libzmq/src/mailbox.cpp
2014-07-09 14:07:32 +02:00

87 lines
2.3 KiB
C++

/*
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 "mailbox.hpp"
#include "err.hpp"
zmq::mailbox_t::mailbox_t ()
{
// Get the pipe into passive state. That way, if the users starts by
// polling on the associated file descriptor it will get woken up when
// new command is posted.
const bool ok = cpipe.read (NULL);
zmq_assert (!ok);
active = false;
}
zmq::mailbox_t::~mailbox_t ()
{
// TODO: Retrieve and deallocate commands inside the cpipe.
// Work around problem that other threads might still be in our
// send() method, by waiting on the mutex before disappearing.
sync.lock ();
sync.unlock ();
}
zmq::fd_t zmq::mailbox_t::get_fd () const
{
return signaler.get_fd ();
}
void zmq::mailbox_t::send (const command_t &cmd_)
{
sync.lock ();
cpipe.write (cmd_, false);
const bool ok = cpipe.flush ();
sync.unlock ();
if (!ok)
signaler.send ();
}
int zmq::mailbox_t::recv (command_t *cmd_, int timeout_)
{
// Try to get the command straight away.
if (active) {
if (cpipe.read (cmd_))
return 0;
// If there are no more commands available, switch into passive state.
active = false;
}
// Wait for signal from the command sender.
const int rc = signaler.wait (timeout_);
if (rc == -1) {
errno_assert (errno == EAGAIN || errno == EINTR);
return -1;
}
// Receive the signal.
signaler.recv ();
// Switch into active state.
active = true;
// Get a command.
const bool ok = cpipe.read (cmd_);
zmq_assert (ok);
return 0;
}