Add support for API accessors that prohibit overwriting by accessors...

include/v8.h

 // Copyright 2007-2008 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 1283 matching lines @@
  */
 typedef Handle<Array> (*IndexedPropertyEnumerator)(const AccessorInfo& info);
 
 
 /**
  * Access control specifications.
  *
  * Some accessors should be accessible across contexts.  These
  * accessors have an explicit access control parameter which specifies
  * the kind of cross-context access that should be allowed.
+ *
+ * Additionally, for security, accessors can prohibit overwriting by
+ * accessors defined in JavaScript.  For objects that have such
+ * accessors either locally or in their prototype chain it is not
+ * possible to overwrite the accessor by using __defineGetter__ or
+ * __defineSetter__ from JavaScript code.
  */
 enum AccessControl {
-  DEFAULT         = 0,
-  ALL_CAN_READ    = 1,
-  ALL_CAN_WRITE   = 2
+  DEFAULT               = 0,
+  ALL_CAN_READ          = 1,
+  ALL_CAN_WRITE         = 1 << 1,
+  PROHIBITS_OVERWRITING = 1 << 2
 };
 
 
 /**
  * Access type specification.
  */
 enum AccessType {
   ACCESS_GET,
   ACCESS_SET,
   ACCESS_HAS,
@@ skipping 1105 matching lines @@
 
 }  // namespace v8
 
 
 #undef EXPORT
 #undef EXPORT_INLINE
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_