lib/poll.cpp

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/*****************************************************************************
** Includes
*****************************************************************************/

#include "../../include/ecl/io/poll.hpp"

/*****************************************************************************
** Namespaces
*****************************************************************************/

namespace ecl {

/*****************************************************************************
** Implementation
*****************************************************************************/

int poll_sockets(socket_pollfd *fds, nfds_t nfds, int timeout) {
#if defined(ECL_IS_WIN32)
        fd_set readfds, writefds, exceptfds;
        struct timeval tv, *ptv;
        socket_descriptor max_fd;
        int rc;
        nfds_t i;

        if (fds == NULL) {
                errno = EFAULT;
                return -1;
        }

        FD_ZERO (&readfds);
        FD_ZERO (&writefds);
        FD_ZERO (&exceptfds);

        /*********************
        ** Compute fd sets
        **********************/
        // also find the largest descriptor.
        for (rc = -1, max_fd = 0, i = 0; i < nfds; i++) {
                if (fds[i].fd == INVALID_SOCKET) {
                        continue;
                }
                if (fds[i].events & (POLLIN | POLLRDNORM)) {
                        FD_SET (fds[i].fd, &readfds);
                }
                if (fds[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND)) {
                        FD_SET (fds[i].fd, &writefds);
                }
                if (fds[i].events & (POLLPRI | POLLRDBAND)) {
                        FD_SET (fds[i].fd, &exceptfds);
                }
                if (fds[i].fd > max_fd &&
                          (fds[i].events & (POLLIN | POLLOUT | POLLPRI |
                                                                POLLRDNORM | POLLRDBAND |
                                                                POLLWRNORM | POLLWRBAND))) {
                        max_fd = fds[i].fd;
                        rc = 0;
                }
        }

        if (rc == -1) {
                errno = EINVAL;
                return -1;
        }
        /*********************
        ** Setting the timeout
        **********************/
        if (timeout < 0) {
                ptv = NULL;
        } else {
                ptv = &tv;
                if (timeout == 0) {
                        tv.tv_sec = 0;
                        tv.tv_usec = 0;
                } else {
                        tv.tv_sec = timeout / 1000;
                        tv.tv_usec = (timeout % 1000) * 1000;
                }
        }

        rc = select (max_fd + 1, &readfds, &writefds, &exceptfds, ptv);
        if (rc < 0) {
                return -1;
        } else if ( rc == 0 ) {
                return 0;
        }

        for (rc = 0, i = 0; i < nfds; i++) {
                if (fds[i].fd != INVALID_SOCKET) {
                        fds[i].revents = 0;

                        if (FD_ISSET(fds[i].fd, &readfds)) {
                                int save_errno = errno;
                                char data[64] = {0};
                                int ret;

                                /* support for POLLHUP */
                                // just check if there's incoming data, without removing it from the queue.
                                ret = recv(fds[i].fd, data, 64, MSG_PEEK);
                                #ifdef WIN32
                                if ((ret == -1) &&
                                                (errno == WSAESHUTDOWN || errno == WSAECONNRESET ||
                                                (errno == WSAECONNABORTED) || errno == WSAENETRESET))
                                #else
                                if ((ret == -1) &&
                                                (errno == ESHUTDOWN || errno == ECONNRESET ||
                                                (errno == ECONNABORTED) || errno == ENETRESET))
                                #endif
                                {
                                        fds[i].revents |= POLLHUP;
                                } else {
                                        fds[i].revents |= fds[i].events & (POLLIN | POLLRDNORM);
                                }
                                errno = save_errno;
                        }
                        if (FD_ISSET(fds[i].fd, &writefds)) {
                                fds[i].revents |= fds[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND);
                        }

                        if (FD_ISSET(fds[i].fd, &exceptfds)) {
                                fds[i].revents |= fds[i].events & (POLLPRI | POLLRDBAND);
                        }

                        if (fds[i].revents & ~POLLHUP) {
                                rc++;
                        }
                } else {
                                fds[i].revents = POLLNVAL;
                }
        }
        return rc;
#else
        // should really put in a cmake check to check that the poll function is present
        // --> do it when necessary.

        // use an existing poll implementation
        int result = poll(fds, nfds, timeout);
        if ( result < 0 ) {
                // EINTR means that we got interrupted by a signal, and is not an error
                if(errno == EINTR) {
                        result = 0;
                }
        }
        return result;
#endif // poll_sockets functions
}

} // namespace ecl