server.cpp

/* SPDX-License-Identifier: MPL-2.0 */

#include "precompiled.hpp"
#include "macros.hpp"
#include "server.hpp"
#include "pipe.hpp"
#include "wire.hpp"
#include "random.hpp"
#include "likely.hpp"
#include "err.hpp"

zmq::server_t::server_t (class ctx_t *parent_, uint32_t tid_, int sid_) :
    socket_base_t (parent_, tid_, sid_, true),
    _next_routing_id (generate_random ())
{
    options.type = ZMQ_SERVER;
    options.can_send_hello_msg = true;
    options.can_recv_disconnect_msg = true;
}

zmq::server_t::~server_t ()
{
    zmq_assert (_out_pipes.empty ());
}

void zmq::server_t::xattach_pipe (pipe_t *pipe_,
                                  bool subscribe_to_all_,
                                  bool locally_initiated_)
{
    LIBZMQ_UNUSED (subscribe_to_all_);
    LIBZMQ_UNUSED (locally_initiated_);

    zmq_assert (pipe_);

    uint32_t routing_id = _next_routing_id++;
    if (!routing_id)
        routing_id = _next_routing_id++; //  Never use Routing ID zero

    pipe_->set_server_socket_routing_id (routing_id);
    //  Add the record into output pipes lookup table
    outpipe_t outpipe = {pipe_, true};
    const bool ok =
      _out_pipes.ZMQ_MAP_INSERT_OR_EMPLACE (routing_id, outpipe).second;
    zmq_assert (ok);

    _fq.attach (pipe_);
}

void zmq::server_t::xpipe_terminated (pipe_t *pipe_)
{
    const out_pipes_t::iterator it =
      _out_pipes.find (pipe_->get_server_socket_routing_id ());
    zmq_assert (it != _out_pipes.end ());
    _out_pipes.erase (it);
    _fq.pipe_terminated (pipe_);
}

void zmq::server_t::xread_activated (pipe_t *pipe_)
{
    _fq.activated (pipe_);
}

void zmq::server_t::xwrite_activated (pipe_t *pipe_)
{
    const out_pipes_t::iterator end = _out_pipes.end ();
    out_pipes_t::iterator it;
    for (it = _out_pipes.begin (); it != end; ++it)
        if (it->second.pipe == pipe_)
            break;

    zmq_assert (it != _out_pipes.end ());
    zmq_assert (!it->second.active);
    it->second.active = true;
}

int zmq::server_t::xsend (msg_t *msg_)
{
    //  SERVER sockets do not allow multipart data (ZMQ_SNDMORE)
    if (msg_->flags () & msg_t::more) {
        errno = EINVAL;
        return -1;
    }
    //  Find the pipe associated with the routing stored in the message.
    const uint32_t routing_id = msg_->get_routing_id ();
    out_pipes_t::iterator it = _out_pipes.find (routing_id);

    if (it != _out_pipes.end ()) {
        if (!it->second.pipe->check_write ()) {
            it->second.active = false;
            errno = EAGAIN;
            return -1;
        }
    } else {
        errno = EHOSTUNREACH;
        return -1;
    }

    //  Message might be delivered over inproc, so we reset routing id
    int rc = msg_->reset_routing_id ();
    errno_assert (rc == 0);

    const bool ok = it->second.pipe->write (msg_);
    if (unlikely (!ok)) {
        // Message failed to send - we must close it ourselves.
        rc = msg_->close ();
        errno_assert (rc == 0);
    } else
        it->second.pipe->flush ();

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

    return 0;
}

int zmq::server_t::xrecv (msg_t *msg_)
{
    pipe_t *pipe = NULL;
    int rc = _fq.recvpipe (msg_, &pipe);

    // Drop any messages with more flag
    while (rc == 0 && msg_->flags () & msg_t::more) {
        // drop all frames of the current multi-frame message
        rc = _fq.recvpipe (msg_, NULL);

        while (rc == 0 && msg_->flags () & msg_t::more)
            rc = _fq.recvpipe (msg_, NULL);

        // get the new message
        if (rc == 0)
            rc = _fq.recvpipe (msg_, &pipe);
    }

    if (rc != 0)
        return rc;

    zmq_assert (pipe != NULL);

    const uint32_t routing_id = pipe->get_server_socket_routing_id ();
    msg_->set_routing_id (routing_id);

    return 0;
}

bool zmq::server_t::xhas_in ()
{
    return _fq.has_in ();
}

bool zmq::server_t::xhas_out ()
{
    //  In theory, SERVER socket is always ready for writing. Whether actual
    //  attempt to write succeeds depends on which pipe the message is going
    //  to be routed to.
    return true;
}