Tab Audio Mirroring: WebContentsAudioInputStream is a new implementation which represents the lifet…

content/browser/renderer_host/media/web_contents_audio_input_stream.cc

+// Copyright (c) 2013 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.
+
+#include "content/browser/renderer_host/media/web_contents_audio_input_stream.h"
+
+#include <string>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop_proxy.h"
+#include "content/browser/browser_main_loop.h"
+#include "content/browser/renderer_host/media/audio_mirroring_manager.h"
+#include "content/browser/renderer_host/media/web_contents_capture_util.h"
+#include "content/public/browser/browser_thread.h"
+#include "media/audio/virtual_audio_input_stream.h"
+#include "media/audio/virtual_audio_output_stream.h"
+
+namespace content {
+
+class WebContentsAudioInputStream::Impl
+    : public base::RefCountedThreadSafe<WebContentsAudioInputStream::Impl>,
+      public AudioMirroringManager::MirroringDestination {
+ public:
+  // Takes ownership of |mixer_stream|.  The rest outlive this instance.
+  Impl(int render_process_id, int render_view_id,
+       base::MessageLoopProxy* message_loop,
+       AudioMirroringManager* mirroring_manager,
+       const scoped_refptr<WebContentsTracker>& tracker,
+       media::VirtualAudioInputStream* mixer_stream);
+
+  // Open underlying VirtualAudioInputStream and start tracker.
+  bool Open();
+
+  // Start the underlying VirtualAudioInputStream and instruct
+  // AudioMirroringManager to begin a mirroring session.
+  void Start(AudioInputCallback* callback);
+
+  // Stop the underlying VirtualAudioInputStream and instruct
+  // AudioMirroringManager to shutdown a mirroring session.
+  void Stop();
+
+  // Close the underlying VirtualAudioInputStream and stop the tracker.
+  void Close();
+
+  // Accessor to underlying VirtualAudioInputStream.
+  media::VirtualAudioInputStream* mixer_stream() const {
+    return mixer_stream_.get();
+  }
+
+ private:
+  friend class base::RefCountedThreadSafe<WebContentsAudioInputStream::Impl>;
+
+  enum State {
+    CONSTRUCTED,
+    OPENED,
+    MIRRORING,
+    CLOSED
+  };
+
+  virtual ~Impl();
+
+  // Returns true if the mirroring target has been permanently lost.
+  bool IsTargetLost() const;
+
+  // Notifies the consumer callback that the stream is now dead.
+  void ReportError();
+
+  // Start/Stop mirroring by posting a call to AudioMirroringManager on the IO
+  // BrowserThread.
+  void StartMirroring();
+  void StopMirroring();
+
+  // AudioMirroringManager::MirroringDestination implementation
+  virtual media::AudioOutputStream* AddInput(
+      const media::AudioParameters& params) OVERRIDE;
+
+  // Callback which is run when |stream| is closed.  Deletes |stream|.
+  void ReleaseInput(media::VirtualAudioOutputStream* stream);
+
+  // Called by WebContentsTracker when the target of the audio mirroring has
+  // changed.
+  void OnTargetChanged(int render_process_id, int render_view_id);
+
+  // Injected dependencies.
+  base::MessageLoopProxy* const message_loop_;
+  AudioMirroringManager* const mirroring_manager_;
+  const scoped_refptr<WebContentsTracker> tracker_;
+  // The AudioInputStream implementation that handles the audio conversion and
+  // mixing details.
+  const scoped_ptr<media::VirtualAudioInputStream> mixer_stream_;
+
+  State state_;
+
+  // Current audio mirroring target.
+  int target_render_process_id_;
+  int target_render_view_id_;
+
+  // Current callback used to consume the resulting mixed audio data.
+  AudioInputCallback* callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(Impl);
+};
+
+WebContentsAudioInputStream::Impl::Impl(
+    int render_process_id, int render_view_id,
+    base::MessageLoopProxy* message_loop,
+    AudioMirroringManager* mirroring_manager,
+    const scoped_refptr<WebContentsTracker>& tracker,
+    media::VirtualAudioInputStream* mixer_stream)
+    : message_loop_(message_loop), mirroring_manager_(mirroring_manager),
+      tracker_(tracker), mixer_stream_(mixer_stream), state_(CONSTRUCTED),
+      target_render_process_id_(render_process_id),
+      target_render_view_id_(render_view_id),
+      callback_(NULL) {
+  DCHECK(message_loop_);
+  DCHECK(mirroring_manager_);
+  DCHECK(tracker_);
+  DCHECK(mixer_stream_.get());
+}
+
+WebContentsAudioInputStream::Impl::~Impl() {
+  DCHECK(state_ == CONSTRUCTED || state_ == CLOSED);
+}
+
+bool WebContentsAudioInputStream::Impl::Open() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+
