Holder.h

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/*  Copyright (C) 2008 National Institute For Space Research (INPE) - Brazil.

    This file is part of the TerraLib - a Framework for building GIS enabled applications.

    TerraLib is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License,
    or (at your option) any later version.

    TerraLib 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 Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with TerraLib. See COPYING. If not, write to
    TerraLib Team at <terralib-team@terralib.org>.
 */

/*!
  \file terralib/common/Holder.h

  \brief An auxiliary data structure for helping to control the garbage collection of C++ objects.
*/

#ifndef __TERRALIB_COMMON_INTERNAL_HOLDER_H
#define __TERRALIB_COMMON_INTERNAL_HOLDER_H

// Boost
#include <boost/noncopyable.hpp>

namespace te
{
  namespace common
  {
    /*!
      \struct Holder

      \brief An auxiliary data structure for helping to control the garbage collection of C++ objects.

      \ingroup common
    */
    template<class T> struct Holder : public boost::noncopyable
    {
      T* m_handle;      //!< A pointer to a C++ object.
      bool m_isOwner;   //!< If true it specifies that JsObject has the ownership of the C++ handle.

      /*!
        \brief Initializes a new garbage collection helper object.

        \param handle  A pointer to a C++ object.
        \param isOwner If true the JsObject will have the ownership of the pointer.
      */
      Holder(T* handle, bool isOwner)
        : m_handle(handle),
          m_isOwner(isOwner)
      {
      }

      /*! \brief The destructor will check if it is necessary to release the C++ object handle. */
      ~Holder()
      {
        if(m_isOwner)
          delete m_handle;
      }

      T& operator*() const
      {
        return *m_handle;
      }

      T* operator->() const
      {
        return m_handle;
      }

      T* get() const
      {
        return m_handle;
      }
    };

  } // end namespace common
}   // end namespace te

#endif  // __TERRALIB_COMMON_INTERNAL_HOLDER_H