[banshee] gst#: Improve Volume handling.

[Bertrand Lorentz <blorentz src gnome org>]

commit 68537e130e4ba5fbefa132fdd277bbdadd9379fc
Author: Christopher James Halse Rogers <chrishr src gnome org>
Date:   Mon May 16 03:04:26 2011 +0800

    gst#: Improve Volume handling.
    
    This brings gst# in line with libbanshee's volume handling.
    That is, if the sink has its own volume control use that and
    don't try to save our own volume.  If the sink does not have
    its own volume control, add one to the pipeline and save
    that volume.

 .../Banshee.GStreamerSharp/PlayerEngine.cs         |   77 +++++++++++++++++---
 1 files changed, 68 insertions(+), 9 deletions(-)
---
diff --git a/src/Backends/Banshee.GStreamerSharp/Banshee.GStreamerSharp/PlayerEngine.cs b/src/Backends/Banshee.GStreamerSharp/Banshee.GStreamerSharp/PlayerEngine.cs
index 64270dc..ceceb5b 100644
--- a/src/Backends/Banshee.GStreamerSharp/Banshee.GStreamerSharp/PlayerEngine.cs
+++ b/src/Backends/Banshee.GStreamerSharp/Banshee.GStreamerSharp/PlayerEngine.cs
@@ -56,12 +56,55 @@ namespace Banshee.GStreamerSharp
         private class AudioSinkBin : Bin
         {
             Element hw_audio_sink;
+            Element volume;
+            Element first;
+
             public AudioSinkBin (string elementName) : base(elementName)
             {
                 hw_audio_sink = SelectAudioSink ();
                 Add (hw_audio_sink);
+                first = hw_audio_sink;
+
+                volume = FindVolumeProvider (hw_audio_sink);
+                if (volume != null) {
+                    // If the sink provides its own volume property we assume that it will
+                    // also save that value across program runs.  Pulsesink has this behaviour.
+                    VolumeNeedsSaving = false;
+                } else {
+                    volume = ElementFactory.Make ("volume", "volume");
+                    VolumeNeedsSaving = true;
+                    Add (volume);
+                    volume.Link (hw_audio_sink);
+                    first = volume;
+                }
+
+                AddPad (new GhostPad ("sink", first.GetStaticPad ("sink")));
+            }
 
-                AddPad (new GhostPad ("sink", hw_audio_sink.GetStaticPad ("sink")));
+            static Element FindVolumeProvider (Element sink)
+            {
+                Element volumeProvider = null;
+                // Sinks which automatically select between a number of possibilities
+                // (such as autoaudiosink and gconfaudiosink) need to be at least in
+                // the Ready state before they'll contain an actual sink.
+                sink.SetState (State.Ready);
+
+                if (sink.HasProperty ("volume")) {
+                    volumeProvider = sink;
+                    Log.DebugFormat ("Sink {0} has native volume.", volumeProvider.Name);
+                } else {
+                    var sinkBin = sink as Bin;
+                    if (sinkBin != null) {
+                        foreach (Element e in sinkBin.ElementsRecurse) {
+                            if (e.HasProperty ("volume")) {
+                                volumeProvider = e;
+                                Log.DebugFormat ("Found volume provider {0} in {1}.",
+                                    volumeProvider.Name, sink.Name);
+                            }
+                        }
+                    }
+                }
+                return volumeProvider;
             }
 
             static Element SelectAudioSink ()
@@ -87,8 +130,23 @@ namespace Banshee.GStreamerSharp
                 }
                 return audiosink;
             }
+
+            public bool VolumeNeedsSaving { get; private set; }
+            public double Volume {
+                get {
+                    return (double)volume["volume"];
+                }
+                set {
+                    if (value < 0 || value > 10.0) {
+                        throw new ArgumentOutOfRangeException ("value", "Volume must be between 0 and 10.0");
+                    }
+                    Log.DebugFormat ("Setting volume to {0:0.00}", value);
+                    volume["volume"] = value;
+                }
+            }
         }
 
+
         PlayBin2 playbin;
         AudioSinkBin audio_sink;
         uint iterate_timeout_id = 0;
@@ -127,8 +185,10 @@ namespace Banshee.GStreamerSharp
 
             playbin["audio-sink"] = audio_sink;
 
-            // Remember the volume from last time
-            Volume = (ushort)PlayerEngineService.VolumeSchema.Get ();
+            if (audio_sink.VolumeNeedsSaving) {
+                // Remember the volume from last time
+                Volume = (ushort)PlayerEngineService.VolumeSchema.Get ();
+            }
 
             playbin.AddNotification ("volume", OnVolumeChanged);
             playbin.Bus.AddWatch (OnBusMessage);
@@ -386,9 +446,6 @@ namespace Banshee.GStreamerSharp
 
         public override void Play ()
         {
-            // HACK, I think that directsoundsink has a bug that resets its volume to 1.0 every time
-            // This seems to fix bgo#641427
-            Volume = Volume;
             playbin.SetState (Gst.State.Playing);
             OnStateChanged (PlayerState.Playing);
         }
@@ -414,11 +471,13 @@ namespace Banshee.GStreamerSharp
         }
 
         public override ushort Volume {
-            get { return (ushort) Math.Round (playbin.Volume * 100.0); }
+            get { return (ushort) Math.Round (audio_sink.Volume * 100.0); }
             set {
                 double volume = Math.Min (1.0, Math.Max (0, value / 100.0));
-                playbin.Volume = volume;
-                PlayerEngineService.VolumeSchema.Set (value);
+                audio_sink.Volume = volume;
+                if (audio_sink.VolumeNeedsSaving) {
+                    PlayerEngineService.VolumeSchema.Set (value);
+                }
             }
         }