funnel: handle GAP event to forwards sticky events into downstream

If no data is coming and funnel receive GAP event, need to forwards sticky events
into downstream if it needs.

https://bugzilla.gnome.org/show_bug.cgi?id=738202

plugins/elements/gstfunnel.c

@@ -317,6 +317,15 @@ gst_funnel_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
     GST_OBJECT_LOCK (funnel);
     fpad->got_eos = FALSE;
     GST_OBJECT_UNLOCK (funnel);
+  } else if (GST_EVENT_TYPE (event) == GST_EVENT_GAP) {
+    /* If no data is coming and we receive GAP event, need to forward sticky events. */
+    unlock = TRUE;
+    GST_PAD_STREAM_LOCK (funnel->srcpad);
+    GST_OBJECT_LOCK (funnel);
+    gst_object_replace ((GstObject **) & funnel->last_sinkpad,
+        GST_OBJECT (pad));
+    GST_OBJECT_UNLOCK (funnel);
+    gst_pad_sticky_events_foreach (pad, forward_events, funnel->srcpad);
   }
 
   if (forward)

tests/check/elements/funnel.c

@@ -243,6 +243,135 @@ GST_START_TEST (test_funnel_eos)
 
 GST_END_TEST;
 
+guint nb_stream_start_event = 0;
+guint nb_caps_event = 0;
+guint nb_segment_event = 0;
+guint nb_gap_event = 0;
+
+static GstPadProbeReturn
+event_counter (GstObject * pad, GstPadProbeInfo * info, gpointer user_data)
+{
+  GstEvent *event = GST_PAD_PROBE_INFO_EVENT (info);
+
+  fail_unless (event != NULL);
+  fail_unless (GST_IS_EVENT (event));
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_STREAM_START:
+      ++nb_stream_start_event;
+      break;
+    case GST_EVENT_CAPS:
+      ++nb_caps_event;
+      break;
+    case GST_EVENT_SEGMENT:
+      ++nb_segment_event;
+      break;
+    case GST_EVENT_GAP:
+      ++nb_gap_event;
+      break;
+    default:
+      break;
+  }
+
+  return GST_PAD_PROBE_OK;
+}
+
+/*
+ * Push GAP events into funnel to forward sticky events.
+ * Funnel element shoud also treat GAP events likes buffers.
+ * For example, funnel can be used for internal subtitle with streamiddemux. 
+ *  +--------------------------------------------------------------------------+
+ *  | playbin                               +--------------------------------+ |
+ *  | +--------------+  +----------------+  | +------------+     playsink    | |
+ *  | | uridecodebin |  | input-selector |  | | video-sink |                 | |
+ *  | |              |  +----------------+  | +------------+                 | |
+ *  | |              |                      |                                | |
+ *  | |              |  +----------------+  | +------------+                 | |
+ *  | |              |  | input-selector |  | | audio-sink |                 | |
+ *  | |              |  +----------------+  | +------------+                 | |
+ *  | |              |                      |                                | |
+ *  | |              |  +----------------+  | +---------------+ +----------+ | |
+ *  | |              |  | funnel         |  | | streamiddemux | | appsink0 | | |
+ *  | +--------------+  +----------------+  | +---------------+ +----------+ | |
+ *  |                                       |                   +----------+ | |
+ *  |                                       |                   | appsinkn | | |
+ *  |                                       |                   +----------+ | |
+ *  |                                       +--------------------------------+ |
+ *  +--------------------------------------------------------------------------+
+ * If no data was received in funnel and then sticky events can be pending continuously. 
+ * And streamiddemux only receive gap events continuously. 
+ * Thus, pipeline can not be constructed completely.
+ * For support it, need to handle GAP events likes buffers.
+ */
+GST_START_TEST (test_funnel_gap_event)
+{
+  struct TestData td;
+  guint probe = 0;
+
+  setup_test_objects (&td, chain_ok);
+
+  nb_stream_start_event = 0;
+  nb_caps_event = 0;
+  nb_segment_event = 0;
+  nb_gap_event = 0;
+  bufcount = 0;
+
+  probe = gst_pad_add_probe (td.mysink, GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM,
+      (GstPadProbeCallback) event_counter, NULL, NULL);
+
+  /* push a gap event to srcpad1 to push sticky events */
+  fail_unless (gst_pad_push_event (td.mysrc1, gst_event_new_gap (0,
+              GST_SECOND)));
+
+  fail_unless (nb_stream_start_event == 1);
+  fail_unless (nb_caps_event == 1);
+  fail_unless (nb_segment_event == 1);
+  fail_unless (nb_gap_event == 1);
+
+  /* push a gap event to srcpad2 to push sticky events */
+  fail_unless (gst_pad_push_event (td.mysrc2, gst_event_new_gap (0,
+              GST_SECOND)));
+
+  fail_unless (nb_stream_start_event == 2);
+  fail_unless (nb_caps_event == 2);
+  fail_unless (nb_segment_event == 2);
+  fail_unless (nb_gap_event == 2);
+
+  /* push a gap event to srcpad2 */
+  fail_unless (gst_pad_push_event (td.mysrc2, gst_event_new_gap (0,
+              GST_SECOND)));
+
+  fail_unless (nb_stream_start_event == 2);
+  fail_unless (nb_caps_event == 2);
+  fail_unless (nb_segment_event == 2);
+  fail_unless (nb_gap_event == 3);
+
+  /* push a gap event to srcpad1 */
+  fail_unless (gst_pad_push_event (td.mysrc1, gst_event_new_gap (0,
+              GST_SECOND)));
+
+  fail_unless (nb_stream_start_event == 3);
+  fail_unless (nb_caps_event == 3);
+  fail_unless (nb_segment_event == 3);
+  fail_unless (nb_gap_event == 4);
+
+  /* push buffer */
+  fail_unless (gst_pad_push (td.mysrc1, gst_buffer_new ()) == GST_FLOW_OK);
+  fail_unless (gst_pad_push (td.mysrc2, gst_buffer_new ()) == GST_FLOW_OK);
+
+  fail_unless (nb_stream_start_event == 4);
+  fail_unless (nb_caps_event == 4);
+  fail_unless (nb_segment_event == 4);
+  fail_unless (nb_gap_event == 4);
+  fail_unless (bufcount == 2);
+
+  gst_pad_remove_probe (td.mysink, probe);
+
+  release_test_objects (&td);
+}
+
+GST_END_TEST;
+
 static Suite *
 funnel_suite (void)
 {
@@ -252,6 +381,7 @@ funnel_suite (void)
   tc_chain = tcase_create ("funnel simple");
   tcase_add_test (tc_chain, test_funnel_simple);
   tcase_add_test (tc_chain, test_funnel_eos);
+  tcase_add_test (tc_chain, test_funnel_gap_event);
   suite_add_tcase (s, tc_chain);
 
   return s;