media/audio/audio_output_device.cc

   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 <string>
   8
   9 #include "base/callback_helpers.h"
  10 #include "base/threading/thread_restrictions.h"
  11 #include "base/time/time.h"
  12 #include "base/trace_event/trace_event.h"
  13 #include "media/audio/audio_output_controller.h"
  14 #include "media/base/limits.h"
  15
  16 namespace media {
  17
  18 // Takes care of invoking the render callback on the audio thread.
  19 // An instance of this class is created for each capture stream in
  20 // OnStreamCreated().
  21 class AudioOutputDevice::AudioThreadCallback
  22     : public AudioDeviceThread::Callback {
  23  public:
  24   AudioThreadCallback(const AudioParameters& audio_parameters,
  25                       base::SharedMemoryHandle memory,
  26                       int memory_length,
  27                       AudioRendererSink::RenderCallback* render_callback);
  28   ~AudioThreadCallback() override;
  29
  30   void MapSharedMemory() override;
  31
  32   // Called whenever we receive notifications about pending data.
  33   void Process(uint32 pending_data) override;
  34
  35  private:
  36   AudioRendererSink::RenderCallback* render_callback_;
  37   scoped_ptr<AudioBus> output_bus_;
  38   uint64 callback_num_;
  39   DISALLOW_COPY_AND_ASSIGN(AudioThreadCallback);
  40 };
  41
  42 AudioOutputDevice::AudioOutputDevice(
  43     scoped_ptr<AudioOutputIPC> ipc,
  44     const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner)
  45     : ScopedTaskRunnerObserver(io_task_runner),
  46       callback_(NULL),
  47       ipc_(ipc.Pass()),
  48       state_(IDLE),
  49       play_on_start_(true),
  50       session_id_(-1),
  51       stopping_hack_(false),
  52       current_switch_request_id_(0) {
  53   CHECK(ipc_);
  54
  55   // The correctness of the code depends on the relative values assigned in the
  56   // State enum.
  57   static_assert(IPC_CLOSED < IDLE, "invalid enum value assignment 0");
  58   static_assert(IDLE < CREATING_STREAM, "invalid enum value assignment 1");
  59   static_assert(CREATING_STREAM < PAUSED, "invalid enum value assignment 2");
  60   static_assert(PAUSED < PLAYING, "invalid enum value assignment 3");
  61 }
  62
  63 void AudioOutputDevice::InitializeWithSessionId(const AudioParameters& params,
  64                                                 RenderCallback* callback,
  65                                                 int session_id) {
  66   DCHECK(!callback_) << "Calling InitializeWithSessionId() twice?";
  67   DCHECK(params.IsValid());
  68   audio_parameters_ = params;
  69   callback_ = callback;
  70   session_id_ = session_id;
  71 }
  72
  73 void AudioOutputDevice::Initialize(const AudioParameters& params,
  74                                    RenderCallback* callback) {
  75   InitializeWithSessionId(params, callback, 0);
  76 }
  77
  78 AudioOutputDevice::~AudioOutputDevice() {
  79   // The current design requires that the user calls Stop() before deleting
  80   // this class.
  81   DCHECK(audio_thread_.IsStopped());
  82
  83   // The following makes it possible for |current_switch_callback_| to release
  84   // its bound parameters in the correct thread instead of implicitly releasing
  85   // them in the thread where this destructor runs.
