boost/python/return_opaque_pointer.hpp

   1 // Copyright Gottfried Ganßauge 2003.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5 /*
   6  * Generic Return value converter generator for opaque C++-pointers
   7  */
   8 # ifndef RETURN_OPAQUE_POINTER_HPP_
   9 # define RETURN_OPAQUE_POINTER_HPP_
  10
  11 # include <boost/python/detail/prefix.hpp>
  12 # include <boost/python/opaque_pointer_converter.hpp>
  13 # include <boost/python/detail/force_instantiate.hpp>
  14 # include <boost/python/to_python_value.hpp>
  15 # include <boost/python/detail/value_arg.hpp>
  16 # include <boost/mpl/assert.hpp>
  17
  18 namespace boost { namespace python {
  19
  20 namespace detail
  21 {
  22   template <class Pointee>
  23   static void opaque_pointee(Pointee const volatile*)
  24   {
  25       force_instantiate(opaque<Pointee>::instance);
  26   }
  27 }
  28
  29 struct return_opaque_pointer
  30 {
  31     template <class R>
  32     struct apply
  33     {
  34         BOOST_MPL_ASSERT_MSG( is_pointer<R>::value, RETURN_OPAQUE_POINTER_EXPECTS_A_POINTER_TYPE, (R));
  35
  36         struct type :
  37           boost::python::to_python_value<
  38               typename detail::value_arg<R>::type
  39           >
  40         {
  41             type() { detail::opaque_pointee(R()); }
  42         };
  43     };
  44 };
  45
  46 }} // namespace boost::python
  47 # endif // RETURN_OPAQUE_POINTER_HPP_