diff -r 000000000000 -r 6474c204b198 js/xpconnect/src/XPCLocale.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/xpconnect/src/XPCLocale.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,281 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "mozilla/Assertions.h"
+
+#include "jsapi.h"
+
+#include "nsCollationCID.h"
+#include "nsJSUtils.h"
+#include "nsICharsetConverterManager.h"
+#include "nsIPlatformCharset.h"
+#include "nsILocaleService.h"
+#include "nsICollation.h"
+#include "nsUnicharUtils.h"
+#include "nsComponentManagerUtils.h"
+#include "nsServiceManagerUtils.h"
+
+#include "xpcpublic.h"
+
+using namespace JS;
+
+/**
+ * JS locale callbacks implemented by XPCOM modules.  These are theoretically
+ * safe for use on multiple threads.  Unfortunately, the intl code underlying
+ * these XPCOM modules doesn't yet support this, so in practice
+ * XPCLocaleCallbacks are limited to the main thread.
+ */
+struct XPCLocaleCallbacks : public JSLocaleCallbacks
+{
+  XPCLocaleCallbacks()
+#ifdef DEBUG
+    : mThread(PR_GetCurrentThread())
+#endif
+  {
+    MOZ_COUNT_CTOR(XPCLocaleCallbacks);
+
+    localeToUpperCase = LocaleToUpperCase;
+    localeToLowerCase = LocaleToLowerCase;
+    localeCompare = LocaleCompare;
+    localeToUnicode = LocaleToUnicode;
+    localeGetErrorMessage = nullptr;
+  }
+
+  ~XPCLocaleCallbacks()
+  {
+    AssertThreadSafety();
+    MOZ_COUNT_DTOR(XPCLocaleCallbacks);
+  }
+
+  /**
+   * Return the XPCLocaleCallbacks that's hidden away in |rt|. (This impl uses
+   * the locale callbacks struct to store away its per-runtime data.)
+   */
+  static XPCLocaleCallbacks*
+  This(JSRuntime *rt)
+  {
+    // Locale information for |rt| was associated using xpc_LocalizeRuntime;
+    // assert and double-check this.
+    JSLocaleCallbacks* lc = JS_GetLocaleCallbacks(rt);
+    MOZ_ASSERT(lc);
+    MOZ_ASSERT(lc->localeToUpperCase == LocaleToUpperCase);
+    MOZ_ASSERT(lc->localeToLowerCase == LocaleToLowerCase);
+    MOZ_ASSERT(lc->localeCompare == LocaleCompare);
+    MOZ_ASSERT(lc->localeToUnicode == LocaleToUnicode);
+
+    XPCLocaleCallbacks* ths = static_cast<XPCLocaleCallbacks*>(lc);
+    ths->AssertThreadSafety();
+    return ths;
+  }
+
+  static bool
+  LocaleToUpperCase(JSContext *cx, HandleString src, MutableHandleValue rval)
+  {
+    return ChangeCase(cx, src, rval, ToUpperCase);
+  }
+
+  static bool
+  LocaleToLowerCase(JSContext *cx, HandleString src, MutableHandleValue rval)
+  {
+    return ChangeCase(cx, src, rval, ToLowerCase);
+  }
+
+  static bool
+  LocaleToUnicode(JSContext* cx, const char* src, MutableHandleValue rval)
+  {
+    return This(JS_GetRuntime(cx))->ToUnicode(cx, src, rval);
+  }
+
+  static bool
+  LocaleCompare(JSContext *cx, HandleString src1, HandleString src2, MutableHandleValue rval)
+  {
+    return This(JS_GetRuntime(cx))->Compare(cx, src1, src2, rval);
+  }
+
+private:
+  static bool
+  ChangeCase(JSContext* cx, HandleString src, MutableHandleValue rval,
+             void(*changeCaseFnc)(const nsAString&, nsAString&))
+  {
+    nsDependentJSString depStr;
+    if (!depStr.init(cx, src)) {
+      return false;
+    }
+
+    nsAutoString result;
+    changeCaseFnc(depStr, result);
+
+    JSString *ucstr =
+      JS_NewUCStringCopyN(cx, result.get(), result.Length());
+    if (!ucstr) {
+      return false;
+    }
+
+    rval.set(STRING_TO_JSVAL(ucstr));
+    return true;
+  }
+
+  bool
+  Compare(JSContext *cx, HandleString src1, HandleString src2, MutableHandleValue rval)
+  {
+    nsresult rv;
+
+    if (!mCollation) {
+      nsCOMPtr<nsILocaleService> localeService =
+        do_GetService(NS_LOCALESERVICE_CONTRACTID, &rv);
+
+      if (NS_SUCCEEDED(rv)) {
+        nsCOMPtr<nsILocale> locale;
+        rv = localeService->GetApplicationLocale(getter_AddRefs(locale));
+
+        if (NS_SUCCEEDED(rv)) {
+          nsCOMPtr<nsICollationFactory> colFactory =
+            do_CreateInstance(NS_COLLATIONFACTORY_CONTRACTID, &rv);
+
+          if (NS_SUCCEEDED(rv)) {
+            rv = colFactory->CreateCollation(locale, getter_AddRefs(mCollation));
+          }
+        }
+      }
+
+      if (NS_FAILED(rv)) {
