Added volume adjust sound behind the flag.

media/audio/sounds/audio_stream_handler.cc

Index: media/audio/sounds/audio_stream_handler.cc
diff --git a/media/audio/sounds/audio_stream_handler.cc b/media/audio/sounds/audio_stream_handler.cc
index 08608ac4187aa0863b777e5e42701f2b7a327f69..7d6145d13ad06e3e2207f6a292180e3f50b7d3c7 100644
--- a/media/audio/sounds/audio_stream_handler.cc
+++ b/media/audio/sounds/audio_stream_handler.cc
@@ -6,8 +6,11 @@
 
 #include <string>
 
+#include "base/cancelable_callback.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop_proxy.h"
+#include "base/synchronization/lock.h"
+#include "base/time/time.h"
 #include "media/audio/audio_manager.h"
 #include "media/audio/audio_manager_base.h"
 #include "media/base/channel_layout.h"
@@ -19,6 +22,9 @@ namespace {
 // Volume percent.
 const double kOutputVolumePercent = 0.8;
 
+// Delay between end of sound and call to AudioOutputStream::Stop().
+const int kStopStreamDelaySec = 3;
+
 // The number of frames each OnMoreData() call will request.
 const int kDefaultFrameCount = 1024;
 
@@ -30,36 +36,67 @@ AudioOutputStream::AudioSourceCallback* g_audio_source_for_testing = NULL;
 class AudioStreamHandler::AudioStreamContainer
     : public AudioOutputStream::AudioSourceCallback {
  public:
-  AudioStreamContainer(const WavAudioHandler& wav_audio,
-                       const AudioParameters& params)
+  AudioStreamContainer(const WavAudioHandler& wav_audio)
       : stream_(NULL),
         wav_audio_(wav_audio),
-        params_(params),
-        cursor_(0) {
-  }
+        cursor_(0),
+        replay_scheduled_(false),
+        is_stream_stopped_(true),
+        schedule_replay_request_for_testing_(0) {}
 
   virtual ~AudioStreamContainer() {
     DCHECK(AudioManager::Get()->GetMessageLoop()->BelongsToCurrentThread());
+    stop_stream_closure_.Cancel();
+
+    if (stream_) {
+      stream_->Stop();
+      stream_->Close();
+    }
   }
 
   void Play() {
     DCHECK(AudioManager::Get()->GetMessageLoop()->BelongsToCurrentThread());
 
-    if (!stream_) {
-      stream_ = AudioManager::Get()->MakeAudioOutputStreamProxy(params_,
-                                                                std::string(),
-                                                                std::string());
-      if (!stream_ || !stream_->Open()) {
-        LOG(ERROR) << "Failed to open an output stream.";
+    {
+      base::AutoLock sl(state_lock_);
+
+      if (!stream_) {
+        const AudioParameters& p = wav_audio_.params();
+        const AudioParameters params(AudioParameters::AUDIO_PCM_LOW_LATENCY,
+                                     p.channel_layout(),
+                                     p.sample_rate(),
+                                     p.bits_per_sample(),
+                                     kDefaultFrameCount);
+        stream_ = AudioManager::Get()->MakeAudioOutputStreamProxy(
+            params, std::string(), std::string());
+        if (!stream_ || !stream_->Open()) {
+          LOG(ERROR) << "Failed to open an output stream.";
+          return;
+        }
+        cursor_ = 0;
+        stream_->SetVolume(kOutputVolumePercent);
+      } else if (is_stream_stopped_) {
+        // If stream exists and idle, just stop the stream and start again.
+        cursor_ = 0;
+        StopStreamWithoutLock();

[DaleCurtis, 2014/01/02 20:11:17]

Method says WithoutLock but in under state_lock_.

[ygorshenin1, 2014/01/09 19:26:57]

Removed.

+      } else {
+        // Stream exists and not idle, so let the current sound to
+        // finish playing.  If less than |wav_audio_.duration()| / 2
+        // until the end (including all replay requests), then replay is
+        // sheduled.  The main purpose of this strategy is to smooth
+        // sound reproduction when multiple requests are made, for
+        // instance, when user presses volume(up|down) button for a long
+        // time.
+        if (ReplayRequestCouldBeScheduled())
+          replay_scheduled_ = true;
         return;
       }
-      stream_->SetVolume(kOutputVolumePercent);
-    } else {
-      // TODO (ygorshenin@): implement smart stream rewind.
-      stream_->Stop();
+
+      last_play_start_time_ = base::TimeTicks::Now();
+      replay_scheduled_ = false;
+      is_stream_stopped_ = false;
     }
 
