[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 1536 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")));
+  }
+
+  // TODO(neis): For now, we ignore proxies.

[rossberg, 2015/10/15 10:54:40]

Actually, the case distinction should not be made here, it should be in a new
method JSReceiver::PreventExtensions. The same probably goes for all other
Reflect methods.

+
+  if (target->IsJSObject()) {
+    bool result;
+    MAYBE_ASSIGN_RETURN_ON_EXCEPTION(
+        isolate, bool, result,
+        JSObject::PreventExtensionsInternal(Handle<JSObject>::cast(target)));
+    return *isolate->factory()->ToBoolean(result);
+  }
+  return *isolate->factory()->false_value();
+}
+
+
 // 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