Add an API for enumerating persistent 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 372 matching lines @@
   inline void Dispose();
 
   /**
    * 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::WeakReferenceCallback function, passing
    * it the object reference and the given parameters.
    */
   inline void MakeWeak(void* parameters, WeakReferenceCallback callback);
 
-  /** Clears the weak reference to this object.*/
+  /** Clears the weak reference to this object. */
   inline void ClearWeak();
 
   /**
    * 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.
    */
   inline void MarkIndependent();
 
-  /**
-   *Checks if the handle holds the only reference to an object.
-   */
+  /** Returns true if this handle was previously marked as independent. */
+  inline bool IsIndependent() const;
+
+  /** Checks if the handle holds the only reference to an object. */
   inline bool IsNearDeath() const;
 
-  /**
-   * Returns true if the handle's reference is weak.
-   */
+  /** Returns true if the handle's reference is weak.  */
   inline bool IsWeak() const;
 
   /**
    * Assigns a wrapper class ID to the handle. See RetainedObjectInfo
    * interface description in v8-profiler.h for details.
    */
   inline void SetWrapperClassId(uint16_t class_id);
 
+  /**
+   * Returns the class ID previously assigned to this handle or 0 if no class
+   * ID was previously assigned.
+   */
+  inline uint16_t WrapperClassId() const;
+
  private:
   friend class ImplementationUtilities;
   friend class ObjectTemplate;
 };
 
 
  /**
  * 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
@@ skipping 2573 matching lines @@
 
 /**
  * Callback function passed to SetJitCodeEventHandler.
  *
  * \param event code add, move or removal event.
  */
 typedef void (*JitCodeEventHandler)(const JitCodeEvent* event);
 
 
 /**
- * Interface for iterating though all external resources in the heap.
+ * Interface for iterating through all external resources in the heap.
  */
 class V8EXPORT ExternalResourceVisitor {  // NOLINT
  public:
   virtual ~ExternalResourceVisitor() {}
   virtual void VisitExternalString(Handle<String> string) {}
 };
 
 
 /**
+ * Interface for iterating through all the persistent handles in the heap.
+ */
+class V8EXPORT PersistentHandleVisitor {  // NOLINT
+ public:
+  virtual ~PersistentHandleVisitor() {}
+  virtual void VisitPersistentHandle(Persistent<Value> value,
+                                     uint16_t class_id) {}
+};
+
+
+/**
  * Container class for static utility functions.
  */
 class V8EXPORT V8 {
  public:
   /** Set the callback to invoke in case of fatal errors. */
   static void SetFatalErrorHandler(FatalErrorCallback that);
 
   /**
    * Set the callback to invoke to check if code generation from
    * strings should be allowed.
@@ skipping 387 matching lines @@
   static void GetHeapStatistics(HeapStatistics* heap_statistics);
 
   /**
    * Iterates through all external resources referenced from current isolate
    * heap. This method is not expected to be used except for debugging purposes
    * and may be quite slow.
    */
   static void VisitExternalResources(ExternalResourceVisitor* visitor);
 
   /**
+   * Iterates through all the persistent handles in the current isolate's heap
+   * that have class_ids.
+   */
+  static void VisitHandlesWithClassIds(PersistentHandleVisitor* visitor);
+
+  /**
    * Optional notification that the embedder is idle.
    * V8 uses the notification to reduce memory footprint.
    * This call can be used repeatedly if the embedder remains idle.
    * Returns true if the embedder should stop calling IdleNotification
    * until real work has been done.  This indicates that V8 has done
    * as much cleanup as it will be able to do.
    *
    * The hint argument specifies the amount of work to be done in the function
    * on scale from 1 to 1000. There is no guarantee that the actual work will
    * match the hint.
@@ skipping 17 matching lines @@
  private:
   V8();
 
   static internal::Object** GlobalizeReference(internal::Object** handle);
   static void DisposeGlobal(internal::Object** global_handle);
   static void MakeWeak(internal::Object** global_handle,
                        void* data,
                        WeakReferenceCallback);
   static void ClearWeak(internal::Object** global_handle);
   static void MarkIndependent(internal::Object** global_handle);
+  static bool IsGlobalIndependent(internal::Object** global_handle);
   static bool IsGlobalNearDeath(internal::Object** global_handle);
   static bool IsGlobalWeak(internal::Object** global_handle);
   static void SetWrapperClassId(internal::Object** global_handle,
                                 uint16_t class_id);
+  static uint16_t GetWrapperClassId(internal::Object** global_handle);
 
   template <class T> friend class Handle;
   template <class T> friend class Local;
   template <class T> friend class Persistent;
   friend class Context;
 };
 
 
 /**
  * An external exception handler.
@@ skipping 697 matching lines @@
 
 template <class T>
 Persistent<T> Persistent<T>::New(Handle<T> that) {
   if (that.IsEmpty()) return Persistent<T>();
   internal::Object** p = reinterpret_cast<internal::Object**>(*that);
   return Persistent<T>(reinterpret_cast<T*>(V8::GlobalizeReference(p)));
 }
 
 
 template <class T>
+bool Persistent<T>::IsIndependent() const {
+  if (this->IsEmpty()) return false;
+  return V8::IsGlobalIndependent(reinterpret_cast<internal::Object**>(**this));
+}
+
+
+template <class T>
 bool Persistent<T>::IsNearDeath() const {
   if (this->IsEmpty()) return false;
   return V8::IsGlobalNearDeath(reinterpret_cast<internal::Object**>(**this));
 }
 
 
 template <class T>
 bool Persistent<T>::IsWeak() const {
   if (this->IsEmpty()) return false;
   return V8::IsGlobalWeak(reinterpret_cast<internal::Object**>(**this));
@@ skipping 25 matching lines @@
 template <class T>
 void Persistent<T>::MarkIndependent() {
   V8::MarkIndependent(reinterpret_cast<internal::Object**>(**this));
 }
 
 template <class T>
 void Persistent<T>::SetWrapperClassId(uint16_t class_id) {
   V8::SetWrapperClassId(reinterpret_cast<internal::Object**>(**this), class_id);
 }
 
+template <class T>
+uint16_t Persistent<T>::WrapperClassId() const {
+  return V8::GetWrapperClassId(reinterpret_cast<internal::Object**>(**this));
+}
+
 Arguments::Arguments(internal::Object** implicit_args,
                      internal::Object** values, int length,
                      bool is_construct_call)
     : implicit_args_(implicit_args),
       values_(values),
       length_(length),
       is_construct_call_(is_construct_call) { }
 
 
 Local<Value> Arguments::operator[](int i) const {
@@ skipping 410 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_