1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "media/audio/audio_output_device.h"
6
7#include "base/basictypes.h"
8#include "base/debug/trace_event.h"
9#include "base/threading/thread_restrictions.h"
10#include "base/time/time.h"
11#include "media/audio/audio_output_controller.h"
12#include "media/base/limits.h"
13
14namespace media {
15
16// Takes care of invoking the render callback on the audio thread.
17// An instance of this class is created for each capture stream in
18// OnStreamCreated().
19class AudioOutputDevice::AudioThreadCallback
20    : public AudioDeviceThread::Callback {
21 public:
22  AudioThreadCallback(const AudioParameters& audio_parameters,
23                      base::SharedMemoryHandle memory,
24                      int memory_length,
25                      AudioRendererSink::RenderCallback* render_callback);
26  virtual ~AudioThreadCallback();
27
28  virtual void MapSharedMemory() OVERRIDE;
29
30  // Called whenever we receive notifications about pending data.
31  virtual void Process(int pending_data) OVERRIDE;
32
33 private:
34  AudioRendererSink::RenderCallback* render_callback_;
35  scoped_ptr<AudioBus> output_bus_;
36  DISALLOW_COPY_AND_ASSIGN(AudioThreadCallback);
37};
38
39AudioOutputDevice::AudioOutputDevice(
40    scoped_ptr<AudioOutputIPC> ipc,
41    const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner)
42    : ScopedTaskRunnerObserver(io_task_runner),
43      callback_(NULL),
44      ipc_(ipc.Pass()),
45      state_(IDLE),
46      play_on_start_(true),
47      session_id_(-1),
48      stopping_hack_(false) {
49  CHECK(ipc_);
50
51  // The correctness of the code depends on the relative values assigned in the
52  // State enum.
53  COMPILE_ASSERT(IPC_CLOSED < IDLE, invalid_enum_value_assignment_0);
54  COMPILE_ASSERT(IDLE < CREATING_STREAM, invalid_enum_value_assignment_1);
55  COMPILE_ASSERT(CREATING_STREAM < PAUSED, invalid_enum_value_assignment_2);
56  COMPILE_ASSERT(PAUSED < PLAYING, invalid_enum_value_assignment_3);
57}
58
59void AudioOutputDevice::InitializeWithSessionId(const AudioParameters& params,
60                                                RenderCallback* callback,
61                                                int session_id) {
62  DCHECK(!callback_) << "Calling InitializeWithSessionId() twice?";
63  DCHECK(params.IsValid());
64  audio_parameters_ = params;
65  callback_ = callback;
66  session_id_ = session_id;
67}
68
69void AudioOutputDevice::Initialize(const AudioParameters& params,
70                                   RenderCallback* callback) {
71  InitializeWithSessionId(params, callback, 0);
72}
73
74AudioOutputDevice::~AudioOutputDevice() {
75  // The current design requires that the user calls Stop() before deleting
76  // this class.
