Bug 1174386 - Make workers inherit the default Intl locale from the main thread, rather than using a bogus fallback value. r=jwalden

--HG--
extra : rebase_source : bb58c75416d4942affef3617ec427b2745261cf3

dom/workers/RuntimeService.cpp

@@ -987,6 +987,7 @@ class WorkerThreadPrimaryRunnable final : public Runnable
   WorkerPrivate* mWorkerPrivate;
   RefPtr<WorkerThread> mThread;
   JSRuntime* mParentRuntime;
+  JS::UniqueChars mDefaultLocale;
 
   class FinishedRunnable final : public Runnable
   {
@@ -1011,8 +1012,10 @@ class WorkerThreadPrimaryRunnable final : public Runnable
 public:
   WorkerThreadPrimaryRunnable(WorkerPrivate* aWorkerPrivate,
                               WorkerThread* aThread,
-                              JSRuntime* aParentRuntime)
-  : mWorkerPrivate(aWorkerPrivate), mThread(aThread), mParentRuntime(aParentRuntime)
+                              JSRuntime* aParentRuntime,
+                              JS::UniqueChars aDefaultLocale)
+  : mWorkerPrivate(aWorkerPrivate), mThread(aThread)
+  , mParentRuntime(aParentRuntime), mDefaultLocale(Move(aDefaultLocale))
   {
     MOZ_ASSERT(aWorkerPrivate);
     MOZ_ASSERT(aThread);
@@ -1626,9 +1629,15 @@ RuntimeService::ScheduleWorker(WorkerPrivate* aWorkerPrivate)
   }
 
   JSRuntime* rt = CycleCollectedJSRuntime::Get()->Runtime();
+  JSRuntime* parentRuntime = JS_GetParentRuntime(rt);
+  JS::UniqueChars defaultLocale = parentRuntime ? JS_GetDefaultLocale(parentRuntime) : nullptr;
+  if (!parentRuntime) {
+    NS_WARNING("Could not obtain parent runtime's locale!");
+  }
+
   nsCOMPtr<nsIRunnable> runnable =
-    new WorkerThreadPrimaryRunnable(aWorkerPrivate, thread,
-                                    JS_GetParentRuntime(rt));
+    new WorkerThreadPrimaryRunnable(aWorkerPrivate, thread, parentRuntime,
+                                    Move(defaultLocale));
   if (NS_FAILED(thread->DispatchPrimaryRunnable(friendKey, runnable.forget()))) {
     UnregisterWorker(aWorkerPrivate);
     return false;
@@ -2540,6 +2549,14 @@ WorkerThreadPrimaryRunnable::Run()
 
     JSRuntime* rt = runtime.Runtime();
 
+    if (mDefaultLocale) {
+      if (!JS_SetDefaultLocale(rt, mDefaultLocale.get())) {
+        NS_WARNING("Could not set worker locale!");
+      }
+
+      mDefaultLocale = nullptr;
+    }
+
     JSContext* cx = InitJSContextForWorker(mWorkerPrivate, rt);
     if (!cx) {
       // XXX need to fire an error at parent.

intl/locale/tests/unit/data/bug1174386_worker.js

@@ -0,0 +1,5 @@
+self.onmessage = function (data) {
+  let myLocale = Intl.NumberFormat().resolvedOptions().locale;
+  self.postMessage(myLocale);
+};
+

intl/locale/tests/unit/data/chrome.manifest

@@ -0,0 +1 @@
+content locale ./

intl/locale/tests/unit/test_bug1174386.js

@@ -0,0 +1,12 @@
+function run_test() {
+  do_load_manifest("data/chrome.manifest");
+  do_test_pending();
+  let mainThreadLocale = Intl.NumberFormat().resolvedOptions().locale;
+  let testWorker = new Worker("chrome://locale/content/bug1174386_worker.js");
+  testWorker.onmessage = function (e) {
+    let workerLocale = e.data;
+    equal(mainThreadLocale, workerLocale, "Worker should inherit Intl locale from main thread.");
+    do_test_finished();
+  };
+  testWorker.postMessage("go!");
+}

intl/locale/tests/unit/xpcshell.ini

@@ -2,6 +2,9 @@
 head = 
 tail = 
 skip-if = toolkit == 'gonk'
+support-files =
+  data/bug1174386_worker.js
+  data/chrome.manifest
 
 [test_bug22310.js]
 skip-if = toolkit != "windows" && toolkit != "cocoa"
@@ -14,6 +17,7 @@ skip-if = toolkit == "windows" || toolkit == "cocoa"
 skip-if = toolkit != "cocoa"
 
 [test_bug1086527.js]
+[test_bug1174386.js]
 [test_pluralForm.js]
 [test_pluralForm_english.js]
 [test_pluralForm_makeGetter.js]

js/src/jsapi.cpp

@@ -5819,6 +5819,16 @@ JS_SetDefaultLocale(JSContext* cx, const char* locale)
     return cx->setDefaultLocale(locale);
 }
 
+JS_PUBLIC_API(UniqueChars)
+JS_GetDefaultLocale(JSRuntime* rt)
+{
+    AssertHeapIsIdle(rt);
+    if (const char* locale = rt->getDefaultLocale())
+        return UniqueChars(JS_strdup(rt, locale));
+
+    return nullptr;
+}
+
 JS_PUBLIC_API(void)
 JS_ResetDefaultLocale(JSContext* cx)
 {

js/src/jsapi.h

@@ -5038,6 +5038,12 @@ JS_ParseJSONWithReviver(JSContext* cx, JS::HandleString str, JS::HandleValue rev
 extern JS_PUBLIC_API(bool)
 JS_SetDefaultLocale(JSContext* cx, const char* locale);
 
+/**
+ * Look up the default locale for the ECMAScript Internationalization API.
+ */
+extern JS_PUBLIC_API(JS::UniqueChars)
+JS_GetDefaultLocale(JSRuntime* rt);
+
 /**
  * Reset the default locale to OS defaults.
  */