WeakReferenceClass.hpp

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/******************************************************************************/
/* REXX Memory access                                                         */
/*                                                                            */
/* Implementation of a weak reference model                                   */
/*                                                                            */
/******************************************************************************/
 
#ifndef Included_WeakReference
#define Included_WeakReference
 
#include "RexxCore.h"
 
 
// A weak reference handler.  When the object referenced by a weak reference
// goes out of scope, the reference field is nulled, and the WeakReference object
// is enqueued to notify the owning object that a state change has occurred.
class WeakReference : public RexxObject
{
    friend class RexxMemory;
public:
    inline WeakReference(RESTORETYPE restoreType) { ; };
    WeakReference();
    WeakReference(RexxObject *referent);
 
    inline void *operator new(size_t, void *ptr) {return ptr;}
    inline void  operator delete(void *, void *) {;}
    void *operator new(size_t);
    inline void  operator delete(void *) {;}
 
    void        live(size_t);
    void        liveGeneral(int);
    void        flatten(RexxEnvelope *);
    RexxObject *unflatten(RexxEnvelope *);
 
    RexxObject *value();
    inline RexxObject *get() { return referentObject; }
    void   clear();
 
    RexxObject *newRexx(RexxObject **args, size_t argc, size_t named_argc);
 
    static void createInstance();
 
    static RexxClass *classInstance;   // singleton class instance
 
protected:
 
    RexxObject *referentObject;      // the object we refer to
    WeakReference *nextReferenceList;  // used by memory management to keep track of reference objects
};
 
#endif