Refactoring of chrome speech recognition architecture (CL1.2)

content/browser/speech/speech_recognizer_impl.cc

 // Copyright (c) 2012 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/speech/speech_recognizer_impl.h"
 
 #include "base/bind.h"
 #include "base/time.h"
 #include "content/browser/browser_main_loop.h"
 #include "content/browser/speech/audio_buffer.h"
-#include "content/public/browser/speech_recognizer_delegate.h"
+#include "content/public/browser/speech_recognition_event_listener.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/speech_recognition_result.h"
 #include "net/url_request/url_request_context_getter.h"
 
 using content::BrowserMainLoop;
 using content::BrowserThread;
+using content::SpeechRecognitionEventListener;
 using content::SpeechRecognizer;
-using content::SpeechRecognizerDelegate;
 using media::AudioInputController;
 using std::string;
 
 namespace {
 
 // The following constants are related to the volume level indicator shown in
 // the UI for recorded audio.
 // Multiplier used when new volume is greater than previous level.
 const float kUpSmoothingFactor = 1.0f;
 // Multiplier used when new volume is lesser than previous level.
@@ skipping 19 matching lines @@
       if (++clipping_samples > kThreshold)
         return true;
     }
   }
   return false;
 }
 
 }  // namespace
 
 SpeechRecognizer* SpeechRecognizer::Create(
-    SpeechRecognizerDelegate* delegate,
+    SpeechRecognitionEventListener* listener,
     int caller_id,
     const std::string& language,
     const std::string& grammar,
     net::URLRequestContextGetter* context_getter,
     bool filter_profanities,
     const std::string& hardware_info,
     const std::string& origin_url) {
   return new speech::SpeechRecognizerImpl(
-      delegate, caller_id, language, grammar, context_getter,
+      listener, caller_id, language, grammar, context_getter,
       filter_profanities, hardware_info, origin_url);
 }
 
 namespace speech {
 
 const int SpeechRecognizerImpl::kAudioSampleRate = 16000;
 const int SpeechRecognizerImpl::kAudioPacketIntervalMs = 100;
 const ChannelLayout SpeechRecognizerImpl::kChannelLayout = CHANNEL_LAYOUT_MONO;
 const int SpeechRecognizerImpl::kNumBitsPerAudioSample = 16;
 const int SpeechRecognizerImpl::kNoSpeechTimeoutSec = 8;
 const int SpeechRecognizerImpl::kEndpointerEstimationTimeMs = 300;
 
 SpeechRecognizerImpl::SpeechRecognizerImpl(
-    SpeechRecognizerDelegate* delegate,
+    SpeechRecognitionEventListener* listener,
     int caller_id,
     const std::string& language,
     const std::string& grammar,
     net::URLRequestContextGetter* context_getter,
     bool filter_profanities,
     const std::string& hardware_info,
     const std::string& origin_url)
-    : delegate_(delegate),
+    : listener_(listener),
       caller_id_(caller_id),
       language_(language),
       grammar_(grammar),
       filter_profanities_(filter_profanities),
       hardware_info_(hardware_info),
       origin_url_(origin_url),
       context_getter_(context_getter),
       codec_(AudioEncoder::CODEC_FLAC),
       encoder_(NULL),
       endpointer_(kAudioSampleRate),
@@ skipping 10 matching lines @@
 
 SpeechRecognizerImpl::~SpeechRecognizerImpl() {
   // Recording should have stopped earlier due to the endpointer or
   // |StopRecording| being called.
   DCHECK(!audio_controller_.get());
   DCHECK(!request_.get() || !request_->HasPendingRequest());
   DCHECK(!encoder_.get());
   endpointer_.EndSession();
 }
 
-bool SpeechRecognizerImpl::StartRecording() {
+bool SpeechRecognizerImpl::StartRecognition() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DCHECK(!audio_controller_.get());
   DCHECK(!request_.get() || !request_->HasPendingRequest());
   DCHECK(!encoder_.get());
 
   // The endpointer needs to estimate the environment/background noise before
   // starting to treat the audio as user input. In |HandleOnData| we wait until
   // such time has passed before switching to user input mode.
   endpointer_.SetEnvironmentEstimationMode();
 
   encoder_.reset(AudioEncoder::Create(codec_, kAudioSampleRate,
                                       kNumBitsPerAudioSample));
   int samples_per_packet = (kAudioSampleRate * kAudioPacketIntervalMs) / 1000;
   AudioParameters params(AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout,
                          kAudioSampleRate, kNumBitsPerAudioSample,
                          samples_per_packet);
   audio_controller_ = AudioInputController::Create(
       audio_manager_ ? audio_manager_ : BrowserMainLoop::GetAudioManager(),
       this, params);
   DCHECK(audio_controller_.get());
   VLOG(1) << "SpeechRecognizer starting record.";
   num_samples_recorded_ = 0;
   audio_controller_->Record();
 
   return true;
 }
 
-void SpeechRecognizerImpl::CancelRecognition() {
+void SpeechRecognizerImpl::AbortRecognition() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DCHECK(audio_controller_.get() || request_.get());
 
