#ifndef BOOST_NETWORK_MESSAGE_MODIFIER_CLEAR_HEADERS_HPP_20100824
#define BOOST_NETWORK_MESSAGE_MODIFIER_CLEAR_HEADERS_HPP_20100824

// Copyright 2010 (c) Dean Michael Berris
// 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)

#include <boost/network/support/is_async.hpp>
#include <boost/network/support/is_pod.hpp>
#include <boost/thread/future.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/mpl/not.hpp>
#include <boost/mpl/and.hpp>

namespace boost { namespace network {

    namespace impl {
        template <class Message, class Tag>
        inline typename enable_if<
            mpl::and_<
                mpl::not_<is_pod<Tag> >
                , mpl::not_<is_async<Tag> > 
                >
            , void
            >::type
        clear_headers(Message const & message, Tag const &) {
            (typename Message::headers_container_type()).swap(message.headers());
        }

        template <class Message, class Tag>
        inline typename enable_if<is_pod<Tag>, void>::type
        clear_headers(Message const & message, Tag const &) {
            (typename Message::headers_container_type()).swap(message.headers);
        }

        template <class Message, class Tag>
        inline typename enable_if<
            mpl::and_<
                mpl::not_<is_pod<Tag> >
                , is_async<Tag>
                >
            , void
            >::type
        clear_headers(Message const & message, Tag const &) {
            boost::promise<typename Message::headers_container_type> header_promise;
            boost::shared_future<typename Message::headers_container_type> headers_future(header_promise.get_future());
            message.headers(headers_future);
            header_promise.set_value(typename Message::headers_container_type());
        }

    } // namespace impl

    template <class Tag, template <class> class Message>
    inline void clear_headers(Message<Tag> const & message) {
        impl::clear_headers(message, Tag());
    }

} // namespace network

} // namespace boost

#endif // BOOST_NETWORK_MESSAGE_MODIFIER_CLEAR_HEADERS_HPP_20100824
