[clutter] ClutterDragAction: do not dereference a NULL priv->stage

[Alban Crequy <albanc src gnome org>]

commit 2be42c333ae621df085005e08b7c5c08c02dcbe5
Author: Alban Crequy <alban crequy collabora co uk>
Date:   Mon Apr 29 14:59:20 2013 +0100

    ClutterDragAction: do not dereference a NULL priv->stage
    
    When destroying an actor during a drag-action with a drag_handle, the
    ClutterDragAction's priv->stage could be set to NULL in _set_actor().
    _dispose() must not assume that priv->stage is not NULL.
    
    See also https://bugzilla.gnome.org/show_bug.cgi?id=681814

 clutter/clutter-drag-action.c |   44 ++++++++++++++++++++++++----------------
 1 files changed, 26 insertions(+), 18 deletions(-)
---
diff --git a/clutter/clutter-drag-action.c b/clutter/clutter-drag-action.c
index 7e1a600..3d3ff57 100644
--- a/clutter/clutter-drag-action.c
+++ b/clutter/clutter-drag-action.c
@@ -657,30 +657,38 @@ clutter_drag_action_dispose (GObject *gobject)
   /* if we're being disposed while a capture is still present, we
    * need to reset the state we are currently holding
    */
-  if (priv->last_motion_device != NULL)
+  if (priv->stage != NULL)
     {
-      _clutter_stage_remove_pointer_drag_actor (priv->stage,
-                                                priv->last_motion_device);
-      priv->last_motion_device = NULL;
-    }
+      if (priv->last_motion_device != NULL)
+        {
+          _clutter_stage_remove_pointer_drag_actor (priv->stage,
+                                                    priv->last_motion_device);
+          priv->last_motion_device = NULL;
+        }
 
-  if (priv->sequence != NULL)
-    {
-      _clutter_stage_remove_touch_drag_actor (priv->stage,
-                                              priv->sequence);
-      priv->sequence = NULL;
-    }
+      if (priv->sequence != NULL)
+        {
+          _clutter_stage_remove_touch_drag_actor (priv->stage,
+                                                  priv->sequence);
+          priv->sequence = NULL;
+        }
 
-  if (priv->capture_id != 0)
-    {
-      clutter_stage_set_motion_events_enabled (priv->stage,
-                                               priv->motion_events_enabled);
+      if (priv->capture_id != 0)
+        {
+          clutter_stage_set_motion_events_enabled (priv->stage,
+                                                   priv->motion_events_enabled);
 
-      if (priv->stage != NULL)
-        g_signal_handler_disconnect (priv->stage, priv->capture_id);
+          g_signal_handler_disconnect (priv->stage, priv->capture_id);
 
+          priv->capture_id = 0;
+          priv->stage = NULL;
+        }
+    }
+  else
+    {
+      priv->last_motion_device = NULL;
+      priv->sequence = NULL;
       priv->capture_id = 0;
-      priv->stage = NULL;
     }
 
   if (priv->button_press_id != 0)