64 lines
2.1 KiB
C++
64 lines
2.1 KiB
C++
// Copyright David Abrahams 2002.
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef INSTANCE_HOLDER_DWA2002517_HPP
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# define INSTANCE_HOLDER_DWA2002517_HPP
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# include <boost/python/detail/prefix.hpp>
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# include <boost/noncopyable.hpp>
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# include <boost/python/type_id.hpp>
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# include <cstddef>
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namespace boost { namespace python {
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// Base class for all holders
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struct BOOST_PYTHON_DECL instance_holder : private noncopyable
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{
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public:
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instance_holder();
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virtual ~instance_holder();
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// return the next holder in a chain
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instance_holder* next() const;
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// When the derived holder actually holds by [smart] pointer and
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// null_ptr_only is set, only report that the type is held when
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// the pointer is null. This is needed for proper shared_ptr
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// support, to prevent holding shared_ptrs from being found when
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// converting from python so that we can use the conversion method
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// that always holds the Python object.
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virtual void* holds(type_info, bool null_ptr_only) = 0;
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void install(PyObject* inst) throw();
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// These functions should probably be located elsewhere.
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// Allocate storage for an object of the given size at the given
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// offset in the Python instance<> object if bytes are available
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// there. Otherwise allocate size bytes of heap memory.
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static void* allocate(PyObject*, std::size_t offset, std::size_t size);
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// Deallocate storage from the heap if it was not carved out of
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// the given Python object by allocate(), above.
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static void deallocate(PyObject*, void* storage) throw();
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private:
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instance_holder* m_next;
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};
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// This macro is needed for implementation of derived holders
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# define BOOST_PYTHON_UNFORWARD(N,ignored) (typename unforward<A##N>::type)(a##N)
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//
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// implementation
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//
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inline instance_holder* instance_holder::next() const
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{
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return m_next;
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}
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}} // namespace boost::python
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#endif // INSTANCE_HOLDER_DWA2002517_HPP
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