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/* $Id: cursesobject.H,v 1.1 2003/05/27 14:09:07 mrsam Exp $
**
** Copyright 2002, Double Precision Inc.
**
** See COPYING for distribution information.
*/
#ifndef cursesobject_H
#define cursesobject_H
///////////////////////////////////////////////////////////////////////////
//
// Helper class that detects when the object being pointed to is destroyed.
//
// Subclass cursesObj. Declare CursesPtr<T>, where T is cursesObj's
// subclass. After CursesObj is destroyed, CursesPtr<T>::operator T *()
// will return NULL.
//
// The cursesObj object maintains a list of all CursesPtr<T>s that point to
// it. cursesObj's destructor nulls them out.
#include "../curses/curses_config.h"
#include <set>
class cursesPtrBase {
public:
cursesPtrBase();
virtual ~cursesPtrBase();
virtual void ptrDestroyed()=0;
};
template<class T> class cursesPtr : public cursesPtrBase {
T *ptr;
public:
cursesPtr(T *ptrArg) : ptr(NULL)
{
if (ptrArg)
ptrArg->cursesBase.insert(this);
ptr=ptrArg;
}
cursesPtr(const cursesPtr &o) : ptr(NULL)
{
(*this)=o;
}
cursesPtr &operator=(const cursesPtr &o)
{
if (o.ptr == NULL ||
o.ptr->cursesBase.count(this) == 0)
{
if (o.ptr)
o.ptr->cursesBase.insert(this);
if (ptr && ptr->cursesBase.count(this) > 0)
ptr->cursesBase.erase(ptr->cursesBase
.find(this));
}
ptr=o.ptr;
return *this;
}
~cursesPtr()
{
if (ptr && ptr->cursesBase.count(this) > 0)
ptr->cursesBase.erase(ptr->cursesBase
.find(this));
}
operator T *() const
{
return ptr;
}
T * operator->() const
{
return ptr;
}
bool isDestroyed() const { return ptr == 0; }
void ptrDestroyed() { ptr=NULL; }
};
class CursesObj {
public:
std::set<cursesPtrBase *> cursesBase;
CursesObj();
virtual ~CursesObj();
// UNDEFINED:
CursesObj(const CursesObj &);
CursesObj &operator=(const CursesObj &);
};
#endif
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