Tab Audio Capture: Browser-side connect/disconnect functionality.

content/browser/renderer_host/media/web_contents_audio_input_stream.h

+// Copyright (c) 2012 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_BROWSER_RENDERER_HOST_MEDIA_WEB_CONTENTS_AUDIO_INPUT_STREAM_H_
+#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_WEB_CONTENTS_AUDIO_INPUT_STREAM_H_
+
+#include <set>
+#include <string>
+
+#include "base/memory/ref_counted.h"
+#include "base/synchronization/lock.h"
+#include "base/threading/thread_checker.h"
+#include "content/browser/renderer_host/media/web_contents_capture_util.h"
+#include "content/common/content_export.h"
+#include "media/audio/audio_io.h"
+
+namespace media {
+class DivertedAudioOutputStream;
+}
+
+namespace content {
+
+class AudioRendererHost;
+
+class CONTENT_EXPORT WebContentsAudioInputStream
+    : NON_EXPORTED_BASE(public media::AudioInputStream),
+      public base::RefCountedThreadSafe<WebContentsAudioInputStream> {
+ public:
+  // Construct from the a |device_id| string of the form:
+  //   "render_process_id:render_view_id"
+  static WebContentsAudioInputStream* Create(const std::string& device_id);
+
+  // media::AudioInputStream implementation
+  virtual bool Open() OVERRIDE;
+  virtual void Start(AudioInputCallback* callback) OVERRIDE;
+  virtual void Stop() OVERRIDE;
+  virtual void Close() OVERRIDE;
+  virtual double GetMaxVolume() OVERRIDE;
+  virtual void SetVolume(double volume) OVERRIDE;
+  virtual double GetVolume() OVERRIDE;
+  virtual void SetAutomaticGainControl(bool enabled) OVERRIDE;
+  virtual bool GetAutomaticGainControl() OVERRIDE;
+
+  // Begin pulling data from the given AudioOutputStream.  Caller retains
+  // ownership.
+  void AddAudioOutputStream(media::DivertedAudioOutputStream* aos);
+
+  // Stop pulling data from the given AudioOutputStream.  After this method
+  // returns, the caller can safely destroy the AOS.
+  void RemoveAudioOutputStream(media::DivertedAudioOutputStream* aos);
+
+ private:
+  friend class base::RefCountedThreadSafe<WebContentsAudioInputStream>;
+
+  enum State {
+    kConstructed,
+    kOpened,
+    kRecording,
+    kClosed
+  };
+
+  WebContentsAudioInputStream(int render_process_id, int render_view_id);
+
+  virtual ~WebContentsAudioInputStream();
+
+  // Called by RenderViewTracker when the the target of the audio mirroring has
+  // changed.
+  void OnTargetChanged(int render_process_id, int render_view_id);
+
+  // Ensures calls to the media::AudioInputStream methods all occur from the
+  // same thread.
+  base::ThreadChecker thread_checker_;
+
+  State state_;
+
+  // Current audio mirroring target.
+  int target_render_process_id_;
+  int target_render_view_id_;
+  scoped_refptr<AudioRendererHost> target_host_;

[Alpha Left Google, 2012/11/26 22:59:59]

Owning AudioRendererHost scares me.. AudioRendererHost should only be owned by
the IPC channel. This adds uncertainty as to when ARH is destroyed.

[miu, 2012/11/28 05:05:01]

Done.

+
+  // Tracks swapping of render views to maintain mirroring of the correct
+  // render view.
+  scoped_refptr<WebContentsCaptureUtil::RenderViewTracker> tracker_;
+
+  base::Lock streams_lock_;
+  std::set<media::DivertedAudioOutputStream*> streams_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebContentsAudioInputStream);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_WEB_CONTENTS_AUDIO_INPUT_STREAM_H_