pad: Handle changing sticky events in pad probes

In the case where the user sets a new padprobeinfo->data in a probe
where the data is a sticky event, the new sticky event should be automatically
sticked on the probed pad.

https://bugzilla.gnome.org/show_bug.cgi?id=795330

diff --git a/gst/gstpad.c b/gst/gstpad.c
index 47cace9..902eaef 100644 (file)
--- a/gst/gstpad.c
+++ b/gst/gstpad.c
@@ -192,7 +192,7 @@ static GstFlowReturn gst_pad_chain_list_default (GstPad * pad,
 static GstFlowReturn gst_pad_send_event_unchecked (GstPad * pad,
     GstEvent * event, GstPadProbeType type);
 static GstFlowReturn gst_pad_push_event_unchecked (GstPad * pad,
-    GstEvent * event, GstPadProbeType type);
+    GstEvent ** event, GstPadProbeType type);
 
 static gboolean activate_mode_internal (GstPad * pad, GstObject * parent,
     GstPadMode mode, gboolean active);
@@ -647,7 +647,8 @@ restart:
 
 /* should be called with LOCK */
 static GstEvent *
-_apply_pad_offset (GstPad * pad, GstEvent * event, gboolean upstream)
+_apply_pad_offset (GstPad * pad, GstEvent * event, gint64 applied_offset,
+    gboolean upstream)
 {
   gint64 offset;
 
@@ -663,16 +664,16 @@ _apply_pad_offset (GstPad * pad, GstEvent * event, gboolean upstream)
     gst_event_copy_segment (event, &segment);
     gst_event_unref (event);
 
-    gst_segment_offset_running_time (&segment, segment.format, pad->offset);
+    gst_segment_offset_running_time (&segment, segment.format, applied_offset);
     event = gst_event_new_segment (&segment);
   }
 
   event = gst_event_make_writable (event);
   offset = gst_event_get_running_time_offset (event);
   if (upstream)
-    offset -= pad->offset;
+    offset -= applied_offset;
   else
-    offset += pad->offset;
+    offset += applied_offset;
   gst_event_set_running_time_offset (event, offset);
 
   return event;
@@ -682,7 +683,7 @@ static inline GstEvent *
 apply_pad_offset (GstPad * pad, GstEvent * event, gboolean upstream)
 {
   if (G_UNLIKELY (pad->offset != 0))
-    return _apply_pad_offset (pad, event, upstream);
+    return _apply_pad_offset (pad, event, pad->offset, upstream);
   return event;
 }
 
@@ -3803,9 +3804,16 @@ gst_pad_get_offset (GstPad * pad)
   return result;
 }
 
+/* This function will make sure that previously set offset is
+ * reverted as otherwise we would end up applying the new offset
+ * on top of the previously set one, which is not what we want.
+ * The event is also marked as not received. */
 static gboolean
-mark_event_not_received (GstPad * pad, PadEvent * ev, gpointer user_data)
+reschedule_event (GstPad * pad, PadEvent * ev, gint64 * prev_offset)
 {
+  if (*prev_offset != 0)
+    ev->event = _apply_pad_offset (pad, ev->event, -*prev_offset, FALSE);
+
   ev->received = FALSE;
   return TRUE;
 }
@@ -3820,6 +3828,7 @@ mark_event_not_received (GstPad * pad, PadEvent * ev, gpointer user_data)
 void
 gst_pad_set_offset (GstPad * pad, gint64 offset)
 {
+  gint64 prev_offset;
   g_return_if_fail (GST_IS_PAD (pad));
 
   GST_OBJECT_LOCK (pad);
@@ -3827,14 +3836,16 @@ gst_pad_set_offset (GstPad * pad, gint64 offset)
   if (pad->offset == offset)
     goto done;
 
+  prev_offset = pad->offset;
   pad->offset = offset;
   GST_DEBUG_OBJECT (pad, "changed offset to %" GST_STIME_FORMAT,
       GST_STIME_ARGS (offset));
 
   /* resend all sticky events with updated offset on next buffer push */
-  events_foreach (pad, mark_event_not_received, NULL);
+  events_foreach (pad, (PadEventFunction) reschedule_event, &prev_offset);
   GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_PENDING_EVENTS);
 
+
 done:
   GST_OBJECT_UNLOCK (pad);
 }
@@ -3876,8 +3887,10 @@ push_sticky (GstPad * pad, PadEvent * ev, gpointer user_data)
       GST_EVENT_TYPE (data->event) < GST_EVENT_TYPE (event)) {
     data->ret = GST_FLOW_CUSTOM_SUCCESS_1;
   } else {
-    data->ret = gst_pad_push_event_unchecked (pad, gst_event_ref (event),
+    gst_event_ref (event);
+    data->ret = gst_pad_push_event_unchecked (pad, &event,
         GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM);
+    gst_event_replace (&ev->event, event);
     if (data->ret == GST_FLOW_CUSTOM_SUCCESS_1)
       data->ret = GST_FLOW_OK;
   }
@@ -3948,7 +3961,8 @@ check_sticky (GstPad * pad, GstEvent * event)
       PadEvent *ev = find_event_by_type (pad, GST_EVENT_EOS, 0);
 
       if (ev && !ev->received) {
-        data.ret = gst_pad_push_event_unchecked (pad, gst_event_ref (ev->event),
+        gst_event_ref (ev->event);
+        data.ret = gst_pad_push_event_unchecked (pad, &ev->event,
             GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM);
         /* the event could have been dropped. Because this can only
          * happen if the user asked for it, it's not an error */
@@ -5250,12 +5264,13 @@ sticky_changed (GstPad * pad, PadEvent * ev, gpointer user_data)
 
