python/object/make_ptr_instance.hpp

0001 // Copyright David Abrahams 2002.
0002 // Distributed under the Boost Software License, Version 1.0. (See
0003 // accompanying file LICENSE_1_0.txt or copy at
0004 // http://www.boost.org/LICENSE_1_0.txt)
0005 #ifndef MAKE_PTR_INSTANCE_DWA200296_HPP
0006 # define MAKE_PTR_INSTANCE_DWA200296_HPP
0007
0008 # include <boost/python/object/make_instance.hpp>
0009 # include <boost/python/converter/registry.hpp>
0010 # include <boost/python/detail/type_traits.hpp>
0011 # include <boost/get_pointer.hpp>
0012 # include <boost/detail/workaround.hpp>
0013 # include <typeinfo>
0014
0015 namespace boost { namespace python { namespace objects {
0016
0017 template <class T, class Holder>
0018 struct make_ptr_instance
0019     : make_instance_impl<T, Holder, make_ptr_instance<T,Holder> >
0020 {
0021     template <class Arg>
0022     static inline Holder* construct(void* storage, PyObject*, Arg& x)
0023     {
0024 #if defined(BOOST_NO_CXX11_SMART_PTR)
0025       return new (storage) Holder(x);
0026 #else
0027       return new (storage) Holder(std::move(x));
0028 #endif
0029     }
0030
0031     template <class Ptr>
0032     static inline PyTypeObject* get_class_object(Ptr const& x)
0033     {
0034         return get_class_object_impl(get_pointer(x));
0035     }
0036 #ifndef BOOST_PYTHON_NO_PY_SIGNATURES
0037     static inline PyTypeObject const* get_pytype()
0038     {
0039         return converter::registered<T>::converters.get_class_object();
0040     }
0041 #endif
0042  private:
0043     template <class U>
0044     static inline PyTypeObject* get_class_object_impl(U const volatile* p)
0045     {
0046         if (p == 0)
0047             return 0; // means "return None".
0048
0049         PyTypeObject* derived = get_derived_class_object(
0050             BOOST_DEDUCED_TYPENAME boost::python::detail::is_polymorphic<U>::type(), p);
0051
0052         if (derived)
0053             return derived;
0054         return converter::registered<T>::converters.get_class_object();
0055     }
0056
0057     template <class U>
0058     static inline PyTypeObject* get_derived_class_object(boost::python::detail::true_, U const volatile* x)
0059     {
0060         converter::registration const* r = converter::registry::query(
0061             type_info(typeid(*x))
0062         );
0063         return r ? r->m_class_object : 0;
0064     }
0065
0066     template <class U>
0067     static inline PyTypeObject* get_derived_class_object(boost::python::detail::false_, U*)
0068     {
0069         return 0;
0070     }
0071 };
0072
0073
0074 }}} // namespace boost::python::object
0075
0076 #endif // MAKE_PTR_INSTANCE_DWA200296_HPP