/*
 * libev poll fd activity backend
 *
 * Copyright (c) 2007 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)
{
  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)
{
  int i;
  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)
        syserr ("(libev) poll");
 
      return;
    }
 
  for (i = 0; i < pollcnt; ++i)
    if (expect_false (polls [i].revents & POLLNVAL))
      fd_kill (EV_A_ polls [i].fd);
    else
      fd_event (
        EV_A_
        polls [i].fd,
        (polls [i].revents & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)
        | (polls [i].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);
}