select.hpp

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#ifndef LIBSOCKET_SELECT_H_7F761B91E8A84EB685E898542039D68F
#define LIBSOCKET_SELECT_H_7F761B91E8A84EB685E898542039D68F

#include <cstring>
#include <list>
#include <map>
#include <utility>
#include <vector>

#include <errno.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

namespace poll {
#include <poll.h>
}

#include "exception.hpp"

/*
   The committers of the libsocket project, all rights reserved
   (c) 2012, 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 "socket.hpp"

namespace libsocket {
template <typename SocketT>
class selectset {
   private:
    std::map<int, SocketT*>
        fdsockmap;  

    bool set_up;  

    std::vector<poll::pollfd> pollfd_set;  // Set of pollfd structs to poll

   public:
    selectset();

    void add_fd(const SocketT& sock, int method);

    std::pair<std::vector<SocketT*>, std::vector<SocketT*> > wait(
        long long microsecs = 0);
    typedef std::pair<std::vector<SocketT*>, std::vector<SocketT*> >
        ready_socks;
};
extern int highestfd(const std::vector<int>& v);

template <typename SockT>
selectset<SockT>::selectset(void) : set_up(false) {}

template <typename SocketT>
void selectset<SocketT>::add_fd(const SocketT& sock, int method) {
    int fd = sock.getfd();

    if (method == LIBSOCKET_READ) {
        poll::pollfd fdinfo{fd, POLLIN, 0};
        pollfd_set.push_back(fdinfo);
        fdsockmap[fd] = const_cast<SocketT*>(&sock);
        set_up = true;

    } else if (method == LIBSOCKET_WRITE) {
        poll::pollfd fdinfo{fd, POLLOUT, 0};
        pollfd_set.push_back(fdinfo);
        fdsockmap[fd] = const_cast<SocketT*>(&sock);
        set_up = true;
    } else if (method ==
               (LIBSOCKET_READ | LIBSOCKET_WRITE)) {  // don't put the fd in our
                                                      // data structures twice.
        poll::pollfd fdinfo{fd, (POLLIN | POLLOUT), 0};
        pollfd_set.push_back(fdinfo);
        fdsockmap[fd] = const_cast<SocketT*>(&sock);
        set_up = true;
    }
}

template <typename SockT>
typename selectset<SockT>::ready_socks selectset<SockT>::wait(
    long long microsecs) {
    int n = 0;

    struct timespec* timeout = NULL;
    struct timespec _timeout;

    if (microsecs != 0) {
        timeout = &_timeout;

        long long nanosecs = microsecs * 1000;
        long long nanopart = nanosecs % 1000000000;
        long long secpart = (nanosecs - nanopart) / 1000000000;

        _timeout.tv_sec = secpart;
        _timeout.tv_nsec = nanopart;
    }

    n = ppoll((poll::pollfd*)pollfd_set.data(), pollfd_set.size(), timeout,
              NULL);

    ready_socks rwfds;

    if (n < 0) {
        std::string err(strerror(errno));

        throw socket_exception(__FILE__, __LINE__,
                               "selectset::wait(): Error at ppoll(): " + err);

    } else if (n == 0)  // time is over, no filedescriptor is ready
    {
        rwfds.first.resize(0);
        rwfds.second.resize(0);

        return rwfds;
    }

    std::vector<poll::pollfd>::iterator end = pollfd_set.end();

    for (std::vector<poll::pollfd>::iterator iter = pollfd_set.begin();
         iter != end; ++iter) {
        if (iter->revents & POLLIN) rwfds.first.push_back(fdsockmap[iter->fd]);

        if (iter->revents & POLLOUT)
            rwfds.second.push_back(fdsockmap[iter->fd]);
    }

    return rwfds;
}

}  // namespace libsocket

#endif