A patch making the pulseaudio working with the threaded mainloop.

media/audio/linux/pulse_output.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Creates an audio output stream based on the PulseAudio asynchronous API.
 //
 // If the stream is successfully opened, Close() must be called before the
 // stream is deleted as Close() is responsible for ensuring resource cleanup
 // occurs.
 //
 // This object is designed so that all AudioOutputStream methods will be called
 // on the same thread that created the object.
 //
 // WARNING: This object blocks on internal PulseAudio calls in Open() while
-// waiting for PulseAudio's context structure to be ready.  It also blocks in
-// inside PulseAudio in Start() and repeated during playback, waiting for
-// PulseAudio write callbacks to occur.
+// waiting for PulseAudio's context structure to be ready.
 
 #ifndef MEDIA_AUDIO_LINUX_PULSE_OUTPUT_H_
 #define MEDIA_AUDIO_LINUX_PULSE_OUTPUT_H_
 
+#include <pulse/glib-mainloop.h>
 #include <pulse/pulseaudio.h>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/task.h"
 #include "media/audio/audio_io.h"
 #include "media/base/channel_layout.h"
 
 namespace media {
 class SeekableBuffer;
@@ skipping 14 matching lines @@
   // Implementation of AudioOutputStream.
   virtual bool Open();
   virtual void Close();
   virtual void Start(AudioSourceCallback* callback);
   virtual void Stop();
   virtual void SetVolume(double volume);
   virtual void GetVolume(double* volume);
 
  private:
   // PulseAudio Callbacks.
-  static void ContextStateCallback(pa_context* context, void* state_addr);
+  static void ContextStateCallback(pa_context* context, void* p_this);

[tommi (sloooow) - chröme, 2011/11/08 10:51:36]

p_this -> this_ptr

Actually, the documentation for this callback says that the name of the last
argument is |user_data|. Can we just use that?

[no longer working on chromium, 2011/11/09 12:57:33]

Done.

   static void WriteRequestCallback(pa_stream* playback_handle, size_t length,
-                                   void* stream_addr);
+                                   void* p_this);

[tommi (sloooow) - chröme, 2011/11/08 10:51:36]

same here

[no longer working on chromium, 2011/11/09 12:57:33]

Done.

 
-  // Iterate the PulseAudio mainloop to get write requests.
-  void WaitForWriteRequest();
-
-  // Get another packet from the data source and write it to the client buffer.
-  bool BufferPacketFromSource();
-
-  // Fulfill a write request from the write request callback.  If the write
+  // Fulfills a write request from the write request callback.  If the write
   // can't be finished a first, post a new attempt to the message loop.
   void FulfillWriteRequest(size_t requested_bytes);
 
-  // Write data from the client buffer to the PulseAudio stream.
-  void WriteToStream(size_t bytes_to_write, size_t* bytes_written);
-
-  // API for Proxying calls to the AudioSourceCallback provided during Start().
-  uint32 RunDataCallback(uint8* dest, uint32 max_size,
-                         AudioBuffersState buffers_state);
-
   // Close() helper function to free internal structs.
   void Reset();
 
   // Configuration constants from the constructor.  Referencable by all threads
   // since they are constants.
-  const ChannelLayout channel_layout_;
-  const uint32 channel_count_;
+  const uint32 channels_;
   const pa_sample_format_t sample_format_;
   const uint32 sample_rate_;
   const uint32 bytes_per_frame_;
+  const uint32 packet_size_;
+  const uint32 frames_per_packet_;
 
   // Audio manager that created us.  Used to report that we've closed.
   AudioManagerLinux* manager_;
 
   // PulseAudio API structs.
   pa_context* pa_context_;
-  pa_mainloop* pa_mainloop_;
+  pa_glib_mainloop* pa_glib_mainloop_;
 
   // Handle to the actual PulseAudio playback stream.
   pa_stream* playback_handle_;
 
   // Device configuration data.  Populated after Open() completes.
-  uint32 packet_size_;
-  uint32 frames_per_packet_;
+  uint32 pa_buffer_size_;
 
   // Client side audio buffer feeding pulse audio's server side buffer.
-  scoped_ptr<media::SeekableBuffer> client_buffer_;
+  scoped_ptr<media::SeekableBuffer> buffer_;
 
   // Float representation of volume from 0.0 to 1.0.
   float volume_;
 
   // Flag indicating the code should stop reading from the data source or
   // writing to the PulseAudio server.  This is set because the device has
   // entered an unrecoverable error state, or the Close() has executed.
   bool stream_stopped_;
 
-  // Whether or not PulseAudio has called the WriteCallback for the most recent
-  // set of pa_mainloop iterations.
-  bool write_callback_handled_;
+  // Flag indicating the state of the context has been changed.
+  bool context_state_changed_;
 
   // Message loop used to post WaitForWriteTasks.  Used to prevent blocking on
   // the audio thread while waiting for PulseAudio write callbacks.
   MessageLoop* message_loop_;
 
   // Allows us to run tasks on the PulseAudioOutputStream instance which are
   // bound by its lifetime.
   base::WeakPtrFactory<PulseAudioOutputStream> weak_factory_;
 
   // Callback to audio data source.
   AudioSourceCallback* source_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(PulseAudioOutputStream);
 };
 
 #endif  // MEDIA_AUDIO_LINUX_PULSE_OUTPUT_H_