Implement Object.defineProperty for proxies.

src/v8natives.js

Index: src/v8natives.js
diff --git a/src/v8natives.js b/src/v8natives.js
index 0afe231c8cdbf2863cc281a7110a9025f581683f..738e08f0baabf9796b39269dc50f778b5f63d429 100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -354,6 +354,19 @@ function FromPropertyDescriptor(desc) {
   return obj;
 }
 
+// Harmony Proxies
+function FromGenericPropertyDescriptor(desc) {
+  if (IS_UNDEFINED(desc)) return desc;
+  var obj = new $Object();
+  if (desc.hasValue_) obj.value = desc.getValue();

[Kevin Millikin (Chromium), 2011/07/07 08:12:02]

It's not obvious why you use the property hasValue_ in the test and the accessor
getValue() in the assignment.

[rossberg, 2011/07/07 09:19:32]

True. I copied from pre-existing functions. I fixed those, too.

+  if (desc.hasWritable_) obj.writable = desc.isWritable();
+  if (desc.hasGetter_) obj.get = desc.getGet();
+  if (desc.hasSetter_) obj.set = desc.getSet();
+  if (desc.hasEnumerable_) obj.enumerable = desc.isEnumerable();
+  if (desc.hasConfigurable_) obj.configurable = desc.isConfigurable();
+  return obj;
+}
+
 // ES5 8.10.5.
 function ToPropertyDescriptor(obj) {
   if (!IS_SPEC_OBJECT(obj)) {
@@ -616,8 +629,32 @@ function GetOwnProperty(obj, p) {
 }
 
 
+// Harmony proxies.
+function DefineProxyProperty(obj, p, attributes, should_throw) {
+  var handler = %GetHandler(obj);
+  var defineProperty = handler.defineProperty;
+  if (IS_UNDEFINED(defineProperty)) {
+    throw MakeTypeError("handler_trap_missing", [handler, "defineProperty"]);
+  }
+  var result = defineProperty.call(handler, p, attributes);
+  if (!ToBoolean(result)) {
+    if (should_throw) {
+      throw MakeTypeError("handler_failed", [handler, "defineProperty"]);
+    } else {
+      return false;
+    }
+  }
+  return true;
+}
+
+
 // ES5 8.12.9.
 function DefineOwnProperty(obj, p, desc, should_throw) {
+  if (%IsJSProxy(obj)) {
+    var attributes = FromGenericPropertyDescriptor(desc);
+    return DefineProxyProperty(obj, p, attributes, should_throw);
+  }
+
   var current_or_access = %GetOwnProperty(ToObject(obj), ToString(p));
   // A false value here means that access checks failed.
   if (current_or_access === false) return void 0;
@@ -900,8 +937,37 @@ function ObjectDefineProperty(obj, p, attributes) {
     throw MakeTypeError("obj_ctor_property_non_object", ["defineProperty"]);
   }
   var name = ToString(p);
-  var desc = ToPropertyDescriptor(attributes);
-  DefineOwnProperty(obj, name, desc, true);
+  if (%IsJSProxy(obj)) {
+    // Clone the attributes object for protection.
+    // TODO(rossberg): not spec'ed yet, so not sure if this should involve
+    // non-own properties as it does (or non-enumerable ones, as it doesn't?).
+    var attributesClone = {}
+    for (var a in attributes) {
+      attributesClone[a] = attributes[a];
+    }
+    DefineProxyProperty(obj, name, attributesClone, true);
+    // The following would implement the spec as in the current proposal,
+    // but after recent comments on es-discuss, is most likely obsolete.
+    /*
+    var defineObj = FromGenericPropertyDescriptor(desc);
+    var names = ObjectGetOwnPropertyNames(attributes);
+    var standardNames =
+      {value: 0, writable: 0, get: 0, set: 0, enumerable: 0, configurable: 0};
+    for (var i = 0; i < names.length; i++) {
+      var N = names[i];
+      if (!(%HasLocalProperty(standardNames, N))) {
+        var attr = GetOwnProperty(attributes, N);
+        DefineOwnProperty(descObj, N, attr, true);
+      }
+    }
+    // This is really confusing the types, but it is what the proxies spec
+    // currently requires:
+    desc = descObj;
+    */
+  } else {
+    var desc = ToPropertyDescriptor(attributes);
+    DefineOwnProperty(obj, name, desc, true);
+  }
   return obj;
 }