77  DCHECK(audio_thread_.IsStopped());
78}
79
80void AudioOutputDevice::Start() {
81  DCHECK(callback_) << "Initialize hasn't been called";
82  task_runner()->PostTask(FROM_HERE,
83      base::Bind(&AudioOutputDevice::CreateStreamOnIOThread, this,
84                 audio_parameters_));
85}
86
87void AudioOutputDevice::Stop() {
88  {
89    base::AutoLock auto_lock(audio_thread_lock_);
90    audio_thread_.Stop(base::MessageLoop::current());
91    stopping_hack_ = true;
92  }
93
94  task_runner()->PostTask(FROM_HERE,
95      base::Bind(&AudioOutputDevice::ShutDownOnIOThread, this));
96}
97
98void AudioOutputDevice::Play() {
99  task_runner()->PostTask(FROM_HERE,
100      base::Bind(&AudioOutputDevice::PlayOnIOThread, this));
101}
102
103void AudioOutputDevice::Pause() {
104  task_runner()->PostTask(FROM_HERE,
105      base::Bind(&AudioOutputDevice::PauseOnIOThread, this));
106}
107
108bool AudioOutputDevice::SetVolume(double volume) {
109  if (volume < 0 || volume > 1.0)
110    return false;
111
112  if (!task_runner()->PostTask(FROM_HERE,
113          base::Bind(&AudioOutputDevice::SetVolumeOnIOThread, this, volume))) {
114    return false;
115  }
116
117  return true;
118}
119
120void AudioOutputDevice::CreateStreamOnIOThread(const AudioParameters& params) {
121  DCHECK(task_runner()->BelongsToCurrentThread());
122  if (state_ == IDLE) {
123    state_ = CREATING_STREAM;
124    ipc_->CreateStream(this, params, session_id_);
125  }
126}
127
128void AudioOutputDevice::PlayOnIOThread() {
129  DCHECK(task_runner()->BelongsToCurrentThread());
130  if (state_ == PAUSED) {
131    ipc_->PlayStream();
132    state_ = PLAYING;
133    play_on_start_ = false;
134  } else {
135    play_on_start_ = true;
136  }
137}
138
139void AudioOutputDevice::PauseOnIOThread() {
140  DCHECK(task_runner()->BelongsToCurrentThread());
141  if (state_ == PLAYING) {
142    ipc_->PauseStream();
143    state_ = PAUSED;
144  }
145  play_on_start_ = false;
146}
147
148void AudioOutputDevice::ShutDownOnIOThread() {
149  DCHECK(task_runner()->BelongsToCurrentThread());
150
151  // Close the stream, if we haven't already.
152  if (state_ >= CREATING_STREAM) {
153    ipc_->CloseStream();
154    state_ = IDLE;
155  }
156
157  // We can run into an issue where ShutDownOnIOThread is called right after
158  // OnStreamCreated is called in cases where Start/Stop are called before we
159  // get the OnStreamCreated callback.  To handle that corner case, we call
160  // Stop(). In most cases, the thread will already be stopped.
161  //
162  // Another situation is when the IO thread goes away before Stop() is called
163  // in which case, we cannot use the message loop to close the thread handle
164  // and can't rely on the main thread existing either.
165  base::AutoLock auto_lock_(audio_thread_lock_);
166  base::ThreadRestrictions::ScopedAllowIO allow_io;
167  audio_thread_.Stop(NULL);
168  audio_callback_.reset();
169  stopping_hack_ = false;
170}
171
172void AudioOutputDevice::SetVolumeOnIOThread(double volume) {
173  DCHECK(task_runner()->BelongsToCurrentThread());
174  if (state_ >= CREATING_STREAM)
175    ipc_->SetVolume(volume);
176}
177
178void AudioOutputDevice::OnStateChanged(AudioOutputIPCDelegate::State state) {
179  DCHECK(task_runner()->BelongsToCurrentThread());
180
181  // Do nothing if the stream has been closed.
182  if (state_ < CREATING_STREAM)
183    return;
184
185  // TODO(miu): Clean-up inconsistent and incomplete handling here.
186  // http://crbug.com/180640
187  switch (state) {
188    case AudioOutputIPCDelegate::kPlaying:
189    case AudioOutputIPCDelegate::kPaused:
190      break;
191    case AudioOutputIPCDelegate::kError:
192      DLOG(WARNING) << "AudioOutputDevice::OnStateChanged(kError)";
193      // Don't dereference the callback object if the audio thread
194      // is stopped or stopping.  That could mean that the callback
195      // object has been deleted.
196      // TODO(tommi): Add an explicit contract for clearing the callback
197      // object.  Possibly require calling Initialize again or provide
198      // a callback object via Start() and clear it in Stop().
