epoll.hpp

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#ifndef LIBSOCKET_EPOLL_H_E58EF2DF7057FA0C7A95D6E753414229
#define LIBSOCKET_EPOLL_H_E58EF2DF7057FA0C7A95D6E753414229

/*
   The committers of the libsocket project, all rights reserved
   (c) 2014, dermesser <lbo@spheniscida.de>

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are met:

   1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

   THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS “AS IS” AND ANY
   EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
   DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

#include <cstring>
#include <memory>
#include <vector>

#include <sys/epoll.h>

#include "exception.hpp"
#include "socket.hpp"

using std::vector;

namespace libsocket {
template <typename SocketT>
class epollset {
   public:
    typedef std::pair<std::vector<SocketT*>, std::vector<SocketT*> >
        ready_socks;

    epollset(unsigned int maxevents = 128);
    epollset(const epollset&) = delete;
    epollset(epollset&&);
    ~epollset(void);

    void add_fd(SocketT& sock, int method);
    void del_fd(const SocketT& sock);
    ready_socks wait(int timeout = -1);

   private:
    unsigned int maxevents;
    int epollfd;
    struct epoll_event* events;
};

template <typename SocketT>
epollset<SocketT>::epollset(unsigned int maxevs)
    : maxevents(maxevs), events(new struct epoll_event[maxevs]) {
    epollfd = epoll_create1(0);

    if (epollfd < 0)
        throw socket_exception(
            __FILE__, __LINE__,
            string("epoll_create1 failed: ") + strerror(errno));
}

template <typename SocketT>
epollset<SocketT>::epollset(epollset&& new_epollset) {
    maxevents = new_epollset.maxevents;
    epollfd = new_epollset.epollfd;
    events = new_epollset.events;

    new_epollset.epollfd = -1;
    new_epollset.events = nullptr;
}

template <typename SocketT>
epollset<SocketT>::~epollset(void) {
    close(epollfd);
    delete[] events;
}

template <typename SocketT>
void epollset<SocketT>::add_fd(SocketT& sock, int method) {
    struct epoll_event new_event;

    new_event.data.ptr = 0;  // ptr is the largest field (8 bytes on 64bit)
    new_event.events = 0;

    if (method & LIBSOCKET_READ) new_event.events |= EPOLLIN;
    if (method & LIBSOCKET_WRITE) new_event.events |= EPOLLOUT;

    new_event.data.ptr = &sock;

    if (0 > epoll_ctl(epollfd, EPOLL_CTL_ADD, sock.getfd(), &new_event))
        throw socket_exception(__FILE__, __LINE__,
                               string("epoll_ctl failed: ") + strerror(errno));
}

template <typename SocketT>
void epollset<SocketT>::del_fd(const SocketT& sock) {
    if (0 > epoll_ctl(epollfd, EPOLL_CTL_DEL, sock.getfd(), nullptr))
        throw socket_exception(__FILE__, __LINE__,
                               string("epoll_ctl failed: ") + strerror(errno));
}

template <typename SocketT>
typename epollset<SocketT>::ready_socks epollset<SocketT>::wait(int timeout) {
    int nfds;
    ready_socks ready;

    if (0 > (nfds = epoll_wait(epollfd, events, maxevents, timeout)))
        throw socket_exception(__FILE__, __LINE__,
                               string("epoll_wait failed: ") + strerror(errno));

    for (int i = 0; i < nfds; i++) {
        if (events[i].events == EPOLLIN)
            ready.first.push_back(static_cast<SocketT*>(events[i].data.ptr));
        if (events[i].events == EPOLLOUT)
            ready.second.push_back(static_cast<SocketT*>(events[i].data.ptr));
    }

    return ready;
}

}  // namespace libsocket
#endif