framepositionner: add a weak ref on track element to know when it is finalized

Otherwise if frame positionner is disposed after track element has been
finalized, it will raise a critical message because we will try to
disconnect a signal handler on a freed track element object.

https://bugzilla.gnome.org/show_bug.cgi?id=766525

diff --git a/ges/gstframepositioner.c b/ges/gstframepositioner.c
index a624751..fd1fc9e 100644 (file)
--- a/ges/gstframepositioner.c
+++ b/ges/gstframepositioner.c
@@ -200,6 +200,12 @@ _track_changed_cb (GESTrackElement * trksrc, GParamSpec * arg G_GNUC_UNUSED,
   set_track (pos);
 }
 
+static void
+_trk_element_weak_notify_cb (GstFramePositioner * pos, GObject * old)
+{
+  pos->track_source = NULL;
+}
+
 void
 ges_frame_positioner_set_source_and_filter (GstFramePositioner * pos,
     GESTrackElement * trksrc, GstElement * capsfilter)
@@ -208,6 +214,8 @@ ges_frame_positioner_set_source_and_filter (GstFramePositioner * pos,
   pos->capsfilter = capsfilter;
   pos->current_track = ges_track_element_get_track (trksrc);
 
+  g_object_weak_ref (G_OBJECT (trksrc),
+      (GWeakNotify) _trk_element_weak_notify_cb, pos);
   g_signal_connect (trksrc, "notify::track", (GCallback) _track_changed_cb,
       pos);
   set_track (pos);