buffer_body.hpp

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//
// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
//
// 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)
//
// Official repository: https://github.com/boostorg/beast
//

#ifndef BOOST_BEAST_HTTP_BUFFER_BODY_HPP
#define BOOST_BEAST_HTTP_BUFFER_BODY_HPP

#include <boost/beast/config.hpp>
#include <boost/beast/http/error.hpp>
#include <boost/beast/http/message.hpp>
#include <boost/beast/http/type_traits.hpp>
#include <boost/optional.hpp>
#include <type_traits>
#include <utility>

namespace boost {
namespace beast {
namespace http {

struct buffer_body
{
    struct value_type
    {
        void* data = nullptr;

        std::size_t size = 0;

        bool more = true;
    };

#if BOOST_BEAST_DOXYGEN
    using reader = implementation_defined;
#else
    class reader
    {
        bool toggle_ = false;
        value_type const& body_;

    public:
        using const_buffers_type =
            boost::asio::const_buffers_1;

        template<bool isRequest, class Fields>
        explicit
        reader(message<isRequest,
                buffer_body, Fields> const& msg)
            : body_(msg.body)
        {
        }

        void
        init(error_code& ec)
        {
            ec.assign(0, ec.category());
        }

        boost::optional<
            std::pair<const_buffers_type, bool>>
        get(error_code& ec)
        {
            if(toggle_)
            {
                if(body_.more)
                {
                    toggle_ = false;
                    ec = error::need_buffer;
                }
                else
                {
                    ec.assign(0, ec.category());
                }
                return boost::none;
            }
            if(body_.data)
            {
                ec.assign(0, ec.category());
                toggle_ = true;
                return {{const_buffers_type{
                    body_.data, body_.size}, body_.more}};
            }
            if(body_.more)
                ec = error::need_buffer;
            else
                ec.assign(0, ec.category());
            return boost::none;
        }
    };
#endif

#if BOOST_BEAST_DOXYGEN
    using writer = implementation_defined;
#else
    class writer
    {
        value_type& body_;

    public:
        template<bool isRequest, class Fields>
        explicit
        writer(message<isRequest, buffer_body, Fields>& m)
            : body_(m.body)
        {
        }

        void
        init(boost::optional<std::uint64_t> const&, error_code& ec)
        {
            ec.assign(0, ec.category());
        }

        template<class ConstBufferSequence>
        std::size_t
        put(ConstBufferSequence const& buffers,
            error_code& ec)
        {
            using boost::asio::buffer_size;
            using boost::asio::buffer_copy;
            if(! body_.data)
            {
                ec = error::need_buffer;
                return 0;
            }
            auto const bytes_transferred =
                buffer_copy(boost::asio::buffer(
                    body_.data, body_.size), buffers);
            body_.data = reinterpret_cast<char*>(
                body_.data) + bytes_transferred;
            body_.size -= bytes_transferred;
            if(bytes_transferred == buffer_size(buffers))
                ec.assign(0, ec.category());
            else
                ec = error::need_buffer;
            return bytes_transferred;
        }

        void
        finish(error_code& ec)
        {
            ec.assign(0, ec.category());
        }
    };
#endif
};

#if ! BOOST_BEAST_DOXYGEN
// operator<< is not supported for buffer_body
template<bool isRequest, class Fields>
std::ostream&
operator<<(std::ostream& os, message<isRequest,
    buffer_body, Fields> const& msg) = delete;
#endif

} // http
} // beast
} // boost

#endif