libzmq/src/socket_poller.hpp

/*
    Copyright (c) 2007-2015 Contributors as noted in the AUTHORS file

    This file is part of libzmq, the ZeroMQ core engine in C++.

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

    As a special exception, the Contributors give you permission to link
    this library with independent modules to produce an executable,
    regardless of the license terms of these independent modules, and to
    copy and distribute the resulting executable under terms of your choice,
    provided that you also meet, for each linked independent module, the
    terms and conditions of the license of that module. An independent
    module is a module which is not derived from or based on this library.
    If you modify this library, you must extend this exception to your
    version of the library.

    libzmq 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/>.
*/

#ifndef __ZMQ_SOCKET_POLLER_HPP_INCLUDED__
#define __ZMQ_SOCKET_POLLER_HPP_INCLUDED__

#include "poller.hpp"

#if defined ZMQ_POLL_BASED_ON_POLL
#include <poll.h>
#endif

#if defined ZMQ_HAVE_WINDOWS
#include "windows.hpp"
#else
#include <unistd.h>
#endif

#include <vector>
#include <algorithm>

#include "socket_base.hpp"
#include "signaler.hpp"

namespace zmq
{

    class socket_poller_t
    {
    public:
        socket_poller_t ();
        ~socket_poller_t ();

        typedef struct event_t
        {
            socket_base_t *socket;
            fd_t fd;
            void *user_data; 
            short events;
        } event_t;

        int add (socket_base_t *socket, void *user_data, short events);
        int modify (socket_base_t *socket, short events);
        int remove (socket_base_t *socket);

        int add_fd (fd_t fd, void *user_data, short events);
        int modify_fd (fd_t fd, short events);
        int remove_fd (fd_t fd);

        int wait (event_t *event, long timeout);

        //  Return false if object is not a socket.
        bool check_tag ();

    private:
        int rebuild ();     

        //  Used to check whether the object is a socket_poller.
        uint32_t tag;

        //  Signaler used for thread safe sockets polling
        signaler_t signaler;

        typedef struct item_t {
            socket_base_t *socket;
            fd_t fd;
            void *user_data; 
            short events;
#if defined ZMQ_POLL_BASED_ON_POLL
            int  pollfd_index;
#endif
        } item_t;

        //  List of sockets
        typedef std::vector <item_t> items_t;
        items_t items;

        //  Does the pollset needs rebuilding?
        bool need_rebuild;

        //  Should the signaler be used for the thread safe polling?
        bool use_signaler;
   
        //  Size of the pollset
        int poll_size;
   
#if defined ZMQ_POLL_BASED_ON_POLL
        pollfd *pollfds;
#elif defined ZMQ_POLL_BASED_ON_SELECT
        fd_set pollset_in;
        fd_set pollset_out;
        fd_set pollset_err;
        zmq::fd_t maxfd;
#endif
        
        socket_poller_t (const socket_poller_t&);
        const socket_poller_t &operator = (const socket_poller_t&);
    };

}

#endif