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// Copyright 2017 The Cobalt Authors. All Rights Reserved.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
#include <memory>
#include <string>
#include <vector>
#include "base/threading/thread.h"
#include "cobalt/loader/url_fetcher_string_writer.h"
#include "cobalt/media/base/audio_bus.h"
#include "cobalt/network/network_module.h"
#include "cobalt/speech/audio_encoder_flac.h"
#include "cobalt/speech/google_streaming_api.pb.h"
#include "cobalt/speech/speech_recognition_config.h"
#include "cobalt/speech/speech_recognition_event.h"
#include "content/browser/speech/chunked_byte_buffer.h"
#include "net/url_request/url_fetcher.h"
#include "net/url_request/url_fetcher_delegate.h"
namespace cobalt {
namespace speech {
// Interacts with Google speech recognition service, and then parses recognition
// results and forms speech recognition event.
// It creates an upstream fetcher to upload the encoded audio and a downstream
// fetcher to fetch the speech recognition result. The fetched speech
// recognition result is parsed by JSON parser and a SpeechRecognitionEvent,
// is formed based on the parsed result, would be sent to speech recognition
// manager.
class GoogleSpeechService : public net::URLFetcherDelegate {
typedef media::AudioBus AudioBus;
typedef base::Callback<void(const scoped_refptr<dom::Event>&)> EventCallback;
typedef SpeechRecognitionResultList::SpeechRecognitionResults
typedef base::Callback<std::unique_ptr<net::URLFetcher>(
const GURL&, net::URLFetcher::RequestType, net::URLFetcherDelegate*)>
GoogleSpeechService(network::NetworkModule* network_module,
const EventCallback& event_callback,
const URLFetcherCreator& fetcher_creator);
~GoogleSpeechService() override;
// Multiple calls to Start/Stop are allowed, the implementation should take
// care of multiple calls.
// Start speech recognizer.
void Start(const SpeechRecognitionConfig& config, int sample_rate);
// Stop speech recognizer.
void Stop();
// An encoded audio data is available and ready to be recognized.
void RecognizeAudio(std::unique_ptr<AudioBus> audio_bus, bool is_last_chunk);
// net::URLFetcherDelegate interface
void OnURLFetchDownloadProgress(const net::URLFetcher* source,
int64_t current, int64_t total,
int64_t current_network_bytes) override;
void OnURLFetchComplete(const net::URLFetcher* source) override;
void OnURLFetchUploadProgress(const net::URLFetcher* source, int64 current,
int64 total) override {}
static base::Optional<std::string> GetSpeechAPIKey();
void StartInternal(const SpeechRecognitionConfig& config, int sample_rate);
void StopInternal();
// This method handles wrappables and should run on the MainWebModule thread.
void ClearFinalResults();
void UploadAudioDataInternal(std::unique_ptr<AudioBus> audio_bus,
bool is_last_chunk);
// This method handles wrappables, and so it must run on the MainWebModule.
void ProcessAndFireSuccessEvent(proto::SpeechRecognitionEvent event);
// This is used for creating fetchers.
network::NetworkModule* network_module_;
// Track the start/stop state of speech recognizer.
bool started_;
// Encoder for encoding raw audio data to flac codec.
std::unique_ptr<AudioEncoderFlac> encoder_;
// Fetcher for posting the audio data.
std::unique_ptr<net::URLFetcher> upstream_fetcher_;
// Fetcher for receiving the streaming results.
std::unique_ptr<net::URLFetcher> downstream_fetcher_;
// Used to send speech recognition event.
const EventCallback event_callback_;
// Used to create url fetcher.
const URLFetcherCreator fetcher_creator_;
// Used for processing proto buffer data.
content::ChunkedByteBuffer chunked_byte_buffer_;
// Used for accumulating final results.
SpeechRecognitionResults final_results_;
// Speech recognizer is operating in its own thread.
base::Thread thread_;
// Stores fetched response.
loader::URLFetcherStringWriter* download_data_writer_ = nullptr;
// Use a task runner to deal with all wrappables.
base::WeakPtrFactory<GoogleSpeechService> weak_ptr_factory_;
base::WeakPtr<GoogleSpeechService> weak_this_;
scoped_refptr<base::SingleThreadTaskRunner> const wrappables_task_runner_;
} // namespace speech
} // namespace cobalt