[es6] Partially implement Reflect.preventExtensions.

src/builtins.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/builtins.h"
 
 #include "src/api.h"
 #include "src/api-natives.h"
 #include "src/arguments.h"
 #include "src/base/once.h"
@@ skipping 1499 matching lines @@
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate, NewTypeError(MessageTemplate::kCalledOnNonObject,
                               isolate->factory()->NewStringFromAsciiChecked(
                                   "Reflect.has")));
   }
 
   Handle<Name> name;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, name,
                                      Object::ToName(isolate, key));
 
-  Maybe<bool> maybe =
+  Maybe<bool> result =
       JSReceiver::HasProperty(Handle<JSReceiver>::cast(target), name);
-  if (!maybe.IsJust()) return isolate->heap()->exception();
-  return *isolate->factory()->ToBoolean(maybe.FromJust());
+  return result.IsJust() ? *isolate->factory()->ToBoolean(result.FromJust())
+                         : isolate->heap()->exception();
 }
 
 
 // ES6 section 26.1.10 Reflect.isExtensible
 BUILTIN(ReflectIsExtensible) {
   HandleScope scope(isolate);
   DCHECK_EQ(2, args.length());
   Handle<Object> target = args.at<Object>(1);
 
   if (!target->IsJSReceiver()) {
@@ skipping 13 matching lines @@
   */
 
   if (target->IsJSObject()) {
     return *isolate->factory()->ToBoolean(
         JSObject::IsExtensible(Handle<JSObject>::cast(target)));
   }
   return *isolate->factory()->false_value();
 }
 
 
+// ES6 section 26.1.12 Reflect.preventExtensions
+BUILTIN(ReflectPreventExtensions) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(2, args.length());
+  Handle<Object> target = args.at<Object>(1);
+
+  if (!target->IsJSReceiver()) {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate, NewTypeError(MessageTemplate::kCalledOnNonObject,
+                              isolate->factory()->NewStringFromAsciiChecked(
+                                  "Reflect.preventExtensions")));
+  }
+
+  Maybe<bool> result = JSReceiver::PreventExtensions(
+      Handle<JSReceiver>::cast(target), DONT_THROW);
+  return result.IsJust() ? *isolate->factory()->ToBoolean(result.FromJust())
+                         : isolate->heap()->exception();
+}
+
+
 // ES6 section 20.3.4.45 Date.prototype [ @@toPrimitive ] ( hint )
 BUILTIN(DateToPrimitive) {
   HandleScope scope(isolate);
   DCHECK_EQ(2, args.length());
   if (!args.receiver()->IsJSReceiver()) {
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate, NewTypeError(MessageTemplate::kIncompatibleMethodReceiver,
                               isolate->factory()->NewStringFromAsciiChecked(
                                   "Date.prototype [ @@toPrimitive ]"),
                               args.receiver()));
@@ skipping 632 matching lines @@
 BUILTIN_LIST_C(DEFINE_BUILTIN_ACCESSOR_C)
 BUILTIN_LIST_A(DEFINE_BUILTIN_ACCESSOR_A)
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 
 
 }  // namespace internal
 }  // namespace v8