From 9a26e6c7bc232dbdc70a0877e02ddd38eadbb2c6 Mon Sep 17 00:00:00 2001
From: Stefan Kost <ensonic@users.sf.net>
Date: Mon, 25 Jul 2011 19:39:55 +0200
Subject: [PATCH] adder: rework pending event handling

Use atomic ops on pending flags. Rename the segment_pending to
new_segment_pending. Set new_segment_pending not when we received seek, but
when we received the first upstream new_segment.
---
 gst/adder/gstadder.c | 27 ++++++++++++++++++---------
 gst/adder/gstadder.h |  5 +++--
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/gst/adder/gstadder.c b/gst/adder/gstadder.c
index 6eb9f51..7d06239 100644
--- a/gst/adder/gstadder.c
+++ b/gst/adder/gstadder.c
@@ -672,7 +672,7 @@ gst_adder_src_event (GstPad * pad, GstEvent * event)
          * forwarding the seek upstream or from gst_adder_collected,
          * whichever happens first.
          */
-        adder->flush_stop_pending = TRUE;
+        g_atomic_int_set (&adder->flush_stop_pending, TRUE);
       }
       GST_DEBUG_OBJECT (adder, "handling seek event: %" GST_PTR_FORMAT, event);
 
@@ -688,9 +688,6 @@ gst_adder_src_event (GstPad * pad, GstEvent * event)
         adder->segment_end = end;
       else
         adder->segment_end = GST_CLOCK_TIME_NONE;
-      /* make sure we push a new segment, to inform about new basetime
-       * see FIXME in gst_adder_collected() */
-      adder->segment_pending = TRUE;
       if (flush) {
         /* Yes, we need to call _set_flushing again *WHEN* the streaming threads
          * have stopped so that the cookie gets properly updated. */
@@ -700,6 +697,9 @@ gst_adder_src_event (GstPad * pad, GstEvent * event)
       GST_DEBUG_OBJECT (adder, "forwarding seek event: %" GST_PTR_FORMAT,
           event);
 
+      /* we're forwarding seek to all upstream peers and wait for one to reply
+       * with a newsegment-event before we send a newsegment-event downstream */
+      g_atomic_int_set (&adder->wait_for_new_segment, TRUE);
       result = forward_event (adder, event, flush);
       if (!result) {
         /* seek failed. maybe source is a live source. */
@@ -755,8 +755,8 @@ gst_adder_sink_event (GstPad * pad, GstEvent * event)
        * flush-stop from the collect function later.
        */
       GST_OBJECT_LOCK (adder->collect);
-      adder->segment_pending = TRUE;
-      adder->flush_stop_pending = FALSE;
+      g_atomic_int_set (&adder->new_segment_pending, TRUE);
+      g_atomic_int_set (&adder->flush_stop_pending, FALSE);
       /* Clear pending tags */
       if (adder->pending_events) {
         g_list_foreach (adder->pending_events, (GFunc) gst_event_unref, NULL);
@@ -771,6 +771,14 @@ gst_adder_sink_event (GstPad * pad, GstEvent * event)
       adder->pending_events = g_list_append (adder->pending_events, event);
       GST_OBJECT_UNLOCK (adder->collect);
       goto beach;
+    case GST_EVENT_NEWSEGMENT:
+      if (g_atomic_int_compare_and_exchange (&adder->wait_for_new_segment,
+              TRUE, FALSE)) {
+        /* make sure we push a new segment, to inform about new basetime
+         * see FIXME in gst_adder_collected() */
+        g_atomic_int_set (&adder->new_segment_pending, TRUE);
+      }
+      break;
     default:
       break;
   }
@@ -1150,7 +1158,8 @@ gst_adder_collected (GstCollectPads * pads, gpointer user_data)
     /* we had an output buffer, unref the gapbuffer we kept */
     gst_buffer_unref (gapbuf);
 
-  if (adder->segment_pending) {
+  if (g_atomic_int_compare_and_exchange (&adder->new_segment_pending, TRUE,
+          FALSE)) {
     GstEvent *event;
 
     /* FIXME, use rate/applied_rate as set on all sinkpads.
@@ -1180,7 +1189,6 @@ gst_adder_collected (GstCollectPads * pads, gpointer user_data)
         GST_WARNING_OBJECT (adder->srcpad, "Sending event  %p (%s) failed.",
             event, GST_EVENT_TYPE_NAME (event));
       }
-      adder->segment_pending = FALSE;
     } else {
       GST_WARNING_OBJECT (adder->srcpad, "Creating new segment event for "
           "start:%" G_GINT64_FORMAT "  end:%" G_GINT64_FORMAT " failed",
@@ -1268,7 +1276,8 @@ gst_adder_change_state (GstElement * element, GstStateChange transition)
       adder->timestamp = 0;
       adder->offset = 0;
       adder->flush_stop_pending = FALSE;
-      adder->segment_pending = TRUE;
+      adder->new_segment_pending = TRUE;
+      adder->wait_for_new_segment = FALSE;
       adder->segment_start = 0;
       adder->segment_end = GST_CLOCK_TIME_NONE;
       adder->segment_rate = 1.0;
diff --git a/gst/adder/gstadder.h b/gst/adder/gstadder.h
index f0151b4..7fbdde6 100644
--- a/gst/adder/gstadder.h
+++ b/gst/adder/gstadder.h
@@ -85,11 +85,12 @@ struct _GstAdder {
   /* sink event handling */
   GstPadEventFunction  collect_event;
   GstSegment      segment;
-  gboolean        segment_pending;
   guint64         segment_start, segment_end;
   gdouble         segment_rate;
+  volatile gboolean new_segment_pending;
+  volatile gboolean wait_for_new_segment;
   /* src event handling */
-  gboolean        flush_stop_pending;
+  volatile gboolean flush_stop_pending;
   
   /* target caps */
   GstCaps *filter_caps;
-- 
2.7.4