+        xpc::Throw(cx, rv);
+        return false;
+      }
+    }
+
+    nsDependentJSString depStr1, depStr2;
+    if (!depStr1.init(cx, src1) || !depStr2.init(cx, src2)) {
+      return false;
+    }
+
+    int32_t result;
+    rv = mCollation->CompareString(nsICollation::kCollationStrengthDefault,
+                                   depStr1, depStr2, &result);
+
+    if (NS_FAILED(rv)) {
+      xpc::Throw(cx, rv);
+      return false;
+    }
+
+    rval.set(INT_TO_JSVAL(result));
+    return true;
+  }
+
+  bool
+  ToUnicode(JSContext* cx, const char* src, MutableHandleValue rval)
+  {
+    nsresult rv;
+
+    if (!mDecoder) {
+      // use app default locale
+      nsCOMPtr<nsILocaleService> localeService =
+        do_GetService(NS_LOCALESERVICE_CONTRACTID, &rv);
+      if (NS_SUCCEEDED(rv)) {
+        nsCOMPtr<nsILocale> appLocale;
+        rv = localeService->GetApplicationLocale(getter_AddRefs(appLocale));
+        if (NS_SUCCEEDED(rv)) {
+          nsAutoString localeStr;
+          rv = appLocale->
+               GetCategory(NS_LITERAL_STRING(NSILOCALE_TIME), localeStr);
+          MOZ_ASSERT(NS_SUCCEEDED(rv), "failed to get app locale info");
+
+          nsCOMPtr<nsIPlatformCharset> platformCharset =
+            do_GetService(NS_PLATFORMCHARSET_CONTRACTID, &rv);
+
+          if (NS_SUCCEEDED(rv)) {
+            nsAutoCString charset;
+            rv = platformCharset->GetDefaultCharsetForLocale(localeStr, charset);
+            if (NS_SUCCEEDED(rv)) {
+              // get/create unicode decoder for charset
+              nsCOMPtr<nsICharsetConverterManager> ccm =
+                do_GetService(NS_CHARSETCONVERTERMANAGER_CONTRACTID, &rv);
+              if (NS_SUCCEEDED(rv))
+                ccm->GetUnicodeDecoder(charset.get(), getter_AddRefs(mDecoder));
+            }
+          }
+        }
+      }
+    }
+
+    int32_t srcLength = strlen(src);
+
+    if (mDecoder) {
+      int32_t unicharLength = srcLength;
+      char16_t *unichars =
+        (char16_t *)JS_malloc(cx, (srcLength + 1) * sizeof(char16_t));
+      if (unichars) {
+        rv = mDecoder->Convert(src, &srcLength, unichars, &unicharLength);
+        if (NS_SUCCEEDED(rv)) {
+          // terminate the returned string
+          unichars[unicharLength] = 0;
+
+          // nsIUnicodeDecoder::Convert may use fewer than srcLength PRUnichars
+          if (unicharLength + 1 < srcLength + 1) {
+            char16_t *shrunkUnichars =
+              (char16_t *)JS_realloc(cx, unichars,
+                                      (unicharLength + 1) * sizeof(char16_t));
+            if (shrunkUnichars)
+              unichars = shrunkUnichars;
+          }
+          JSString *str = JS_NewUCString(cx, reinterpret_cast<jschar*>(unichars), unicharLength);
+          if (str) {
+            rval.setString(str);
+            return true;
+          }
+        }
+        JS_free(cx, unichars);
+      }
+    }
+
+    xpc::Throw(cx, NS_ERROR_OUT_OF_MEMORY);
+    return false;
+  }
+
+  void AssertThreadSafety()
+  {
+    MOZ_ASSERT(mThread == PR_GetCurrentThread(),
+               "XPCLocaleCallbacks used unsafely!");
+  }
+
+  nsCOMPtr<nsICollation> mCollation;
+  nsCOMPtr<nsIUnicodeDecoder> mDecoder;
+#ifdef DEBUG
+  PRThread* mThread;
+#endif
+};
+
+bool
+xpc_LocalizeRuntime(JSRuntime *rt)
+{
+  JS_SetLocaleCallbacks(rt, new XPCLocaleCallbacks());
+
+  // Set the default locale.
+  nsCOMPtr<nsILocaleService> localeService =
+    do_GetService(NS_LOCALESERVICE_CONTRACTID);
+  if (!localeService)
+    return false;
+
+  nsCOMPtr<nsILocale> appLocale;
+  nsresult rv = localeService->GetApplicationLocale(getter_AddRefs(appLocale));
+  if (NS_FAILED(rv))
+    return false;
+
+  nsAutoString localeStr;
+  rv = appLocale->GetCategory(NS_LITERAL_STRING(NSILOCALE_TIME), localeStr);
+  MOZ_ASSERT(NS_SUCCEEDED(rv), "failed to get app locale info");
+  NS_LossyConvertUTF16toASCII locale(localeStr);
+
+  return !!JS_SetDefaultLocale(rt, locale.get());
+}
+
+void
+xpc_DelocalizeRuntime(JSRuntime *rt)
+{
+  XPCLocaleCallbacks* lc = XPCLocaleCallbacks::This(rt);
+  JS_SetLocaleCallbacks(rt, nullptr);
+  delete lc;
+}