Use InternalArray in Object.getOwnPropertyNames() implementation

src/v8natives.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 999 matching lines @@
   // Special handling for proxies.
   if (%IsJSProxy(obj)) {
     var handler = %GetHandler(obj);
     var names = CallTrap0(handler, "getOwnPropertyNames", void 0);
     return ToStringArray(names, "getOwnPropertyNames");
   }
 
   // Find all the indexed properties.
 
   // Get the local element names.
-  var propertyNames = %GetLocalElementNames(obj);
+  var propertyNames = new InternalArray;
+  %MoveArrayContents(%GetLocalElementNames(obj), propertyNames);
   for (var i = 0; i < propertyNames.length; ++i) {
     propertyNames[i] = %_NumberToString(propertyNames[i]);
   }
 
   // Get names for indexed interceptor properties.
   var interceptorInfo = %GetInterceptorInfo(obj);
   if ((interceptorInfo & 1) != 0) {
     var indexedInterceptorNames =
         %GetIndexedInterceptorElementNames(obj);
     if (indexedInterceptorNames) {
       propertyNames = propertyNames.concat(indexedInterceptorNames);

[Vyacheslav Egorov (Google), 2013/02/26 01:21:33]

I guess here you should %MoveArrayContents instead of assigning

     }
   }
 
   // Find all the named properties.
 
   // Get the local property names.
   propertyNames = propertyNames.concat(%GetLocalPropertyNames(obj));

[Vyacheslav Egorov (Google), 2013/02/26 01:21:33]

ditto

 
   // Get names for named interceptor properties if any.
   if ((interceptorInfo & 2) != 0) {
     var namedInterceptorNames =
         %GetNamedInterceptorPropertyNames(obj);
     if (namedInterceptorNames) {
       propertyNames = propertyNames.concat(namedInterceptorNames);

[Vyacheslav Egorov (Google), 2013/02/26 01:21:33]

here I guess you can leave assignment. though for consistency you might want to
%Move...

     }
   }
 
   // Property names are expected to be unique strings,
   // but interceptors can interfere with that assumption.
   if (interceptorInfo != 0) {
     var propertySet = { __proto__: null };
     var j = 0;
     for (var i = 0; i < propertyNames.length; ++i) {
       var name = ToString(propertyNames[i]);
       // We need to check for the exact property value since for intrinsic

[Vyacheslav Egorov (Google), 2013/02/26 01:21:33]

I think this comment is out of date

[adamk, 2013/02/26 02:28:12]

Happy to remove if mstarzinger agrees.

       // properties like toString if(propertySet["toString"]) will always
       // succeed.
       if (propertySet[name] === true) {
         continue;
       }
       propertySet[name] = true;
       propertyNames[j++] = name;
     }
     propertyNames.length = j;
   }
 
-  return propertyNames;
+  var result = [];

[Vyacheslav Egorov (Google), 2013/02/26 01:21:33]

I wonder if it should be new $Array() for consistency with some other places
(e.g. map).

[adamk, 2013/02/26 02:28:12]

Changed to $Array.

+  %MoveArrayContents(propertyNames, result);
+  return result;
 }
 
 
 // ES5 section 15.2.3.5.
 function ObjectCreate(proto, properties) {
   if (!IS_SPEC_OBJECT(proto) && proto !== null) {
     throw MakeTypeError("proto_object_or_null", [proto]);
   }
   var obj = new $Object();
   obj.__proto__ = proto;
@@ skipping 645 matching lines @@
 
 function SetUpFunction() {
   %CheckIsBootstrapping();
   InstallFunctions($Function.prototype, DONT_ENUM, $Array(
     "bind", FunctionBind,
     "toString", FunctionToString
   ));
 }
 
 SetUpFunction();