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/***************************************************************************
* Copyright (C) 2006-2007 by Rajko Albrecht *
* ral@alwins-world.de *
* *
* 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., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
***************************************************************************/
#ifndef _smart_pointer_hpp
#define _smart_pointer_hpp
#if defined TQT_THREAD_SUPPORT
#include "tqmutex.h"
#endif
#include "svnqt/svnqt_defines.hpp"
/*!
* \file smart_pointer.h
* \brief smart pointer and reference counter
* \author Rajko Albrecht
*
*/
namespace svn
{
//! simple reference counter class
class ref_count {
protected:
//! reference count member
long m_RefCount;
#ifdef TQT_THREAD_SUPPORT
TQMutex m_RefcountMutex;
#endif
public:
//! first reference must be added after "new" via Pointer()
ref_count() : m_RefCount(0)
#ifdef TQT_THREAD_SUPPORT
,m_RefcountMutex()
#endif
{}
virtual ~ref_count() {}
//! add a reference
void Incr() {
#ifdef TQT_THREAD_SUPPORT
TQMutexLocker a(&m_RefcountMutex);
#endif
++m_RefCount;
}
//! delete a reference
bool Decr() {
#ifdef TQT_THREAD_SUPPORT
TQMutexLocker a(&m_RefcountMutex);
#endif
--m_RefCount;
return Shared();
}
//! is it referenced
bool Shared() { return (m_RefCount > 0); }
};
//! reference counting wrapper class
template<class T> class smart_pointer {
//! pointer to object
/*!
* this object must contain Incr(), Decr() and Shared()
* methode as public members. The best way is, that it will be a child
* class of RefCount
*/
T *ptr;
public:
//! standart constructor
smart_pointer() { ptr = 0; }
//! standart destructor
/*!
* release the reference, if it were the last reference, destroys
* ptr
*/
~smart_pointer()
{
if (ptr && !ptr->Decr()) {
delete ptr;
}
}
//! construction
smart_pointer(T* t) { if ( (ptr = t) ) ptr->Incr(); }
//! Pointer copy
smart_pointer(const smart_pointer<T>& p)
{ if ( (ptr = p.ptr) ) ptr->Incr(); }
//! pointer copy by assignment
smart_pointer<T>& operator= (const smart_pointer<T>& p)
{
// already same: nothing to do
if (ptr == p.ptr) return *this;
// decouple reference
if ( ptr && !ptr->Decr()) delete ptr;
// establish new reference
if ( (ptr = p.ptr) ) ptr->Incr();
return *this;
}
smart_pointer<T>& operator= (T*p)
{
if (ptr==p)return *this;
if (ptr && !ptr->Decr()) delete ptr;
if ( (ptr=p) ) ptr->Incr();
return *this;
}
//! cast to conventional pointer
operator T* () const { return ptr; }
//! deref: fails for 0 pointer
T& operator* () {return *ptr; }
//! deref: fails for 0 pointer
const T& operator* ()const {return *ptr; }
//! deref with method call
T* operator-> () {return ptr; }
//! deref with const method call
const T* operator-> ()const {return ptr; }
//! supports "if (pointer)"
operator bool () const { return (ptr != 0); }
//! "if (pointer)" as non const
operator bool () { return ptr != 0;}
//! support if (!pointer)"
bool operator! () const { return (ptr == 0); }
//! support if (!pointer)" as non const
bool operator! () { return (ptr == 0); }
};
} // namespace svn
#endif
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