libzmq/src/pair.cpp

/*
    Copyright (c) 2007-2014 Contributors as noted in the AUTHORS file

    This file is part of 0MQ.

    0MQ is free software; you can redistribute it and/or modify it under
    the terms of the GNU Lesser 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
    GNU Lesser General Public License for more details.

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

#include "pair.hpp"
#include "err.hpp"
#include "pipe.hpp"
#include "msg.hpp"

zmq::pair_t::pair_t (class ctx_t *parent_, uint32_t tid_, int sid_) :
    socket_base_t (parent_, tid_, sid_),
    pipe (NULL),
    last_in (NULL)
{
    options.type = ZMQ_PAIR;
}

zmq::pair_t::~pair_t ()
{
    zmq_assert (!pipe);
}

void zmq::pair_t::xattach_pipe (pipe_t *pipe_, bool subscribe_to_all_)
{
    // subscribe_to_all_ is unused
    (void)subscribe_to_all_;

    zmq_assert (pipe_ != NULL);

    //  ZMQ_PAIR socket can only be connected to a single peer.
    //  The socket rejects any further connection requests.
    if (pipe == NULL)
        pipe = pipe_;
    else
        pipe_->terminate (false);
}

void zmq::pair_t::xpipe_terminated (pipe_t *pipe_)
{
    if (pipe_ == pipe) {
        if (last_in == pipe) {
            saved_credential = last_in->get_credential ();
            last_in = NULL;
        }
        pipe = NULL;
    }
}

void zmq::pair_t::xread_activated (pipe_t *)
{
    //  There's just one pipe. No lists of active and inactive pipes.
    //  There's nothing to do here.
}

void zmq::pair_t::xwrite_activated (pipe_t *)
{
    //  There's just one pipe. No lists of active and inactive pipes.
    //  There's nothing to do here.
}

int zmq::pair_t::xsend (msg_t *msg_)
{
    if (!pipe || !pipe->write (msg_)) {
        errno = EAGAIN;
        return -1;
    }

    if (!(msg_->flags () & msg_t::more))
        pipe->flush ();

    //  Detach the original message from the data buffer.
    int rc = msg_->init ();
    errno_assert (rc == 0);

    return 0;
}

int zmq::pair_t::xrecv (msg_t *msg_)
{
    //  Deallocate old content of the message.
    int rc = msg_->close ();
    errno_assert (rc == 0);

    if (!pipe || !pipe->read (msg_)) {

        //  Initialise the output parameter to be a 0-byte message.
        rc = msg_->init ();
        errno_assert (rc == 0);

        errno = EAGAIN;
        return -1;
    }
    last_in = pipe;
    return 0;
}

bool zmq::pair_t::xhas_in ()
{
    if (!pipe)
        return false;

    return pipe->check_read ();
}

bool zmq::pair_t::xhas_out ()
{
    if (!pipe)
        return false;

    return pipe->check_write ();
}

zmq::blob_t zmq::pair_t::get_credential () const
{
    return last_in? last_in->get_credential (): saved_credential;
}