MD Settings: Languages model for language pages

chrome/browser/resources/settings/languages_page/languages.js

Index: chrome/browser/resources/settings/languages_page/languages.js
diff --git a/chrome/browser/resources/settings/languages_page/languages.js b/chrome/browser/resources/settings/languages_page/languages.js
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+// Copyright 2015 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.
+
+/**
+ * @fileoverview 'cr-settings-languages' provides convenient access to
+ * Chrome's language and input method settings.
+ *
+ * Instances of this element have a 'languages' property, which reflects the
+ * current language settings. The 'languages' property is read-only, meaning
+ * hosts using this element cannot change it directly. Instead, changes to
+ * language settings should be made using this element's public functions.
+ *
+ * Use two-way binding syntax to propagate changes from child to host, so that
+ * changes made internally to 'languages' propagate to your host element:
+ *
+ *     <template>
+ *       <cr-settings-languages languages="{{languages}}">
+ *       </cr-settings-languages>
+ *       <div>[[languages.someProperty]]</div>
+ *     </template>
+ *
+ * @group Chrome Settings Elements
+ * @element cr-settings-languages
+ */
+
+/** @typedef {{spellCheckEnabled: boolean}} */
+var LanguageState;
+
+/**
+ * @typedef {{language: !chrome.languageSettingsPrivate.Language,
+ *            state: !LanguageState}}
+ */
+var LanguageInfo;
+
+/**
+ * supportedLanguages: an array of languages, ordered alphabetically.
+ * enabledLanguages: an array of enabled language info and state, ordered by
+ *     preference.
+ * @typedef {{
+ *      supportedLanguages: !Array<!chrome.languageSettingsPrivate.Language>,
+ *      enabledLanguages: !Array<!LanguageInfo>
+ *  }}
+ */
+var LanguagesModel;
+
+(function() {
+'use strict';
+
+/**
+ * This element has a reference to the singleton, exposing the singleton's
+ * language model to the host of this element as the 'languages' property.
+ */
+Polymer({
+  is: 'cr-settings-languages',
+
+  properties: {
+    /**
+     * Singleton element created at startup which provides the languages model.
+     * @type {!Element}
+     */
+    singleton_: {
+      type: Object,
+      value: document.createElement('cr-settings-languages-singleton'),
+    },
+
+    /**
+     * A reference to the languages model from the singleton, exposed as a
+     * read-only property so hosts can bind to it, but not change it.
+     * @type {LanguagesModel|undefined}
+     */
+    languages: {
+      type: Object,
+      notify: true,
+      readOnly: true,
+    },
+  },
+
+  ready: function() {
+    // Set the 'languages' property to reference the singleton's model.
+    this._setLanguages(this.singleton_.languages);
+    // Listen for changes to the singleton's languages property, so we know
+    // when to notify hosts of changes to (our reference to) the property.
+    this.listen(
+        this.singleton_, 'languages-changed', 'singletonLanguagesChanged_');
+  },
+
+  /**
+   * Takes changes reported by the singleton and forwards them to the host,
+   * manually sending a change notification for our 'languages' property (since
+   * it's the same object as the singleton's property, but isn't bound by
+   * Polymer).
+   * @private
+   */
+  singletonLanguagesChanged_: function(e) {
+    // Forward the change notification to the host.
+    this.fire(e.type, e.detail, {bubbles: false});
+  },
+
+  // Forward public methods to the singleton.
+
+  /** @param {string} languageCode */
+  setUILanguage: function(languageCode) {
+    if (cr.isWindows || cr.isChromeOS)
+      this.singleton_.setUILanguage(languageCode);
+  },
+
+  /** @param {string} languageCode */
+  enableLanguage: function(languageCode) {
+    this.singleton_.enableLanguage(languageCode);
+  },
+
+  /** @param {string} languageCode */
+  disableLanguage: function(languageCode) {
+    this.singleton_.disableLanguage(languageCode);
+  },
+
+  /**
+   * @param {string} languageCode
+   * @return {boolean}
+   */
+  isEnabled: function(languageCode) {
+    return this.singleton_.isEnabled(languageCode);
+  },
+
+  /**
+   * @param {string} languageCode
+   * @param {boolean} enable
+   */
+  toggleSpellCheck: function(languageCode, enable) {
+    this.singleton_.toggleSpellCheck(languageCode, enable);
+  },
+});
+
+var preferredLanguagesPrefName = cr.isChromeOS ?
