AudioRendererHost and unit test files

AudioRendererHost provide service in browser process for AudioRenderer to access hardware in render process.
There will be one AudioRendererHost for every RenderProcessHost, each one of AudioRendererHost will service multiple AudioRenderer in the related render process.
The main functionality of AudioRendererHost is to group audio related services and provide access to AudioRenderer through IPC. It maps an internal stream id to the actual AudioOutputStream which most calls are delegated to.
AudioRendererHost::IPCAudioSource is to implement audio data source using IPC.

Review URL: http://codereview.chromium.org/21008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@9159 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 132 insertions, 0 deletions

diff --git a/chrome/browser/renderer_host/audio_renderer_host.h b/chrome/browser/renderer_host/audio_renderer_host.h
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+// Copyright (c) 2006-2009 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.
+//
+// AudioRendererHost serves audio related requests from AudioRenderer which
+// lives inside the render process and provide access to audio hardware. It maps
+// an internal ID to AudioRendererHost::IPCAudioSource in a map, which is the
+// actual object providing audio packets through IPC. It creates the actual
+// AudioOutputStream object when requested by the renderer and returns an
+// internal ID. It then delegates calls to the AudioOutputStream object indexed
+// by the internal id.
+//
+// AudioRendererHost::IPCAudioSource is a container of AudioOutputStream and
+// provide audio packets to the associated AudioOutputStream through IPC. It
+// transforms the pull data model to a push model used for IPC. When asked by
+// AudioOutputStream for an audio packet, it would send a message to renderer,
+// passing a SharedMemoryHandle for filling the buffer.
+// NotifyPacketReady(|stream_id|) would be called when the buffer is filled
+// and ready to be consumed.
+
+#ifndef CHROME_BROWSER_RENDERER_HOST_AUDIO_RENDERER_HOST_H_
+#define CHROME_BROWSER_RENDERER_HOST_AUDIO_RENDERER_HOST_H_
+
+#include "base/id_map.h"
+#include "base/shared_memory.h"
+#include "chrome/common/ipc_message.h"
+#include "media/audio/audio_output.h"
+
+class AudioManager;
+class MessageLoop;
+
+class AudioRendererHost {
+ public:
+  static const int32 INVALID_ID = 0;
+
+  explicit AudioRendererHost(MessageLoop* message_loop);
+  ~AudioRendererHost();
+
+  // Creates an audio output stream with the specified format, returns the
+  // stream id if successful, otherwise INVALID_ID. If this call is successful
+  // this object would keep an internal entry of the stream about the
+  // required properties, renderer process handle and IPC channel for sending
+  // buffer request messages.
+  int32 CreateStream(IPC::Message::Sender* sender, base::ProcessHandle handle,
+                     AudioManager::Format format, int channels, int sample_rate,
+                     int bits_per_sample, size_t packet_size);
+
+  // Start the audio output strean, return false if stream doesn't exist or the
+  // cannot start.
+  bool Start(int32 stream_id);
+
+  // Stop the audio output stream, return false if stream doesn't exist or
+  // cannot stop.
+  bool Stop(int32 stream_id);
+
+  // Close the audio output stream, return false if stream doesn't exist or
+  // cannot close. If this call is successful, the AudioOutputStream correspond
+  // to |stream_id| would go unmanaged by this class, subsequent calls to
+  // this object with the same |stream_id| would fail.
+  bool Close(int32 stream_id);
+
+  // Set the volume for the stream specified, returns true if successful, false
+  // if stream doesn't exist or cann't set volume.
+  bool SetVolume(
+      int32 stream_id, double left_channel, double right_channel);
+
+  // Get the volume of the stream specified, returns true if successful, false
+  // is stream doesn't exist or can't get volume.
+  bool GetVolume(
+      int32 stream_id, double* left_channel, double* right_channel);
+
+  // Notify packet has been prepared for stream specified by |stream_id|. The
+  // buffer associated with |stream_id| has been filled and is ready to be
+  // consumed.
+  void NotifyPacketReady(int32 stream_id);
+
+  // Destroy all audio output streams.
+  void DestroyAllStreams();
+
+  // Destroy the stream specified by |stream_id| and remove it from map.
+  // *DO NOT* call this method other than from IPCAudioSource.
+  void DestroySource(int32 stream_id);
+
+ private:
+  // The container for AudioOutputStream and serves audio packet for it by IPC.
+  class IPCAudioSource : public AudioOutputStream::AudioSourceCallback {
+   public:
+    IPCAudioSource(AudioRendererHost* host,         // Host of this source.
+                   int32 id,                        // ID of this source.
+                   AudioOutputStream* stream,       // Stream associated.
+                   IPC::Message::Sender* sender,    // IPC sender to user.
+                   base::ProcessHandle process,     // Render process handle.
+                   size_t packet_size);             // Size of shared memory
+                                                    // buffer for writing.
+    ~IPCAudioSource();
+
+     // AudioSourceCallback methods.
+    virtual size_t OnMoreData(AudioOutputStream* stream,
+                              void* dest, size_t max_size);
+    virtual void OnClose(AudioOutputStream* stream);
+    virtual void OnError(AudioOutputStream* stream, int code);
+
+    // Notify this source that buffer has been filled and is ready to be
+    // consumed.
+    void NotifyPacketReady();
+
+    int32 id() { return id_; }
+    AudioOutputStream* stream() { return stream_; }
+
+   private:
+    AudioRendererHost* host_;
+    int32 id_;
+    AudioOutputStream* stream_;
+    IPC::Message::Sender* sender_;
+    base::SharedMemory shared_memory_;
+    base::SharedMemoryHandle foreign_memory_handle_;
+  };
+
+  // A map of id to audio sources.
+  IDMap<IPCAudioSource> sources_;
+
+  // An internal id for streams.
+  int32 next_id_;
+
+  // Only used for DCHECKs to make sure all methods calls are from the same
+  // thread as this object is created.
+  MessageLoop* message_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioRendererHost);
+};
+
+#endif  // CHROME_BROWSER_RENDERER_HOST_AUDIO_RENDERER_HOST_H_