AutoResource.hpp

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* Copyright (C) 2006, Novell, Inc. All rights reserved.
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#ifndef BLOCXX_AUTO_RESOURCE_HPP_INCLUDE_GUARD_
#define BLOCXX_AUTO_RESOURCE_HPP_INCLUDE_GUARD_

#include "blocxx/BLOCXX_config.h"
#include "blocxx/SafeBool.hpp"

namespace BLOCXX_NAMESPACE
{

   template <typename Policy>
   struct AutoResourceRef
   {
      typedef typename Policy::handle_type ref_type;
      ref_type hdl;

      explicit AutoResourceRef(ref_type h)
      : hdl(h)
      {
      }
   };

   template <typename Policy>
   class AutoResource
   {
      typedef typename Policy::handle_type handle_type;
      handle_type hdl;

   public:

      AutoResource() // throw()
      : hdl(Policy::null())
      {
      }

      explicit AutoResource(handle_type h) // throw()
      : hdl(h)
      {
      }

#if defined __HP_aCC
      //
      AutoResource(const AutoResource & x) // throw()
      : hdl(const_cast<AutoResource &>(x).release())
      {
      }
#else
      //
      AutoResource(AutoResource & x) // throw()
      : hdl(x.release())
      {
      }
#endif

#if defined __HP_aCC
      //
      AutoResource & operator=(const AutoResource & x) // throw()
      {
         reset(const_cast<AutoResource &>(x).release());
         return *this;
      }
#else
      //
      AutoResource & operator=(AutoResource & x) // throw()
      {
         reset(x.release());
         return *this;
      }
#endif
      //
      ~AutoResource() // throw()
      {
         Policy::free(hdl);
      }

      BLOCXX_SAFE_BOOL_IMPL(AutoResource<Policy>, handle_type, AutoResource<Policy>::hdl, (hdl != Policy::null()));
      
      //
      handle_type get() const // throw()
      {
         return hdl;
      }
      
      //
      handle_type release() // throw()
      {
         handle_type h = hdl;
         hdl = Policy::null();
         return h;
      }

      void reset(handle_type h) // throw()
      {
         if (!Policy::equal(h, hdl)) {
            Policy::free(hdl);
            hdl = h;
         }
      }

      void reset() // throw()
      {
         reset(Policy::null());
      }

      AutoResource(AutoResourceRef<Policy> href) // throw()
      : hdl(href.hdl)
      {
      }
      
      operator AutoResourceRef<Policy>() // throw()
      {
         return AutoResourceRef<Policy>(this->release());
      }

      AutoResource & operator=(AutoResourceRef<Policy> href) // throw()
      {
         if (!Policy::equal(href.hdl, this->get()))
         {
            Policy::free(hdl);
            hdl = href.hdl;
         }
         return *this;
      }

   };

} // namespace BLOCXX_NAMESPACE

#endif