Bug 1346616 - Migrate callsites that are retrieving requested locale from pref, to use LocaleService::GetRequestedLocales. r=jfkthame,Pike

I'm adding a helper function mozILocaleService::GetRequestedLocale to simplify
most of the callsites that are looking for the first of the requested locales.

In most cases, I'm just matching the behavior of the code with reusing
LocaleService API instead of direct manipulation on the prefs.
That includes how I handle error case scenarios.

In case of sdk/l10n/locale.js I am reusing LocaleService heuristics over
the custom one from the file since the ones in LocaleService are just
more correct and unified accross the whole platform.

In case of FallbackEncoding I have to turn it into a nsIObserver to listen
to intl:requested-locales-changed.

MozReview-Commit-ID: 7rOr2CovLK

--HG--
extra : rebase_source : 2f166cf1746f389a035f7cf557edcadeacb10fa0

addon-sdk/source/lib/sdk/l10n/locale.js

@@ -11,58 +11,8 @@ const prefs = require("../preferences/service");
 const { Cu, Cc, Ci } = require("chrome");
 const { Services } = Cu.import("resource://gre/modules/Services.jsm");
 
-/**
- * Gets the currently selected locale for display.
- * Gets all usable locale that we can use sorted by priority of relevance
- * @return  Array of locales, begins with highest priority
- */
-const PREF_MATCH_OS_LOCALE  = "intl.locale.matchOS";
-const PREF_SELECTED_LOCALE  = "general.useragent.locale";
-const PREF_ACCEPT_LANGUAGES = "intl.accept_languages";
-
 function getPreferedLocales(caseSensitve) {
-  let locales = [];
+  return Services.locale.getRequestedLocales();
-  function addLocale(locale) {
-    locale = locale.trim();
-    if (!caseSensitve)
-      locale = locale.toLowerCase();
-    if (locales.indexOf(locale) === -1)
-      locales.push(locale);
-  }
-
-  // Most important locale is OS one. But we use it, only if
-  // "intl.locale.matchOS" pref is set to `true`.
-  // Currently only used for multi-locales mobile builds.
-  // http://mxr.mozilla.org/mozilla-central/source/mobile/android/installer/Makefile.in#46
-  if (prefs.get(PREF_MATCH_OS_LOCALE, false)) {
-    let localeService = Cc["@mozilla.org/intl/nslocaleservice;1"].
-                        getService(Ci.nsILocaleService);
-    let osLocale = localeService.getLocaleComponentForUserAgent();
-    addLocale(osLocale);
-  }
-
-  // In some cases, mainly on Fennec and on Linux version,
-  // `general.useragent.locale` is a special 'localized' value, like:
-  // "chrome://global/locale/intl.properties"
-  let browserUiLocale = prefs.getLocalized(PREF_SELECTED_LOCALE, "") ||
-                        prefs.get(PREF_SELECTED_LOCALE, "");
-  if (browserUiLocale)
-    addLocale(browserUiLocale);
-
-  // Third priority is the list of locales used for web content
-  let contentLocales = prefs.getLocalized(PREF_ACCEPT_LANGUAGES, "") ||
-                       prefs.get(PREF_ACCEPT_LANGUAGES, "");
-  if (contentLocales) {
-    // This list is a string of locales seperated by commas.
-    // There is spaces after commas, so strip each item
-    for (let locale of contentLocales.split(","))
-      addLocale(locale.replace(/(^\s+)|(\s+$)/g, ""));
-  }
-
-  // Finally, we ensure that en-US is the final fallback if it wasn't added
-  addLocale("en-US");
-
-  return locales;
 }
 exports.getPreferedLocales = getPreferedLocales;
 