-    cursor_ = 0;
     if (g_audio_source_for_testing)
       stream_->Start(g_audio_source_for_testing);
     else
@@ -71,27 +108,43 @@ class AudioStreamHandler::AudioStreamContainer
 
   void Stop() {
     DCHECK(AudioManager::Get()->GetMessageLoop()->BelongsToCurrentThread());
-    if (!stream_)
-      return;
-    stream_->Stop();
-    stream_->Close();
-    stream_ = NULL;
-
-    if (g_observer_for_testing)
-      g_observer_for_testing->OnStop(cursor_);
+    StopStream();
   }
 
  private:
+  friend class AudioStreamHandler;
+
   // AudioOutputStream::AudioSourceCallback overrides:
   // Following methods could be called from *ANY* thread.
   virtual int OnMoreData(AudioBus* dest,
                          AudioBuffersState /* state */) OVERRIDE {
+    base::AutoLock sl(state_lock_);
+
+    if (is_stream_stopped_)
+      return 0;
+
     size_t bytes_written = 0;
     if (wav_audio_.AtEnd(cursor_) ||
         !wav_audio_.CopyTo(dest, cursor_, &bytes_written)) {
-      AudioManager::Get()->GetMessageLoop()->PostTask(
-          FROM_HERE,
-          base::Bind(&AudioStreamContainer::Stop, base::Unretained(this)));
+      // If there are replay requests, |cursor_| is reset and will
+      // continue to play from the start. Otherwise, stream will be
+      // stopped (not closed!) in |kStopStreamDelaySec| seconds,
+      // unless new Play() requests arrive during this time period.
+      if (replay_scheduled_) {
+        cursor_ = 0;
+        last_play_start_time_ = base::TimeTicks::Now();
+        replay_scheduled_ = false;
+        if (g_observer_for_testing)
+          g_observer_for_testing->OnReplay();
+      } else {
+        is_stream_stopped_ = true;
+        stop_stream_closure_.Reset(base::Bind(&AudioStreamContainer::StopStream,
+                                              base::Unretained(this)));
+        AudioManager::Get()->GetMessageLoop()->PostDelayedTask(
+            FROM_HERE,
+            stop_stream_closure_.callback(),
+            base::TimeDelta::FromSeconds(kStopStreamDelaySec));
+      }
       return 0;
     }
     cursor_ += bytes_written;
@@ -109,13 +162,56 @@ class AudioStreamHandler::AudioStreamContainer
     LOG(ERROR) << "Error during system sound reproduction.";
   }
 
+  void StopStreamWithoutLock() {
+    stop_stream_closure_.Cancel();
+    replay_scheduled_ = false;
+    if (stream_)
+      stream_->Stop();
+    if (g_observer_for_testing)
+      g_observer_for_testing->OnStop(cursor_);
+  }
+
+  void StopStream() {
+    base::AutoLock sl(state_lock_);
+    StopStreamWithoutLock();
+  }
+
+  bool ReplayRequestCouldBeScheduled() {
+    if (schedule_replay_request_for_testing_) {
+      --schedule_replay_request_for_testing_;
+      return true;
+    }
+    const base::TimeDelta delta =
+        base::TimeTicks::Now() - last_play_start_time_;
+    return 2 * delta > wav_audio_.params().GetBufferDuration() &&
+        !replay_scheduled_;
+  }
+
+  void AllowReplayOnceForTesting() {
+    base::AutoLock st(state_lock_);
+    ++schedule_replay_request_for_testing_;
+  }
+
   AudioOutputStream* stream_;
 
-  const WavAudioHandler wav_audio_;
-  const AudioParameters params_;
+  WavAudioHandler wav_audio_;
 
   size_t cursor_;
 
+  // True if replay of the current sound is scheduled.
+  bool replay_scheduled_;
+
+  base::CancelableClosure stop_stream_closure_;
+  bool is_stream_stopped_;
+
+  // Last time sound started to play from the start.
+  base::TimeTicks last_play_start_time_;
+
+  int schedule_replay_request_for_testing_;
+
+  // State lock for all fields except stream_ and wav_audio_.
+  base::Lock state_lock_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioStreamContainer);
 };
 
@@ -127,16 +223,11 @@ AudioStreamHandler::AudioStreamHandler(const base::StringPiece& wav_data)
     LOG(ERROR) << "Can't get access to audio manager.";
     return;
   }
-  AudioParameters params(AudioParameters::AUDIO_PCM_LOW_LATENCY,
-                         GuessChannelLayout(wav_audio_.num_channels()),
-                         wav_audio_.sample_rate(),
-                         wav_audio_.bits_per_sample(),
-                         kDefaultFrameCount);
-  if (!params.IsValid()) {
+  if (!wav_audio_.params().IsValid()) {
     LOG(ERROR) << "Audio params are invalid.";
     return;
   }
-  stream_.reset(new AudioStreamContainer(wav_audio_, params));
+  stream_.reset(new AudioStreamContainer(wav_audio_));
   initialized_ = true;
 }
 
@@ -185,4 +276,11 @@ void AudioStreamHandler::SetAudioSourceForTesting(
   g_audio_source_for_testing = source;
 }
 
+void AudioStreamHandler::AllowReplayOnceForTesting() {
+  AudioManager::Get()->GetMessageLoop()->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioStreamContainer::AllowReplayOnceForTesting,
+                 base::Unretained(stream_.get())));
+}
+
 }  // namespace media