container/group/clip: Allow creating an empty group.

This is a legitimate use case.

3 files changed, 21 insertions, 8 deletions

diff --git a/ges/ges-clip.c b/ges/ges-clip.c
index de40280..bcc3cdf 100644
--- a/ges/ges-clip.c
+++ b/ges/ges-clip.c
@@ -440,6 +440,9 @@ _group (GList * containers)
 
   start = inpoint = duration = GST_CLOCK_TIME_NONE;
 
+  if (!containers)
+    return NULL;
+
   /* First check if all the containers are clips, if they
    * all have the same start/inpoint/duration and are in the same
    * layer.
diff --git a/ges/ges-container.c b/ges/ges-container.c
index 7f0e956..b9cdb69 100644
--- a/ges/ges-container.c
+++ b/ges/ges-container.c
@@ -643,7 +643,7 @@ ges_container_ungroup (GESContainer * container, gboolean recursive)
 
 /**
  * ges_container_group:
- * @containers: (transfer none)(element-type GESContainer): The
+ * @containers: (transfer none)(element-type GESContainer) (allow-none): The
  * #GESContainer to group, they must all be in a same #GESTimeline
  *
  * Groups the #GESContainer-s provided in @containers. It creates a subclass
@@ -669,10 +669,11 @@ ges_container_group (GList * containers)
   guint i = 0;
   GESContainer *ret = NULL;
 
-  g_return_val_if_fail (containers, NULL);
-  element = GES_TIMELINE_ELEMENT (containers->data);
-  timeline = GES_TIMELINE_ELEMENT_TIMELINE (element);
-  g_return_val_if_fail (timeline, NULL);
+  if (containers) {
+    element = GES_TIMELINE_ELEMENT (containers->data);
+    timeline = GES_TIMELINE_ELEMENT_TIMELINE (element);
+    g_return_val_if_fail (timeline, NULL);
+  }
 
   if (g_list_length (containers) == 1)
     return containers->data;
diff --git a/ges/ges-group.c b/ges/ges-group.c
index 4410f66..63f2577 100644
--- a/ges/ges-group.c
+++ b/ges/ges-group.c
@@ -380,6 +380,11 @@ _child_added (GESContainer * group, GESTimelineElement * child)
   GESGroupPrivate *priv = GES_GROUP (group)->priv;
   GstClockTime last_child_end = 0, first_child_start = G_MAXUINT64;
 
+  if (!GES_TIMELINE_ELEMENT_TIMELINE (group)) {
+    timeline_add_group (GES_TIMELINE_ELEMENT_TIMELINE (child),
+        GES_GROUP (group));
+  }
+
   children = GES_CONTAINER_CHILDREN (group);
 
   for (tmp = children; tmp; tmp = tmp->next) {
@@ -432,6 +437,8 @@ _child_removed (GESContainer * group, GESTimelineElement * child)
 
   if (children == NULL) {
     GST_FIXME_OBJECT (group, "Auto destroy myself?");
+    timeline_remove_group (GES_TIMELINE_ELEMENT_TIMELINE (group),
+        GES_GROUP (group));
     return;
   }
 
@@ -460,8 +467,7 @@ _ungroup (GESContainer * group, gboolean recursive)
   }
   g_list_free_full (children, gst_object_unref);
 
-  timeline_remove_group (GES_TIMELINE_ELEMENT_TIMELINE (group),
-      GES_GROUP (group));
+  /* No need to remove from the timeline here, this will be done in _child_removed */
 
   return ret;
 }
@@ -473,6 +479,9 @@ _group (GList * containers)
   GESTimeline *timeline = NULL;
   GESContainer *ret = g_object_new (GES_TYPE_GROUP, NULL);
 
+  if (!containers)
+    return ret;
+
   for (tmp = containers; tmp; tmp = tmp->next) {
     if (!timeline) {
       timeline = GES_TIMELINE_ELEMENT_TIMELINE (tmp->data);
@@ -485,7 +494,7 @@ _group (GList * containers)
     ges_container_add (ret, tmp->data);
   }
 
-  timeline_add_group (timeline, GES_GROUP (ret));
+  /* No need to add to the timeline here, this will be done in _child_added */
 
   return ret;
 }