first step to remove unsafe handles

include/v8.h

 // Copyright 2012 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 97 matching lines @@
 class Date;
 class DeclaredAccessorDescriptor;
 class External;
 class Function;
 class FunctionTemplate;
 class HeapProfiler;
 class ImplementationUtilities;
 class Int32;
 class Integer;
 class Isolate;
+class LocalContext;
 class Number;
 class NumberObject;
 class Object;
 class ObjectOperationDescriptor;
 class ObjectTemplate;
 class Primitive;
 class RawOperationDescriptor;
 class Signature;
 class StackFrame;
 class StackTrace;
@@ skipping 37 matching lines @@
                                   Persistent<Value> object,
                                   void* parameter);
 
 // --- Handles ---
 
 #define TYPE_CHECK(T, S)                                       \
   while (false) {                                              \
     *(static_cast<T* volatile*>(0)) = static_cast<S*>(0);      \
   }
 
+
+#define V8_USE_UNSAFE_HANDLES
+
 /**
  * An object reference managed by the v8 garbage collector.
  *
  * All objects returned from v8 have to be tracked by the garbage
  * collector so that it knows that the objects are still alive.  Also,
  * because the garbage collector may move objects, it is unsafe to
  * point directly to an object.  Instead, all objects are stored in
  * handles which are known by the garbage collector and updated
  * whenever an object moves.  Handles should always be passed by value
  * (except in cases like out-parameters) and they should never be
@@ skipping 12 matching lines @@
  * behind the scenes and the same rules apply to these values as to
  * their handles.
  */
 template <class T> class Handle {
  public:
   /**
    * Creates an empty handle.
    */
   V8_INLINE(Handle()) : val_(0) {}
 
+#ifdef V8_USE_UNSAFE_HANDLES
   /**
    * Creates a new handle for the specified value.
    */
   V8_INLINE(explicit Handle(T* val)) : val_(val) {}
+#endif
 
   /**
    * Creates a handle for the contents of the specified handle.  This
    * constructor allows you to pass handles as arguments by value and
    * to assign between handles.  However, if you try to assign between
    * incompatible handles, for instance from a Handle<String> to a
    * Handle<Number> it will cause a compile-time error.  Assigning
    * between compatible handles, for instance assigning a
    * Handle<String> to a variable declared as Handle<Value>, is legal
    * because String is a subclass of Value.
@@ skipping 21 matching lines @@
   V8_INLINE(T* operator->() const) { return val_; }
 
   V8_INLINE(T* operator*() const) { return val_; }
 
   /**
    * Checks whether two handles are the same.
    * Returns true if both are empty, or if the objects
    * to which they refer are identical.
    * The handles' references are not checked.
    */
-  template <class S> V8_INLINE(bool operator==(Handle<S> that) const) {
+  template <class S> V8_INLINE(bool operator==(const Handle<S> that) const) {
     internal::Object** a = reinterpret_cast<internal::Object**>(**this);
     internal::Object** b = reinterpret_cast<internal::Object**>(*that);
     if (a == 0) return b == 0;
     if (b == 0) return false;
     return *a == *b;
   }
 
+#ifndef V8_USE_UNSAFE_HANDLES
+  template <class S> V8_INLINE(
+      bool operator==(const Persistent<S>& that) const) {
+    internal::Object** a = reinterpret_cast<internal::Object**>(**this);
+    internal::Object** b = reinterpret_cast<internal::Object**>(*that);
+    if (a == 0) return b == 0;
+    if (b == 0) return false;
+    return *a == *b;
+  }
+#endif
+
   /**
    * Checks whether two handles are different.
    * Returns true if only one of the handles is empty, or if
    * the objects to which they refer are different.
    * The handles' references are not checked.
    */
   template <class S> V8_INLINE(bool operator!=(Handle<S> that) const) {
     return !operator==(that);
   }
 
   template <class S> V8_INLINE(static Handle<T> Cast(Handle<S> that)) {
 #ifdef V8_ENABLE_CHECKS
     // If we're going to perform the type check then we have to check
     // that the handle isn't empty before doing the checked cast.
     if (that.IsEmpty()) return Handle<T>();
 #endif
     return Handle<T>(T::Cast(*that));
   }
 
   template <class S> V8_INLINE(Handle<S> As()) {
     return Handle<S>::Cast(*this);
   }
 
