MySources/boost_graph/boost/python/object/make_instance.hpp

80 lines
2.4 KiB
C++

// Copyright David Abrahams 2002.
// 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)
#ifndef MAKE_INSTANCE_DWA200296_HPP
# define MAKE_INSTANCE_DWA200296_HPP
# include <boost/python/detail/prefix.hpp>
# include <boost/python/object/instance.hpp>
# include <boost/python/converter/registered.hpp>
# include <boost/python/detail/decref_guard.hpp>
# include <boost/python/detail/type_traits.hpp>
# include <boost/python/detail/none.hpp>
# include <boost/mpl/assert.hpp>
# include <boost/mpl/or.hpp>
namespace boost { namespace python { namespace objects {
template <class T, class Holder, class Derived>
struct make_instance_impl
{
typedef objects::instance<Holder> instance_t;
template <class Arg>
static inline PyObject* execute(Arg& x)
{
BOOST_MPL_ASSERT((mpl::or_<boost::python::detail::is_class<T>,
boost::python::detail::is_union<T> >));
PyTypeObject* type = Derived::get_class_object(x);
if (type == 0)
return python::detail::none();
PyObject* raw_result = type->tp_alloc(
type, objects::additional_instance_size<Holder>::value);
if (raw_result != 0)
{
python::detail::decref_guard protect(raw_result);
instance_t* instance = (instance_t*)raw_result;
// construct the new C++ object and install the pointer
// in the Python object.
Derived::construct(&instance->storage, (PyObject*)instance, x)->install(raw_result);
// Note the position of the internally-stored Holder,
// for the sake of destruction
Py_SIZE(instance) = offsetof(instance_t, storage);
// Release ownership of the python object
protect.cancel();
}
return raw_result;
}
};
template <class T, class Holder>
struct make_instance
: make_instance_impl<T, Holder, make_instance<T,Holder> >
{
template <class U>
static inline PyTypeObject* get_class_object(U&)
{
return converter::registered<T>::converters.get_class_object();
}
static inline Holder* construct(void* storage, PyObject* instance, reference_wrapper<T const> x)
{
return new (storage) Holder(instance, x);
}
};
}}} // namespace boost::python::object
#endif // MAKE_INSTANCE_DWA200296_HPP