python/include/boost/python/object/make_instance.hpp at python313 · boostorg/python · GitHub

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// 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.

Holder *holder =Derived::construct(instance->storage.bytes, (PyObject*)instance, x);

holder->install(raw_result);

// Note the position of the internally-stored Holder,

// for the sake of destruction

const size_t offset = reinterpret_cast<size_t>(holder) -

reinterpret_cast<size_t>(instance->storage.bytes) + offsetof(instance_t, storage);

Py_SET_SIZE(instance, offset);

// 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)

{

size_t allocated = objects::additional_instance_size<Holder>::value;

void* aligned_storage = ::boost::alignment::align(boost::python::detail::alignment_of<Holder>::value,

sizeof(Holder), storage, allocated);

return new (aligned_storage) Holder(instance, x);

}

};

}}} // namespace boost::python::object

#endif // MAKE_INSTANCE_DWA200296_HPP

python/include/boost/python/object/make_instance.hpp at python313 · boostorg/python · GitHub

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