new persistent semantics

src/global-handles.h

 // Copyright 2011 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 110 matching lines @@
 };
 
 
 class GlobalHandles {
  public:
   ~GlobalHandles();
 
   // Creates a new global handle that is alive until Destroy is called.
   Handle<Object> Create(Object* value);
 
+  // Copy a global handle
+  static Handle<Object> CopyGlobal(Object** location);
+
   // Destroy a global handle.
   static void Destroy(Object** location);
 
+  typedef WeakCallbackData<v8::Value, void>::Callback WeakCallback;
   typedef WeakReferenceCallbacks<v8::Value, void>::Revivable RevivableCallback;
 
   // Make the global handle weak and set the callback parameter for the
   // handle.  When the garbage collector recognizes that only weak global
   // handles point to an object the handles are cleared and the callback
   // function is invoked (for each handle) with the handle and corresponding
   // parameter as arguments.  Note: cleared means set to Smi::FromInt(0). The
   // reason is that Smi::FromInt(0) does not change during garage collection.
   static void MakeWeak(Object** location,
                        void* parameter,
-                       RevivableCallback weak_reference_callback);
+                       WeakCallback weak_callback,

[Sven Panne, 2013/09/05 08:24:09]

I'm a bit lost here: Why do we need a 2nd kind of callback (again)?

[dcarney, 2013/09/05 08:32:05]

this handle removes direct access to the underlying persistent, forcing the user
to dispose the handle directly themselves, which has always been an issue

[Sven Panne, 2013/09/05 08:43:01]

Ah, OK. So the revivable stuff is only there for a transitional phase, right?

+                       RevivableCallback revivable_callback);
+
+  static inline void MakeWeak(Object** location,
+                              void* parameter,
+                              RevivableCallback revivable_callback) {
+    MakeWeak(location, parameter, NULL, revivable_callback);
+  }
 
   void RecordStats(HeapStats* stats);
 
   // Returns the current number of weak handles.
   int NumberOfWeakHandles();
 
   // Returns the current number of weak handles to global objects.
   // These handles are also included in NumberOfWeakHandles().
   int NumberOfGlobalObjectWeakHandles();
 
@@ skipping 243 matching lines @@
   List<int> new_space_indices_;
   int singleton_handles_[NUMBER_OF_SINGLETON_HANDLES];
 
   DISALLOW_COPY_AND_ASSIGN(EternalHandles);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_GLOBAL_HANDLES_H_