  86   if (!current_switch_callback_.is_null()) {
  87     base::ResetAndReturn(&current_switch_callback_).Run(
  88         SWITCH_OUTPUT_DEVICE_RESULT_ERROR_OBSOLETE);
  89   }
  90 }
  91
  92 void AudioOutputDevice::Start() {
  93   DCHECK(callback_) << "Initialize hasn't been called";
  94   task_runner()->PostTask(FROM_HERE,
  95       base::Bind(&AudioOutputDevice::CreateStreamOnIOThread, this,
  96                  audio_parameters_));
  97 }
  98
  99 void AudioOutputDevice::Stop() {
 100   {
 101     base::AutoLock auto_lock(audio_thread_lock_);
 102     audio_thread_.Stop(base::MessageLoop::current());
 103     stopping_hack_ = true;
 104   }
 105
 106   task_runner()->PostTask(FROM_HERE,
 107       base::Bind(&AudioOutputDevice::ShutDownOnIOThread, this));
 108 }
 109
 110 void AudioOutputDevice::Play() {
 111   task_runner()->PostTask(FROM_HERE,
 112       base::Bind(&AudioOutputDevice::PlayOnIOThread, this));
 113 }
 114
 115 void AudioOutputDevice::Pause() {
 116   task_runner()->PostTask(FROM_HERE,
 117       base::Bind(&AudioOutputDevice::PauseOnIOThread, this));
 118 }
 119
 120 bool AudioOutputDevice::SetVolume(double volume) {
 121   if (volume < 0 || volume > 1.0)
 122     return false;
 123
 124   if (!task_runner()->PostTask(FROM_HERE,
 125           base::Bind(&AudioOutputDevice::SetVolumeOnIOThread, this, volume))) {
 126     return false;
 127   }
 128
 129   return true;
 130 }
 131
 132 OutputDevice* AudioOutputDevice::GetOutputDevice() {
 133   return this;
 134 }
 135
 136 void AudioOutputDevice::SwitchOutputDevice(
 137     const std::string& device_id,
 138     const GURL& security_origin,
 139     const SwitchOutputDeviceCB& callback) {
 140   DVLOG(1) << __FUNCTION__ << "(" << device_id << ")";
 141   task_runner()->PostTask(
 142       FROM_HERE, base::Bind(&AudioOutputDevice::SwitchOutputDeviceOnIOThread,
 143                             this, device_id, security_origin, callback));
 144 }
 145
 146 void AudioOutputDevice::CreateStreamOnIOThread(const AudioParameters& params) {
 147   DCHECK(task_runner()->BelongsToCurrentThread());
 148   if (state_ == IDLE) {
 149     state_ = CREATING_STREAM;
 150     ipc_->CreateStream(this, params, session_id_);
 151   }
 152 }
 153
 154 void AudioOutputDevice::PlayOnIOThread() {
 155   DCHECK(task_runner()->BelongsToCurrentThread());
 156   if (state_ == PAUSED) {
 157     TRACE_EVENT_ASYNC_BEGIN0(
 158         "audio", "StartingPlayback", audio_callback_.get());
 159     ipc_->PlayStream();
 160     state_ = PLAYING;
 161     play_on_start_ = false;
 162   } else {
 163     play_on_start_ = true;
 164   }
 165 }
 166
 167 void AudioOutputDevice::PauseOnIOThread() {
 168   DCHECK(task_runner()->BelongsToCurrentThread());
 169   if (state_ == PLAYING) {
 170     TRACE_EVENT_ASYNC_END0(
 171         "audio", "StartingPlayback", audio_callback_.get());
 172     ipc_->PauseStream();
 173     state_ = PAUSED;
 174   }
 175   play_on_start_ = false;
 176 }
 177
 178 void AudioOutputDevice::ShutDownOnIOThread() {
 179   DCHECK(task_runner()->BelongsToCurrentThread());
 180
 181   // Close the stream, if we haven't already.
 182   if (state_ >= CREATING_STREAM) {
 183     ipc_->CloseStream();
 184     state_ = IDLE;
 185   }
 186
 187   // We can run into an issue where ShutDownOnIOThread is called right after
 188   // OnStreamCreated is called in cases where Start/Stop are called before we
 189   // get the OnStreamCreated callback.  To handle that corner case, we call
 190   // Stop(). In most cases, the thread will already be stopped.
 191   //
 192   // Another situation is when the IO thread goes away before Stop() is called
 193   // in which case, we cannot use the message loop to close the thread handle
 194   // and can't rely on the main thread existing either.