+#ifndef V8_USE_UNSAFE_HANDLES
+  V8_INLINE(static Handle<T> New(Isolate* isolate, Handle<T> that)) {
+    return New(isolate, that.val_);
+  }
+  // TODO(dcarney): remove before cutover
+  V8_INLINE(static Handle<T> New(Isolate* isolate, const Persistent<T>& that)) {
+    return New(isolate, that.val_);
+  }
+
+#ifndef V8_ALLOW_ACCESS_TO_RAW_HANDLE_CONSTRUCTOR
+
  private:
+#endif
+  /**
+   * Creates a new handle for the specified value.
+   */
+  V8_INLINE(explicit Handle(T* val)) : val_(val) {}
+#endif
+
+ private:
+  template<class F>
+  friend class Persistent;
+  template<class F>
+  friend class Local;
+  friend class Arguments;
+  friend class String;
+  friend class Object;
+  friend class AccessorInfo;
+  friend Handle<Primitive> Undefined(Isolate* isolate);
+  friend Handle<Primitive> Null(Isolate* isolate);
+  friend Handle<Boolean> True(Isolate* isolate);
+  friend Handle<Boolean> False(Isolate* isolate);
+  friend class Context;
+  friend class InternalHandleHelper;
+  friend class LocalContext;
+
+#ifndef V8_USE_UNSAFE_HANDLES
+  V8_INLINE(static Handle<T> New(Isolate* isolate, T* that));
+#endif
+
   T* val_;
 };
 
 
 /**
  * A light-weight stack-allocated object handle.  All operations
  * that return objects from within v8 return them in local handles.  They
  * are created within HandleScopes, and all local handles allocated within a
  * handle scope are destroyed when the handle scope is destroyed.  Hence it
  * is not necessary to explicitly deallocate local handles.
  */
+// TODO(dcarney): deprecate entire class
 template <class T> class Local : public Handle<T> {
  public:
   V8_INLINE(Local());
   template <class S> V8_INLINE(Local(Local<S> that))
       : Handle<T>(reinterpret_cast<T*>(*that)) {
     /**
      * This check fails when trying to convert between incompatible
      * handles. For example, converting from a Handle<String> to a
      * Handle<Number>.
      */
     TYPE_CHECK(T, S);
   }
+
+
+#ifdef V8_USE_UNSAFE_HANDLES
   template <class S> V8_INLINE(Local(S* that) : Handle<T>(that)) { }
+#endif
+
   template <class S> V8_INLINE(static Local<T> Cast(Local<S> that)) {
 #ifdef V8_ENABLE_CHECKS
     // If we're going to perform the type check then we have to check
     // that the handle isn't empty before doing the checked cast.
     if (that.IsEmpty()) return Local<T>();
 #endif
     return Local<T>(T::Cast(*that));
   }
+#ifndef V8_USE_UNSAFE_HANDLES
+  template <class S> V8_INLINE(Local(Handle<S> that))
+      : Handle<T>(reinterpret_cast<T*>(*that)) {
+    TYPE_CHECK(T, S);
+  }
+#endif
 
   template <class S> V8_INLINE(Local<S> As()) {
     return Local<S>::Cast(*this);
   }
 
   /**
    * Create a local handle for the content of another handle.
    * The referee is kept alive by the local handle even when
    * the original handle is destroyed/disposed.
    */
   V8_INLINE(static Local<T> New(Handle<T> that));
   V8_INLINE(static Local<T> New(Isolate* isolate, Handle<T> that));
+#ifndef V8_USE_UNSAFE_HANDLES
+  // TODO(dcarney): remove before cutover
+  V8_INLINE(static Local<T> New(Isolate* isolate, const Persistent<T>& that));
+
+#ifndef V8_ALLOW_ACCESS_TO_RAW_HANDLE_CONSTRUCTOR
+
+ private:
+#endif
+  template <class S> V8_INLINE(Local(S* that) : Handle<T>(that)) { }
+#endif
+
+ private:
+  template<class F>
+  friend class Persistent;
+  template<class F>
+  friend class Handle;
+  friend class Arguments;
+  friend class String;
+  friend class Object;
+  friend class AccessorInfo;
+  friend class Context;
+  friend class InternalHandleHelper;
+  friend class LocalContext;
+
+  V8_INLINE(static Local<T> New(Isolate* isolate, T* that));
 };
 