+  DCHECK_EQ(CONSTRUCTED, state_) << "Illegal to Open more than once.";
+
+  if (!mixer_stream_->Open())
+    return false;
+
+  state_ = OPENED;
+
+  tracker_->Start(
+      target_render_process_id_, target_render_view_id_,
+      base::Bind(&Impl::OnTargetChanged, this));
+
+  return true;
+}
+
+void WebContentsAudioInputStream::Impl::Start(AudioInputCallback* callback) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  DCHECK(callback);
+
+  if (state_ != OPENED)
+    return;
+
+  if (IsTargetLost()) {
+    ReportError();
+    return;
+  }
+
+  state_ = MIRRORING;
+
+  callback_ = callback;
+  mixer_stream_->Start(callback);
+
+  StartMirroring();
+}
+
+void WebContentsAudioInputStream::Impl::Stop() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+
+  if (state_ != MIRRORING)
+    return;
+
+  state_ = OPENED;
+
+  mixer_stream_->Stop();
+  callback_ = NULL;
+
+  if (!IsTargetLost())
+    StopMirroring();
+}
+
+void WebContentsAudioInputStream::Impl::Close() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+
+  Stop();
+
+  if (state_ == OPENED) {
+    state_ = CONSTRUCTED;
+    tracker_->Stop();
+    mixer_stream_->Close();
+  }
+
+  DCHECK_EQ(CONSTRUCTED, state_);
+  state_ = CLOSED;
+}
+
+bool WebContentsAudioInputStream::Impl::IsTargetLost() const {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+
+  return target_render_process_id_ <= 0 || target_render_view_id_ <= 0;
+}
+
+void WebContentsAudioInputStream::Impl::ReportError() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+
+  // TODO(miu): Need clean-up of AudioInputCallback interface in a future
+  // change, since its only implementation ignores the first argument entirely
+  // and the values for the second argument are undefined.
+  callback_->OnError(NULL, 0);
+}
+
+void WebContentsAudioInputStream::Impl::StartMirroring() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+
+  BrowserThread::PostTask(
+      BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&AudioMirroringManager::StartMirroring,
+                 base::Unretained(mirroring_manager_),
+                 target_render_process_id_, target_render_view_id_,
+                 make_scoped_refptr(this)));
+}
+
+void WebContentsAudioInputStream::Impl::StopMirroring() {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+
+  BrowserThread::PostTask(
+      BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&AudioMirroringManager::StopMirroring,
+                 base::Unretained(mirroring_manager_),
+                 target_render_process_id_, target_render_view_id_,
+                 make_scoped_refptr(this)));
+}
+
+media::AudioOutputStream* WebContentsAudioInputStream::Impl::AddInput(
+    const media::AudioParameters& params) {
+  // Note: The closure created here holds a reference to "this," which will
+  // guarantee the VirtualAudioInputStream (mixer_stream_) outlives the
+  // VirtualAudioOutputStream.
+  return new media::VirtualAudioOutputStream(
+      params, message_loop_, mixer_stream_.get(),
+      base::Bind(&Impl::ReleaseInput, this));
+}
+
+void WebContentsAudioInputStream::Impl::ReleaseInput(
+    media::VirtualAudioOutputStream* stream) {
+  delete stream;
+}
+
+void WebContentsAudioInputStream::Impl::OnTargetChanged(int render_process_id,
+                                                        int render_view_id) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+
+  if (target_render_process_id_ == render_process_id &&
+      target_render_view_id_ == render_view_id) {
+    return;
+  }
+
+  DVLOG(1) << "Target RenderView has changed from "
+           << target_render_process_id_ << ':' << target_render_view_id_
+           << " to " << render_process_id << ':' << render_view_id;
+
+  if (state_ == MIRRORING)
+    StopMirroring();
+
+  target_render_process_id_ = render_process_id;
+  target_render_view_id_ = render_view_id;
+
+  if (state_ == MIRRORING) {
+    if (IsTargetLost()) {
+      ReportError();
+      Stop();
+    } else {
+      StartMirroring();
+    }
+  }
+}
+
+// static
+WebContentsAudioInputStream* WebContentsAudioInputStream::Create(
+    const std::string& device_id,
+    const media::AudioParameters& params,
+    base::MessageLoopProxy* message_loop) {
+  int render_process_id;
+  int render_view_id;
+  if (!WebContentsCaptureUtil::ExtractTabCaptureTarget(
+          device_id, &render_process_id, &render_view_id)) {
+    return NULL;
+  }
+
+  struct Helper {