 195   base::AutoLock auto_lock_(audio_thread_lock_);
 196   base::ThreadRestrictions::ScopedAllowIO allow_io;
 197   audio_thread_.Stop(NULL);
 198   audio_callback_.reset();
 199   stopping_hack_ = false;
 200 }
 201
 202 void AudioOutputDevice::SetVolumeOnIOThread(double volume) {
 203   DCHECK(task_runner()->BelongsToCurrentThread());
 204   if (state_ >= CREATING_STREAM)
 205     ipc_->SetVolume(volume);
 206 }
 207
 208 void AudioOutputDevice::SwitchOutputDeviceOnIOThread(
 209     const std::string& device_id,
 210     const GURL& security_origin,
 211     const SwitchOutputDeviceCB& callback) {
 212   DCHECK(task_runner()->BelongsToCurrentThread());
 213   DVLOG(1) << __FUNCTION__ << "(" << device_id << "," << security_origin << ")";
 214   if (state_ >= CREATING_STREAM) {
 215     SetCurrentSwitchRequest(callback);
 216     ipc_->SwitchOutputDevice(device_id, security_origin,
 217                              current_switch_request_id_);
 218   } else {
 219     callback.Run(SWITCH_OUTPUT_DEVICE_RESULT_ERROR_NOT_SUPPORTED);
 220   }
 221 }
 222
 223 void AudioOutputDevice::OnStateChanged(AudioOutputIPCDelegateState state) {
 224   DCHECK(task_runner()->BelongsToCurrentThread());
 225
 226   // Do nothing if the stream has been closed.
 227   if (state_ < CREATING_STREAM)
 228     return;
 229
 230   // TODO(miu): Clean-up inconsistent and incomplete handling here.
 231   // http://crbug.com/180640
 232   switch (state) {
 233     case AUDIO_OUTPUT_IPC_DELEGATE_STATE_PLAYING:
 234     case AUDIO_OUTPUT_IPC_DELEGATE_STATE_PAUSED:
 235       break;
 236     case AUDIO_OUTPUT_IPC_DELEGATE_STATE_ERROR:
 237       DLOG(WARNING) << "AudioOutputDevice::OnStateChanged(ERROR)";
 238       // Don't dereference the callback object if the audio thread
 239       // is stopped or stopping.  That could mean that the callback
 240       // object has been deleted.
 241       // TODO(tommi): Add an explicit contract for clearing the callback
 242       // object.  Possibly require calling Initialize again or provide
 243       // a callback object via Start() and clear it in Stop().
 244       if (!audio_thread_.IsStopped())
 245         callback_->OnRenderError();
 246       break;
 247     default:
 248       NOTREACHED();
 249       break;
 250   }
 251 }
 252
 253 void AudioOutputDevice::OnStreamCreated(
 254     base::SharedMemoryHandle handle,
 255     base::SyncSocket::Handle socket_handle,
 256     int length) {
 257   DCHECK(task_runner()->BelongsToCurrentThread());
 258   DCHECK(base::SharedMemory::IsHandleValid(handle));
 259 #if defined(OS_WIN)
 260   DCHECK(socket_handle);
 261 #else
 262   DCHECK_GE(socket_handle, 0);
 263 #endif
 264   DCHECK_GT(length, 0);
 265
 266   if (state_ != CREATING_STREAM)
 267     return;
 268
 269   // We can receive OnStreamCreated() on the IO thread after the client has
 270   // called Stop() but before ShutDownOnIOThread() is processed. In such a
 271   // situation |callback_| might point to freed memory. Instead of starting
 272   // |audio_thread_| do nothing and wait for ShutDownOnIOThread() to get called.
 273   //
 274   // TODO(scherkus): The real fix is to have sane ownership semantics. The fact
 275   // that |callback_| (which should own and outlive this object!) can point to
 276   // freed memory is a mess. AudioRendererSink should be non-refcounted so that
 277   // owners (WebRtcAudioDeviceImpl, AudioRendererImpl, etc...) can Stop() and
 278   // delete as they see fit. AudioOutputDevice should internally use WeakPtr
 279   // to handle teardown and thread hopping. See http://crbug.com/151051 for
 280   // details.
 281   base::AutoLock auto_lock(audio_thread_lock_);
 282   if (stopping_hack_)
 283     return;
 284
 285   DCHECK(audio_thread_.IsStopped());
 286   audio_callback_.reset(new AudioOutputDevice::AudioThreadCallback(
 287       audio_parameters_, handle, length, callback_));
 288   audio_thread_.Start(
 289       audio_callback_.get(), socket_handle, "AudioOutputDevice", true);
 290   state_ = PAUSED;
 291
 292   // We handle the case where Play() and/or Pause() may have been called
 293   // multiple times before OnStreamCreated() gets called.
