Support configuring the audio buffer duration in the Pepper MediaStream API.

content/renderer/pepper/pepper_media_stream_audio_track_host.h

 // Copyright 2014 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 CONTENT_RENDERER_PEPPER_PEPPER_MEDIA_STREAM_AUDIO_TRACK_HOST_H_
 #define CONTENT_RENDERER_PEPPER_PEPPER_MEDIA_STREAM_AUDIO_TRACK_HOST_H_
 
 #include <deque>
 
 #include "base/compiler_specific.h"
@@ skipping 27 matching lines @@
    public:
     explicit AudioSink(PepperMediaStreamAudioTrackHost* host);
     virtual ~AudioSink();
 
     // Enqueues a free buffer index into |buffers_| which will be used for
     // sending audio samples to plugin.
     // This function is called on the main thread.
     void EnqueueBuffer(int32_t index);
 
     // This function is called on the main thread.
-    void Configure(int32_t number_of_buffers);
+    void Configure(int32_t number_of_buffers, int32_t duration);
 
    private:
     // Initializes buffers on the main thread.
-    void SetFormatOnMainThread(int bytes_per_second);
+    void SetFormatOnMainThread(int bytes_per_second, int bytes_per_frame);
 
     void InitBuffers();
 
     // Send enqueue buffer message on the main thread.
     void SendEnqueueBufferMessageOnMainThread(int32_t index,
                                               int32_t buffers_generation);
 
     // MediaStreamAudioSink overrides:
     // These two functions should be called on the audio thread.
     virtual void OnData(const int16* audio_data,
@@ skipping 23 matching lines @@
 
     // The original audio parameters which is set in the first time of
     // OnSetFormat being called.
     // Access only on the audio thread.
     media::AudioParameters original_audio_params_;
 
     // The audio data size of one audio buffer in bytes.
     // Access only on the audio thread.
     uint32_t buffer_data_size_;
 
-    // A lock to protect the index queue |buffers_|, |buffers_generation_| and
-    // buffers in |host_->buffer_manager()|.
+    // Index of the currently active buffer.
+    // Access only on the audio thread.
+    int active_buffer_index_;
+
+    // Generation of buffers corresponding to the currently active
+    // buffer. Used to make sure the active buffer is still valid.
+    // Access only on the audio thread.
+    int32_t active_buffers_generation_;
+
+    // Current offset, in bytes, within the currently active buffer.
+    // Access only on the audio thread.
+    uint32_t active_buffer_offset_;
+
+    // A lock to protect the index queue |buffers_|, |buffers_generation_|,
+    // buffers in |host_->buffer_manager()|, and |output_buffer_size_|.
     base::Lock lock_;
 
     // A queue for free buffer indices.
     std::deque<int32_t> buffers_;
 
     // Generation of buffers. It is increased by every |InitBuffers()| call.
     int32_t buffers_generation_;
 
+    // Intended size of each output buffer.
+    int32_t output_buffer_size_;
+
     scoped_refptr<base::MessageLoopProxy> main_message_loop_proxy_;
 
     base::ThreadChecker audio_thread_checker_;
 
     base::WeakPtrFactory<AudioSink> weak_factory_;
 
     // Number of buffers.
     int32_t number_of_buffers_;
 
     // Number of bytes per second.
     int bytes_per_second_;
 
+    // Number of bytes per frame = channels * bytes per sample.
+    int bytes_per_frame_;
+
+    // User-configured buffer duration, in milliseconds.
+    int32_t user_buffer_duration_;
+
     DISALLOW_COPY_AND_ASSIGN(AudioSink);
   };
 
   virtual ~PepperMediaStreamAudioTrackHost();
 
   // ResourceMessageHandler overrides:
   virtual int32_t OnResourceMessageReceived(
       const IPC::Message& msg,
       ppapi::host::HostMessageContext* context) OVERRIDE;
 
@@ skipping 18 matching lines @@
   bool connected_;
 
   AudioSink audio_sink_;
 
   DISALLOW_COPY_AND_ASSIGN(PepperMediaStreamAudioTrackHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_MEDIA_STREAM_AUDIO_TRACK_HOST_H_