MySources/boost_graph/boost/python/instance_holder.hpp

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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 INSTANCE_HOLDER_DWA2002517_HPP
# define INSTANCE_HOLDER_DWA2002517_HPP
# include <boost/python/detail/prefix.hpp>
# include <boost/noncopyable.hpp>
# include <boost/python/type_id.hpp>
# include <cstddef>
namespace boost { namespace python {
// Base class for all holders
struct BOOST_PYTHON_DECL instance_holder : private noncopyable
{
public:
instance_holder();
virtual ~instance_holder();
// return the next holder in a chain
instance_holder* next() const;
// When the derived holder actually holds by [smart] pointer and
// null_ptr_only is set, only report that the type is held when
// the pointer is null. This is needed for proper shared_ptr
// support, to prevent holding shared_ptrs from being found when
// converting from python so that we can use the conversion method
// that always holds the Python object.
virtual void* holds(type_info, bool null_ptr_only) = 0;
void install(PyObject* inst) throw();
// These functions should probably be located elsewhere.
// Allocate storage for an object of the given size at the given
// offset in the Python instance<> object if bytes are available
// there. Otherwise allocate size bytes of heap memory.
static void* allocate(PyObject*, std::size_t offset, std::size_t size);
// Deallocate storage from the heap if it was not carved out of
// the given Python object by allocate(), above.
static void deallocate(PyObject*, void* storage) throw();
private:
instance_holder* m_next;
};
// This macro is needed for implementation of derived holders
# define BOOST_PYTHON_UNFORWARD(N,ignored) (typename unforward<A##N>::type)(a##N)
//
// implementation
//
inline instance_holder* instance_holder::next() const
{
return m_next;
}
}} // namespace boost::python
#endif // INSTANCE_HOLDER_DWA2002517_HPP