Bug 907077: Change for-of to conform to latest ES6 specification. r=jwalden

js/src/jsiter.cpp

@@ -565,12 +565,12 @@ bool
 js::GetIterator(JSContext *cx, HandleObject obj, unsigned flags, MutableHandleValue vp)
 {
     if (flags == JSITER_FOR_OF) {
-        // for-of loop. The iterator is simply |obj.iterator()|.
+        // for-of loop. The iterator is simply |obj[@@iterator]()|.
         RootedValue method(cx);
-        if (!JSObject::getProperty(cx, obj, obj, cx->names().iterator, &method))
+        if (!JSObject::getProperty(cx, obj, obj, cx->names().std_iterator, &method))
             return false;
 
-        // Throw if obj.iterator isn't callable. js::Invoke is about to check
+        // Throw if obj[@@iterator] isn't callable. js::Invoke is about to check
         // for this kind of error anyway, but it would throw an inscrutable
         // error message about |method| rather than this nice one about |obj|.
         if (!method.isObject() || !method.toObject().isCallable()) {
@@ -593,6 +593,8 @@ js::GetIterator(JSContext *cx, HandleObject obj, unsigned flags, MutableHandleVa
         return true;
     }
 
+    JS_ASSERT(!(flags & JSITER_FOR_OF));
+
     Vector<Shape *, 8> shapes(cx);
     uint32_t key = 0;
 
@@ -725,6 +727,30 @@ js::GetIteratorObject(JSContext *cx, HandleObject obj, uint32_t flags)
     return &value.toObject();
 }
 
+JSObject *
+js::CreateItrResultObject(JSContext *cx, HandleValue value, bool done)
+{
+    // FIXME: We can cache the iterator result object shape somewhere.
+    AssertHeapIsIdle(cx);
+
+    RootedObject proto(cx, cx->global()->getOrCreateObjectPrototype(cx));
+    if (!proto)
+        return nullptr;
+
+    RootedObject obj(cx, NewObjectWithGivenProto(cx, &JSObject::class_, proto, cx->global()));
+    if (!obj)
+        return nullptr;
+
+    if (!JSObject::defineProperty(cx, obj, cx->names().value, value))
+        return nullptr;
+
+    RootedValue doneBool(cx, BooleanValue(done));
+    if (!JSObject::defineProperty(cx, obj, cx->names().done, doneBool))
+        return nullptr;
+
+    return obj;
+}
+
 bool
 js_ThrowStopIteration(JSContext *cx)
 {
@@ -781,14 +807,6 @@ iterator_next_impl(JSContext *cx, CallArgs args)
     return js_IteratorNext(cx, thisObj, args.rval());
 }
 
-static bool
-iterator_iterator(JSContext *cx, unsigned argc, Value *vp)
-{
-    CallArgs args = CallArgsFromVp(argc, vp);
-    args.rval().set(args.thisv());
-    return true;
-}
-
 bool
 iterator_next(JSContext *cx, unsigned argc, Value *vp)
 {
@@ -797,7 +815,7 @@ iterator_next(JSContext *cx, unsigned argc, Value *vp)
 }
 
 static const JSFunctionSpec iterator_methods[] = {
-    JS_FN("iterator",  iterator_iterator,   0, 0),
+    JS_SELF_HOSTED_FN("@@iterator", "LegacyIteratorShim", 0, 0),
     JS_FN("next",      iterator_next,       0, 0),
     JS_FS_END
 };
@@ -948,6 +966,7 @@ const Class ElementIteratorObject::class_ = {
 };
 
 const JSFunctionSpec ElementIteratorObject::methods[] = {
+    JS_SELF_HOSTED_FN("@@iterator", "LegacyIteratorShim", 0, 0),
     JS_FN("next", next, 0, 0),
     JS_FS_END
 };
@@ -1302,6 +1321,38 @@ const Class StopIterationObject::class_ = {
     NULL                     /* construct   */
 };
 
+bool
+ForOfIterator::next(MutableHandleValue vp, bool *done)
+{
+    JS_ASSERT(iterator);
+
+    RootedValue method(cx);
+    if (!JSObject::getProperty(cx, iterator, iterator, cx->names().next, &method))
+        return false;
+
+    InvokeArgs args(cx);
+    if (!args.init(1))
+        return false;
+    args.setCallee(method);
+    args.setThis(ObjectValue(*iterator));
+    args[0].setUndefined();
+    if (!Invoke(cx, args))
+        return false;
+
+    RootedObject resultObj(cx, ToObject(cx, args.rval()));
+    if (!resultObj)
+        return false;
+    RootedValue doneVal(cx);
+    if (!JSObject::getProperty(cx, resultObj, resultObj, cx->names().done, &doneVal))
+        return false;
+    *done = ToBoolean(doneVal);
+    if (*done) {
+        vp.setUndefined();
+        return true;
+    }
+    return JSObject::getProperty(cx, resultObj, resultObj, cx->names().value, vp);
+}
+
 /*** Generators **********************************************************************************/
 
 template<typename T>
@@ -1790,14 +1841,14 @@ NativeMethod(JSContext *cx, unsigned argc, Value *vp)
 #define JS_METHOD(name, T, impl, len, attrs) JS_FN(name, (NativeMethod<T,impl>), len, attrs)
 
 static const JSFunctionSpec star_generator_methods[] = {
-    JS_FN("iterator", iterator_iterator, 0, 0),
+    JS_SELF_HOSTED_FN("@@iterator", "IteratorIdentity", 0, 0),
     JS_METHOD("next", StarGeneratorObject, star_generator_next, 1, 0),
     JS_METHOD("throw", StarGeneratorObject, star_generator_throw, 1, 0),
     JS_FS_END
 };
 
 static const JSFunctionSpec legacy_generator_methods[] = {
-    JS_FN("iterator", iterator_iterator, 0, 0),
+    JS_SELF_HOSTED_FN("@@iterator", "LegacyGeneratorIteratorShim", 0, 0),
     // "send" is an alias for "next".
     JS_METHOD("next", LegacyGeneratorObject, legacy_generator_next, 1, JSPROP_ROPERM),
     JS_METHOD("send", LegacyGeneratorObject, legacy_generator_next, 1, JSPROP_ROPERM),