Introducing the basic functionality to the speech input experimental API.

chrome/browser/extensions/extension_speech_input_manager.h

 // Copyright (c) 2011 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_EXTENSIONS_EXTENSION_SPEECH_INPUT_MANAGER_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SPEECH_INPUT_MANAGER_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/singleton.h"
+#include "base/synchronization/lock.h"
+#include "content/browser/speech/speech_recognizer.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
+#include "content/common/speech_input_result.h"
 #include <string>
 
 class Extension;
 class NotificationDetails;
 class NotificationSource;
 class Profile;
 
+namespace net {
+class URLRequestContextGetter;
+}
+
 // Manages the speech input requests and responses from the extensions
 // associated to the given profile.
 class ExtensionSpeechInputManager : public NotificationObserver,
-    public base::RefCountedThreadSafe<ExtensionSpeechInputManager> {
+    public base::RefCountedThreadSafe<ExtensionSpeechInputManager>,
+    public speech_input::SpeechRecognizerDelegate {
  public:
+  enum State {
+    kIdle = 0,
+    kStarting,
+    kRecording,
+    kStopping,
+    kShutdown // Internal sink state when the profile is destroyed on shutdown.
+  };
+
+  // Structure containing the details of the speech input failed notification.
+  struct ExtensionError {
+    const std::string& extension_id_;

[Satish, 2011/10/11 13:37:16]

these shouldn't be a reference as they'll point to invalid objects once the
calling code goes out of scope

[Leandro Graciá Gil, 2011/10/11 18:08:00]

Used references because the notification is synchronous. In any case, it's safer
to do as you suggest. Fixed.

On 2011/10/11 13:37:16, Satish wrote:

+    const std::string& error_;
+
+    ExtensionError(const std::string& extension_id, const std::string& error)
+        : extension_id_(extension_id), error_(error) {}
+  };
+
   // Should not be used directly. Managed by a ProfileKeyedServiceFactory.
   explicit ExtensionSpeechInputManager(Profile* profile);
 
   // Returns the corresponding manager for the given profile, creating
   // a new one if required.
   static ExtensionSpeechInputManager* GetForProfile(Profile* profile);
 
   // Initialize the ProfileKeyedServiceFactory.
   static void InitializeFactory();
 
+  // Request to start speech recognition for the provided extension.
+  bool Start(const std::string& extension_id,
+             const std::string& language,
+             const std::string& grammar,
+             bool filter_profanities,
+             std::string* error);
+
+  // Request to stop an ongoing speech recognition.
+  bool Stop(const std::string& extension_id, std::string* error);
+
+  // Retrieve the actual state of the API manager.
+  State state() const { return state_; }
+
+  // Called by internal ProfileKeyedService class.
+  void ShutdownOnUIThread();
+
   // Methods from NotificationObserver.
   virtual void Observe(int type,
                        const NotificationSource& source,
-                       const NotificationDetails& details);
+                       const NotificationDetails& details) OVERRIDE;
 
-  // Request to start speech recognition for the provided extension.
-  void Start(const Extension *extension);
+  // Methods from SpeechRecognizerDelegate.
+  virtual void SetRecognitionResult(
+      int caller_id,
+      const speech_input::SpeechInputResult& result) OVERRIDE;
 
-  // Request to stop an ongoing speech recognition.
-  void Stop(const Extension *extension);
-
-  // Called by internal ProfileKeyedService class.
-  void ShutdownOnUIThread();
+  virtual void DidStartReceivingAudio(int caller_id) OVERRIDE;
+  virtual void DidCompleteRecording(int caller_id) OVERRIDE;
+  virtual void DidCompleteRecognition(int caller_id) OVERRIDE;
+  virtual void DidStartReceivingSpeech(int caller_id) OVERRIDE;
+  virtual void DidStopReceivingSpeech(int caller_id) OVERRIDE;
+  virtual void OnRecognizerError(int caller_id,
+                                 speech_input::SpeechInputError error)
+                                 OVERRIDE;
+  virtual void DidCompleteEnvironmentEstimation(int caller_id) OVERRIDE;
+  virtual void SetInputVolume(int caller_id, float volume,
+                              float noise_volume) OVERRIDE {}
 
  private:
-  void ExtensionUnloaded(const std::string& id);
+  void StartOnIOThread(
+      net::URLRequestContextGetter* context_getter,
+      const std::string& language,
+      const std::string& grammar,
+      bool filter_profanities);
+  void ForceStopOnIOThread();
+
+  void SetRecognitionResultOnUIThread(
+      const speech_input::SpeechInputResult& result);
+  void DidStartReceivingAudioOnUIThread();
+  void StopSucceededOnUIThread();
+
+  void DispatchError(const std::string& error);
+  void DispatchEventToExtension(const std::string& event,
+                                const std::string& json_args);
+  void ExtensionUnloaded(const std::string& extension_id);
+
+  virtual ~ExtensionSpeechInputManager();
 
   friend class base::RefCountedThreadSafe<ExtensionSpeechInputManager>;
   class Factory;
 
-  virtual ~ExtensionSpeechInputManager();
+  // Since only one extension can be recording on the same time a constant
+  // value is enough as id.
+  static const int kSpeechCallerId = 1;

[Satish, 2011/10/11 13:37:16]

suggest moving this to the anonymous namespace in the .cc file, its an
implementation detail that users of this class shouldn't care about

[Leandro Graciá Gil, 2011/10/11 18:08:00]

Done.

 
+  // Lock used to allow exclusive access to the state variable and methods that
+  // either read or write on it. This is required since the speech code
+  // operates in the IO thread while the extension code uses the UI thread.
+  base::Lock state_lock_;
+
+  // Used in the UI thread but also its raw value as notification
+  // source in the IO thread, guarded by the state lock and value.
   Profile* profile_;
-  scoped_refptr<Extension> extension_;
+
+  // Used in both threads, guarded by the state lock.
+  State state_;
+  std::string extension_id_in_use_;
+
+  // Used in the UI thread.
   NotificationRegistrar registrar_;
+
+  // Used in the IO thread. Checked on the UI thread under the state lock.
+  scoped_refptr<speech_input::SpeechRecognizer> recognizer_;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SPEECH_INPUT_MANAGER_H_