133 lines
3.6 KiB
Plaintext
133 lines
3.6 KiB
Plaintext
// 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 INHERITANCE_DWA200216_HPP
|
|
# define INHERITANCE_DWA200216_HPP
|
|
|
|
# include <boost/python/type_id.hpp>
|
|
# include <boost/shared_ptr.hpp>
|
|
# include <boost/mpl/if.hpp>
|
|
# include <boost/type_traits/is_polymorphic.hpp>
|
|
# include <boost/type_traits/is_base_and_derived.hpp>
|
|
# include <boost/detail/workaround.hpp>
|
|
|
|
namespace boost { namespace python { namespace objects {
|
|
|
|
typedef type_info class_id;
|
|
using python::type_id;
|
|
|
|
// Types used to get address and id of most derived type
|
|
typedef std::pair<void*,class_id> dynamic_id_t;
|
|
typedef dynamic_id_t (*dynamic_id_function)(void*);
|
|
|
|
BOOST_PYTHON_DECL void register_dynamic_id_aux(
|
|
class_id static_id, dynamic_id_function get_dynamic_id);
|
|
|
|
BOOST_PYTHON_DECL void add_cast(
|
|
class_id src_t, class_id dst_t, void* (*cast)(void*), bool is_downcast);
|
|
|
|
//
|
|
// a generator with an execute() function which, given a source type
|
|
// and a pointer to an object of that type, returns its most-derived
|
|
// /reachable/ type identifier and object pointer.
|
|
//
|
|
|
|
// first, the case where T has virtual functions
|
|
template <class T>
|
|
struct polymorphic_id_generator
|
|
{
|
|
static dynamic_id_t execute(void* p_)
|
|
{
|
|
T* p = static_cast<T*>(p_);
|
|
return std::make_pair(dynamic_cast<void*>(p), class_id(typeid(*p)));
|
|
}
|
|
};
|
|
|
|
// now, the non-polymorphic case.
|
|
template <class T>
|
|
struct non_polymorphic_id_generator
|
|
{
|
|
static dynamic_id_t execute(void* p_)
|
|
{
|
|
return std::make_pair(p_, python::type_id<T>());
|
|
}
|
|
};
|
|
|
|
// Now the generalized selector
|
|
template <class T>
|
|
struct dynamic_id_generator
|
|
: mpl::if_<
|
|
boost::is_polymorphic<T>
|
|
, boost::python::objects::polymorphic_id_generator<T>
|
|
, boost::python::objects::non_polymorphic_id_generator<T>
|
|
>
|
|
{};
|
|
|
|
// Register the dynamic id function for T with the type-conversion
|
|
// system.
|
|
template <class T>
|
|
void register_dynamic_id(T* = 0)
|
|
{
|
|
typedef typename dynamic_id_generator<T>::type generator;
|
|
register_dynamic_id_aux(
|
|
python::type_id<T>(), &generator::execute);
|
|
}
|
|
|
|
//
|
|
// a generator with an execute() function which, given a void*
|
|
// pointing to an object of type Source will attempt to convert it to
|
|
// an object of type Target.
|
|
//
|
|
|
|
template <class Source, class Target>
|
|
struct dynamic_cast_generator
|
|
{
|
|
static void* execute(void* source)
|
|
{
|
|
return dynamic_cast<Target*>(
|
|
static_cast<Source*>(source));
|
|
}
|
|
|
|
};
|
|
|
|
template <class Source, class Target>
|
|
struct implicit_cast_generator
|
|
{
|
|
static void* execute(void* source)
|
|
{
|
|
Target* result = static_cast<Source*>(source);
|
|
return result;
|
|
}
|
|
};
|
|
|
|
template <class Source, class Target>
|
|
struct cast_generator
|
|
: mpl::if_<
|
|
is_base_and_derived<Target,Source>
|
|
, implicit_cast_generator<Source,Target>
|
|
, dynamic_cast_generator<Source,Target>
|
|
>
|
|
{
|
|
};
|
|
|
|
template <class Source, class Target>
|
|
inline void register_conversion(
|
|
bool is_downcast = ::boost::is_base_and_derived<Source,Target>::value
|
|
// These parameters shouldn't be used; they're an MSVC bug workaround
|
|
, Source* = 0, Target* = 0)
|
|
{
|
|
typedef typename cast_generator<Source,Target>::type generator;
|
|
|
|
add_cast(
|
|
python::type_id<Source>()
|
|
, python::type_id<Target>()
|
|
, &generator::execute
|
|
, is_downcast
|
|
);
|
|
}
|
|
|
|
}}} // namespace boost::python::object
|
|
|
|
#endif // INHERITANCE_DWA200216_HPP
|