include/EDoc/StackRef.h

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/*******************************************************************************

   Copyright (C) 2007 by Brendon Costa

   This library is free software; you can redistribute it and/or modify 
   it under the terms of the "LGPL Like" License defined in the file COPYING 
   that should have been distributed along with this source.

   This library 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.  

   You should have received a copy of the "LGPL Like" License 
   along with this library; see the file COPYING. if not, it can be 
   obtained from the EDoc++ website: 
   http://edoc.sourceforge.net/license.html

*******************************************************************************/
#ifndef EDOC_STACKREF_H
#define EDOC_STACKREF_H

#include "EDoc/PStack.h"

namespace EDoc
{
   //===========================================================================
   /** \brief Pushes/Pops pointers into a PStack instance.
    *
    * This is primarily used to ensure that pointers are pop'ed off the stack
    * when a function call goes out of scope.
    */
   class StackRef
   {
      typedef void(StackRef::*safe_bool_t)() const;
      void this_type_does_not_support_comparison() const {}
   public:

      //------------------------------------------------------------------------
      /** \brief Returns true if the pointer was successfully pushed onto the
       * stack during construction.
       */
      operator safe_bool_t() const
      {
         return ((valid) ? 
            &StackRef::this_type_does_not_support_comparison : 
            NULL);
      }

      //------------------------------------------------------------------------
      /** \brief Pushes the given pointer onto the stack.
       */
      StackRef(PStack& stack_in, const void* item_in);
      
      //------------------------------------------------------------------------
      /** \brief Pops the pointer from the stack upon destruction.
       */
      ~StackRef();

      //------------------------------------------------------------------------

   private:

      //------------------------------------------------------------------------
      /** \brief True if pointer was successfully pushed onto stack.
       */
      bool valid;

      //------------------------------------------------------------------------
      /** \brief Stack pointer was pushed onto.
       */
      PStack& stack;

      //------------------------------------------------------------------------
      /** \brief Pointer value that was pushed onto the stack.
       */
      const void* item;

      //------------------------------------------------------------------------
   };
   //===========================================================================

}

#endif // EDOC_STACKREF_H

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