199      if (!audio_thread_.IsStopped())
200        callback_->OnRenderError();
201      break;
202    default:
203      NOTREACHED();
204      break;
205  }
206}
207
208void AudioOutputDevice::OnStreamCreated(
209    base::SharedMemoryHandle handle,
210    base::SyncSocket::Handle socket_handle,
211    int length) {
212  DCHECK(task_runner()->BelongsToCurrentThread());
213#if defined(OS_WIN)
214  DCHECK(handle);
215  DCHECK(socket_handle);
216#else
217  DCHECK_GE(handle.fd, 0);
218  DCHECK_GE(socket_handle, 0);
219#endif
220  DCHECK_GT(length, 0);
221
222  if (state_ != CREATING_STREAM)
223    return;
224
225  // We can receive OnStreamCreated() on the IO thread after the client has
226  // called Stop() but before ShutDownOnIOThread() is processed. In such a
227  // situation |callback_| might point to freed memory. Instead of starting
228  // |audio_thread_| do nothing and wait for ShutDownOnIOThread() to get called.
229  //
230  // TODO(scherkus): The real fix is to have sane ownership semantics. The fact
231  // that |callback_| (which should own and outlive this object!) can point to
232  // freed memory is a mess. AudioRendererSink should be non-refcounted so that
233  // owners (WebRtcAudioDeviceImpl, AudioRendererImpl, etc...) can Stop() and
234  // delete as they see fit. AudioOutputDevice should internally use WeakPtr
235  // to handle teardown and thread hopping. See http://crbug.com/151051 for
236  // details.
237  base::AutoLock auto_lock(audio_thread_lock_);
238  if (stopping_hack_)
239    return;
240
241  DCHECK(audio_thread_.IsStopped());
242  audio_callback_.reset(new AudioOutputDevice::AudioThreadCallback(
243      audio_parameters_, handle, length, callback_));
244  audio_thread_.Start(
245      audio_callback_.get(), socket_handle, "AudioOutputDevice", true);
246  state_ = PAUSED;
247
248  // We handle the case where Play() and/or Pause() may have been called
249  // multiple times before OnStreamCreated() gets called.
250  if (play_on_start_)
251    PlayOnIOThread();
252}
253
254void AudioOutputDevice::OnIPCClosed() {
255  DCHECK(task_runner()->BelongsToCurrentThread());
256  state_ = IPC_CLOSED;
257  ipc_.reset();
258}
259
260void AudioOutputDevice::WillDestroyCurrentMessageLoop() {
261  LOG(ERROR) << "IO loop going away before the audio device has been stopped";
262  ShutDownOnIOThread();
263}
264
265// AudioOutputDevice::AudioThreadCallback
266
267AudioOutputDevice::AudioThreadCallback::AudioThreadCallback(
268    const AudioParameters& audio_parameters,
269    base::SharedMemoryHandle memory,
270    int memory_length,
271    AudioRendererSink::RenderCallback* render_callback)
272    : AudioDeviceThread::Callback(audio_parameters, memory, memory_length, 1),
273      render_callback_(render_callback) {}
274
275AudioOutputDevice::AudioThreadCallback::~AudioThreadCallback() {
276}
277
278void AudioOutputDevice::AudioThreadCallback::MapSharedMemory() {
279  CHECK_EQ(total_segments_, 1);
280  CHECK(shared_memory_.Map(memory_length_));
281  DCHECK_EQ(memory_length_, AudioBus::CalculateMemorySize(audio_parameters_));
282
283  output_bus_ =
284      AudioBus::WrapMemory(audio_parameters_, shared_memory_.memory());
285}
286
287// Called whenever we receive notifications about pending data.
288void AudioOutputDevice::AudioThreadCallback::Process(int pending_data) {
289  // Negative |pending_data| indicates the browser side stream has stopped.
290  if (pending_data < 0)
291    return;
292
293  // Convert the number of pending bytes in the render buffer into milliseconds.
294  int audio_delay_milliseconds = pending_data / bytes_per_ms_;
295
296  TRACE_EVENT0("audio", "AudioOutputDevice::FireRenderCallback");
297
298  // Update the audio-delay measurement then ask client to render audio.  Since
299  // |output_bus_| is wrapping the shared memory the Render() call is writing
300  // directly into the shared memory.
301  render_callback_->Render(output_bus_.get(), audio_delay_milliseconds);
302}
303
304}  // namespace media.
305