Refactoring of chrome speech recognition architecture (CL1.3)

content/browser/speech/google_ssfe_remote_engine.h

Index: content/browser/speech/google_ssfe_remote_engine.h
diff --git a/content/browser/speech/google_ssfe_remote_engine.h b/content/browser/speech/google_ssfe_remote_engine.h
new file mode 100644
index 0000000000000000000000000000000000000000..de58b6c79d576b1e013130f539ae55a99e93daaa
--- /dev/null
+++ b/content/browser/speech/google_ssfe_remote_engine.h
@@ -0,0 +1,84 @@
+// 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.
+
+#ifndef CONTENT_BROWSER_SPEECH_GOOGLE_SSFE_REMOTE_ENGINE_H_
+#define CONTENT_BROWSER_SPEECH_GOOGLE_SSFE_REMOTE_ENGINE_H_
+#pragma once
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/browser/speech/audio_encoder.h"
+#include "content/browser/speech/speech_recognition_engine.h"
+#include "content/common/content_export.h"
+#include "content/public/common/url_fetcher_delegate.h"
+#include "googleurl/src/gurl.h"
+
+class URLFetcher;
+
+namespace content {
+struct SpeechRecognitionResult;
+}
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace speech {
+
+class AudioChunk;
+
+struct GoogleSSFERemoteEngineConfig {
+  std::string language;
+  std::string grammar;
+  bool filter_profanities;
+  std::string hardware_info;
+  std::string origin_url;
+  int audio_sample_rate;
+  int audio_num_bits_per_sample;

[Satish, 2012/03/16 17:00:35]

could add a newline below this

[Primiano Tucci (use gerrit), 2012/03/20 13:14:50]

Done.

+  GoogleSSFERemoteEngineConfig();
+  ~GoogleSSFERemoteEngineConfig();
+};
+
+// Implements a SpeechRecognitionEngine by means of remote interaction with
+// Google Speech Server Front End (SSFE) webservice, according to the HTTP-based
+// protocol defined in Google Speech API 1.3.2.
+class GoogleSSFERemoteEngine : public SpeechRecognitionEngine,

[Satish, 2012/03/16 17:00:35]

I don't think SSFERemoteEngine is a good name for the class and file. Can you
use a different name, e.g. GoogleOneShotRecognitionEngine since this performs
recognition only after all the audio has been given? Please update comment above
accordingly

+                               public content::URLFetcherDelegate {
+ public:
+  // Duration of each audio packet.
+  static const int kAudioPacketIntervalMs;

[Satish, 2012/03/16 17:00:35]

are these statics used outside this class? If not, suggest moving to the .cc
file into an anonymous namespace

[Primiano Tucci (use gerrit), 2012/03/20 13:14:50]

Yes, they are needed by the recognizer unittest.

+  // ID passed to URLFetcher::Create(). Used for testing.
+  static int url_fetcher_id_for_tests;
+
+  explicit GoogleSSFERemoteEngine(net::URLRequestContextGetter* context);
+  void SetConfiguration(const GoogleSSFERemoteEngineConfig& config);

[Satish, 2012/03/16 17:00:35]

suggest moving this below the constructor/destructor pair

[Primiano Tucci (use gerrit), 2012/03/20 13:14:50]

Done.

+  virtual ~GoogleSSFERemoteEngine();
+
+  // SpeechRecognitionEngine methods.
+  virtual void SpeechRecognitionBegins() OVERRIDE;
+  virtual void SpeechRecognitionEnds() OVERRIDE;
+  virtual void PushSpeechAudio(const AudioChunk& data) OVERRIDE;
+  virtual void SpeechAudioStreamComplete() OVERRIDE;
+  virtual bool IsRecognitionPending() const OVERRIDE;
+  virtual int DesiredAudioChunkDurationMs() const OVERRIDE;
+
+  // content::URLFetcherDelegate methods.
+  virtual void OnURLFetchComplete(const content::URLFetcher* source) OVERRIDE;
+
+ private:
+  GoogleSSFERemoteEngineConfig config_;
+  scoped_ptr<content::URLFetcher> url_fetcher_;
+  scoped_refptr<net::URLRequestContextGetter> url_context_;
+  AudioEncoder::Codec codec_;

[Satish, 2012/03/16 17:00:35]

is this member required since it is hardcodec to FLAC? You could remove it now
and if necessary to switch between codecs add later

[Primiano Tucci (use gerrit), 2012/03/20 13:14:50]

Moved to a constant into the anonymous namespace (in the corresponding .cc
file).

+  scoped_ptr<AudioEncoder> encoder_;
+
+  DISALLOW_COPY_AND_ASSIGN(GoogleSSFERemoteEngine);
+};
+
+}  // namespace speech
+
+#endif  // CONTENT_BROWSER_SPEECH_GOOGLE_SSFE_REMOTE_ENGINE_H_