new persistent semantics

src/global-handles.h

Index: src/global-handles.h
diff --git a/src/global-handles.h b/src/global-handles.h
index 5a4ad13e2f59c3b8342a6b03328f2336f4bcb06f..2d4076db1a8270f0dd4843c1cdc70a69f79679b4 100644
--- a/src/global-handles.h
+++ b/src/global-handles.h
@@ -128,9 +128,13 @@ class 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
@@ -141,7 +145,14 @@ class GlobalHandles {
   // 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);