addon-sdk/source/test/test-l10n-locale.js

@@ -2,128 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-const { getPreferedLocales, findClosestLocale } = require("sdk/l10n/locale");
+const { findClosestLocale } = require("sdk/l10n/locale");
-const prefs = require("sdk/preferences/service");
-const { Cc, Ci, Cu } = require("chrome");
-const { Services } = Cu.import("resource://gre/modules/Services.jsm");
-const BundleService = Cc["@mozilla.org/intl/stringbundle;1"].getService(Ci.nsIStringBundleService);
-
-const PREF_MATCH_OS_LOCALE  = "intl.locale.matchOS";
-const PREF_SELECTED_LOCALE  = "general.useragent.locale";
-const PREF_ACCEPT_LANGUAGES = "intl.accept_languages";
-
-function assertPrefered(assert, expected, msg) {
-  assert.equal(JSON.stringify(getPreferedLocales()), JSON.stringify(expected),
-                   msg);
-}
-
-exports.testGetPreferedLocales = function(assert) {
-  prefs.set(PREF_MATCH_OS_LOCALE, false);
-  prefs.set(PREF_SELECTED_LOCALE, "");
-  prefs.set(PREF_ACCEPT_LANGUAGES, "");
-  assertPrefered(assert, ["en-us"],
-                 "When all preferences are empty, we only have en-us");
-
-  prefs.set(PREF_SELECTED_LOCALE, "fr");
-  prefs.set(PREF_ACCEPT_LANGUAGES, "jp");
-  assertPrefered(assert, ["fr", "jp", "en-us"],
-                 "We first have useragent locale, then web one and finally en-US");
-
-  prefs.set(PREF_SELECTED_LOCALE, "en-US");
-  prefs.set(PREF_ACCEPT_LANGUAGES, "en-US");
-  assertPrefered(assert, ["en-us"],
-                 "We do not have duplicates");
-
-  prefs.set(PREF_SELECTED_LOCALE, "en-US");
-  prefs.set(PREF_ACCEPT_LANGUAGES, "fr");
-  assertPrefered(assert, ["en-us", "fr"],
-                 "en-US can be first if specified by higher priority preference");
-
-  // Reset what we changed
-  prefs.reset(PREF_MATCH_OS_LOCALE);
-  prefs.reset(PREF_SELECTED_LOCALE);
-  prefs.reset(PREF_ACCEPT_LANGUAGES);
-}
-
-// In some cases, mainly on Fennec and on Linux version,
-// `general.useragent.locale` is a special 'localized' value, like:
-// "chrome://global/locale/intl.properties"
-exports.testPreferedLocalizedLocale = function(assert) {
-  prefs.set(PREF_MATCH_OS_LOCALE, false);
-  let bundleURL = "chrome://global/locale/intl.properties";
-  prefs.setLocalized(PREF_SELECTED_LOCALE, bundleURL);
-  let contentLocale = "ja";
-  prefs.set(PREF_ACCEPT_LANGUAGES, contentLocale);
-
-  // Read manually the expected locale value from the property file
-  let expectedLocale = BundleService.createBundle(bundleURL).
-    GetStringFromName(PREF_SELECTED_LOCALE).
-    toLowerCase();
-
-  // First add the useragent locale
-  let expectedLocaleList = [expectedLocale];
-
-  // Then the content locale
-  if (expectedLocaleList.indexOf(contentLocale) == -1)
-    expectedLocaleList.push(contentLocale);
-
-  // Add default "en-us" fallback if the main language is not already en-us
-  if (expectedLocaleList.indexOf("en-us") == -1)
-    expectedLocaleList.push("en-us");
-
-  assertPrefered(assert, expectedLocaleList, "test localized pref value");
-
-  // Reset what we have changed
-  prefs.reset(PREF_MATCH_OS_LOCALE);
-  prefs.reset(PREF_SELECTED_LOCALE);
-  prefs.reset(PREF_ACCEPT_LANGUAGES);
-}
-
-// On Linux the PREF_ACCEPT_LANGUAGES pref can be a localized pref.
-exports.testPreferedContentLocale = function(assert) {
-  prefs.set(PREF_MATCH_OS_LOCALE, false);
-  let noLocale = "",
-      bundleURL = "chrome://global/locale/intl.properties";
-  prefs.set(PREF_SELECTED_LOCALE, noLocale);
-  prefs.setLocalized(PREF_ACCEPT_LANGUAGES, bundleURL);
-
-  // Read the expected locale values from the property file
-  let expectedLocaleList = BundleService.createBundle(bundleURL).
-    GetStringFromName(PREF_ACCEPT_LANGUAGES).
-    split(",").
-    map(locale => locale.trim().toLowerCase());
-
-  // Add default "en-us" fallback if the main language is not already en-us
-  if (expectedLocaleList.indexOf("en-us") == -1)
-    expectedLocaleList.push("en-us");
-
-  assertPrefered(assert, expectedLocaleList, "test localized content locale pref value");
-
-  // Reset what we have changed
-  prefs.reset(PREF_MATCH_OS_LOCALE);
-  prefs.reset(PREF_SELECTED_LOCALE);
-  prefs.reset(PREF_ACCEPT_LANGUAGES);
-}
-
-exports.testPreferedOsLocale = function(assert) {
-  prefs.set(PREF_MATCH_OS_LOCALE, true);
-  prefs.set(PREF_SELECTED_LOCALE, "");
-  prefs.set(PREF_ACCEPT_LANGUAGES, "");
-
-  let expectedLocale = Services.locale.getAppLocaleAsLangTag().toLowerCase();
-  let expectedLocaleList = [expectedLocale];
-
-  // Add default "en-us" fallback if the main language is not already en-us
-  if (expectedLocale != "en-us")
-    expectedLocaleList.push("en-us");
-
-  assertPrefered(assert, expectedLocaleList, "Ensure that we select OS locale when related preference is set");
-
-  // Reset what we have changed
-  prefs.reset(PREF_MATCH_OS_LOCALE);
-  prefs.reset(PREF_SELECTED_LOCALE);
-  prefs.reset(PREF_ACCEPT_LANGUAGES);
-}
 