 /* should be called with pad LOCK */
 static GstFlowReturn
-gst_pad_push_event_unchecked (GstPad * pad, GstEvent * event,
+gst_pad_push_event_unchecked (GstPad * pad, GstEvent ** in_event,
     GstPadProbeType type)
 {
   GstFlowReturn ret;
   GstPad *peerpad;
   GstEventType event_type;
+  GstEvent *event = *in_event;
 
   /* pass the adjusted event on. We need to do this even if
    * there is no peer pad because of the probes. */
@@ -5367,6 +5382,9 @@ gst_pad_push_event_unchecked (GstPad * pad, GstEvent * event,
     PROBE_NO_DATA (pad, GST_PAD_PROBE_TYPE_PUSH | GST_PAD_PROBE_TYPE_IDLE,
         idle_probe_stopped, ret);
   }
+
+  *in_event = event;
+
   return ret;
 
   /* ERROR handling */
@@ -5487,7 +5505,7 @@ gst_pad_push_event (GstPad * pad, GstEvent * event)
     GstFlowReturn ret;
 
     /* other events are pushed right away */
-    ret = gst_pad_push_event_unchecked (pad, event, type);
+    ret = gst_pad_push_event_unchecked (pad, &event, type);
     /* dropped events by a probe are not an error */
     res = (ret == GST_FLOW_OK || ret == GST_FLOW_CUSTOM_SUCCESS
         || ret == GST_FLOW_CUSTOM_SUCCESS_1);

diff --git a/tests/check/gst/gstpad.c b/tests/check/gst/gstpad.c
index b9def0f..f13f8f1 100644 (file)
--- a/tests/check/gst/gstpad.c
+++ b/tests/check/gst/gstpad.c
@@ -23,6 +23,7 @@
 #endif
 
 #include <gst/check/gstcheck.h>
+#include <gst/check/gstharness.h>
 
 static GstSegment dummy_segment;
 
@@ -3282,6 +3283,61 @@ GST_START_TEST (test_pad_offset_src)
 
 GST_END_TEST;
 
+static GstPadProbeReturn
+update_stream_start_event_cb (GstPad * pad, GstPadProbeInfo * info,
+    const gchar * wanted_stream_id)
+{
+  GstEvent *event = info->data;
+
+  if (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START) {
+    const gchar *stream_id;
+
+    gst_event_parse_stream_start (event, &stream_id);
+    g_assert_cmpstr (stream_id, !=, wanted_stream_id);
+
+    gst_event_unref (event);
+
+    info->data = gst_event_new_stream_start (wanted_stream_id);
+  }
+
+  return GST_PAD_PROBE_OK;
+}
+
+GST_START_TEST (test_sticky_events_changed_in_probe)
+{
+  GstPad *srcpad;
+  GstHarness *harness;
+  GstEvent *stream_start;
+  const gchar *stream_id;
+  const gchar *wanted_stream_id = "The right stream ID";
+  harness = gst_harness_new ("fakesrc");
+
+  gst_harness_add_probe (harness, "fakesrc", "src",
+      GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM,
+      (GstPadProbeCallback) update_stream_start_event_cb,
+      (gpointer) wanted_stream_id, NULL);
+  gst_harness_play (harness);
+  gst_harness_set_blocking_push_mode (harness);
+  gst_buffer_unref (gst_harness_pull (harness));
+
+  stream_start =
+      gst_pad_get_sticky_event (harness->sinkpad, GST_EVENT_STREAM_START, 0);
+  gst_event_parse_stream_start (stream_start, &stream_id);
+  fail_unless_equals_string (stream_id, wanted_stream_id);
+  gst_event_unref (stream_start);
+
+  srcpad = gst_element_get_static_pad (harness->element, "src");
+  stream_start = gst_pad_get_sticky_event (srcpad, GST_EVENT_STREAM_START, 0);
+  gst_event_unref (stream_start);
+  gst_object_unref (srcpad);
+  gst_event_parse_stream_start (stream_start, &stream_id);
+  fail_unless_equals_string (stream_id, wanted_stream_id);
+
+  gst_harness_teardown (harness);
+}
+
+GST_END_TEST;
+
 static Suite *
 gst_pad_suite (void)
 {
@@ -3335,6 +3391,7 @@ gst_pad_suite (void)
   tcase_add_test (tc_chain, test_block_async_full_destroy_dispose);
   tcase_add_test (tc_chain, test_block_async_replace_callback_no_flush);
   tcase_add_test (tc_chain, test_sticky_events);
+  tcase_add_test (tc_chain, test_sticky_events_changed_in_probe);
   tcase_add_test (tc_chain, test_last_flow_return_push);
   tcase_add_test (tc_chain, test_last_flow_return_pull);
   tcase_add_test (tc_chain, test_flush_stop_inactive);