-
 /**
  * An object reference that is independent of any handle scope.  Where
  * a Local handle only lives as long as the HandleScope in which it was
  * allocated, a Persistent handle remains valid until it is explicitly
  * disposed.
  *
  * A persistent handle contains a reference to a storage cell within
  * the v8 engine which holds an object value and which is updated by
  * the garbage collector whenever the object is moved.  A new storage
  * cell can be created using Persistent::New and existing handles can
  * be disposed using Persistent::Dispose.  Since persistent handles
  * are passed by value you may have many persistent handle objects
  * that point to the same storage cell.  For instance, if you pass a
  * persistent handle as an argument to a function you will not get two
  * different storage cells but rather two references to the same
  * storage cell.
  */
-template <class T> class Persistent : public Handle<T> {
+template <class T> class Persistent // NOLINT
+#ifdef V8_USE_UNSAFE_HANDLES
+    : public Handle<T> {
+#else
+  { // NOLINT
+#endif
  public:
+#ifndef V8_USE_UNSAFE_HANDLES
+  V8_INLINE(Persistent()) : val_(0) { }
+  V8_INLINE(~Persistent()) {
+    // TODO(dcarney): add this back before cutover.
+    // Dispose();
+  }
+  V8_INLINE(bool IsEmpty() const) { return val_ == 0; }
+  // TODO(dcarney): remove somehow before cutover
+  // The handle should either be 0, or a pointer to a live cell.
+  V8_INLINE(void Clear()) { val_ = 0; }
+
+  /**
+   * A constructor that creates a new global cell pointing to that. In contrast
+   * to the copy constructor, this creates a new persistent handle which needs
+   * to be separately disposed.
+   */
+  template <class S> V8_INLINE(Persistent(Isolate* isolate, Handle<S> that))
+      : val_(*New(isolate, that)) { }
+
+#else
   /**
    * Creates an empty persistent handle that doesn't point to any
    * storage cell.
    */
-  V8_INLINE(Persistent());
+  V8_INLINE(Persistent()) : Handle<T>() { }
 
   /**
    * Creates a persistent handle for the same storage cell as the
    * specified handle.  This constructor allows you to pass persistent
    * handles as arguments by value and to assign between persistent
    * handles.  However, attempting to assign between incompatible
    * persistent handles, for instance from a Persistent<String> to a
    * Persistent<Number> will cause a compile-time error.  Assigning
    * between compatible persistent handles, for instance assigning a
    * Persistent<String> to a variable declared as Persistent<Value>,
@@ skipping 19 matching lines @@
   template <class S> V8_INLINE(Persistent(Isolate* isolate, Handle<S> that))
       : Handle<T>(New(isolate, that)) { }
 
   /**
    * "Casts" a plain handle which is known to be a persistent handle
    * to a persistent handle.
    */
   template <class S> explicit V8_INLINE(Persistent(Handle<S> that))
       : Handle<T>(*that) { }
 
+#endif
+
   template <class S> V8_INLINE(static Persistent<T> Cast(Persistent<S> that)) {
 #ifdef V8_ENABLE_CHECKS
     // If we're going to perform the type check then we have to check
     // that the handle isn't empty before doing the checked cast.
     if (that.IsEmpty()) return Persistent<T>();
 #endif
     return Persistent<T>(T::Cast(*that));
   }
 
   template <class S> V8_INLINE(Persistent<S> As()) {
     return Persistent<S>::Cast(*this);
   }
 
-  /** Deprecated. Use Isolate version instead. */
   V8_DEPRECATED(static Persistent<T> New(Handle<T> that));
 