 exports.testFindClosestLocale = function(assert) {
   // Second param of findClosestLocale (aMatchLocales) have to be in lowercase

browser/components/dirprovider/DirectoryProvider.cpp

@@ -19,11 +19,14 @@
 #include "nsCOMArray.h"
 #include "nsDirectoryServiceUtils.h"
 #include "mozilla/ModuleUtils.h"
+#include "mozilla/intl/LocaleService.h"
 #include "nsServiceManagerUtils.h"
 #include "nsString.h"
 #include "nsXULAppAPI.h"
 #include "nsIPrefLocalizedString.h"
 
+using mozilla::intl::LocaleService;
+
 namespace mozilla {
 namespace browser {
 
@@ -125,31 +128,18 @@ AppendDistroSearchDirs(nsIProperties* aDirSvc, nsCOMArray<nsIFile> &array)
     }
 
     // we didn't have a defaultLocale, use the user agent locale
-    nsCString locale;
+    nsAutoCString locale;
-    nsCOMPtr<nsIPrefLocalizedString> prefString;
+    LocaleService::GetInstance()->GetAppLocaleAsLangTag(locale);
-    rv = prefs->GetComplexValue("general.useragent.locale",
-                                NS_GET_IID(nsIPrefLocalizedString),
-                                getter_AddRefs(prefString));
-    if (NS_SUCCEEDED(rv)) {
-      nsAutoString wLocale;
-      prefString->GetData(getter_Copies(wLocale));
-      CopyUTF16toUTF8(wLocale, locale);
-    } else {
-      rv = prefs->GetCharPref("general.useragent.locale", getter_Copies(locale));
-    }
 
+    nsCOMPtr<nsIFile> curLocalePlugins;
+    rv = localePlugins->Clone(getter_AddRefs(curLocalePlugins));
     if (NS_SUCCEEDED(rv)) {
 
-      nsCOMPtr<nsIFile> curLocalePlugins;
+      curLocalePlugins->AppendNative(locale);
-      rv = localePlugins->Clone(getter_AddRefs(curLocalePlugins));
+      rv = curLocalePlugins->Exists(&exists);
-      if (NS_SUCCEEDED(rv)) {
+      if (NS_SUCCEEDED(rv) && exists) {
-
+        array.AppendObject(curLocalePlugins);
-        curLocalePlugins->AppendNative(locale);
+        return; // all done
-        rv = curLocalePlugins->Exists(&exists);
-        if (NS_SUCCEEDED(rv) && exists) {
-          array.AppendObject(curLocalePlugins);
-          return; // all done
-        }
       }
     }
   }

browser/components/distribution.js

@@ -57,7 +57,7 @@ DistributionCustomizer.prototype = {
   },
 
   get _locale() {
-    let locale = this._prefs.getCharPref("general.useragent.locale", "en-US");
+    const locale = Services.locale.getRequestedLocale() || "en-US";
     this.__defineGetter__("_locale", () => locale);
     return this._locale;
   },

browser/components/extensions/test/browser/head_pageAction.js

@@ -133,7 +133,8 @@ function* runTests(options) {
     });
   });
 
-  yield SpecialPowers.pushPrefEnv({set: [["general.useragent.locale", "es-ES"]]});
+  let reqLoc = Services.locale.getRequestedLocales();
+  Services.locale.setRequestedLocales(["es-ES"]);
 
   yield extension.startup();
 
@@ -141,7 +142,7 @@ function* runTests(options) {
 
   yield extension.unload();
 
