chrome/browser/speech/tts_platform.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_BROWSER_SPEECH_TTS_PLATFORM_H_
   6 #define CHROME_BROWSER_SPEECH_TTS_PLATFORM_H_
   7
   8 #include <string>
   9
  10 #include "chrome/browser/speech/tts_controller.h"
  11
  12 // Abstract class that defines the native platform TTS interface,
  13 // subclassed by specific implementations on Win, Mac, etc.
  14 class TtsPlatformImpl {
  15  public:
  16   static TtsPlatformImpl* GetInstance();
  17
  18   // Returns true if this platform implementation is supported and available.
  19   virtual bool PlatformImplAvailable() = 0;
  20
  21   // Some platforms may provide a built-in TTS extension. Returns true
  22   // if the extension was not previously loaded and is now loading, and
  23   // false if it's already loaded or if there's no extension to load.
  24   // Will call TtsController::RetrySpeakingQueuedUtterances when
  25   // the extension finishes loading.
  26   virtual bool LoadBuiltInTtsExtension(Profile* profile);
  27
  28   // Speak the given utterance with the given parameters if possible,
  29   // and return true on success. Utterance will always be nonempty.
  30   // If rate, pitch, or volume are -1.0, they will be ignored.
  31   //
  32   // The TtsController will only try to speak one utterance at
  33   // a time. If it wants to interrupt speech, it will always call Stop
  34   // before speaking again.
  35   virtual bool Speak(
  36       int utterance_id,
  37       const std::string& utterance,
  38       const std::string& lang,
  39       const UtteranceContinuousParameters& params) = 0;
  40
  41   // Stop speaking immediately and return true on success.
  42   virtual bool StopSpeaking() = 0;
  43
  44   // Returns whether any speech is on going.
  45   virtual bool IsSpeaking() = 0;
  46
  47   // Return true if this platform implementation will fire the given event.
  48   // All platform implementations must fire the TTS_EVENT_END event at a
  49   // minimum.
  50   virtual bool SendsEvent(TtsEventType event_type) = 0;
  51
  52   // Return the gender of the voice, should be either "male" or "female"
  53   // if known, otherwise the empty string.
  54   virtual std::string gender();
  55
  56   virtual std::string error();
  57   virtual void clear_error();
  58   virtual void set_error(const std::string& error);
  59
  60  protected:
  61   TtsPlatformImpl() {}
  62
  63   // On some platforms this may be a leaky singleton - do not rely on the
  64   // destructor being called!  http://crbug.com/122026
  65   virtual ~TtsPlatformImpl() {}
  66
  67   std::string error_;
  68
  69   DISALLOW_COPY_AND_ASSIGN(TtsPlatformImpl);
  70 };
  71
  72 #endif  // CHROME_BROWSER_SPEECH_TTS_PLATFORM_H_