michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: "use strict";
michael@0: 
michael@0: module.metadata = {
michael@0:   "stability": "unstable"
michael@0: };
michael@0: 
michael@0: const prefs = require("../preferences/service");
michael@0: const { Cu, Cc, Ci } = require("chrome");
michael@0: const { Services } = Cu.import("resource://gre/modules/Services.jsm");
michael@0: 
michael@0: /**
michael@0:  * Gets the currently selected locale for display.
michael@0:  * Gets all usable locale that we can use sorted by priority of relevance
michael@0:  * @return  Array of locales, begins with highest priority
michael@0:  */
michael@0: const PREF_MATCH_OS_LOCALE  = "intl.locale.matchOS";
michael@0: const PREF_SELECTED_LOCALE  = "general.useragent.locale";
michael@0: const PREF_ACCEPT_LANGUAGES = "intl.accept_languages";
michael@0: 
michael@0: function getPreferedLocales(caseSensitve) {
michael@0:   let locales = [];
michael@0:   function addLocale(locale) {
michael@0:     locale = locale.trim();
michael@0:     if (!caseSensitve)
michael@0:       locale = locale.toLowerCase();
michael@0:     if (locales.indexOf(locale) === -1)
michael@0:       locales.push(locale);
michael@0:   }
michael@0: 
michael@0:   // Most important locale is OS one. But we use it, only if
michael@0:   // "intl.locale.matchOS" pref is set to `true`.
michael@0:   // Currently only used for multi-locales mobile builds.
michael@0:   // http://mxr.mozilla.org/mozilla-central/source/mobile/android/installer/Makefile.in#46
michael@0:   if (prefs.get(PREF_MATCH_OS_LOCALE, false)) {
michael@0:     let localeService = Cc["@mozilla.org/intl/nslocaleservice;1"].
michael@0:                         getService(Ci.nsILocaleService);
michael@0:     let osLocale = localeService.getLocaleComponentForUserAgent();
michael@0:     addLocale(osLocale);
michael@0:   }
michael@0: 
michael@0:   // In some cases, mainly on Fennec and on Linux version,
michael@0:   // `general.useragent.locale` is a special 'localized' value, like:
michael@0:   // "chrome://global/locale/intl.properties"
michael@0:   let browserUiLocale = prefs.getLocalized(PREF_SELECTED_LOCALE, "") ||
michael@0:                         prefs.get(PREF_SELECTED_LOCALE, "");
michael@0:   if (browserUiLocale)
michael@0:     addLocale(browserUiLocale);
michael@0: 
michael@0:   // Third priority is the list of locales used for web content
michael@0:   let contentLocales = prefs.get(PREF_ACCEPT_LANGUAGES, "");
michael@0:   if (contentLocales) {
michael@0:     // This list is a string of locales seperated by commas.
michael@0:     // There is spaces after commas, so strip each item
michael@0:     for each(let locale in contentLocales.split(","))
michael@0:       addLocale(locale.replace(/(^\s+)|(\s+$)/g, ""));
michael@0:   }
michael@0: 
michael@0:   // Finally, we ensure that en-US is the final fallback if it wasn't added
michael@0:   addLocale("en-US");
michael@0: 
michael@0:   return locales;
michael@0: }
michael@0: exports.getPreferedLocales = getPreferedLocales;
michael@0: 
michael@0: /**
michael@0:  * Selects the closest matching locale from a list of locales.
michael@0:  *
michael@0:  * @param  aLocales
michael@0:  *         An array of available locales
michael@0:  * @param  aMatchLocales
michael@0:  *         An array of prefered locales, ordered by priority. Most wanted first.
michael@0:  *         Locales have to be in lowercase.
michael@0:  *         If null, uses getPreferedLocales() results
michael@0:  * @return the best match for the currently selected locale
michael@0:  *
michael@0:  * Stolen from http://mxr.mozilla.org/mozilla-central/source/toolkit/mozapps/extensions/internal/XPIProvider.jsm
michael@0:  */
michael@0: exports.findClosestLocale = function findClosestLocale(aLocales, aMatchLocales) {
michael@0:   aMatchLocales = aMatchLocales || getPreferedLocales();
michael@0: 
michael@0:   // Holds the best matching localized resource
michael@0:   let bestmatch = null;
michael@0:   // The number of locale parts it matched with
michael@0:   let bestmatchcount = 0;
michael@0:   // The number of locale parts in the match
michael@0:   let bestpartcount = 0;
michael@0: 
michael@0:   for each (let locale in aMatchLocales) {
michael@0:     let lparts = locale.split("-");
michael@0:     for each (let localized in aLocales) {
michael@0:       let found = localized.toLowerCase();
michael@0:       // Exact match is returned immediately
michael@0:       if (locale == found)
michael@0:         return localized;
michael@0: 
michael@0:       let fparts = found.split("-");
michael@0:       /* If we have found a possible match and this one isn't any longer
michael@0:          then we dont need to check further. */
michael@0:       if (bestmatch && fparts.length < bestmatchcount)
michael@0:         continue;
michael@0: 
michael@0:       // Count the number of parts that match
michael@0:       let maxmatchcount = Math.min(fparts.length, lparts.length);
michael@0:       let matchcount = 0;
michael@0:       while (matchcount < maxmatchcount &&
michael@0:              fparts[matchcount] == lparts[matchcount])
michael@0:         matchcount++;
michael@0: 
michael@0:       /* If we matched more than the last best match or matched the same and
michael@0:          this locale is less specific than the last best match. */
michael@0:       if (matchcount > bestmatchcount ||
michael@0:          (matchcount == bestmatchcount && fparts.length < bestpartcount)) {
michael@0:         bestmatch = localized;
michael@0:         bestmatchcount = matchcount;
michael@0:         bestpartcount = fparts.length;
michael@0:       }
michael@0:     }
michael@0:     // If we found a valid match for this locale return it
michael@0:     if (bestmatch)
michael@0:       return bestmatch;
michael@0:   }
michael@0:   return null;
michael@0: }