[banshee/gapless-ng] [Banshee.GStreamer] Handle slow RequestNextTrack responses better.

[Christopher James Halse Rogers <chrishr src gnome org>]

commit 3accec29f5494ae24d19c5ad0670aeb8b5a62160
Author: Christopher James Halse Rogers <chrishr src gnome org>
Date:   Sat Feb 27 17:50:59 2010 +1100

    [Banshee.GStreamer] Handle slow RequestNextTrack responses better.
    
    When the RequestNextTrack signal is not handled within 1 sec of being raised we
    release the block on about-to-finish handler to let the pipeline continue.
    
    Because state-change transitions are handled in the main thread, as is the
    RequestNextTrack signal SetNextTrack will be called before the EOS transition is
    handled.  In this case, store the uri sent to SetNextTrack and transition to it
    in the EOS handler.

 .../Banshee.GStreamer/PlayerEngine.cs              |   23 +++++++++++++++++++-
 1 files changed, 22 insertions(+), 1 deletions(-)
---
diff --git a/src/Backends/Banshee.GStreamer/Banshee.GStreamer/PlayerEngine.cs b/src/Backends/Banshee.GStreamer/Banshee.GStreamer/PlayerEngine.cs
index a9e27c8..4b67a17 100644
--- a/src/Backends/Banshee.GStreamer/Banshee.GStreamer/PlayerEngine.cs
+++ b/src/Backends/Banshee.GStreamer/Banshee.GStreamer/PlayerEngine.cs
@@ -90,6 +90,8 @@ namespace Banshee.GStreamer
         private BansheePlayerAboutToFinishCallback about_to_finish_callback;
 #endif
 
+        private SafeUri pending_uri;
+
         private bool buffering_finished;
         private int pending_volume = -1;
         private bool xid_is_set = false;
@@ -165,7 +167,7 @@ namespace Banshee.GStreamer
             bp_set_next_track_starting_callback (handle, next_track_starting_callback);
             bp_set_video_pipeline_setup_callback (handle, video_pipeline_setup_callback);
 
-            next_track_set = new EventWaitHandle (false, EventResetMode.AutoReset);
+            next_track_set = new EventWaitHandle (false, EventResetMode.ManualReset);
         }
 
         protected override void Initialize ()
@@ -236,6 +238,13 @@ namespace Banshee.GStreamer
 
         public override void SetNextTrackUri (SafeUri uri)
         {
+            if (next_track_set.WaitOne (0)) {
+                // We're not waiting for the next track to be set.
+                // This means that we've missed the window for gapless.
+                // Save this URI to be played when we receive EOS.
+                pending_uri = uri;
+                return;
+            }
             // If there isn't a next track for us, release the block on the about-to-finish callback.
             if (uri == null) {
                 next_track_set.Set ();
@@ -272,6 +281,14 @@ namespace Banshee.GStreamer
             OnEventChanged (PlayerEvent.EndOfStream);
             if (!GaplessEnabled) {
                 OnEventChanged (PlayerEvent.RequestNextTrack);
+            } else if (pending_uri != null) {
+                Log.Warning ("[Gapless] EOS signalled while waiting for next track.");
+                Log.Warning ("[Gapless] This means that Banshee was too slow at calculating what track to play next");
+                Log.Warning ("[Gapless] If this happens frequently, please file a bug.");
+                OnStateChanged (PlayerState.Loading);
+                OpenUri (pending_uri);
+                Play ();
+                pending_uri = null;
             }
         }
 
@@ -295,12 +312,16 @@ namespace Banshee.GStreamer
             CurrentTrack.LastPlayed = DateTime.Now;
             CurrentTrack.Save ();
 
+            next_track_set.Reset ();
+            pending_uri = null;
+
             OnEventChanged (PlayerEvent.RequestNextTrack);
             // Gapless playback with Playbin2 requires that the about-to-finish callback does not return until
             // the next uri has been set.  Block here for a second or until the RequestNextTrack event has
             // finished triggering.
             if (!next_track_set.WaitOne (1000, false)) {
                 Log.Debug ("[Gapless] Timed out while waiting for next_track_set to be raised");
+                next_track_set.Set ();
             }
         }
 #endif