boost/python/object/class_converters.hpp
// Copyright David Abrahams 2002. Permission to copy, use,
// modify, sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided
// "as is" without express or implied warranty, and with no claim as
// to its suitability for any purpose.
#ifndef CLASS_CONVERTERS_DWA2002119_HPP
# define CLASS_CONVERTERS_DWA2002119_HPP
# include <boost/python/converter/registry.hpp>
# include <boost/python/converter/shared_ptr_from_python.hpp>
# include <boost/python/object/inheritance.hpp>
# include <boost/python/detail/force_instantiate.hpp>
# include <boost/type_traits/add_pointer.hpp>
# include <boost/type_traits/is_polymorphic.hpp>
# include <boost/mpl/for_each.hpp>
# include <boost/detail/workaround.hpp>
namespace boost { namespace python { namespace objects {
//////////////////////////////////////////////////////////////////////
//
// register_base_of<T> -
// A BinaryMetaFunction object which registers a single base
// class of T, and the corresponding cast(s)
//
// register_downcast/do_nothing -
// Helpers for register_base_of<> which take care of registering
// down-casts
template <class Base, class Derived>
struct register_downcast
{
static void execute()
{
register_conversion<Base, Derived>(true);
}
};
struct do_nothing
{
static void execute() { }
};
// Here's where the real work gets done:
template <class Derived>
struct register_base_of
{
// Here's the runtime part:
template <class Base>
void operator()(Base*) const
{
// Register the Base class
register_dynamic_id<Base>();
// Register the up-cast
register_conversion<Derived,Base>(false);
// Register the down-cast, if appropriate.
mpl::if_<
# if BOOST_WORKAROUND(__MWERKS__, <= 0x2407)
mpl::true_
# else
is_polymorphic<Base>
# endif
, register_downcast<Base,Derived>
, do_nothing
>::type::execute();
}
};
// Brings into existence all converters associated with a class. Bases
// is expected to be an mpl sequence of base types.
template <class Derived, class Bases>
inline void register_class_from_python(Derived* = 0, Bases* = 0)
{
// Static object constructor performs registration
static converter::shared_ptr_from_python<Derived> shared_ptr_registration;
// register all up/downcasts here
register_dynamic_id<Derived>();
// register each base in the sequence
mpl::for_each(register_base_of<Derived>(), (Bases*)0, (add_pointer<mpl::_>*)0);
}
}}} // namespace boost::python::object
#endif // CLASS_CONVERTERS_DWA2002119_HPP