aggregator: add finish_buffer() vfunc

So subclasses can override the finish behaviour
and/or decorate or modify buffers before they
get pushed out.

https://bugzilla.gnome.org/show_bug.cgi?id=760981

2 files changed, 34 insertions, 12 deletions

diff --git a/libs/gst/base/gstaggregator.c b/libs/gst/base/gstaggregator.c
index 7b8b093d1..06c7cbb37 100644
--- a/libs/gst/base/gstaggregator.c
+++ b/libs/gst/base/gstaggregator.c
@@ -539,17 +539,8 @@ gst_aggregator_set_src_caps (GstAggregator * self, GstCaps * caps)
   GST_PAD_STREAM_UNLOCK (self->srcpad);
 }
 
-/**
- * gst_aggregator_finish_buffer:
- * @self: The #GstAggregator
- * @buffer: (transfer full): the #GstBuffer to push.
- *
- * This method will push the provided output buffer downstream. If needed,
- * mandatory events such as stream-start, caps, and segment events will be
- * sent before pushing the buffer.
- */
-GstFlowReturn
-gst_aggregator_finish_buffer (GstAggregator * self, GstBuffer * buffer)
+static GstFlowReturn
+gst_aggregator_default_finish_buffer (GstAggregator * self, GstBuffer * buffer)
 {
   gst_aggregator_push_mandatory_events (self);
 
@@ -567,6 +558,25 @@ gst_aggregator_finish_buffer (GstAggregator * self, GstBuffer * buffer)
   }
 }
 
+/**
+ * gst_aggregator_finish_buffer:
+ * @aggregator: The #GstAggregator
+ * @buffer: (transfer full): the #GstBuffer to push.
+ *
+ * This method will push the provided output buffer downstream. If needed,
+ * mandatory events such as stream-start, caps, and segment events will be
+ * sent before pushing the buffer.
+ */
+GstFlowReturn
+gst_aggregator_finish_buffer (GstAggregator * aggregator, GstBuffer * buffer)
+{
+  GstAggregatorClass *klass = GST_AGGREGATOR_GET_CLASS (aggregator);
+
+  g_assert (klass->finish_buffer != NULL);
+
+  return klass->finish_buffer (aggregator, buffer);
+}
+
 static void
 gst_aggregator_push_eos (GstAggregator * self)
 {
@@ -2233,6 +2243,8 @@ gst_aggregator_class_init (GstAggregatorClass * klass)
   GST_DEBUG_CATEGORY_INIT (aggregator_debug, "aggregator",
       GST_DEBUG_FG_MAGENTA, "GstAggregator");
 
+  klass->finish_buffer = gst_aggregator_default_finish_buffer;
+
   klass->sink_event = gst_aggregator_default_sink_event;
   klass->sink_query = gst_aggregator_default_sink_query;
 
diff --git a/libs/gst/base/gstaggregator.h b/libs/gst/base/gstaggregator.h
index ecbd1529b..a2bff124b 100644
--- a/libs/gst/base/gstaggregator.h
+++ b/libs/gst/base/gstaggregator.h
@@ -159,6 +159,13 @@ struct _GstAggregator
  *                  clipping of input buffer. This function takes ownership of
  *                  buf and should output a buffer or return NULL in
  *                  if the buffer should be dropped.
+ * @finish_buffer:  Optional.
+ *                  Called when a subclass calls gst_aggregator_finish_buffer()
+ *                  from their aggregate function to push out a buffer.
+ *                  Subclasses can override this to modify or decorate buffers
+ *                  before they get pushed out. This function takes ownership
+ *                  of the buffer passed. Subclasses that override this method
+ *                  should always chain up to the parent class virtual method.
  * @sink_event:     Optional.
  *                  Called when an event is received on a sink pad, the subclass
  *                  should always chain up.
@@ -231,6 +238,9 @@ struct _GstAggregatorClass {
                                        GstAggregatorPad *  aggregator_pad,
                                        GstBuffer        *  buf);
 
+  GstFlowReturn     (*finish_buffer)  (GstAggregator    * aggregator,
+                                       GstBuffer        * buffer);
+
   /* sinkpads virtual methods */
   gboolean          (*sink_event)     (GstAggregator    *  aggregator,
                                        GstAggregatorPad *  aggregator_pad,
@@ -300,7 +310,7 @@ struct _GstAggregatorClass {
  ************************/
 
 GST_EXPORT
-GstFlowReturn  gst_aggregator_finish_buffer         (GstAggregator                *  self,
+GstFlowReturn  gst_aggregator_finish_buffer         (GstAggregator                *  aggregator,
                                                      GstBuffer                    *  buffer);
 
 GST_EXPORT