-  yield SpecialPowers.popPrefEnv();
+  Services.locale.setRequestedLocales(reqLoc);
 
   let node = document.getElementById(pageActionId);
   is(node, null, "pageAction image removed from document");

browser/components/search/test/head.js

@@ -21,22 +21,7 @@ function isSubObjectOf(expectedObj, actualObj, name) {
 }
 
 function getLocale() {
-  const localePref = "general.useragent.locale";
+  return Services.locale.getRequestedLocale() || undefined;
-  return getLocalizedPref(localePref, Services.prefs.getCharPref(localePref));
-}
-
-/**
- * Wrapper for nsIPrefBranch::getComplexValue.
- * @param aPrefName
- *        The name of the pref to get.
- * @returns aDefault if the requested pref doesn't exist.
- */
-function getLocalizedPref(aPrefName, aDefault) {
-  try {
-    return Services.prefs.getComplexValue(aPrefName, Ci.nsIPrefLocalizedString).data;
-  } catch (ex) {
-    return aDefault;
-  }
 }
 
 function promiseEvent(aTarget, aEventName, aPreventDefault) {

browser/extensions/pdfjs/content/PdfStreamConverter.jsm

@@ -314,7 +314,7 @@ class ChromeActions {
   }
 
   getLocale() {
-    return getStringPref("general.useragent.locale", "en-US");
+    return Services.locale.getRequestedLocale() || "en-US";
   }
 
   getStrings(data) {

browser/modules/DirectoryLinksProvider.jsm

@@ -49,12 +49,6 @@ XPCOMUtils.defineLazyGetter(this, "gUnicodeConverter", function() {
 const DIRECTORY_LINKS_FILE = "directoryLinks.json";
 const DIRECTORY_LINKS_TYPE = "application/json";
 
-// The preference that tells whether to match the OS locale
-const PREF_MATCH_OS_LOCALE = "intl.locale.matchOS";
-
-// The preference that tells what locale the user selected
-const PREF_SELECTED_LOCALE = "general.useragent.locale";
-
 // The preference that tells where to obtain directory links
 const PREF_DIRECTORY_SOURCE = "browser.newtabpage.directory.source";
 
@@ -166,8 +160,6 @@ var DirectoryLinksProvider = {
     return Object.freeze({
       enhanced: PREF_NEWTAB_ENHANCED,
       linksURL: PREF_DIRECTORY_SOURCE,
-      matchOSLocale: PREF_MATCH_OS_LOCALE,
-      prefSelectedLocale: PREF_SELECTED_LOCALE,
     });
   },
 
@@ -188,26 +180,7 @@ var DirectoryLinksProvider = {
    * @return  the selected locale or "en-US" if none is selected
    */
   get locale() {
-    let matchOS = Services.prefs.getBoolPref(PREF_MATCH_OS_LOCALE, false);
+    return Services.locale.getRequestedLocale() || "en-US";
-
-    if (matchOS) {
-      return Cc["@mozilla.org/intl/ospreferences;1"].
-             getService(Ci.mozIOSPreferences).systemLocale;
-    }
-
-    try {
-      let locale = Services.prefs.getComplexValue(PREF_SELECTED_LOCALE,
-                                                  Ci.nsIPrefLocalizedString);
-      if (locale) {
-        return locale.data;
-      }
-    } catch (e) {}
-
-    try {
-      return Services.prefs.getCharPref(PREF_SELECTED_LOCALE);
-    } catch (e) {}
-
-    return "en-US";
   },
 
   /**
@@ -236,14 +209,11 @@ var DirectoryLinksProvider = {
 
         case this._observedPrefs.linksURL:
           delete this.__linksURL;
-          // fallthrough
-
-        // Force directory download on changes to fetch related prefs
-        case this._observedPrefs.matchOSLocale:
-        case this._observedPrefs.prefSelectedLocale:
           this._fetchAndCacheLinksIfNecessary(true);
           break;
       }
+    } else if (aTopic === "intl:requested-locales-changed") {
+      this._fetchAndCacheLinksIfNecessary(true);
     }
   },
 
@@ -690,6 +660,7 @@ var DirectoryLinksProvider = {
   init: function DirectoryLinksProvider_init() {
     this._setDefaultEnhanced();
     this._addPrefsObserver();
+    Services.obs.addObserver(this, "intl:requested-locales-changed", false);
     // setup directory file path and last download timestamp
     this._directoryFilePath = OS.Path.join(OS.Constants.Path.localProfileDir, DIRECTORY_LINKS_FILE);
     this._lastDownloadMS = 0;
@@ -1213,6 +1184,7 @@ var DirectoryLinksProvider = {
     delete this.__linksURL;
     this._removePrefsObserver();
     this._removeObservers();
+    Services.obs.removeObserver(this, "intl:requested-locales-changed");
   },
 
   addObserver: function DirectoryLinksProvider_addObserver(aObserver) {

browser/modules/test/unit/test_DirectoryLinksProvider.js

@@ -34,7 +34,6 @@ const kURLData = {"directory": [{"url": "http://example.com", "title": "LocalSou
 const kTestURL = "data:application/json," + JSON.stringify(kURLData);
 
