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/*
* $Id: RefCount.h,v 1.9 2005/11/21 22:45:16 wessels Exp $
*
* DEBUG: section xx Refcount allocator
* AUTHOR: Robert Collins
*
* SQUID Web Proxy Cache http://www.squid-cache.org/
* ----------------------------------------------------------
*
* Squid is the result of efforts by numerous individuals from
* the Internet community; see the CONTRIBUTORS file for full
* details. Many organizations have provided support for Squid's
* development; see the SPONSORS file for full details. Squid is
* Copyrighted (C) 2001 by the Regents of the University of
* California; see the COPYRIGHT file for full details. Squid
* incorporates software developed and/or copyrighted by other
* sources; see the CREDITS file for full details.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
*
*/
#ifndef _SQUID_REFCOUNT_H_
#define _SQUID_REFCOUNT_H_
template <class C>
class RefCount
{
public:
RefCount () : p_ (NULL) {}
RefCount (C const *p) : p_(p) { reference (*this); }
~RefCount()
{
dereference();
}
RefCount (const RefCount &p) : p_(p.p_)
{
reference (p);
}
RefCount& operator = (const RefCount& p)
{
// DO NOT CHANGE THE ORDER HERE!!!
// This preserves semantics on self assignment
C const *newP_ = p.p_;
reference(p);
dereference(newP_);
return *this;
}
bool operator !() const { return !p_; }
C const * operator-> () const {return p_; }
C * operator-> () {return const_cast<C *>(p_); }
C const & operator * () const {return *p_; }
C & operator * () {return *const_cast<C *>(p_); }
C const * getRaw() const{return p_; }
C * getRaw() {return const_cast<C *>(p_); }
bool operator == (const RefCount& p) const
{
return p.p_ == p_;
}
bool operator != (const RefCount &p) const
{
return p.p_ != p_;
}
private:
void dereference(C const *newP = NULL)
{
/* Setting p_ first is important:
* we may be freed ourselves as a result of
* delete p_;
*/
C const (*tempP_) (p_);
p_ = newP;
if (tempP_ && tempP_->RefCountDereference() == 0)
delete tempP_;
}
void reference (const RefCount& p)
{
if (p.p_)
p.p_->RefCountReference();
}
C const *p_;
};
struct RefCountable_
{
RefCountable_():count_(0){}
virtual ~RefCountable_(){}
/* Not private, to allow class hierarchies */
void RefCountReference() const
{
#if REFCOUNT_DEBUG
debug (0,1)("Incrementing this %p from count %u\n",this,count_);
#endif
++count_;
}
unsigned RefCountDereference() const
{
#if REFCOUNT_DEBUG
debug (0,1)("Decrementing this %p from count %u\n",this,count_);
#endif
return --count_;
}
private:
mutable unsigned count_;
};
#define RefCountable virtual RefCountable_
#endif /* _SQUID_REFCOUNT_H_ */
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