   /**
    * Creates a new persistent handle for an existing local or persistent handle.
    */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(static Persistent<T> New(Isolate* isolate, Handle<T> that));
+#ifndef V8_USE_UNSAFE_HANDLES
+  // TODO(dcarney): remove before cutover
+  V8_INLINE(static Persistent<T> New(Isolate* isolate, Persistent<T> that));
+#endif
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(void Dispose());
+#ifndef V8_USE_UNSAFE_HANDLES
+  template <class S> V8_INLINE(
+      bool operator==(const Persistent<S>& that) const) {
+    internal::Object** a = reinterpret_cast<internal::Object**>(**this);
+    internal::Object** b = reinterpret_cast<internal::Object**>(*that);
+    if (a == 0) return b == 0;
+    if (b == 0) return false;
+    return *a == *b;
+  }
+
+  template <class S> V8_INLINE(bool operator==(const Handle<S> that) const) {
+    internal::Object** a = reinterpret_cast<internal::Object**>(**this);
+    internal::Object** b = reinterpret_cast<internal::Object**>(*that);
+    if (a == 0) return b == 0;
+    if (b == 0) return false;
+    return *a == *b;
+  }
+#endif
+
+  V8_INLINE(void Dispose());

[Sven Panne, 2013/04/30 07:31:22]

Why is V8_DEPRECATED changed to V8_INLINE here and at a few other places? To me
it seems like a typo...

[dcarney, 2013/04/30 07:43:21]

we need to revert that behaviour and change handle functions not to have isolate
parameters.  we talked about this a bit earlier (a month ago, though...)

 
   /**
    * Releases the storage cell referenced by this persistent handle.
    * Does not remove the reference to the cell from any handles.
    * This handle's reference, and any other references to the storage
    * cell remain and IsEmpty will still return false.
    */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(void Dispose(Isolate* isolate));
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(void MakeWeak(void* parameters,
+  V8_INLINE(void MakeWeak(void* parameters,
                               WeakReferenceCallback callback));
 
   /**
    * Make the reference to this object weak.  When only weak handles
    * refer to the object, the garbage collector will perform a
    * callback to the given V8::NearDeathCallback function, passing
    * it the object reference and the given parameters.
    */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(void MakeWeak(Isolate* isolate,
                           void* parameters,
                           NearDeathCallback callback));
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(void ClearWeak());
+  V8_INLINE(void ClearWeak());
 
-  /** Clears the weak reference to this object. */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(void ClearWeak(Isolate* isolate));
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(void MarkIndependent());
+  V8_INLINE(void MarkIndependent());
 
   /**
    * Marks the reference to this object independent. Garbage collector is free
    * to ignore any object groups containing this object. Weak callback for an
    * independent handle should not assume that it will be preceded by a global
    * GC prologue callback or followed by a global GC epilogue callback.
    */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(void MarkIndependent(Isolate* isolate));
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(void MarkPartiallyDependent());
+  V8_INLINE(void MarkPartiallyDependent());
 
   /**
    * Marks the reference to this object partially dependent. Partially dependent
    * handles only depend on other partially dependent handles and these
    * dependencies are provided through object groups. It provides a way to build
    * smaller object groups for young objects that represent only a subset of all
    * external dependencies. This mark is automatically cleared after each
    * garbage collection.
    */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(void MarkPartiallyDependent(Isolate* isolate));
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(bool IsIndependent() const);
+  V8_INLINE(bool IsIndependent() const);
 
-  /** Returns true if this handle was previously marked as independent. */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(bool IsIndependent(Isolate* isolate) const);
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(bool IsNearDeath() const);
+  V8_INLINE(bool IsNearDeath() const);
 
   /** Checks if the handle holds the only reference to an object. */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(bool IsNearDeath(Isolate* isolate) const);
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(bool IsWeak() const);
+  V8_INLINE(bool IsWeak() const);
 
   /** Returns true if the handle's reference is weak.  */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(bool IsWeak(Isolate* isolate) const);
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(void SetWrapperClassId(uint16_t class_id));
+  V8_INLINE(void SetWrapperClassId(uint16_t class_id));
 
   /**
    * Assigns a wrapper class ID to the handle. See RetainedObjectInfo interface
    * description in v8-profiler.h for details.
    */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(void SetWrapperClassId(Isolate* isolate, uint16_t class_id));
 
-  /** Deprecated. Use Isolate version instead. */
-  V8_DEPRECATED(uint16_t WrapperClassId() const);
+  V8_INLINE(uint16_t WrapperClassId() const);
 
   /**
    * Returns the class ID previously assigned to this handle or 0 if no class ID
    * was previously assigned.
    */
+  // TODO(dcarney): remove before cutover
   V8_INLINE(uint16_t WrapperClassId(Isolate* isolate) const);
 
