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   // Speak the given utterance with the given parameters if possible,
  22   // and return true on success. Utterance will always be nonempty.
  23   // If rate, pitch, or volume are -1.0, they will be ignored.
  24   //
  25   // The TtsController will only try to speak one utterance at
  26   // a time. If it wants to interrupt speech, it will always call Stop
  27   // before speaking again.
  28   virtual bool Speak(
  29       int utterance_id,
  30       const std::string& utterance,
  31       const std::string& lang,
  32       const VoiceData& voice,
  33       const UtteranceContinuousParameters& params) = 0;
  34
  35   // Stop speaking immediately and return true on success.
  36   virtual bool StopSpeaking() = 0;
  37
  38   // Returns whether any speech is on going.
  39   virtual bool IsSpeaking() = 0;
  40
  41   // Append information about voices provided by this platform implementation
  42   // to |out_voices|.
  43   virtual void GetVoices(std::vector<VoiceData>* out_voices) = 0;
  44
  45   // Pause the current utterance, if any, until a call to Resume,
  46   // Speak, or StopSpeaking.
  47   virtual void Pause() = 0;
  48
  49   // Resume speaking the current utterance, if it was paused.
  50   virtual void Resume() = 0;
  51
  52   // Allows the platform to monitor speech commands and the voices used
  53   // for each one.
  54   virtual void WillSpeakUtteranceWithVoice(const Utterance* utterance,
  55                                            const VoiceData& voice_data);
  56
  57   virtual std::string error();
  58   virtual void clear_error();
  59   virtual void set_error(const std::string& error);
  60
  61  protected:
  62   TtsPlatformImpl() {}
  63
  64   // On some platforms this may be a leaky singleton - do not rely on the
  65   // destructor being called!  http://crbug.com/122026
  66   virtual ~TtsPlatformImpl() {}
  67
  68   std::string error_;
  69
  70   DISALLOW_COPY_AND_ASSIGN(TtsPlatformImpl);
  71 };
  72
  73 #endif  // CHROME_BROWSER_SPEECH_TTS_PLATFORM_H_