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
14 namespace 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().
19 class 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
AudioOutputDevice(scoped_ptr<AudioOutputIPC> ipc,const scoped_refptr<base::SingleThreadTaskRunner> & io_task_runner)39 AudioOutputDevice::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
InitializeWithSessionId(const AudioParameters & params,RenderCallback * callback,int session_id)59 void 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
Initialize(const AudioParameters & params,RenderCallback * callback)69 void AudioOutputDevice::Initialize(const AudioParameters& params,
70 RenderCallback* callback) {
71 InitializeWithSessionId(params, callback, 0);
72 }
73
~AudioOutputDevice()74 AudioOutputDevice::~AudioOutputDevice() {
75 // The current design requires that the user calls Stop() before deleting
76 // this class.
77 DCHECK(audio_thread_.IsStopped());
78 }
79
Start()80 void 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
Stop()87 void 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
Play()98 void AudioOutputDevice::Play() {
99 task_runner()->PostTask(FROM_HERE,
100 base::Bind(&AudioOutputDevice::PlayOnIOThread, this));
101 }
102
Pause()103 void AudioOutputDevice::Pause() {
104 task_runner()->PostTask(FROM_HERE,
105 base::Bind(&AudioOutputDevice::PauseOnIOThread, this));
106 }
107
SetVolume(double volume)108 bool 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
CreateStreamOnIOThread(const AudioParameters & params)120 void 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
PlayOnIOThread()128 void 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
PauseOnIOThread()139 void 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
ShutDownOnIOThread()148 void 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
SetVolumeOnIOThread(double volume)172 void AudioOutputDevice::SetVolumeOnIOThread(double volume) {
173 DCHECK(task_runner()->BelongsToCurrentThread());
174 if (state_ >= CREATING_STREAM)
175 ipc_->SetVolume(volume);
176 }
177
OnStateChanged(AudioOutputIPCDelegate::State state)178 void 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
OnStreamCreated(base::SharedMemoryHandle handle,base::SyncSocket::Handle socket_handle,int length)208 void 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
OnIPCClosed()254 void AudioOutputDevice::OnIPCClosed() {
255 DCHECK(task_runner()->BelongsToCurrentThread());
256 state_ = IPC_CLOSED;
257 ipc_.reset();
258 }
259
WillDestroyCurrentMessageLoop()260 void AudioOutputDevice::WillDestroyCurrentMessageLoop() {
261 LOG(ERROR) << "IO loop going away before the audio device has been stopped";
262 ShutDownOnIOThread();
263 }
264
265 // AudioOutputDevice::AudioThreadCallback
266
AudioThreadCallback(const AudioParameters & audio_parameters,base::SharedMemoryHandle memory,int memory_length,AudioRendererSink::RenderCallback * render_callback)267 AudioOutputDevice::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
~AudioThreadCallback()275 AudioOutputDevice::AudioThreadCallback::~AudioThreadCallback() {
276 }
277
MapSharedMemory()278 void 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.
Process(int pending_data)288 void 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