 // DirectoryLinksProvider preferences
-const kLocalePref = DirectoryLinksProvider._observedPrefs.prefSelectedLocale;
 const kSourceUrlPref = DirectoryLinksProvider._observedPrefs.linksURL;
 const kPingUrlPref = "browser.newtabpage.directory.ping";
 const kNewtabEnhancedPref = "browser.newtabpage.enhanced";
@@ -51,7 +50,8 @@ const kFailURL = kBaseUrl + kFailPath;
 const kPingUrl = kBaseUrl + kPingPath;
 
 // app/profile/firefox.js are not avaialble in xpcshell: hence, preset them
-Services.prefs.setCharPref(kLocalePref, "en-US");
+const origReqLocales = Services.locale.getRequestedLocales();
+Services.locale.setRequestedLocales(["en-US"]);
 Services.prefs.setCharPref(kSourceUrlPref, kTestURL);
 Services.prefs.setCharPref(kPingUrlPref, kPingUrl);
 Services.prefs.setBoolPref(kNewtabEnhancedPref, true);
@@ -201,7 +201,7 @@ function promiseSetupDirectoryLinksProvider(options = {}) {
   return Task.spawn(function*() {
     let linksURL = options.linksURL || kTestURL;
     yield DirectoryLinksProvider.init();
-    yield promiseDirectoryDownloadOnPrefChange(kLocalePref, options.locale || "en-US");
+    Services.locale.setRequestedLocales([options.locale || "en-US"]);
     yield promiseDirectoryDownloadOnPrefChange(kSourceUrlPref, linksURL);
     do_check_eq(DirectoryLinksProvider._linksURL, linksURL);
     DirectoryLinksProvider._lastDownloadMS = options.lastDownloadMS || 0;
@@ -210,7 +210,7 @@ function promiseSetupDirectoryLinksProvider(options = {}) {
 
 function promiseCleanDirectoryLinksProvider() {
   return Task.spawn(function*() {
-    yield promiseDirectoryDownloadOnPrefChange(kLocalePref, "en-US");
+    Services.locale.setRequestedLocales(["en-US"]);
     yield promiseDirectoryDownloadOnPrefChange(kSourceUrlPref, kTestURL);
     yield DirectoryLinksProvider._clearFrequencyCap();
     yield DirectoryLinksProvider._loadInadjacentSites();
@@ -233,7 +233,7 @@ function run_test() {
   do_register_cleanup(function() {
     server.stop(function() { });
     DirectoryLinksProvider.reset();
-    Services.prefs.clearUserPref(kLocalePref);
+    Services.locale.setRequestedLocales(origReqLocales);
     Services.prefs.clearUserPref(kSourceUrlPref);
     Services.prefs.clearUserPref(kPingUrlPref);
     Services.prefs.clearUserPref(kNewtabEnhancedPref);

dom/encoding/FallbackEncoding.cpp

@@ -10,6 +10,7 @@
 #include "nsUConvPropertySearch.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Services.h"
+#include "nsIObserverService.h"
 #include "mozilla/intl/LocaleService.h"
 
 using mozilla::intl::LocaleService;
@@ -29,21 +30,17 @@ static constexpr nsUConvProp nonParticipatingDomains[] = {
 #include "nonparticipatingdomains.properties.h"
 };
 
+NS_IMPL_ISUPPORTS(FallbackEncoding, nsIObserver)
+
 FallbackEncoding* FallbackEncoding::sInstance = nullptr;
 bool FallbackEncoding::sGuessFallbackFromTopLevelDomain = true;
 
 FallbackEncoding::FallbackEncoding()
 {
-  MOZ_COUNT_CTOR(FallbackEncoding);
   MOZ_ASSERT(!FallbackEncoding::sInstance,
              "Singleton already exists.");
 }
 
-FallbackEncoding::~FallbackEncoding()
-{
-  MOZ_COUNT_DTOR(FallbackEncoding);
-}
-
 void
 FallbackEncoding::Get(nsACString& aFallback)
 {
@@ -118,6 +115,16 @@ FallbackEncoding::PrefChanged(const char*, void*)
   FallbackEncoding::sInstance->Invalidate();
 }
 
