// Copyright (c) 2003 Daniel Wallin and Arvid Norberg

// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
// SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
// ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.


#ifndef LUABIND_DEPENDENCY_POLICY_HPP_INCLUDED
#define LUABIND_DEPENDENCY_POLICY_HPP_INCLUDED

#include <luabind/config.hpp>
#include <luabind/detail/policy.hpp>

namespace luabind { namespace detail 
{
	// makes A dependent on B, meaning B will outlive A.
	// internally A stores a reference to B
	template<int A, int B>
	struct dependency_policy
	{
		static void postcall(lua_State* L, const index_map& indices)
		{
			int nurse_index = indices[A];
			int patient = indices[B];

			object_rep* nurse = static_cast<object_rep*>(lua_touserdata(L, nurse_index));

			// If the nurse isn't an object_rep, just make this a nop.
			if (nurse == 0)
				return;

			nurse->add_dependency(L, patient);
		}
	};

}}

#if defined (BOOST_MSVC) && (BOOST_MSVC <= 1200)

namespace luabind
{
	// most absurd workaround of all time?
	namespace detail
	{
		template<int N>
		struct size_char_array
		{
			char storage[N + 2];
		};

		template<int N>
		size_char_array<N> deduce_size(LUABIND_PLACEHOLDER_ARG(N));

		template<class T>
		struct get_index_workaround
		{
			static T t;
			BOOST_STATIC_CONSTANT(int, value = sizeof(deduce_size(t)) - 2);
		};
	}

	template<class A, class B>
	detail::policy_cons<detail::dependency_policy<detail::get_index_workaround<A>::value
		, detail::get_index_workaround<B>::value>, detail::null_type> dependency(A,B)
	{
		return detail::policy_cons<detail::dependency_policy<
			detail::get_index_workaround<A>::value, detail::get_index_workaround<B>::value>
			, detail::null_type>();
	}

	template<class A>
	detail::policy_cons<detail::dependency_policy<0
		, detail::get_index_workaround<A>::value>, detail::null_type>
	return_internal_reference(A)
	{
		return detail::policy_cons<detail::dependency_policy<0
			, detail::get_index_workaround<A>::value>, detail::null_type>();
	}
}

#else

namespace luabind
{
	template<int A, int B>
	detail::policy_cons<detail::dependency_policy<A, B>, detail::null_type>
	dependency(LUABIND_PLACEHOLDER_ARG(A), LUABIND_PLACEHOLDER_ARG(B))
	{
		return detail::policy_cons<detail::dependency_policy<A, B>, detail::null_type>();
	}

	template<int A>
	detail::policy_cons<detail::dependency_policy<0, A>, detail::null_type>
	return_internal_reference(LUABIND_PLACEHOLDER_ARG(A))
	{
		return detail::policy_cons<detail::dependency_policy<0, A>, detail::null_type>();
	}
}

#endif

#endif // LUABIND_DEPENDENCY_POLICY_HPP_INCLUDED