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// Copyright (c) 2010 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.
#ifndef CHROME_BROWSER_SPEECH_SPEECH_RECOGNIZER_H_
#define CHROME_BROWSER_SPEECH_SPEECH_RECOGNIZER_H_
#include "base/ref_counted.h"
#include "base/scoped_ptr.h"
#include "media/audio/audio_input_controller.h"
#include "chrome/browser/speech/speech_recognition_request.h"
#include <list>
#include <string>
#include <utility>
namespace speech_input {
// Holds the details of a particular webkit element making a speech request.
// SpeechInputCallerId::first holds the ID of the render view and
// SpeechInputCallerId::second holds the request ID given by the element.
typedef std::pair<int, int> SpeechInputCallerId;
class SpeexEncoder;
// Records audio, sends recorded audio to server and translates server response
// to recognition result.
class SpeechRecognizer
: public base::RefCountedThreadSafe<SpeechRecognizer>,
public media::AudioInputController::EventHandler,
public SpeechRecognitionRequestDelegate {
public:
// Implemented by the caller to receive recognition events.
class Delegate {
public:
virtual void SetRecognitionResult(const SpeechInputCallerId& caller_id,
bool error,
const string16& value) = 0;
// Invoked when audio recording stops, either due to the end pointer
// detecting silence in user input or if |StopRecording| was called. The
// delegate has to wait until |DidCompleteRecognition| is invoked before
// destroying the |SpeechRecognizer| object.
virtual void DidCompleteRecording(const SpeechInputCallerId& caller_id) = 0;
// This is guaranteed to be the last method invoked in the recognition
// sequence and the |SpeechRecognizer| object can be freed up if necessary.
virtual void DidCompleteRecognition(
const SpeechInputCallerId& caller_id) = 0;
protected:
virtual ~Delegate() {}
};
SpeechRecognizer(Delegate* delegate, const SpeechInputCallerId& caller_id);
~SpeechRecognizer();
// Starts audio recording and does recognition after recording ends. The same
// SpeechRecognizer instance can be used multiple times for speech recognition
// though each recognition request can be made only after the previous one
// completes (i.e. after receiving Delegate::DidCompleteRecognition).
bool StartRecording();
// Stops recording audio and starts recognition.
void StopRecording();
// Stops recording audio and cancels recognition. Any audio recorded so far
// gets discarded.
void CancelRecognition();
// AudioInputController::EventHandler methods.
void OnCreated(media::AudioInputController* controller) { }
void OnRecording(media::AudioInputController* controller) { }
void OnError(media::AudioInputController* controller, int error_code);
void OnData(media::AudioInputController* controller, const uint8* data,
uint32 size);
// SpeechRecognitionRequest::Delegate methods.
void SetRecognitionResult(bool error, const string16& value);
private:
void ReleaseAudioBuffers();
void HandleOnError(int error_code); // Handles OnError in the IO thread.
// Handles OnData in the IO thread. Takes ownership of |data|.
void HandleOnData(std::string* data);
Delegate* delegate_;
SpeechInputCallerId caller_id_;
// Buffer holding the recorded audio. Owns the strings inside the list.
typedef std::list<std::string*> AudioBufferQueue;
AudioBufferQueue audio_buffers_;
scoped_ptr<SpeechRecognitionRequest> request_;
scoped_refptr<media::AudioInputController> audio_controller_;
scoped_ptr<SpeexEncoder> encoder_;
DISALLOW_COPY_AND_ASSIGN(SpeechRecognizer);
};
// This typedef is to workaround the issue with certain versions of
// Visual Studio where it gets confused between multiple Delegate
// classes and gives a C2500 error. (I saw this error on the try bots -
// the workaround was not needed for my machine).
typedef SpeechRecognizer::Delegate SpeechRecognizerDelegate;
} // namespace speech_input
#endif // CHROME_BROWSER_SPEECH_SPEECH_RECOGNIZER_H_
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