+#ifndef V8_USE_UNSAFE_HANDLES
+
+#ifndef V8_ALLOW_ACCESS_TO_PERSISTENT_IMPLICIT
+
  private:
+#endif
+  // TODO(dcarney): make unlinkable before cutover
+  V8_INLINE(Persistent(const Persistent& that)) : val_(that.val_) {}
+  // TODO(dcarney): make unlinkable before cutover
+  V8_INLINE(Persistent& operator=(const Persistent& that)) {  // NOLINT
+    this->val_ = that.val_;
+    return *this;
+  }
+
+ public:
+#ifndef V8_ALLOW_ACCESS_TO_RAW_HANDLE_CONSTRUCTOR
+
+ private:
+#endif
+  // TODO(dcarney): remove before cutover
+  template <class S> V8_INLINE(Persistent(S* that)) : val_(that) { }
+  // TODO(dcarney): remove before cutover
+  template <class S> V8_INLINE(Persistent(Persistent<S> that))
+      : val_(*that) {
+    TYPE_CHECK(T, S);
+  }
+  // TODO(dcarney): remove before cutover
+  V8_INLINE(T* operator*() const) { return val_; }
+ public:
+#ifndef V8_ALLOW_ACCESS_TO_PERSISTENT_ARROW
+
+ private:
+#endif
+  // TODO(dcarney): remove before cutover
+  V8_INLINE(T* operator->() const) { return val_; }
+ public:
+#endif
+
+ private:
+  template<class F>
+  friend class Handle;
+  template<class F>
+  friend class Local;
   friend class ImplementationUtilities;
   friend class ObjectTemplate;
+  friend class Context;
+  friend class InternalHandleHelper;
+  friend class LocalContext;
+
+  V8_INLINE(static Persistent<T> New(Isolate* isolate, T* that));
+
+#ifndef V8_USE_UNSAFE_HANDLES
+  T* val_;
+#endif
 };
 
 
  /**
  * A stack-allocated class that governs a number of local handles.
  * After a handle scope has been created, all local handles will be
  * allocated within that handle scope until either the handle scope is
  * deleted or another handle scope is created.  If there is already a
  * handle scope and a new one is created, all allocations will take
  * place in the new handle scope until it is deleted.  After that,
@@ skipping 3624 matching lines @@
 
   /**
    * Stack-allocated class which sets the execution context for all
    * operations executed within a local scope.
    */
   class Scope {
    public:
     explicit V8_INLINE(Scope(Handle<Context> context)) : context_(context) {
       context_->Enter();
     }
+    V8_INLINE(Scope(Isolate* isolate, Persistent<Context>& context)) // NOLINT
+#ifndef V8_USE_UNSAFE_HANDLES
+    : context_(Handle<Context>::New(isolate, context)) {
+#else
+    : context_(Local<Context>::New(isolate, context)) {
+#endif
+      context_->Enter();
+    }
     V8_INLINE(~Scope()) { context_->Exit(); }
+
    private:
     Handle<Context> context_;
   };
 
  private:
   friend class Value;
   friend class Script;
   friend class Object;
   friend class Function;
 
@@ skipping 418 matching lines @@
   if (internal::Internals::CanCastToHeapObject(that_ptr)) {
     return Local<T>(reinterpret_cast<T*>(HandleScope::CreateHandle(
         reinterpret_cast<internal::HeapObject*>(*p))));
   }
   return Local<T>(reinterpret_cast<T*>(HandleScope::CreateHandle(*p)));
 }
 
 
 template <class T>
 Local<T> Local<T>::New(Isolate* isolate, Handle<T> that) {
-  if (that.IsEmpty()) return Local<T>();
-  T* that_ptr = *that;
+  return New(isolate, that.val_);
+}
+
+#ifndef V8_USE_UNSAFE_HANDLES
+template <class T>
+Local<T> Local<T>::New(Isolate* isolate, const Persistent<T>& that) {
+  return New(isolate, that.val_);
+}
+
+template <class T>
+Handle<T> Handle<T>::New(Isolate* isolate, T* that) {
+  if (that == NULL) return Handle<T>();
+  T* that_ptr = that;
+  internal::Object** p = reinterpret_cast<internal::Object**>(that_ptr);
+  return Handle<T>(reinterpret_cast<T*>(HandleScope::CreateHandle(
+      reinterpret_cast<internal::Isolate*>(isolate), *p)));
+}
+#endif
+
+
+template <class T>
+Local<T> Local<T>::New(Isolate* isolate, T* that) {
+  if (that == NULL) return Local<T>();
+  T* that_ptr = that;
   internal::Object** p = reinterpret_cast<internal::Object**>(that_ptr);
   return Local<T>(reinterpret_cast<T*>(HandleScope::CreateHandle(
       reinterpret_cast<internal::Isolate*>(isolate), *p)));
 }
 
