[gnome-shell] dnd: Handle destruction of drag actor during drag

[Maxim Ermilov <mermilov src gnome org>]

commit 95ac478f87f90377bc59e9af0cf894becc126d37
Author: Maxim Ermilov <zaspire rambler ru>
Date:   Sun Oct 24 05:45:54 2010 +0400

    dnd: Handle destruction of drag actor during drag
    
    The shell crashes if the drag actor is destroyed during the drag
    operation. Cancel the drag gracefully in this case.
    https://bugzilla.gnome.org/show_bug.cgi?id=620389

 js/ui/dnd.js |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/js/ui/dnd.js b/js/ui/dnd.js
index 217a839..9ebb2d4 100644
--- a/js/ui/dnd.js
+++ b/js/ui/dnd.js
@@ -86,6 +86,9 @@ _Draggable.prototype = {
                                Lang.bind(this, this._onButtonPress));
 
         this.actor.connect('destroy', Lang.bind(this, function() {
+            this._actorDestroyed = true;
+            if (this._dragInProgress)
+                this._cancelDrag(global.get_current_time());
             this.disconnectAll();
         }));
         this._onEventId = null;
@@ -417,6 +420,8 @@ _Draggable.prototype = {
                                                 targX,
                                                 targY,
                                                 event.get_time())) {
+                    if (this._actorDestroyed)
+                        return true;
                     // If it accepted the drop without taking the actor,
                     // handle it ourselves.
                     if (this._dragActor.get_parent() == this._dragActor.get_stage()) {
@@ -458,6 +463,12 @@ _Draggable.prototype = {
         this._dragInProgress = false;
         let [snapBackX, snapBackY] = this._getRestoreLocation();
 
+        if (this._actorDestroyed) {
+            global.unset_cursor();
+            this.emit('drag-end', eventTime, false);
+            return;
+        }
+
         this._animationInProgress = true;
         // No target, so snap back
         Tweener.addTween(this._dragActor,