   // Stop recording if required.
   if (audio_controller_.get()) {
     CloseAudioControllerSynchronously();
   }
 
   VLOG(1) << "SpeechRecognizer canceling recognition.";
   encoder_.reset();
   request_.reset();
 }
 
-void SpeechRecognizerImpl::StopRecording() {
+void SpeechRecognizerImpl::StopAudioCapture() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   // If audio recording has already stopped and we are in recognition phase,
   // silently ignore any more calls to stop recording.
   if (!audio_controller_.get())
     return;
 
   CloseAudioControllerSynchronously();
 
-  delegate_->DidStopReceivingSpeech(caller_id_);
-  delegate_->DidCompleteRecording(caller_id_);
+  listener_->OnSoundEnd(caller_id_);
+  listener_->OnAudioEnd(caller_id_);
 
   // UploadAudioChunk requires a non-empty final buffer. So we encode a packet
   // of silence in case encoder had no data already.
   std::vector<short> samples((kAudioSampleRate * kAudioPacketIntervalMs) /
                              1000);
   AudioChunk dummy_chunk(reinterpret_cast<uint8*>(&samples[0]),
                          samples.size() * sizeof(short),
                          encoder_->bits_per_sample() / 8);
   encoder_->Encode(dummy_chunk);
   encoder_->Flush();
   scoped_ptr<AudioChunk> encoded_data(encoder_->GetEncodedDataAndClear());
   DCHECK(!encoded_data->IsEmpty());
   encoder_.reset();
 
   // If we haven't got any audio yet end the recognition sequence here.
   if (request_ == NULL) {
-    // Guard against the delegate freeing us until we finish our job.
+    // Guard against the listener freeing us until we finish our job.
     scoped_refptr<SpeechRecognizerImpl> me(this);
-    delegate_->DidCompleteRecognition(caller_id_);
+    listener_->OnRecognitionEnd(caller_id_);
   } else {
     request_->UploadAudioChunk(*encoded_data, true /* is_last_chunk */);
   }
 }
 
 // Invoked in the audio thread.
 void SpeechRecognizerImpl::OnError(AudioInputController* controller,
                                    int error_code) {
   BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
                          base::Bind(&SpeechRecognizerImpl::HandleOnError,
                                     this, error_code));
 }
 
 void SpeechRecognizerImpl::HandleOnError(int error_code) {
   LOG(WARNING) << "SpeechRecognizer::HandleOnError, code=" << error_code;
 
   // Check if we are still recording before canceling recognition, as
   // recording might have been stopped after this error was posted to the queue
   // by |OnError|.
   if (!audio_controller_.get())
     return;
 
-  InformErrorAndCancelRecognition(content::SPEECH_RECOGNITION_ERROR_AUDIO);
+  InformErrorAndAbortRecognition(content::SPEECH_RECOGNITION_ERROR_AUDIO);
 }
 
 void SpeechRecognizerImpl::OnData(AudioInputController* controller,
                                   const uint8* data, uint32 size) {
   if (size == 0)  // This could happen when recording stops and is normal.
     return;
   AudioChunk* raw_audio = new AudioChunk(data, static_cast<size_t>(size),
                                          kNumBitsPerAudioSample / 8);
   BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
                           base::Bind(&SpeechRecognizerImpl::HandleOnData,
@@ skipping 11 matching lines @@
   bool speech_was_heard_before_packet = endpointer_.DidStartReceivingSpeech();
 
   encoder_->Encode(*raw_audio);
   float rms;
   endpointer_.ProcessAudio(*raw_audio, &rms);
   bool did_clip = DetectClipping(*raw_audio);
   num_samples_recorded_ += raw_audio->NumSamples();
 
   if (request_ == NULL) {
     // This was the first audio packet recorded, so start a request to the
-    // server to send the data and inform the delegate.
-    delegate_->DidStartReceivingAudio(caller_id_);
+    // server to send the data and inform the listener.
+    listener_->OnAudioStart(caller_id_);
     request_.reset(new SpeechRecognitionRequest(context_getter_.get(), this));
     request_->Start(language_, grammar_, filter_profanities_,
                     hardware_info_, origin_url_, encoder_->mime_type());
   }
 
   scoped_ptr<AudioChunk> encoded_data(encoder_->GetEncodedDataAndClear());
   DCHECK(!encoded_data->IsEmpty());
   request_->UploadAudioChunk(*encoded_data, false /* is_last_chunk */);
 
   if (endpointer_.IsEstimatingEnvironment()) {
     // Check if we have gathered enough audio for the endpointer to do
     // environment estimation and should move on to detect speech/end of speech.
     if (num_samples_recorded_ >= (kEndpointerEstimationTimeMs *
                                   kAudioSampleRate) / 1000) {
       endpointer_.SetUserInputMode();
-      delegate_->DidCompleteEnvironmentEstimation(caller_id_);
+      listener_->OnEnvironmentEstimationComplete(caller_id_);
     }
     return;  // No more processing since we are still estimating environment.
   }
 
