Speech refactoring: Reimplemented SpeechRecognitionManagerImpl as a FSM. (CL1.7)

content/public/browser/speech_recognition_manager.h

 // 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_PUBLIC_BROWSER_SPEECH_RECOGNITION_MANAGER_H_
 #define CONTENT_PUBLIC_BROWSER_SPEECH_RECOGNITION_MANAGER_H_
 
 #include "base/string16.h"
+#include "base/callback.h"
 #include "content/common/content_export.h"
+#include "content/public/common/speech_recognition_result.h"
 
 namespace content {
 
-// This is the gatekeeper for speech recognition in the browser process. It
-// handles requests received from various render views and makes sure only one
-// of them can use speech recognition at a time. It also sends recognition
-// results and status events to the render views when required.
+class SpeechRecognitionEventListener;
+struct SpeechRecognitionSessionConfig;
+struct SpeechRecognitionSessionContext;
+
+// The SpeechRecognitionManager (SRM) is a singleton class that handles SR
+// functionalities within Chrome. Everyone that needs to perform SR should
+// interface exclusively with the SRM, receiving events through the callback
+// interface SpeechRecognitionEventListener.
+// Since many different sources can use SR in different times (some overlapping
+// is allowed while waiting for results), the SRM has the further responsibility
+// of handling separately and reliably (taking into account also call sequences
+// that might not make sense, e.g., two subsequent AbortSession calls).
+// In this sense a session, within the SRM, models the ongoing evolution of a
+// SR request from the viewpoint of the end-user, abstracting all the concrete
+// operations that must be carried out, that will be handled by inner classes.
 class SpeechRecognitionManager {
  public:
+  static const int kSessionIDInvalid;
+
   // Returns the singleton instance.
-  CONTENT_EXPORT static SpeechRecognitionManager* GetInstance();
+  static CONTENT_EXPORT SpeechRecognitionManager* GetInstance();
 
-  // Starts/restarts recognition for an existing request.
-  virtual void StartRecognitionForRequest(int session_id) = 0;
+  // Creates a new recognition session.
+  virtual int CreateSession(const SpeechRecognitionSessionConfig& config,
+                            SpeechRecognitionEventListener* listener) = 0;
 
-  // Cancels recognition for an existing request.
-  virtual void CancelRecognitionForRequest(int session_id) = 0;
+  // Starts/restarts recognition for an existing session, after performing a
+  // premilinary check on the delegate (CheckRecognitionIsAllowed).
+  virtual void StartSession(int session_id) = 0;
 
-  // Called when the user clicks outside the speech input UI causing it to close
-  // and possibly have speech input go to another element.
-  virtual void FocusLostForRequest(int session_id) = 0;
+  // Aborts recognition for an existing session, without providing any result.
+  virtual void AbortSession(int session_id) = 0;
+
+  // Aborts all sessions for a given listener, without providing any result.
+  virtual void AbortAllSessionsForListener(
+      SpeechRecognitionEventListener* listener) = 0;
+
+  // Stops audio capture for an existing session. The audio captured before the
+  // call will be processed, possibly ending up with a result.
+  virtual void StopAudioCaptureForSession(int session_id) = 0;
+
+  // Sends the session to background preventing it from further interacting with
+  // the browser (typically invoked when the user clicks outside the speech UI).
+  // The session will be silently continued in background if possible (in case
+  // it already finished capturing audio and was just waiting for the result) or
+  // will be aborted if user interaction (e.g., audio recording) was involved
+  // when this function was called.
+  virtual void SendSessionToBackground(int session_id) = 0;
+
+  // Retrieves the context associated to a session.
+  virtual SpeechRecognitionSessionContext GetSessionContext(
+      int session_id) const = 0;
+
+  // Looks-up an existing session using a caller-provided matcher function.
+  virtual int LookupSessionByContext(
+      base::Callback<bool(
+          const content::SpeechRecognitionSessionContext&)> matcher)
+            const = 0;
 
   // Returns true if the OS reports existence of audio recording devices.
   virtual bool HasAudioInputDevices() = 0;
 
   // Used to determine if something else is currently making use of audio input.
   virtual bool IsCapturingAudio() = 0;
 
   // Returns a human readable string for the model/make of the active audio
   // input device for this computer.
   virtual string16 GetAudioInputDeviceModel() = 0;
 
   // Invokes the platform provided microphone settings UI in a non-blocking way,
   // via the BrowserThread::FILE thread.
   virtual void ShowAudioInputSettings() = 0;
 
  protected:
    virtual ~SpeechRecognitionManager() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_SPEECH_RECOGNITION_MANAGER_H_