Fix getOwnPropertyDescriptor() support for index properties.

src/runtime.cc

 // Copyright 2006-2009 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 626 matching lines @@
   HandleScope scope;
   Handle<FixedArray> elms = Factory::NewFixedArray(DESCRIPTOR_SIZE);
   Handle<JSArray> desc = Factory::NewJSArrayWithElements(elms);
   LookupResult result;
   CONVERT_CHECKED(JSObject, obj, args[0]);
   CONVERT_CHECKED(String, name, args[1]);
 
   // This could be an element.
   uint32_t index;
   if (name->AsArrayIndex(&index)) {
-    if (!obj->HasLocalElement(index)) {
-      return Heap::undefined_value();
-    }
+    switch (obj->HasLocalElement(index)) {
+      case JSObject::UNDEFINED_ELEMENT:
+        return Heap::undefined_value();
 
-    // Special handling of string objects according to ECMAScript 5 15.5.5.2.
-    // Note that this might be a string object with elements other than the
-    // actual string value. This is covered by the subsequent cases.
-    if (obj->IsStringObjectWithCharacterAt(index)) {
-      JSValue* js_value = JSValue::cast(obj);
-      String* str = String::cast(js_value->value());
-      elms->set(IS_ACCESSOR_INDEX, Heap::false_value());
-      elms->set(VALUE_INDEX, str->SubString(index, index+1));
-      elms->set(WRITABLE_INDEX, Heap::false_value());
-      elms->set(ENUMERABLE_INDEX,  Heap::false_value());
-      elms->set(CONFIGURABLE_INDEX, Heap::false_value());
-      return *desc;
-    }
+      case JSObject::STRING_CHARACTER_ELEMENT: {
+        // Special handling of string objects according to ECMAScript 5
+        // 15.5.5.2. Note that this might be a string object with elements
+        // other than the actual string value. This is covered by the
+        // subsequent cases.
+        JSValue* js_value = JSValue::cast(obj);
+        String* str = String::cast(js_value->value());
+        elms->set(IS_ACCESSOR_INDEX, Heap::false_value());
+        elms->set(VALUE_INDEX, str->SubString(index, index+1));
+        elms->set(WRITABLE_INDEX, Heap::false_value());
+        elms->set(ENUMERABLE_INDEX,  Heap::false_value());
+        elms->set(CONFIGURABLE_INDEX, Heap::false_value());
+        return *desc;
+      }
 
-    // This can potentially be an element in the elements dictionary or
-    // a fast element.
-    if (obj->HasDictionaryElements()) {
-      NumberDictionary* dictionary = obj->element_dictionary();
-      int entry = dictionary->FindEntry(index);
-      PropertyDetails details = dictionary->DetailsAt(entry);
-      elms->set(IS_ACCESSOR_INDEX, Heap::false_value());
-      elms->set(VALUE_INDEX, dictionary->ValueAt(entry));
-      elms->set(WRITABLE_INDEX, Heap::ToBoolean(!details.IsReadOnly()));
-      elms->set(ENUMERABLE_INDEX, Heap::ToBoolean(!details.IsDontEnum()));
-      elms->set(CONFIGURABLE_INDEX, Heap::ToBoolean(!details.IsDontDelete()));
-      return *desc;
-    } else {
-      // Elements that are stored as array elements always has:
-      // writable: true, configurable: true, enumerable: true.
-      elms->set(IS_ACCESSOR_INDEX, Heap::false_value());
-      elms->set(VALUE_INDEX, obj->GetElement(index));
-      elms->set(WRITABLE_INDEX, Heap::true_value());
-      elms->set(ENUMERABLE_INDEX,  Heap::true_value());
-      elms->set(CONFIGURABLE_INDEX, Heap::true_value());
-      return *desc;
+      case JSObject::INTERCEPTED_ELEMENT:
+      case JSObject::FAST_ELEMENT:
+        elms->set(IS_ACCESSOR_INDEX, Heap::false_value());
+        elms->set(VALUE_INDEX, obj->GetElement(index));
+        elms->set(WRITABLE_INDEX, Heap::true_value());
+        elms->set(ENUMERABLE_INDEX,  Heap::true_value());

[antonm, 2010/09/22 13:26:38]

I am not sure all intercepted elements are enumerable.  You might prefer to use
query to find out precise attributes.

+        elms->set(CONFIGURABLE_INDEX, Heap::true_value());
+        return *desc;
+
+      case JSObject::DICTIONARY_ELEMENT: {
+        NumberDictionary* dictionary = obj->element_dictionary();
+        int entry = dictionary->FindEntry(index);
+        ASSERT(entry != NumberDictionary::kNotFound);
+        PropertyDetails details = dictionary->DetailsAt(entry);
+        if (details.type() == CALLBACKS) {
+          FixedArray* callbacks = FixedArray::cast(dictionary->ValueAt(entry));
+          elms->set(IS_ACCESSOR_INDEX, Heap::true_value());
+          elms->set(GETTER_INDEX, callbacks->get(0));
+          elms->set(SETTER_INDEX, callbacks->get(1));
+        } else {

[Rico, 2010/09/22 15:23:56]

Add comment on why we would go in here

+          elms->set(IS_ACCESSOR_INDEX, Heap::false_value());
+          elms->set(VALUE_INDEX, dictionary->ValueAt(entry));
+          elms->set(WRITABLE_INDEX, Heap::ToBoolean(!details.IsReadOnly()));
+        }
+        elms->set(ENUMERABLE_INDEX, Heap::ToBoolean(!details.IsDontEnum()));
+        elms->set(CONFIGURABLE_INDEX, Heap::ToBoolean(!details.IsDontDelete()));
+        return *desc;
+      }
     }
   }
 
   // Use recursive implementation to also traverse hidden prototypes
   GetOwnPropertyImplementation(obj, name, &result);
 
   if (!result.IsProperty()) {
     return Heap::undefined_value();
   }
   if (result.type() == CALLBACKS) {
@@ skipping 9467 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal