[clutter] actor: Add a comment on the unmapping order

[Emmanuele Bassi <ebassi src gnome org>]

commit 2559fb1d0df32bb30bf35448913fa96b33e6a423
Author: Emmanuele Bassi <ebassi linux intel com>
Date:   Tue Aug 23 10:58:09 2011 +0100

    actor: Add a comment on the unmapping order
    
    Let's add a comment to avoid reshuffling the unmap() implementation and
    end up triggering these bugs:
    
      http://bugzilla.clutter-project.org/show_bug.cgi?id=2621
      https://bugzilla.gnome.org/show_bug.cgi?id=652036

 clutter/clutter-actor.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)
---
diff --git a/clutter/clutter-actor.c b/clutter/clutter-actor.c
index 538f95c..ed76d93 100644
--- a/clutter/clutter-actor.c
+++ b/clutter/clutter-actor.c
@@ -8329,7 +8329,17 @@ clutter_actor_unparent (ClutterActor *self)
 
    /* We take this opportunity to invalidate any queue redraw entry
     * associated with the actor and descendants since we won't be able to
-    * determine the appropriate stage after this. */
+    * determine the appropriate stage after this.
+    *
+    * we do this after we updated the mapped state because actors might
+    * end up queueing redraws inside their mapped/unmapped virtual
+    * functions, and if we invalidate the redraw entry we could end up
+    * with an inconsistent state and weird memory corruption. see
+    * bugs:
+    *
+    *   http://bugzilla.clutter-project.org/show_bug.cgi?id=2621
+    *   https://bugzilla.gnome.org/show_bug.cgi?id=652036
+    */
   _clutter_actor_traverse (self,
                            0,
                            invalidate_queue_redraw_entry,