Introduce an API to force the deletion of a property ignoring...

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 2762 matching lines @@
 
   if (name->AsArrayIndex(&index)) {
     ASSERT(attr == NONE);
     return js_object->SetElement(index, *value);
   } else {
     return js_object->IgnoreAttributesAndSetLocalProperty(*name, *value, attr);
   }
 }
 
 
+Object* Runtime::ForceDeleteObjectProperty(Handle<JSObject> js_object,
+                                           Handle<Object> key) {
+  HandleScope scope;
+
+  // Check if the given key is an array index.
+  uint32_t index;
+  if (Array::IndexFromObject(*key, &index)) {
+    // In Firefox/SpiderMonkey, Safari and Opera you can access the
+    // characters of a string using [] notation.  In the case of a
+    // String object we just need to redirect the deletion to the
+    // underlying string if the index is in range.  Since the
+    // underlying string does nothing with the deletion, we can ignore
+    // such deletions.
+    if (js_object->IsStringObjectWithCharacterAt(index)) {
+      return Heap::true_value();
+    }
+
+    return js_object->DeleteElement(index, JSObject::FORCE_DELETION);
+  }
+
+  Handle<String> key_string;
+  if (key->IsString()) {
+    key_string = Handle<String>::cast(key);
+  } else {
+    // Call-back into JavaScript to convert the key to a string.
+    bool has_pending_exception = false;
+    Handle<Object> converted = Execution::ToString(key, &has_pending_exception);
+    if (has_pending_exception) return Failure::Exception();
+    key_string = Handle<String>::cast(converted);
+  }
+
+  key_string->TryFlattenIfNotFlat();
+  return js_object->DeleteProperty(*key_string, JSObject::FORCE_DELETION);
+}
+
+
 static Object* Runtime_SetProperty(Arguments args) {
   NoHandleAllocation ha;
   RUNTIME_ASSERT(args.length() == 3 || args.length() == 4);
 
   Handle<Object> object = args.at<Object>(0);
   Handle<Object> key = args.at<Object>(1);
   Handle<Object> value = args.at<Object>(2);
 
   // Compute attributes.
   PropertyAttributes attributes = NONE;
@@ skipping 31 matching lines @@
       IgnoreAttributesAndSetLocalProperty(name, args[2], attributes);
 }
 
 
 static Object* Runtime_DeleteProperty(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
   CONVERT_CHECKED(JSObject, object, args[0]);
   CONVERT_CHECKED(String, key, args[1]);
-  return object->DeleteProperty(key);
+  return object->DeleteProperty(key, JSObject::NORMAL_DELETION);
 }
 
 
 static Object* HasLocalPropertyImplementation(Handle<JSObject> object,
                                               Handle<String> key) {
   if (object->HasLocalProperty(*key)) return Heap::true_value();
   // Handle hidden prototypes.  If there's a hidden prototype above this thing
   // then we have to check it for properties, because they are supposed to
   // look like they are on this object.
   Handle<Object> proto(object->GetPrototype());
@@ skipping 4223 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();
   }
 }
 
 
 } }  // namespace v8::internal