+    'settings.language.preferred_languages' : 'intl.accept_languages';
+
+/**
+ * Singleton element created when cr-settings-languages is registered.
+ * Generates the languages model on start-up, and updates it whenever Chrome's
+ * pref store and other settings change. These updates propagate to each
+ * <cr-settings-language> instance so that their 'languages' property updates
+ * like any other Polymer property.
+ */
+Polymer({
+  is: 'cr-settings-languages-singleton',
+
+  properties: {
+    /**
+     * @type {LanguagesModel|undefined}
+     */
+    languages: {
+      type: Object,
+      notify: true,
+    },
+
+    /**
+     * Object containing all preferences.
+     */
+    prefs: {
+      type: Object,
+      notify: true,
+    },
+  },
+
+  /**
+   * Hash map of languages.supportedLanguages using language codes as keys for
+   * fast lookup.
+   * @private {!Object<!chrome.languageSettingsPrivate.Language>}
+   */
+  supportedLanguageMap_: {},
+
+  /**
+   * Hash map of languages.enabledLanguages using language codes as keys for
+   * fast lookup.
+   * @private {!Object<!LanguageInfo>}
+   */
+  enabledLanguageMap_: {},
+
+  observers: [
+    'preferredLanguagesPrefChanged_(prefs.' +
+        preferredLanguagesPrefName + '.value)',
+    'spellCheckDictionariesPrefChanged_(prefs.spellcheck.dictionaries.value.*)',
+  ],
+
+  /** @override */
+  created: function() {
+    chrome.languageSettingsPrivate.getLanguageList(function(languageList) {
+      // Wait until prefs are initialized before creating the model, so we can
+      // include information about enabled languages.
+      CrSettingsPrefs.initialized.then(function() {
+        this.createModel_(languageList);
+        this.initialized_ = true;
+      }.bind(this));
+    }.bind(this));
+  },
+
+  /**
+   * Constructs the languages model from the given language list.
+   * @param {!Array<!chrome.languageSettingsPrivate.Language>}
+   *     supportedLanguages
+   */
+  createModel_: function(supportedLanguages) {
+    // Populate the hash map of supported languages.
+    for (var i = 0; i < supportedLanguages.length; i++) {
+      this.supportedLanguageMap_[supportedLanguages[i].code] =
+          supportedLanguages[i];
+    }
+
+    // Create a list of enabled language info from the supported languages.
+    var enabledLanguages = this.getEnabledLanguages_();
+    // Populate the hash map of enabled languages.
+    for (var i = 0; i < enabledLanguages.length; i++) {
+      var languageInfo = enabledLanguages[i];
+      this.enabledLanguageMap_[languageInfo.language.code] = languageInfo;
+    }
+
+    // Initialize the Polymer languages model.
+    this.languages = {
+      supportedLanguages: supportedLanguages,
+      enabledLanguages: enabledLanguages,
+    };
+  },
+
+  /**
+   * Returns a list of LanguageInfos for each enabled language in the supported
+   * languages list.
+   * @return {!Array<!LanguageInfo>}
+   * @private
+   */
+  getEnabledLanguages_: function() {
+    assert(CrSettingsPrefs.isInitialized);
+
+    var pref = this.getPref_(preferredLanguagesPrefName);
+    var enabledLanguageCodes = pref.value.split(',');
+    var enabledLanguages = [];
+    var spellCheckMap = this.getSpellCheckMap_();
+    for (var i = 0; i < enabledLanguageCodes.length; i++) {
+      var code = enabledLanguageCodes[i];
+      var language = this.supportedLanguageMap_[code];
+      if (!language)
+        continue;
+      var state = {spellCheckEnabled: !!spellCheckMap[code]};
+      enabledLanguages.push({language: language, state: state});
+    }
+    return enabledLanguages;
+  },
+
+  /**
+   * Creates a map whose keys are languages enabled for spell check.
+   * @return {!Object<boolean>}
+   */
+  getSpellCheckMap_: function() {
+    assert(CrSettingsPrefs.isInitialized);
+
+    var spellCheckCodes = this.getPref_('spellcheck.dictionaries').value;
+    var spellCheckMap = {};
+    for (var i = 0; i < spellCheckCodes.length; i++)
+      spellCheckMap[spellCheckCodes[i]] = true;
+    return spellCheckMap;
+  },
+
+  /**
+   * Updates the list of enabled languages from the preferred languages pref.
+   * @private
+   * */
+  preferredLanguagesPrefChanged_: function() {
+    if (!this.initialized_)
+      return;
+
+    var enabledLanguages = this.getEnabledLanguages_();
+    // Reset the enabled language map. Do this before notifying of the change
+    // via languages.enabledLanguages.
