CSE2410 Fall 2014 Bounce

/*

 * libev poll fd activity backend

 *

 * Copyright (c) 2007,2008 Marc Alexander Lehmann <libev@schmorp.de>

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without modifica-

 * tion, 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 AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED

 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-

 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO

 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-

 * CIAL, 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 OTH-

 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * Alternatively, the contents of this file may be used under the terms of

 * the GNU General Public License ("GPL") version 2 or any later version,

 * in which case the provisions of the GPL are applicable instead of

 * the above. If you wish to allow the use of your version of this file

 * only under the terms of the GPL and not to allow others to use your

 * version of this file under the BSD license, indicate your decision

 * by deleting the provisions above and replace them with the notice

 * and other provisions required by the GPL. If you do not delete the

 * provisions above, a recipient may use your version of this file under

 * either the BSD or the GPL.

 */

#include <poll.h>

void inline_size

pollidx_init (int *base, int count)

{

  /* consider using memset (.., -1, ...), which is pratically guarenteed

   * to work on all systems implementing poll */

  while (count--)

    *base++ = -1;

}

static void

poll_modify (EV_P_ int fd, int oev, int nev)

{

  int idx;

  if (oev == nev)

    return;

  array_needsize (int, pollidxs, pollidxmax, fd + 1, pollidx_init);

  idx = pollidxs [fd];

  if (idx < 0) /* need to allocate a new pollfd */

    {

      pollidxs [fd] = idx = pollcnt++;

      array_needsize (struct pollfd, polls, pollmax, pollcnt, EMPTY2);

      polls [idx].fd = fd;

    }

  assert (polls [idx].fd == fd);

  if (nev)

    polls [idx].events =

        (nev & EV_READ ? POLLIN : 0)

        | (nev & EV_WRITE ? POLLOUT : 0);

  else /* remove pollfd */

    {

      pollidxs [fd] = -1;

      if (expect_true (idx < --pollcnt))

        {

          polls [idx] = polls [pollcnt];

          pollidxs [polls [idx].fd] = idx;

        }

    }

}

static void

poll_poll (EV_P_ ev_tstamp timeout)

{

  struct pollfd *p;

  int res = poll (polls, pollcnt, (int)ceil (timeout * 1000.));

  if (expect_false (res < 0))

    {

      if (errno == EBADF)

        fd_ebadf (EV_A);

      else if (errno == ENOMEM && !syserr_cb)

        fd_enomem (EV_A);

      else if (errno != EINTR)

        ev_syserr ("(libev) poll");

    }

  else

    for (p = polls; res; ++p)

      if (expect_false (p->revents)) /* this expect is debatable */

        {

          --res;

          if (expect_false (p->revents & POLLNVAL))

            fd_kill (EV_A_ p->fd);

          else

            fd_event (

              EV_A_

              p->fd,

              (p->revents & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)

              | (p->revents & (POLLIN | POLLERR | POLLHUP) ? EV_READ : 0)

            );

        }

}

int inline_size

poll_init (EV_P_ int flags)

{

  backend_fudge  = 0.; /* posix says this is zero */

  backend_modify = poll_modify;

  backend_poll   = poll_poll;

  pollidxs = 0; pollidxmax = 0;

  polls    = 0; pollmax    = 0; pollcnt = 0;

  return EVBACKEND_POLL;

}

void inline_size

poll_destroy (EV_P)

{

  ev_free (pollidxs);

  ev_free (polls);

}