+NS_IMETHODIMP
+FallbackEncoding::Observe(nsISupports *aSubject, const char *aTopic,
+                         const char16_t *aData)
+{
+  MOZ_ASSERT(FallbackEncoding::sInstance,
+             "Observe callback called with null fallback cache.");
+  FallbackEncoding::sInstance->Invalidate();
+  return NS_OK;
+}
+
 void
 FallbackEncoding::Initialize()
 {
@@ -127,11 +134,13 @@ FallbackEncoding::Initialize()
   Preferences::RegisterCallback(FallbackEncoding::PrefChanged,
                                 "intl.charset.fallback.override",
                                 nullptr);
-  Preferences::RegisterCallback(FallbackEncoding::PrefChanged,
-                                "general.useragent.locale",
-                                nullptr);
   Preferences::AddBoolVarCache(&sGuessFallbackFromTopLevelDomain,
                                "intl.charset.fallback.tld");
+
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->AddObserver(sInstance, "intl:requested-locales-changed", true);
+  }
 }
 
 void
@@ -139,6 +148,10 @@ FallbackEncoding::Shutdown()
 {
   MOZ_ASSERT(FallbackEncoding::sInstance,
              "Releasing non-existent fallback cache.");
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->RemoveObserver(sInstance, "intl:requested-locales-changed");
+  }
   delete FallbackEncoding::sInstance;
   FallbackEncoding::sInstance = nullptr;
 }

dom/encoding/FallbackEncoding.h

@@ -7,14 +7,17 @@
 #ifndef mozilla_dom_FallbackEncoding_h_
 #define mozilla_dom_FallbackEncoding_h_
 
+#include "nsIObserver.h"
 #include "nsString.h"
 
 namespace mozilla {
 namespace dom {
 
-class FallbackEncoding
+class FallbackEncoding : public nsIObserver
 {
 public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
 
   /**
    * Whether FromTopLevelDomain() should be used.
@@ -68,7 +71,7 @@ private:
   static FallbackEncoding* sInstance;
 
   FallbackEncoding();
-  ~FallbackEncoding();
+  virtual ~FallbackEncoding() {};
 
   /**
    * Invalidates the cache.

intl/locale/LocaleService.cpp

@@ -747,6 +747,24 @@ LocaleService::GetRequestedLocales(uint32_t* aCount, char*** aOutArray)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+LocaleService::GetRequestedLocale(nsACString& aRetVal)
+{
+  AutoTArray<nsCString, 16> requestedLocales;
+  bool res = GetRequestedLocales(requestedLocales);
+
+  if (!res) {
+    NS_ERROR("Couldn't retrieve selected locales from prefs!");
+    return NS_ERROR_FAILURE;
+  }
+
+  if (requestedLocales.Length() > 0) {
+    aRetVal = requestedLocales[0];
+  }
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 LocaleService::SetRequestedLocales(const char** aRequested,
                                    uint32_t aRequestedCount)

intl/locale/mozILocaleService.idl

@@ -143,6 +143,11 @@ interface mozILocaleService : nsISupports
   void getRequestedLocales([optional] out unsigned long aCount,
                            [retval, array, size_is(aCount)] out string aLocales);
 
+  /**
+   * Returns the top-requested locale from the user, or an empty string if none is set.
+   */
+  ACString getRequestedLocale();
+
   /**
    * Sets a list of locales that the user requested the app to be
    * localized to.

intl/locale/tests/unit/test_localeService.js

@@ -117,6 +117,24 @@ add_test(function test_getRequestedLocales_matchOS() {
   run_next_test();
 });
 
+add_test(function test_getRequestedLocale() {
+  Services.prefs.setBoolPref(PREF_MATCH_OS_LOCALE, false);
+  Services.prefs.setCharPref(PREF_SELECTED_LOCALE, "tlh");
+
+  let requestedLocale = localeService.getRequestedLocale();
+  do_check_true(requestedLocale === "tlh", "requestedLocale returns the right value");
+
+  Services.prefs.setCharPref(PREF_SELECTED_LOCALE, "");
+
+  requestedLocale = localeService.getRequestedLocale();
+  do_check_true(requestedLocale === "", "requestedLocale returns empty value value");
+
+  Services.prefs.clearUserPref(PREF_MATCH_OS_LOCALE);
+  Services.prefs.clearUserPref(PREF_SELECTED_LOCALE);
+
+  run_next_test();
+});
+
 add_test(function test_setRequestedLocales() {
   localeService.setRequestedLocales([]);
 

mobile/android/chrome/content/browser.js

@@ -1647,15 +1647,7 @@ var BrowserApp = {
   },
 
   getUALocalePref: function () {
-    try {
+    return Services.locale.getRequestedLocale() || undefined;
-      return Services.prefs.getComplexValue("general.useragent.locale", Ci.nsIPrefLocalizedString).data;
-    } catch (e) {
-      try {
-        return Services.prefs.getCharPref("general.useragent.locale");
-      } catch (ee) {
-        return undefined;
-      }
-    }
   },
 
   getOSLocalePref: function () {

mobile/android/components/DirectoryProvider.js

@@ -113,14 +113,9 @@ DirectoryProvider.prototype = {
       return;
 
     let curLocale = "";
-    try {
+    let reqLocales = Services.locales.getRequestedLocales();
-      curLocale = Services.prefs.getComplexValue("general.useragent.locale", Ci.nsIPrefLocalizedString).data;
+    if (reqLocales.length > 0) {
-    } catch (e) {
+      curLocale = reqLocales[0];
-      // eslint-disable-next-line mozilla/use-default-preference-values
-      try {
-        curLocale = Services.prefs.getCharPref("general.useragent.locale");
-      } catch (ee) {
-      }
     }
 
     if (curLocale) {

toolkit/components/downloads/ApplicationReputation.cpp

@@ -36,6 +36,7 @@
 #include "mozilla/SizePrintfMacros.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/TimeStamp.h"
+#include "mozilla/intl/LocaleService.h"
 