+    this.enabledLanguageMap_ = {};
+    for (var i = 0; i < enabledLanguages.length; i++) {
+      var languageInfo = enabledLanguages[i];
+      this.enabledLanguageMap_[languageInfo.language.code] = languageInfo;
+    }
+    this.set('languages.enabledLanguages', enabledLanguages);
+  },
+
+  /**
+   * Updates the spellCheckEnabled state of each enabled language.
+   * @private
+   */
+  spellCheckDictionariesPrefChanged_: function() {
+    if (!this.initialized_)
+      return;
+
+    var spellCheckMap = this.getSpellCheckMap_();
+    for (var i = 0; i < this.languages.enabledLanguages.length; i++) {
+      var languageCode = this.languages.enabledLanguages[i].language.code;
+      this.set('languages.enabledLanguages.' + i + '.state.spellCheckEnabled',
+               !!spellCheckMap[languageCode]);
+    }
+  },
+
+  /**
+   * Gets the pref at the given key. Asserts if the pref is not found.
+   * @param {string} key
+   * @return {!chrome.settingsPrivate.PrefObject}
+   */
+  getPref_: function(key) {
+    var pref = /** @type {!chrome.settingsPrivate.PrefObject} */(
+        this.get(key, this.prefs));
+    assert(typeof pref != 'undefined', 'Pref is missing: ' + key);
+    return pref;
+  },
+
+  /**
+   * Sets the value of the pref at the given key. Asserts if the pref is not
+   * found.
+   * @param {string} key
+   * @param {*} value
+   */
+  setPrefValue_: function(key, value) {
+    this.getPref_(key);
+    this.set('prefs.' + key + '.value', value);
+  },
+
+  /**
+   * Windows and Chrome OS only: Sets the prospective UI language to the chosen
+   * language. This dosen't affect the actual UI language until a restart.
+   * @param {string} languageCode
+   */
+  setUILanguage: function(languageCode) {
+    chrome.send('setUILanguage', [languageCode]);
+  },
+
+  /**
+   * Enables the language, making it available for spell check and input.
+   * @param {string} languageCode
+   */
+  enableLanguage: function(languageCode) {
+    if (!CrSettingsPrefs.isInitialized)
+      return;
+
+    var languageCodes = this.getPref_(preferredLanguagesPrefName).value;
+    var index = languageCodes.split(',').indexOf(languageCode);
+    if (index > -1)
+      return;
+    this.setPrefValue_(preferredLanguagesPrefName,
+                       languageCodes + ',' + languageCode);
+  },
+
+  /**
+   * Disables the language.
+   * @param {string} languageCode
+   */
+  disableLanguage: function(languageCode) {
+    if (!CrSettingsPrefs.isInitialized)
+      return;
+
+    // Cannot disable the UI language.
+    var appLocale = this.getPref_('intl.app_locale').value ||
+                    navigator.language;
+    assert(languageCode != appLocale);
+
+    // Cannot disable the only enabled language.
+    var pref = this.getPref_(preferredLanguagesPrefName);
+    var languageCodes = pref.value.split(',');
+    assert(languageCodes.length > 1);
+
+    // Remove the language from spell check.
+    this.arrayDelete('prefs.spellcheck.dictionaries.value', languageCode);
+
+    var languageIndex = languageCodes.indexOf(languageCode);
+    if (languageIndex == -1)
+      return;
+    languageCodes.splice(languageIndex, 1);
+    this.setPrefValue_(preferredLanguagesPrefName, languageCodes.join(','));
+  },
+
+  /**
+   * @param {string} languageCode
+   * @return {boolean} True if the language is enabled.
+   */
+  isEnabled: function(languageCode) {
+    return !!this.enabledLanguageMap_[languageCode];
+  },
+
+  /**
+   * Enables or disables spell check for the given language.
+   * @param {string} languageCode
+   * @param {boolean} enable
+   */
+  toggleSpellCheck: function(languageCode, enable) {
+    if (!this.initialized_)
+      return;
+
+    if (enable) {
+      var spellCheckPref = this.getPref_('spellcheck.dictionaries');
+      if (spellCheckPref.value.indexOf(languageCode) == -1)
+        this.push('prefs.spellcheck.dictionaries.value', languageCode);
+    } else {
+      this.arrayDelete('prefs.spellcheck.dictionaries.value', languageCode);
+    }
+  },
+});
+})();