diff -r 000000000000 -r 6474c204b198 intl/locale/src/nsLanguageAtomService.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/intl/locale/src/nsLanguageAtomService.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,161 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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/. */
+
+#include "nsLanguageAtomService.h"
+#include "nsICharsetConverterManager.h"
+#include "nsILocaleService.h"
+#include "nsUnicharUtils.h"
+#include "nsIAtom.h"
+#include "mozilla/Services.h"
+#include "nsServiceManagerUtils.h"
+
+NS_IMPL_ISUPPORTS(nsLanguageAtomService, nsILanguageAtomService)
+
+nsLanguageAtomService::nsLanguageAtomService()
+{
+}
+
+nsresult
+nsLanguageAtomService::InitLangGroupTable()
+{
+  if (mLangGroups)
+    return NS_OK;
+
+  nsCOMPtr<nsIStringBundleService> bundleService =
+    mozilla::services::GetStringBundleService();
+  if (!bundleService)
+    return NS_ERROR_FAILURE;
+
+  return bundleService->CreateBundle("resource://gre/res/langGroups.properties",
+                                     getter_AddRefs(mLangGroups));
+}
+
+nsIAtom*
+nsLanguageAtomService::LookupLanguage(const nsACString &aLanguage,
+                                      nsresult *aError)
+{
+  nsAutoCString lowered(aLanguage);
+  ToLowerCase(lowered);
+
+  nsCOMPtr<nsIAtom> lang = do_GetAtom(lowered);
+  return GetLanguageGroup(lang, aError);
+}
+
+already_AddRefed<nsIAtom>
+nsLanguageAtomService::LookupCharSet(const char *aCharSet, nsresult *aError)
+{
+  if (!mCharSets) {
+    mCharSets = do_GetService(NS_CHARSETCONVERTERMANAGER_CONTRACTID);
+    if (!mCharSets) {
+      if (aError)
+        *aError = NS_ERROR_FAILURE;
+
+      return nullptr;
+    }
+  }
+
+  nsCOMPtr<nsIAtom> langGroup;
+  mCharSets->GetCharsetLangGroup(aCharSet, getter_AddRefs(langGroup));
+  if (!langGroup) {
+    if (aError)
+      *aError = NS_ERROR_FAILURE;
+
+    return nullptr;
+  }
+
+  if (aError)
+    *aError = NS_OK;
+
+  return langGroup.forget();
+}
+
+nsIAtom*
+nsLanguageAtomService::GetLocaleLanguage(nsresult *aError)
+{
+  nsresult res = NS_OK;
+
+  do {
+    if (!mLocaleLanguage) {
+      nsCOMPtr<nsILocaleService> localeService;
+      localeService = do_GetService(NS_LOCALESERVICE_CONTRACTID);
+      if (!localeService) {
+        res = NS_ERROR_FAILURE;
+        break;
+      }
+
+      nsCOMPtr<nsILocale> locale;
+      res = localeService->GetApplicationLocale(getter_AddRefs(locale));
+      if (NS_FAILED(res))
+        break;
+
+      nsAutoString loc;
+      res = locale->GetCategory(NS_LITERAL_STRING(NSILOCALE_MESSAGE), loc);
+      if (NS_FAILED(res))
+        break;
+
+      ToLowerCase(loc); // use lowercase for all language atoms
+      mLocaleLanguage = do_GetAtom(loc);
+    }
+  } while (0);
+
+  if (aError)
+    *aError = res;
+
+  return mLocaleLanguage;
+}
+
+nsIAtom*
+nsLanguageAtomService::GetLanguageGroup(nsIAtom *aLanguage,
+                                        nsresult *aError)
+{
+  nsIAtom *retVal;
+  nsresult res = NS_OK;
+
+  retVal = mLangToGroup.GetWeak(aLanguage);
+
+  if (!retVal) {
+    if (!mLangGroups) {
+      if (NS_FAILED(InitLangGroupTable())) {
+        if (aError) {
+          *aError = NS_ERROR_FAILURE;
+        }
+        return nullptr;
+      }
+    }
+
+    nsString langStr;
+    aLanguage->ToString(langStr);
+
+    nsXPIDLString langGroupStr;
+    res = mLangGroups->GetStringFromName(langStr.get(),
+                                         getter_Copies(langGroupStr));
+    if (NS_FAILED(res)) {
+      int32_t hyphen = langStr.FindChar('-');
+      if (hyphen >= 0) {
+        nsAutoString truncated(langStr);
+        truncated.Truncate(hyphen);
+        res = mLangGroups->GetStringFromName(truncated.get(),
+                                             getter_Copies(langGroupStr));
+        if (NS_FAILED(res)) {
+          langGroupStr.AssignLiteral("x-unicode");
+        }
+      } else {
+        langGroupStr.AssignLiteral("x-unicode");
+      }
+    }
+
+    nsCOMPtr<nsIAtom> langGroup = do_GetAtom(langGroupStr);
+
+    // The hashtable will keep an owning reference to the atom
+    mLangToGroup.Put(aLanguage, langGroup);
+    retVal = langGroup.get();
+  }
+
+  if (aError) {
+    *aError = res;
+  }
+
+  return retVal;
+}