[DaleCurtis, 2013/01/17 01:15:52]

bind_helpers exposes a DoNothing you can use instead.

[miu, 2013/01/17 05:33:55]

Fixed.  bind_helpers doesn't provide a DoNothing() with the function signature I
need.  Fortunately, I just realized you can instantiate a "null callback" by
using the zero-arg constructor.

+    static void DoNothingAfterClose(media::VirtualAudioInputStream* stream) {}
+  };
+  return new WebContentsAudioInputStream(
+      render_process_id, render_view_id, message_loop,
+      BrowserMainLoop::GetAudioMirroringManager(),
+      new WebContentsTracker(),
+      new media::VirtualAudioInputStream(
+          params, message_loop, base::Bind(&Helper::DoNothingAfterClose)));
+}
+
+WebContentsAudioInputStream::WebContentsAudioInputStream(
+    int render_process_id, int render_view_id,
+    base::MessageLoopProxy* message_loop,
+    AudioMirroringManager* mirroring_manager,
+    const scoped_refptr<WebContentsTracker>& tracker,
+    media::VirtualAudioInputStream* mixer_stream)
+    : impl_(new Impl(render_process_id, render_view_id, message_loop,
+                     mirroring_manager, tracker, mixer_stream)) {}
+
+WebContentsAudioInputStream::~WebContentsAudioInputStream() {}
+
+bool WebContentsAudioInputStream::Open() {
+  return impl_->Open();
+}
+
+void WebContentsAudioInputStream::Start(AudioInputCallback* callback) {
+  impl_->Start(callback);
+}
+
+void WebContentsAudioInputStream::Stop() {
+  impl_->Stop();
+}
+
+void WebContentsAudioInputStream::Close() {
+  impl_->Close();
+  delete this;
+}
+
+double WebContentsAudioInputStream::GetMaxVolume() {
+  return impl_->mixer_stream()->GetMaxVolume();
+}
+
+void WebContentsAudioInputStream::SetVolume(double volume) {
+  impl_->mixer_stream()->SetVolume(volume);
+}
+
+double WebContentsAudioInputStream::GetVolume() {
+  return impl_->mixer_stream()->GetVolume();
+}
+
+void WebContentsAudioInputStream::SetAutomaticGainControl(bool enabled) {
+  impl_->mixer_stream()->SetAutomaticGainControl(enabled);
+}
+
+bool WebContentsAudioInputStream::GetAutomaticGainControl() {
+  return impl_->mixer_stream()->GetAutomaticGainControl();
+}
+
+}  // namespace content