/*
 * poll.C: poll(2) socket engine.
 * Rights to this code are documented in doc/pod/license.pod.
 *
 * Copyright © 2005-2007 Atheme Project (http://www.atheme.org)
 */

static char const rcsid[] = "$Id: poll.C,v 1.5 2007/08/30 19:56:26 pippijn Exp $";

#include <sys/poll.h>

#include "atheme.h"
#include "internal.h"
#include "datastream.h"
#include "connection.h"

/*
 * linux does not provide POLLWRNORM by default, and we're not _XOPEN_SOURCE.
 * so.... we have to do this crap below.
 */
#ifndef POLLRDNORM
#define POLLRDNORM POLLIN
#endif
#ifndef POLLWRNORM
#define POLLWRNORM POLLOUT
#endif

pollfd pollfds[FD_SETSIZE];	/* XXX We need a define indicating MAXCONN. */

/*
 * init_socket_queues()
 *
 * inputs:
 *       none
 *
 * outputs:
 *       none
 *
 * side effects:
 *       when using select, we don't need to do anything here.
 */
void
init_socket_queues (void)
{
  memset (&pollfds, 0, sizeof (pollfd) * FD_SETSIZE);
}

/*
 * update_poll_fds()
 *
 * inputs:
 *       none
 *
 * outputs:
 *       none
 *
 * side effects:
 *       registered sockets are prepared for the poll() loop.
 */
static void
update_poll_fds (void)
{
  connection_vector::iterator it = connlist.begin ();
  connection_vector::iterator et = connlist.end ();
  int slot = 0;

  while (it != et)
    {
      connection_t *cptr = *it;
      
      cptr->pollslot = slot;
      
      if (cptr->is_connecting () || sendq_nonempty (cptr))
        {
          pollfds[slot].fd = cptr->fd;
          pollfds[slot].events |= POLLWRNORM;
          pollfds[slot].revents = 0;
        }
      else
        {
          pollfds[slot].fd = cptr->fd;
          pollfds[slot].events |= POLLRDNORM;
          pollfds[slot].revents = 0;
        }
      slot++;
      ++it;
    }
}

/*
 * connection_t::select()
 *
 * inputs:
 *       delay in microseconds
 *
 * outputs:
 *       none
 *
 * side effects:
 *       registered sockets and their associated handlers are acted on.
 */
void
connection_t::select (time_t delay)
{
  int sr;
  connection_vector::iterator it = connlist.begin ();
  connection_vector::iterator et = connlist.end ();
  int slot;

  update_poll_fds ();

  if ((sr = poll (pollfds, connlist.size (), delay / 100)) > 0)
    {
      /* Iterate twice, so we don't touch freed memory if
       * a connection is closed.
       * -- jilles */
      while (it != et)
        {
          connection_t *cptr = *it;
          ++it; // increment here or continue will cause an endless loop
          slot = cptr->pollslot;
          
          if (pollfds[slot].revents == 0)
            continue;
          
          if (pollfds[slot].revents & (POLLRDNORM | POLLIN | POLLHUP | POLLERR))
            {
              pollfds[slot].events &= ~(POLLRDNORM | POLLIN | POLLHUP | POLLERR);
              cptr->read_handler (cptr);
            }
        }
      
      for (it = connlist.begin (), et = connlist.end (); it != et; ++it)
        {
          connection_t *cptr = *it;
          slot = cptr->pollslot;
          
          if (pollfds[slot].revents == 0)
            continue;
          if (pollfds[slot].revents & (POLLWRNORM | POLLOUT | POLLHUP | POLLERR))
            {
              pollfds[slot].events &= ~(POLLWRNORM | POLLOUT | POLLHUP | POLLERR);
              if (cptr->is_connecting ())
                cptr->callback.connected (cptr);
              else
                cptr->write_handler (cptr);
            }
        }
      
      for (it = connlist.begin (), et = connlist.end (); it != et; ++it)
        {
          connection_t *cptr = *it;
          if (cptr->flags & CF_DEAD)
            cptr->close ();
        }
    }
}