 
 template <class T>
 Persistent<T> Persistent<T>::New(Handle<T> that) {
-  return New(Isolate::GetCurrent(), that);
+  return New(Isolate::GetCurrent(), that.val_);
 }
 
 
 template <class T>
 Persistent<T> Persistent<T>::New(Isolate* isolate, Handle<T> that) {
-  if (that.IsEmpty()) return Persistent<T>();
-  internal::Object** p = reinterpret_cast<internal::Object**>(*that);
+  return New(Isolate::GetCurrent(), that.val_);
+}
+
+#ifndef V8_USE_UNSAFE_HANDLES
+template <class T>
+Persistent<T> Persistent<T>::New(Isolate* isolate, Persistent<T> that) {
+  return New(Isolate::GetCurrent(), that.val_);
+}
+#endif
+
+template <class T>
+Persistent<T> Persistent<T>::New(Isolate* isolate, T* that) {
+  if (that == NULL) return Persistent<T>();
+  internal::Object** p = reinterpret_cast<internal::Object**>(that);
   return Persistent<T>(reinterpret_cast<T*>(
       V8::GlobalizeReference(reinterpret_cast<internal::Isolate*>(isolate),
                              p)));
 }
 
 
 template <class T>
 bool Persistent<T>::IsIndependent() const {
   return IsIndependent(Isolate::GetCurrent());
 }
 
 
 template <class T>
 bool Persistent<T>::IsIndependent(Isolate* isolate) const {
   typedef internal::Internals I;
   if (this->IsEmpty()) return false;
   if (!I::IsInitialized(isolate)) return false;
-  return I::GetNodeFlag(reinterpret_cast<internal::Object**>(**this),
+  return I::GetNodeFlag(reinterpret_cast<internal::Object**>(this->val_),
                         I::kNodeIsIndependentShift);
 }
 
 
 template <class T>
 bool Persistent<T>::IsNearDeath() const {
   return IsNearDeath(Isolate::GetCurrent());
 }
 
 
 template <class T>
 bool Persistent<T>::IsNearDeath(Isolate* isolate) const {
   typedef internal::Internals I;
   if (this->IsEmpty()) return false;
   if (!I::IsInitialized(isolate)) return false;
-  return I::GetNodeState(reinterpret_cast<internal::Object**>(**this)) ==
+  return I::GetNodeState(reinterpret_cast<internal::Object**>(this->val_)) ==
       I::kNodeStateIsNearDeathValue;
 }
 
 
 template <class T>
 bool Persistent<T>::IsWeak() const {
   return IsWeak(Isolate::GetCurrent());
 }
 
 
 template <class T>
 bool Persistent<T>::IsWeak(Isolate* isolate) const {
   typedef internal::Internals I;
   if (this->IsEmpty()) return false;
   if (!I::IsInitialized(isolate)) return false;
-  return I::GetNodeState(reinterpret_cast<internal::Object**>(**this)) ==
+  return I::GetNodeState(reinterpret_cast<internal::Object**>(this->val_)) ==
       I::kNodeStateIsWeakValue;
 }
 
 
 template <class T>
 void Persistent<T>::Dispose() {
   Dispose(Isolate::GetCurrent());
 }
 
 
 template <class T>
 void Persistent<T>::Dispose(Isolate* isolate) {
   if (this->IsEmpty()) return;
   V8::DisposeGlobal(reinterpret_cast<internal::Isolate*>(isolate),
-                    reinterpret_cast<internal::Object**>(**this));
+                    reinterpret_cast<internal::Object**>(this->val_));
+#ifndef V8_USE_UNSAFE_HANDLES
+  val_ = 0;
+#endif
 }
 