   // Check if we have waited too long without hearing any speech.
   bool speech_was_heard_after_packet = endpointer_.DidStartReceivingSpeech();
   if (!speech_was_heard_after_packet &&
       num_samples_recorded_ >= kNoSpeechTimeoutSec * kAudioSampleRate) {
-    InformErrorAndCancelRecognition(
+    InformErrorAndAbortRecognition(
         content::SPEECH_RECOGNITION_ERROR_NO_SPEECH);
     return;
   }
 
   if (!speech_was_heard_before_packet && speech_was_heard_after_packet)
-    delegate_->DidStartReceivingSpeech(caller_id_);
+    listener_->OnSoundStart(caller_id_);
 
   // Calculate the input volume to display in the UI, smoothing towards the
   // new level.
   float level = (rms - kAudioMeterMinDb) /
       (kAudioMeterDbRange / kAudioMeterRangeMaxUnclipped);
   level = std::min(std::max(0.0f, level), kAudioMeterRangeMaxUnclipped);
   if (level > audio_level_) {
     audio_level_ += (level - audio_level_) * kUpSmoothingFactor;
   } else {
     audio_level_ += (level - audio_level_) * kDownSmoothingFactor;
   }
 
   float noise_level = (endpointer_.NoiseLevelDb() - kAudioMeterMinDb) /
       (kAudioMeterDbRange / kAudioMeterRangeMaxUnclipped);
   noise_level = std::min(std::max(0.0f, noise_level),
       kAudioMeterRangeMaxUnclipped);
 
-  delegate_->SetInputVolume(caller_id_, did_clip ? 1.0f : audio_level_,
-                            noise_level);
+  listener_->OnAudioLevelsChange(caller_id_, did_clip ? 1.0f : audio_level_,
+                                 noise_level);
 
   if (endpointer_.speech_input_complete())
-    StopRecording();
+    StopAudioCapture();
 }
 
 void SpeechRecognizerImpl::SetRecognitionResult(
     const content::SpeechRecognitionResult& result) {
   if (result.error != content::SPEECH_RECOGNITION_ERROR_NONE) {
-    InformErrorAndCancelRecognition(result.error);
+    InformErrorAndAbortRecognition(result.error);
     return;
   }
 
-  // Guard against the delegate freeing us until we finish our job.
+  // Guard against the listener freeing us until we finish our job.
   scoped_refptr<SpeechRecognizerImpl> me(this);
-  delegate_->SetRecognitionResult(caller_id_, result);
-  delegate_->DidCompleteRecognition(caller_id_);
+  listener_->OnRecognitionResult(caller_id_, result);
+  listener_->OnRecognitionEnd(caller_id_);
 }
 
-void SpeechRecognizerImpl::InformErrorAndCancelRecognition(
+void SpeechRecognizerImpl::InformErrorAndAbortRecognition(
     content::SpeechRecognitionErrorCode error) {
   DCHECK_NE(error, content::SPEECH_RECOGNITION_ERROR_NONE);
-  CancelRecognition();
+  AbortRecognition();
 
-  // Guard against the delegate freeing us until we finish our job.
+  // Guard against the listener freeing us until we finish our job.
   scoped_refptr<SpeechRecognizerImpl> me(this);
-  delegate_->OnRecognizerError(caller_id_, error);
+  listener_->OnRecognitionError(caller_id_, error);
 }
 
 void SpeechRecognizerImpl::CloseAudioControllerSynchronously() {
   VLOG(1) << "SpeechRecognizer stopping record.";
 
   // TODO(satish): investigate the possibility to utilize the closure
   // and switch to async. version of this method. Compare with how
   // it's done in e.g. the AudioRendererHost.
   base::WaitableEvent closed_event(true, false);
   audio_controller_->Close(base::Bind(&base::WaitableEvent::Signal,
                            base::Unretained(&closed_event)));
   closed_event.Wait();
   audio_controller_ = NULL;  // Releases the ref ptr.
 }
 
 void SpeechRecognizerImpl::SetAudioManagerForTesting(
     AudioManager* audio_manager) {
   audio_manager_ = audio_manager;
 }
 
+bool SpeechRecognizerImpl::IsActive() const {
+  return (request_.get() != NULL);
+}
+
+bool SpeechRecognizerImpl::IsCapturingAudio() const {
+  return (audio_controller_.get() != NULL);
+}
+
 }  // namespace speech