timeline: Make use of our own knowledge of the timeline duration

Do not use each Track durations as it end going in loop as we have the Tracks
that need to know about timeline's duration to create or not gaps in the end and
then the timeline references on Tracks duration for its duration. We have this
information locally so just make proper use of it.

ges/ges-timeline.c

@@ -449,6 +449,28 @@ sort_layers (gpointer a, gpointer b)
   return 0;
 }
 
+static void
+timeline_update_duration (GESTimeline * timeline)
+{
+  GstClockTime *cduration;
+  GSequenceIter *it = g_sequence_get_end_iter (timeline->priv->starts_ends);
+
+  it = g_sequence_iter_prev (it);
+  if (g_sequence_iter_is_end (it))
+    return;
+
+  cduration = g_sequence_get (it);
+  if (cduration && timeline->priv->duration != *cduration) {
+    GST_DEBUG ("track duration : %" GST_TIME_FORMAT " current : %"
+        GST_TIME_FORMAT, GST_TIME_ARGS (*cduration),
+        GST_TIME_ARGS (timeline->priv->duration));
+
+    timeline->priv->duration = *cduration;
+
+    g_object_notify_by_pspec (G_OBJECT (timeline), properties[PROP_DURATION]);
+  }
+}
+
 static gint
 objects_start_compare (GESTrackObject * a, GESTrackObject * b)
 {
@@ -553,6 +575,7 @@ sort_starts_ends_end (GESTimeline * timeline, GESTrackObject * obj)
   *end = obj->start + obj->duration;
 
   g_sequence_sort_changed (iter, (GCompareDataFunc) compare_uint64, NULL);
+  timeline_update_duration (timeline);
 }
 
 static inline void
@@ -567,6 +590,7 @@ sort_starts_ends_start (GESTimeline * timeline, GESTrackObject * obj)
   *start = obj->start;
 
   g_sequence_sort_changed (iter, (GCompareDataFunc) compare_uint64, NULL);
+  timeline_update_duration (timeline);
 }
 
 static inline void
@@ -590,6 +614,7 @@ resort_all_starts_ends (GESTimeline * timeline)
   }
 
   g_sequence_sort (priv->starts_ends, (GCompareDataFunc) compare_uint64, NULL);
+  timeline_update_duration (timeline);
 }
 
 static inline void
@@ -645,7 +670,7 @@ stop_tracking_for_snapping (GESTimeline * timeline, GESTrackObject * tckobj)
   g_sequence_remove (iter_start);
   g_sequence_remove (iter_end);
   g_sequence_remove (tckobj_iter);
-
+  timeline_update_duration (timeline);
 }
 
 static void
@@ -672,6 +697,8 @@ start_tracking_track_obj (GESTimeline * timeline, GESTrackObject * tckobj)
   g_hash_table_insert (priv->by_object, pend, tckobj);
 
   timeline->priv->movecontext.needs_move_ctx = TRUE;
+
+  timeline_update_duration (timeline);
 }
 
 static inline void
@@ -1707,33 +1734,6 @@ track_object_removed_cb (GESTrack * track, GESTrackObject * object,
   }
 }
 
-static void
-track_duration_cb (GstElement * track,
-    GParamSpec * arg G_GNUC_UNUSED, GESTimeline * timeline)
-{
-  guint64 duration, max_duration = 0;
-  GList *tmp;
-
-  for (tmp = timeline->priv->tracks; tmp; tmp = g_list_next (tmp)) {
-    TrackPrivate *tr_priv = (TrackPrivate *) tmp->data;
-    g_object_get (tr_priv->track, "duration", &duration, NULL);
-
-    GST_DEBUG_OBJECT (track, "track duration : %" GST_TIME_FORMAT,
-        GST_TIME_ARGS (duration));
-    max_duration = MAX (duration, max_duration);
-  }
-
-  if (timeline->priv->duration != max_duration) {
-    GST_DEBUG ("track duration : %" GST_TIME_FORMAT " current : %"
-        GST_TIME_FORMAT, GST_TIME_ARGS (max_duration),
-        GST_TIME_ARGS (timeline->priv->duration));
-
-    timeline->priv->duration = max_duration;
-
-    g_object_notify_by_pspec (G_OBJECT (timeline), properties[PROP_DURATION]);
-  }
-}
-
 static GstStateChangeReturn
 ges_timeline_change_state (GstElement * element, GstStateChange transition)
 {
@@ -2169,11 +2169,6 @@ ges_timeline_add_track (GESTimeline * timeline, GESTrack * track)
   /* ensure that each existing timeline object has the opportunity to create a
    * track object for this track*/
 
-  /* We connect to the duration change notify, so we can update
-   * our duration accordingly */
-  g_signal_connect (G_OBJECT (track), "notify::duration",
-      G_CALLBACK (track_duration_cb), timeline);
-
   /* We connect to the object for the timeline editing mode management */
   g_signal_connect (G_OBJECT (track), "track-object-added",
       G_CALLBACK (track_object_added_cb), timeline);
@@ -2192,8 +2187,6 @@ ges_timeline_add_track (GESTimeline * timeline, GESTrack * track)
     g_list_free (objects);
   }
 
-  track_duration_cb (GST_ELEMENT (track), NULL, timeline);
-
   return TRUE;
 }
 
@@ -2246,8 +2239,6 @@ ges_timeline_remove_track (GESTimeline * timeline, GESTrack * track)
   /* Remove pad-added/-removed handlers */
   g_signal_handlers_disconnect_by_func (track, pad_added_cb, tr_priv);
   g_signal_handlers_disconnect_by_func (track, pad_removed_cb, tr_priv);
-  g_signal_handlers_disconnect_by_func (track, track_duration_cb,
-      tr_priv->track);
   g_signal_handlers_disconnect_by_func (track, track_object_added_cb, timeline);
   g_signal_handlers_disconnect_by_func (track, track_object_removed_cb,
       timeline);