wefts_referenced.h

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/*
   wefts_referenced.h
   Reference counter base class.

   $Id: wefts_referenced.h,v 1.4 2004/03/28 21:45:40 jonnymind Exp $
---------------------------------------------
   Begin      : 2003-08-04 20:15
   Author     : Giancarlo Niccolai

   Last modified because:

*/

/**************************************************************************
*   This program is free software; you can redistribute it and/or modify  *
*   it under the terms of the GNU Library General Public License as       *
*   published by the Free Software Foundation; either version 2.1 of the  *
*   License, or (at your option) any later version.                       *
***************************************************************************/

#ifndef WT_REFERENCED_H
#define WT_REFERENCED_H

#include <wefts_rwmutex.h>
#ifndef NO_ASSERTIONS
#include <cassert>
#endif


namespace Wefts {

class Referenced: public RWMutex
{

private:
   int m_count;
   bool m_disposeable;

protected:
   Referenced( int count = 1, bool dispose = true ):
      RWMutex()
   {
      #ifndef NO_ASSERTIONS
      assert ( count > 0 );
      #endif
      m_count = count > 1 ? count : 1;
      m_disposeable = dispose;
   }

   virtual ~Referenced() {}

public:

   void incRef() {
      lockWrite();
         if (m_count > 0 ) // if m_count == 0 we are going to be destroyed now.
            m_count++;
      unlock();
   }

   void decRef() {
      bool destroy = false;
      lockWrite();
      if ( m_disposeable && m_count > 0 ) m_count--;
      if ( m_count <= 0 ) destroy = true;
      unlock();
      // now, an incref could arrive here, but it would be an error,
      // a race caused by misusing this object.
      // An assert here should do, but I don't know if asserting in this
      // lib would be appreciated by users; anyhow, the user will get a
      // segfault after incref.
      if ( destroy ) delete this;
   }

   int references() { return m_count; }

   void incRefUnlocked() { m_count++; }

   void setRefUnlocked( int count )
   {
      #ifndef NO_ASSERTIONS
      assert( count > 0 );
      #endif
      m_count = count;
   }

};

}

#endif
/* end of wefts_referenced.h */

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