 294   if (play_on_start_)
 295     PlayOnIOThread();
 296 }
 297
 298 void AudioOutputDevice::SetCurrentSwitchRequest(
 299     const SwitchOutputDeviceCB& callback) {
 300   DCHECK(task_runner()->BelongsToCurrentThread());
 301   DVLOG(1) << __FUNCTION__;
 302   // If there is a previous unresolved request, resolve it as obsolete
 303   if (!current_switch_callback_.is_null()) {
 304     base::ResetAndReturn(&current_switch_callback_).Run(
 305         SWITCH_OUTPUT_DEVICE_RESULT_ERROR_OBSOLETE);
 306   }
 307   current_switch_callback_ = callback;
 308   current_switch_request_id_++;
 309 }
 310
 311 void AudioOutputDevice::OnOutputDeviceSwitched(
 312     int request_id,
 313     SwitchOutputDeviceResult result) {
 314   DCHECK(task_runner()->BelongsToCurrentThread());
 315   DCHECK(request_id <= current_switch_request_id_);
 316   DVLOG(1) << __FUNCTION__
 317            << "(" << request_id << ", " << result << ")";
 318   if (request_id != current_switch_request_id_) {
 319     return;
 320   }
 321   base::ResetAndReturn(&current_switch_callback_).Run(result);
 322 }
 323
 324 void AudioOutputDevice::OnIPCClosed() {
 325   DCHECK(task_runner()->BelongsToCurrentThread());
 326   state_ = IPC_CLOSED;
 327   ipc_.reset();
 328 }
 329
 330 void AudioOutputDevice::WillDestroyCurrentMessageLoop() {
 331   LOG(ERROR) << "IO loop going away before the audio device has been stopped";
 332   ShutDownOnIOThread();
 333 }
 334
 335 // AudioOutputDevice::AudioThreadCallback
 336
 337 AudioOutputDevice::AudioThreadCallback::AudioThreadCallback(
 338     const AudioParameters& audio_parameters,
 339     base::SharedMemoryHandle memory,
 340     int memory_length,
 341     AudioRendererSink::RenderCallback* render_callback)
 342     : AudioDeviceThread::Callback(audio_parameters, memory, memory_length, 1),
 343       render_callback_(render_callback),
 344       callback_num_(0) {}
 345
 346 AudioOutputDevice::AudioThreadCallback::~AudioThreadCallback() {
 347 }
 348
 349 void AudioOutputDevice::AudioThreadCallback::MapSharedMemory() {
 350   CHECK_EQ(total_segments_, 1);
 351   CHECK(shared_memory_.Map(memory_length_));
 352   DCHECK_EQ(memory_length_, AudioBus::CalculateMemorySize(audio_parameters_));
 353
 354   output_bus_ =
 355       AudioBus::WrapMemory(audio_parameters_, shared_memory_.memory());
 356 }
 357
 358 // Called whenever we receive notifications about pending data.
 359 void AudioOutputDevice::AudioThreadCallback::Process(uint32 pending_data) {
 360   // Convert the number of pending bytes in the render buffer into milliseconds.
 361   int audio_delay_milliseconds = pending_data / bytes_per_ms_;
 362
 363   callback_num_++;
 364   TRACE_EVENT1("audio", "AudioOutputDevice::FireRenderCallback",
 365                "callback_num", callback_num_);
 366
 367   // When playback starts, we get an immediate callback to Process to make sure
 368   // that we have some data, we'll get another one after the device is awake and
 369   // ingesting data, which is what we want to track with this trace.
 370   if (callback_num_ == 2) {
 371     TRACE_EVENT_ASYNC_END0("audio", "StartingPlayback", this);
 372   }
 373
 374   // Update the audio-delay measurement then ask client to render audio.  Since
 375   // |output_bus_| is wrapping the shared memory the Render() call is writing
 376   // directly into the shared memory.
 377   render_callback_->Render(output_bus_.get(), audio_delay_milliseconds);
 378 }
 379
 380 }  // namespace media.