PulseAudio Sound Playback on Linux

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.
+
+#ifndef MEDIA_AUDIO_LINUX_PULSE_OUTPUT_H_
+#define MEDIA_AUDIO_LINUX_PULSE_OUTPUT_H_
+
+#include <pulse/pulseaudio.h>
+
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+#include "media/audio/audio_io.h"
+#include "media/audio/audio_parameters.h"
+
+namespace media {
+class SeekableBuffer;
+}
+
+class AudioManagerLinux;
+
+class PulseAudioOutputStream : public AudioOutputStream {
+ public:
+  PulseAudioOutputStream(const AudioParameters& params,
+                         AudioManagerLinux* manager);
+
+  virtual ~PulseAudioOutputStream();
+
+  // 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);
+
+  void BufferPacketInClient();

[vrk (LEFT CHROMIUM), 2011/08/05 15:02:26]

As I note in the .cc file, I think you can make this static private

[slock, 2011/08/08 20:30:15]

Done.

+  media::SeekableBuffer* client_buffer_;

[vrk (LEFT CHROMIUM), 2011/08/05 15:02:26]

Make these fields private

[vrk (LEFT CHROMIUM), 2011/08/05 15:02:26]

scoped_ptr instead?

[slock, 2011/08/08 20:30:15]

Done.

[slock, 2011/08/08 20:30:15]

Done.

+  bool source_exhausted_;
+
+ private:
+  // Flags indicating the state of the stream.
+  enum InternalState {

[vrk (LEFT CHROMIUM), 2011/08/05 15:02:26]

Please delete all unused/unimplemented private fields, enums, and functions in
your CL.

[slock, 2011/08/08 20:30:15]

Done.  Pretty sure I got them all.

+    kInError = 0,
+    kCreated,
+    kIsOpened,
+    kIsPlaying,
+    kIsStopped,
+    kIsClosed
+  };
+
+  friend std::ostream& operator<<(std::ostream& os, InternalState);
+
+  // Functions to get another packet from the data source and write it into the
+  // PulseAudio device.
+  void ClientBufferLoop();
+
+  // Functions to safeguard state transitions.  All changes to the object state
+  // should go through these functions.
+  bool CanTransitionTo(InternalState to);
+  InternalState TransitionTo(InternalState to);
+  InternalState state();
+
+  // API for Proxying calls to the AudioSourceCallback provided during Start().
+  uint32 RunDataCallback(uint8* dest,
+                         uint32 max_size,
+                         AudioBuffersState buffers_state);
+  void RunErrorCallback(int code);
+
+  // Changes the AudioSourceCallback to proxy calls to.  Pass in NULL to release
+  // ownership of the currently registered callback.
+  void set_source_callback(AudioSourceCallback* callback);
+
+  // Configuration constants from the constructor.  Referencable by all threads
+  // since they are constants.
+  const ChannelLayout channel_layout_;
+  const pa_sample_format_t sample_format_;
+  const uint32 sample_rate_;
+  const uint32 bytes_per_sample_;
+  const uint32 bytes_per_frame_;
+
+  // Device configuration data.  Populated after OpenTask() completes.
+  bool should_downmix_;
+  bool should_swizzle_;
+  uint32 packet_size_;
+  uint32 micros_per_packet_;
+  uint32 latency_micros_;
+  uint32 bytes_per_output_frame_;
+  uint32 server_buffer_frames_;
+
+  // 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 stop_stream_;
+
+  // Flag indicating that the there is no more data available to buffer.
+
+  // Audio manager that created us.  Used to report that we've closed.
+  AudioManagerLinux* manager_;
+
+  // PulseAudio API structs.
+  pa_mainloop* pa_mainloop_;
+  pa_mainloop_api* pa_mainloop_api_;
+  pa_context* pa_context_;
+
+  // PulseAudio attribute and specification structs.
+  pa_sample_spec* pa_sample_specs_;
+  pa_buffer_attr* pa_buffer_attributes_;
+
+  // Handle to the actual PulseAudio playback stream.
+  pa_stream* playback_handle_;
+
+  uint32 frames_per_packet_;
+
+  InternalState state_;
+  float volume_;  // Volume level from 0.0 to 1.0.
+
+  size_t MicrosToBytes(uint32 micros, uint32 sample_rate,
+                       size_t bytes_per_sample);
+
+  AudioSourceCallback* source_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(PulseAudioOutputStream);
+};
+
+#endif  // MEDIA_AUDIO_LINUX_PULSE_OUTPUT_H_