libzmq/src/req.hpp

/*
    Copyright (c) 2007-2010 iMatix Corporation

    This file is part of 0MQ.

    0MQ is free software; you can redistribute it and/or modify it under
    the terms of the Lesser GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    0MQ is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    Lesser GNU General Public License for more details.

    You should have received a copy of the Lesser GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef __ZMQ_REQ_HPP_INCLUDED__
#define __ZMQ_REQ_HPP_INCLUDED__

#include "socket_base.hpp"
#include "yarray.hpp"
#include "pipe.hpp"

namespace zmq
{

    class req_t :
        public socket_base_t,
        public i_reader_events,
        public i_writer_events
    {
    public:

        req_t (class ctx_t *parent_, uint32_t slot_);
        ~req_t ();

        //  Overloads of functions from socket_base_t.
        void xattach_pipes (reader_t *inpipe_, writer_t *outpipe_,
            const blob_t &peer_identity_);
        void xterm_pipes ();
        bool xhas_pipes ();
        int xsend (zmq_msg_t *msg_, int flags_);
        int xrecv (zmq_msg_t *msg_, int flags_);
        bool xhas_in ();
        bool xhas_out ();

        //  i_reader_events interface implementation.
        void activated (reader_t *pipe_);
        void terminated (reader_t *pipe_);

        //  i_writer_events interface implementation.
        void activated (writer_t *pipe_);
        void terminated (writer_t *pipe_);

    private:

        //  List in outbound and inbound pipes. Note that the two lists are
        //  always in sync. I.e. outpipe with index N communicates with the
        //  same session as inpipe with index N.
        //
        //  TODO: Once we have queue limits in place, list of active outpipes
        //  is to be held (presumably by stacking active outpipes at
        //  the beginning of the array). We don't have to do the same thing for
        //  inpipes, because we know which pipe we want to read the
        //  reply from.
        typedef yarray_t <writer_t> out_pipes_t;
        out_pipes_t out_pipes;
        typedef yarray_t <reader_t> in_pipes_t;
        in_pipes_t in_pipes;

        //  Number of active pipes.
        size_t active;

        //  Req_t load-balances the requests - 'current' points to the session
        //  that's processing the request at the moment.
        out_pipes_t::size_type current;

        //  If true, request was already sent and reply wasn't received yet or
        //  was raceived partially.
        bool receiving_reply;

        //  True, if read can be attempted from the reply pipe.
        bool reply_pipe_active;

        //  True, if message processed at the moment (either sent or received)
        //  is processed only partially.
        bool more;

        //  Pipe we are awaiting the reply from.
        reader_t *reply_pipe;

        req_t (const req_t&);
        void operator = (const req_t&);
    };

}

#endif