 
 template <class T>
-Persistent<T>::Persistent() : Handle<T>() { }
-
-template <class T>
 void Persistent<T>::MakeWeak(void* parameters, WeakReferenceCallback callback) {
   Isolate* isolate = Isolate::GetCurrent();
   V8::MakeWeak(reinterpret_cast<internal::Isolate*>(isolate),
-               reinterpret_cast<internal::Object**>(**this),
+               reinterpret_cast<internal::Object**>(this->val_),
                parameters,
                callback,
                NULL);
 }
 
 template <class T>
 void Persistent<T>::MakeWeak(Isolate* isolate,
                              void* parameters,
                              NearDeathCallback callback) {
   V8::MakeWeak(reinterpret_cast<internal::Isolate*>(isolate),
-               reinterpret_cast<internal::Object**>(**this),
+               reinterpret_cast<internal::Object**>(this->val_),
                parameters,
                NULL,
                callback);
 }
 
 template <class T>
 void Persistent<T>::ClearWeak() {
   ClearWeak(Isolate::GetCurrent());
 }
 
 template <class T>
 void Persistent<T>::ClearWeak(Isolate* isolate) {
   V8::ClearWeak(reinterpret_cast<internal::Isolate*>(isolate),
-                reinterpret_cast<internal::Object**>(**this));
+                reinterpret_cast<internal::Object**>(this->val_));
 }
 
 template <class T>
 void Persistent<T>::MarkIndependent() {
   MarkIndependent(Isolate::GetCurrent());
 }
 
 template <class T>
 void Persistent<T>::MarkIndependent(Isolate* isolate) {
   typedef internal::Internals I;
   if (this->IsEmpty()) return;
   if (!I::IsInitialized(isolate)) return;
-  I::UpdateNodeFlag(reinterpret_cast<internal::Object**>(**this),
+  I::UpdateNodeFlag(reinterpret_cast<internal::Object**>(this->val_),
                     true,
                     I::kNodeIsIndependentShift);
 }
 
 template <class T>
 void Persistent<T>::MarkPartiallyDependent() {
   MarkPartiallyDependent(Isolate::GetCurrent());
 }
 
 template <class T>
 void Persistent<T>::MarkPartiallyDependent(Isolate* isolate) {
   typedef internal::Internals I;
   if (this->IsEmpty()) return;
   if (!I::IsInitialized(isolate)) return;
-  I::UpdateNodeFlag(reinterpret_cast<internal::Object**>(**this),
+  I::UpdateNodeFlag(reinterpret_cast<internal::Object**>(this->val_),
                     true,
                     I::kNodeIsPartiallyDependentShift);
 }
 
 template <class T>
 void Persistent<T>::SetWrapperClassId(uint16_t class_id) {
   SetWrapperClassId(Isolate::GetCurrent(), class_id);
 }
 
 template <class T>
 void Persistent<T>::SetWrapperClassId(Isolate* isolate, uint16_t class_id) {
   typedef internal::Internals I;
   if (this->IsEmpty()) return;
   if (!I::IsInitialized(isolate)) return;
-  internal::Object** obj = reinterpret_cast<internal::Object**>(**this);
+  internal::Object** obj = reinterpret_cast<internal::Object**>(this->val_);
   uint8_t* addr = reinterpret_cast<uint8_t*>(obj) + I::kNodeClassIdOffset;
   *reinterpret_cast<uint16_t*>(addr) = class_id;
 }
 
 template <class T>
 uint16_t Persistent<T>::WrapperClassId() const {
   return WrapperClassId(Isolate::GetCurrent());
 }
 
 template <class T>
 uint16_t Persistent<T>::WrapperClassId(Isolate* isolate) const {
   typedef internal::Internals I;
   if (this->IsEmpty()) return 0;
   if (!I::IsInitialized(isolate)) return 0;
-  internal::Object** obj = reinterpret_cast<internal::Object**>(**this);
+  internal::Object** obj = reinterpret_cast<internal::Object**>(this->val_);
   uint8_t* addr = reinterpret_cast<uint8_t*>(obj) + I::kNodeClassIdOffset;
   return *reinterpret_cast<uint16_t*>(addr);
 }
 
 Arguments::Arguments(internal::Object** implicit_args,
                      internal::Object** values, int length,
                      bool is_construct_call)
     : implicit_args_(implicit_args),
       values_(values),
       length_(length),
@@ skipping 450 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_