Implement "Language Switcher" for Chromium OS.

chrome/browser/chromeos/language_library.cc

+// Copyright (c) 2009 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/chromeos/language_library.h"
+
+#include "base/message_loop.h"
+#include "base/string_util.h"
+#include "chrome/browser/chrome_thread.h"
+#include "chrome/browser/chromeos/cros_library.h"
+
+// Allows InvokeLater without adding refcounting. This class is a Singleton and
+// won't be deleted until it's last InvokeLater is run.
+template <>
+struct RunnableMethodTraits<chromeos::LanguageLibrary> {
+  void RetainCallee(chromeos::LanguageLibrary* obj) {}
+  void ReleaseCallee(chromeos::LanguageLibrary* obj) {}
+};
+
+namespace chromeos {
+
+LanguageLibrary::LanguageLibrary() : language_status_connection_(NULL) {
+  if (EnsureLoaded()) {
+    Init();
+  }
+}
+
+LanguageLibrary::~LanguageLibrary() {
+  if (EnsureLoaded()) {
+    chromeos::DisconnectLanguageStatus(language_status_connection_);
+  }
+}
+
+LanguageLibrary::Observer::~Observer() {
+}
+
+// static
+LanguageLibrary* LanguageLibrary::Get() {
+  return Singleton<LanguageLibrary>::get();
+}
+
+// static
+bool LanguageLibrary::EnsureLoaded() {
+  return CrosLibrary::EnsureLoaded();
+}
+
+void LanguageLibrary::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void LanguageLibrary::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+chromeos::InputLanguageList* LanguageLibrary::GetLanguages() {
+  chromeos::InputLanguageList* result = NULL;
+  if (EnsureLoaded()) {
+    result = chromeos::GetLanguages(language_status_connection_);
+  }
+  return result ? result : CreateFallbackInputLanguageList();
+}
+
+void LanguageLibrary::ChangeLanguage(
+    LanguageCategory category, const std::string& id) {
+  if (EnsureLoaded()) {
+    chromeos::ChangeLanguage(language_status_connection_, category, id.c_str());
+  }
+}
+
+// static
+void LanguageLibrary::LanguageChangedHandler(
+    void* object, const chromeos::InputLanguage& current_language) {
+  LanguageLibrary* language_library = static_cast<LanguageLibrary*>(object);
+  language_library->UpdateCurrentLanguage(current_language);
+}
+
+void LanguageLibrary::Init() {
+  language_status_connection_ = chromeos::MonitorLanguageStatus(
+      &LanguageChangedHandler, this);
+}
+
+void LanguageLibrary::UpdateCurrentLanguage(
+    const chromeos::InputLanguage& current_language) {
+  // Make sure we run on UI thread.
+  if (!ChromeThread::CurrentlyOn(ChromeThread::UI)) {
+    DLOG(INFO) << "UpdateCurrentLanguage (Background thread)";
+    ChromeThread::PostTask(
+        ChromeThread::UI, FROM_HERE,
+        // NewRunnableMethod() copies |current_language| by value.
+        NewRunnableMethod(
+            this, &LanguageLibrary::UpdateCurrentLanguage, current_language));
+    return;
+  }
+
+  DLOG(INFO) << "UpdateCurrentLanguage (UI thread)";
+  current_language_ = current_language;
+  FOR_EACH_OBSERVER(Observer, observers_, LanguageChanged(this));
+}
+
+}  // namespace chromeos