget_has_grab(sGrabWidget)) {
+        gtk_propagate_event(sGrabWidget, event);
     }
+    gdk_event_free(event);
 
     // Cancel this timer;
     // We've already started another if the motion event was dispatched.
@@ -277,27 +260,35 @@ DispatchMotionEventCopy(gpointer aData)
 static void
 OnSourceGrabEventAfter(GtkWidget *widget, GdkEvent *event, gpointer user_data)
 {
-    if (event->type != GDK_MOTION_NOTIFY)
+    // If there is no longer a grab on the widget, then the drag motion is
+    // over (though the data may not be fetched yet).
+    if (!gtk_widget_has_grab(sGrabWidget))
         return;
 
+    GdkModifierType state;
+    if (event->type == GDK_MOTION_NOTIFY) {
+        if (sMotionEvent) {
+            gdk_event_free(sMotionEvent);
+        }
+        sMotionEvent = gdk_event_copy(event);
+
+        // Update the cursor position.  The last of these recorded gets used for
+        // the NS_DRAGDROP_END event.
+        nsDragService *dragService = static_cast<nsDragService*>(user_data);
+        dragService->SetDragEndPoint(nsIntPoint(event->motion.x_root,
+                                                event->motion.y_root));
+    } else if (sMotionEvent && (event->type != GDK_KEY_PRESS ||
+                                event->type != GDK_KEY_RELEASE)) {
+        // Update modifier state from keypress events.
+        sMotionEvent->motion.state = event->key.state;
+    } else {
+        return;
+    }
+
     if (sMotionEventTimerID) {
         g_source_remove(sMotionEventTimerID);
-        sMotionEventTimerID = 0;
     }
 
-    // If there is no longer a grab on the widget, then the drag motion is
-    // over (though the data may not be fetched yet).
-    if (!gtk_widget_has_grab(widget))
-        return;
-
-    // Update the cursor position.  The last of these recorded gets used for
-    // the NS_DRAGDROP_END event.
-    nsDragService *dragService = static_cast<nsDragService*>(user_data);
-    dragService->
-        SetDragEndPoint(nsIntPoint(event->motion.x_root, event->motion.y_root));
-
-    MotionEventData *data = new MotionEventData(widget, event);
-
     // G_PRIORITY_DEFAULT_IDLE is lower priority than GDK's redraw idle source
     // and lower than GTK's idle source that sends drag position messages after
     // motion-notify signals.
@@ -306,7 +297,7 @@ OnSourceGrabEventAfter(GtkWidget *widget, GdkEvent *event, gpointer user_data)
     // recommends an interval of 350ms +/- 200ms.
     sMotionEventTimerID = 
         g_timeout_add_full(G_PRIORITY_DEFAULT_IDLE, 350,
-                           DispatchMotionEventCopy, data, DestroyMotionEventData);
+                           DispatchMotionEventCopy, NULL, NULL);
 }
 
 static GtkWindow*
@@ -353,7 +344,7 @@ nsDragService::InvokeDragSession(nsIDOMNode *aDOMNode,
     PR_LOG(sDragLm, PR_LOG_DEBUG, ("nsDragService::InvokeDragSession"));
 
     // If the previous source drag has not yet completed, signal handlers need
-    // to be removed from mGrabWidget and dragend needs to be dispatched to
+    // to be removed from sGrabWidget and dragend needs to be dispatched to
     // the source node, but we can't call EndDragSession yet because we don't
     // know whether or not the drag succeeded.
     if (mSourceNode)
@@ -421,12 +412,12 @@ nsDragService::InvokeDragSession(nsIDOMNode *aDOMNode,
         StartDragSession();
 
         // GTK uses another hidden window for receiving mouse events.
-        mGrabWidget = gtk_window_group_get_current_grab(window_group);
-        if (mGrabWidget) {
-            g_object_ref(mGrabWidget);
-            // Only motion events are required but connect to
+        sGrabWidget = gtk_window_group_get_current_grab(window_group);
+        if (sGrabWidget) {
+            g_object_ref(sGrabWidget);
+            // Only motion and key events are required but connect to
             // "event-after" as this is never blocked by other handlers.
-            g_signal_connect(mGrabWidget, "event-after",
+            g_signal_connect(sGrabWidget, "event-after",
                              G_CALLBACK(OnSourceGrabEventAfter), this);
         }
         // We don't have a drag end point yet.
@@ -504,16 +495,20 @@ nsDragService::EndDragSession(bool aDoneDrag)
     PR_LOG(sDragLm, PR_LOG_DEBUG, ("nsDragService::EndDragSession %d",
                                    aDoneDrag));
 
-    if (mGrabWidget) {
-        g_signal_handlers_disconnect_by_func(mGrabWidget,
+    if (sGrabWidget) {
+        g_signal_handlers_disconnect_by_func(sGrabWidget,
              FuncToGpointer(OnSourceGrabEventAfter), this);
-        g_object_unref(mGrabWidget);
-        mGrabWidget = NULL;
+        g_object_unref(sGrabWidget);
+        sGrabWidget = NULL;
 
         if (sMotionEventTimerID) {
             g_source_remove(sMotionEventTimerID);
             sMotionEventTimerID = 0;
         }
+        if (sMotionEvent) {
+            gdk_event_free(sMotionEvent);
+            sMotionEvent = NULL;
+        }
     }
 
     // unset our drag action

widget/gtk2/nsDragService.h

@@ -207,8 +207,6 @@ private:
 
     // the source of our drags
     GtkWidget     *mHiddenWidget;
-    // the widget receiving mouse events
-    GtkWidget     *mGrabWidget;
     // our source data items
     nsCOMPtr<nsISupportsArray> mSourceDataItems;