Refactored TTS extension code so that the platform-specific TTS...

chrome/browser/extensions/extension_tts_api_chromeos.cc

+// Copyright (c) 2010 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.
+
+#include "chrome/browser/extensions/extension_tts_api.h"
+
+#include "base/singleton.h"
+#include "chrome/browser/chromeos/cros/cros_library.h"
+#include "chrome/browser/chromeos/cros/speech_synthesis_library.h"
+
+namespace util = extension_tts_api_util;
+
+namespace {
+const char kCrosLibraryNotLoadedError[] = "Cros shared library not loaded.";
+};
+
+class ExtensionTtsPlatformImplChromeOs : public ExtensionTtsPlatformImpl {
+ public:
+  virtual bool Speak(
+      const std::string& utterance,
+      const std::string& language,
+      const std::string& gender,
+      double rate,
+      double pitch,
+      double volume);
+
+  virtual bool StopSpeaking();
+
+  virtual bool IsSpeaking();
+
+  // Get the single instance of this class.
+  static ExtensionTtsPlatformImplChromeOs* GetInstance();
+
+ private:
+  ExtensionTtsPlatformImplChromeOs() {}
+  virtual ~ExtensionTtsPlatformImplChromeOs() {}
+
+  friend struct DefaultSingletonTraits<ExtensionTtsPlatformImplChromeOs>;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionTtsPlatformImplChromeOs);
+};
+
+// static
+ExtensionTtsPlatformImpl* ExtensionTtsPlatformImpl::GetInstance() {
+  return ExtensionTtsPlatformImplChromeOs::GetInstance();
+}
+
+bool ExtensionTtsPlatformImplChromeOs::Speak(
+    const std::string& utterance,
+    const std::string& language,
+    const std::string& gender,
+    double rate,
+    double pitch,
+    double volume) {
+  chromeos::CrosLibrary* cros_library = chromeos::CrosLibrary::Get();
+  if (!cros_library->EnsureLoaded()) {
+    set_error(kCrosLibraryNotLoadedError);
+    return false;
+  }
+
+  std::string options;
+
+  if (!language.empty()) {
+    util::AppendSpeakOption(
+        std::string(util::kNameKey), language, &options);
+  }
+
+  if (!gender.empty()) {
+    util::AppendSpeakOption(
+        std::string(util::kGenderKey), gender, &options);
+  }
+
+  if (rate >= 0.0) {
+    util::AppendSpeakOption(
+        std::string(util::kRateKey), DoubleToString(rate * 5), &options);
+  }
+
+  if (pitch >= 0.0) {
+    // The TTS service allows a range of 0 to 2 for speech pitch.
+    util::AppendSpeakOption(
+        std::string(util::kPitchKey), DoubleToString(pitch * 2), &options);
+  }
+
+  if (volume >= 0.0) {
+    // The TTS service allows a range of 0 to 5 for speech volume.
+    util::AppendSpeakOption(
+        std::string(util::kVolumeKey), DoubleToString(volume * 5), &options);
+  }
+
+  if (!options.empty()) {
+    cros_library->GetSpeechSynthesisLibrary()->SetSpeakProperties(
+        options.c_str());
+  }
+
+  return cros_library->GetSpeechSynthesisLibrary()->Speak(utterance.c_str());
+}
+
+bool ExtensionTtsPlatformImplChromeOs::StopSpeaking() {
+  if (chromeos::CrosLibrary::Get()->EnsureLoaded()) {
+    return chromeos::CrosLibrary::Get()->GetSpeechSynthesisLibrary()->
+        StopSpeaking();
+  }
+
+  set_error(kCrosLibraryNotLoadedError);
+  return false;
+}
+
+bool ExtensionTtsPlatformImplChromeOs::IsSpeaking() {
+  if (chromeos::CrosLibrary::Get()->EnsureLoaded()) {
+    return chromeos::CrosLibrary::Get()->GetSpeechSynthesisLibrary()->
+        IsSpeaking();
+  }
+
+  set_error(kCrosLibraryNotLoadedError);
+  return false;
+}
+
+// static
+ExtensionTtsPlatformImplChromeOs*
+ExtensionTtsPlatformImplChromeOs::GetInstance() {
+  return Singleton<ExtensionTtsPlatformImplChromeOs>::get();
+}