 #include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
@@ -62,6 +63,7 @@ using mozilla::OriginAttributes;
 using mozilla::Preferences;
 using mozilla::TimeStamp;
 using mozilla::Telemetry::Accumulate;
+using mozilla::intl::LocaleService;
 using safe_browsing::ClientDownloadRequest;
 using safe_browsing::ClientDownloadRequest_CertificateChain;
 using safe_browsing::ClientDownloadRequest_Resource;
@@ -73,7 +75,6 @@ using safe_browsing::ClientDownloadRequest_SignatureInfo;
 #define PREF_SB_DOWNLOADS_ENABLED "browser.safebrowsing.downloads.enabled"
 #define PREF_SB_DOWNLOADS_REMOTE_ENABLED "browser.safebrowsing.downloads.remote.enabled"
 #define PREF_SB_DOWNLOADS_REMOTE_TIMEOUT "browser.safebrowsing.downloads.remote.timeout_ms"
-#define PREF_GENERAL_LOCALE "general.useragent.locale"
 #define PREF_DOWNLOAD_BLOCK_TABLE "urlclassifier.downloadBlockTable"
 #define PREF_DOWNLOAD_ALLOW_TABLE "urlclassifier.downloadAllowTable"
 
@@ -1319,8 +1320,8 @@ PendingLookup::SendRemoteQueryInternal()
   mRequest.set_user_initiated(true);
 
   nsCString locale;
-  NS_ENSURE_SUCCESS(Preferences::GetCString(PREF_GENERAL_LOCALE, &locale),
+  rv = LocaleService::GetInstance()->GetAppLocaleAsLangTag(locale);
-                    NS_ERROR_NOT_AVAILABLE);
+  NS_ENSURE_SUCCESS(rv, rv);
   mRequest.set_locale(locale.get());
   nsCString sha256Hash;
   rv = mQuery->GetSha256Hash(sha256Hash);

toolkit/components/search/nsSearchService.js

@@ -875,12 +875,7 @@ function getDir(aKey, aIFace) {
  * exists in nsHttpHandler.cpp when building the UA string.
  */
 function getLocale() {
-  let locale = getLocalizedPref(LOCALE_PREF);
+  return Services.locale.getRequestedLocale();
-  if (locale)
-    return locale;
-
-  // Not localized.
-  return Services.prefs.getCharPref(LOCALE_PREF);
 }
 
 /**

toolkit/modules/Locale.jsm

@@ -9,26 +9,13 @@ const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/Preferences.jsm");
 
-const PREF_MATCH_OS_LOCALE            = "intl.locale.matchOS";
-const PREF_SELECTED_LOCALE            = "general.useragent.locale";
-
 this.Locale = {
   /**
    * Gets the currently selected locale for display.
    * @return  the selected locale or "en-US" if none is selected
    */
   getLocale() {
-    if (Preferences.get(PREF_MATCH_OS_LOCALE, false)) {
+    return Services.locale.getRequestedLocale() || "en-US";
-      const osPrefs =
-        Cc["@mozilla.org/intl/ospreferences;1"].getService(Ci.mozIOSPreferences);
-      return osPrefs.systemLocale;
-    }
-    try {
-      let locale = Preferences.get(PREF_SELECTED_LOCALE, null, Ci.nsIPrefLocalizedString);
-      if (locale)
-        return locale;
-    } catch (e) {}
-    return Preferences.get(PREF_SELECTED_LOCALE, "en-US");
   },
 
