return_opaque_pointer.hpp

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// Copyright Gottfried Gan遖uge 2003.
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
/*
 * Generic Return value converter generator for opaque C++-pointers
 */
# ifndef RETURN_OPAQUE_POINTER_HPP_
# define RETURN_OPAQUE_POINTER_HPP_

# include <boost/python/detail/prefix.hpp>
# include <boost/python/opaque_pointer_converter.hpp>
# include <boost/python/detail/indirect_traits.hpp>
# include <boost/mpl/if.hpp>

namespace boost { namespace python {

namespace detail
{
  template <class Pointer>
  struct opaque_conversion_holder
  {
      inline PyObject *operator()(Pointer p) const
      {
          static opaque_pointer_converter<Pointer> converter (
              typeid (Pointer).name());

          return converter.convert(p);
      }
  };

  template <class R>
  struct return_opaque_pointer_requires_a_pointer_type
# if defined(__GNUC__) && __GNUC__ >= 3 || defined(__EDG__)
  {}
# endif
  ;
}
    
struct return_opaque_pointer
{
    template <class R>
    struct apply
    {
        BOOST_STATIC_CONSTANT(
            bool, ok = is_pointer<R>::value);
        
        typedef typename mpl::if_c<
            ok
          , detail::opaque_conversion_holder<R>
          , detail::return_opaque_pointer_requires_a_pointer_type<R>
        >::type type;
    };
};
}} // namespace boost::python
# endif // RETURN_OPAQUE_POINTER_HPP_