   /**

toolkit/mozapps/extensions/AddonManager.jsm

@@ -41,8 +41,6 @@ const PREF_EM_HOTFIX_LASTVERSION      = "extensions.hotfix.lastVersion";
 const PREF_EM_HOTFIX_URL              = "extensions.hotfix.url";
 const PREF_EM_CERT_CHECKATTRIBUTES    = "extensions.hotfix.cert.checkAttributes";
 const PREF_EM_HOTFIX_CERTS            = "extensions.hotfix.certs.";
-const PREF_MATCH_OS_LOCALE            = "intl.locale.matchOS";
-const PREF_SELECTED_LOCALE            = "general.useragent.locale";
 const UNKNOWN_XPCOM_ABI               = "unknownABI";
 
 const PREF_MIN_WEBEXT_PLATFORM_VERSION = "extensions.webExtensionsMinPlatformVersion";
@@ -326,26 +324,7 @@ function promiseCallProvider(aProvider, aMethod, ...aArgs) {
  * @return  the selected locale or "en-US" if none is selected
  */
 function getLocale() {
-  try {
+  return Services.locale.getRequestedLocale() || "en-US";
-    if (Services.prefs.getBoolPref(PREF_MATCH_OS_LOCALE)) {
-      const osPrefs =
-        Cc["@mozilla.org/intl/ospreferences;1"].getService(Ci.mozIOSPreferences);
-      return osPrefs.systemLocale;
-    }
-  } catch (e) { }
-
-  try {
-    let locale = Services.prefs.getComplexValue(PREF_SELECTED_LOCALE,
-                                                Ci.nsIPrefLocalizedString);
-    if (locale)
-      return locale;
-  } catch (e) { }
-
-  try {
-    return Services.prefs.getCharPref(PREF_SELECTED_LOCALE);
-  } catch (e) { }
-
-  return "en-US";
 }
 
 function webAPIForAddon(addon) {

toolkit/mozapps/extensions/nsBlocklistService.js

@@ -48,7 +48,6 @@ const PREF_BLOCKLIST_PINGCOUNTVERSION = "extensions.blocklist.pingCountVersion";
 const PREF_BLOCKLIST_SUPPRESSUI       = "extensions.blocklist.suppressUI";
 const PREF_ONECRL_VIA_AMO             = "security.onecrl.via.amo";
 const PREF_BLOCKLIST_UPDATE_ENABLED   = "services.blocklist.update_enabled";
-const PREF_GENERAL_USERAGENT_LOCALE   = "general.useragent.locale";
 const PREF_APP_DISTRIBUTION           = "distribution.id";
 const PREF_APP_DISTRIBUTION_VERSION   = "distribution.version";
 const PREF_EM_LOGGING_ENABLED         = "extensions.logging.enabled";
@@ -242,14 +241,7 @@ function matchesOSABI(blocklistElement) {
  * exists in nsHttpHandler.cpp when building the UA string.
  */
 function getLocale() {
-  try {
+  return Services.locale.getRequestedLocales();
-      // Get the default branch
-      var defaultPrefs = gPref.getDefaultBranch(null);
-      return defaultPrefs.getComplexValue(PREF_GENERAL_USERAGENT_LOCALE,
-                                          Ci.nsIPrefLocalizedString).data;
-  } catch (e) {}
-
-  return gPref.getCharPref(PREF_GENERAL_USERAGENT_LOCALE);
 }
 
 /* Get the distribution pref values, from defaults only */

toolkit/xre/nsAppRunner.cpp

@@ -19,6 +19,7 @@
 #include "mozilla/ScopeExit.h"
 #include "mozilla/Services.h"
 #include "mozilla/Telemetry.h"
+#include "mozilla/intl/LocaleService.h"
 
 #include "nsAppRunner.h"
 #include "mozilla/XREAppData.h"
@@ -288,6 +289,7 @@ using mozilla::Unused;
 using mozilla::scache::StartupCache;
 using mozilla::dom::ContentParent;
 using mozilla::dom::ContentChild;
+using mozilla::intl::LocaleService;
 
 // Save literal putenv string to environment variable.
 static void
@@ -4371,13 +4373,8 @@ XREMain::XRE_mainRun()
 
 #ifdef MOZ_CRASHREPORTER
   nsCString userAgentLocale;
-  // Try a localized string first. This pref is always a localized string in
+  LocaleService::GetInstance()->GetAppLocaleAsLangTag(userAgentLocale);
-  // Fennec, and might be elsewhere, too.
+  CrashReporter::AnnotateCrashReport(NS_LITERAL_CSTRING("useragent_locale"), userAgentLocale);
-  if (NS_SUCCEEDED(Preferences::GetLocalizedCString("general.useragent.locale", &userAgentLocale))) {
-    CrashReporter::AnnotateCrashReport(NS_LITERAL_CSTRING("useragent_locale"), userAgentLocale);
-  } else if (NS_SUCCEEDED(Preferences::GetCString("general.useragent.locale", &userAgentLocale))) {
-    CrashReporter::AnnotateCrashReport(NS_LITERAL_CSTRING("useragent_locale"), userAgentLocale);
-  }
 #endif
 
   appStartup->GetShuttingDown(&mShuttingDown);