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lib_twait.c

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 * Copyright (c) 1998-2002,2003 Free Software Foundation, Inc.              *
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 * copy of this software and associated documentation files (the            *
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/****************************************************************************
 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
 ****************************************************************************/

/*
**    lib_twait.c
**
**    The routine _nc_timed_wait().
**
**    (This file was originally written by Eric Raymond; however except for
**    comments, none of the original code remains - T.Dickey).
*/

#include <curses.priv.h>

#ifdef __BEOS__
#undef false
#undef true
#include <OS.h>
#endif

#if USE_FUNC_POLL
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# endif
#elif HAVE_SELECT
# if HAVE_SYS_TIME_H && HAVE_SYS_TIME_SELECT
#  include <sys/time.h>
# endif
# if HAVE_SYS_SELECT_H
#  include <sys/select.h>
# endif
#endif

MODULE_ID("$Id: lib_twait.c,v 1.49 2003/11/30 00:34:36 Philippe.Blain Exp $")

static long
_nc_gettime(bool first)
{
    long res;

#if HAVE_GETTIMEOFDAY
# define PRECISE_GETTIME 1
    static struct timeval t0;
    struct timeval t1;
    gettimeofday(&t1, (struct timezone *) 0);
    if (first) {
      t0 = t1;
      res = 0;
    } else {
      /* .tv_sec and .tv_usec are unsigned, be careful when subtracting */
      if (t0.tv_usec > t1.tv_usec) {      /* Convert 1s in 1e6 microsecs */
          t1.tv_usec += 1000000;
          t1.tv_sec--;
      }
      res = (t1.tv_sec - t0.tv_sec) * 1000
          + (t1.tv_usec - t0.tv_usec) / 1000;
    }
#else
# define PRECISE_GETTIME 0
    static time_t t0;
    time_t t1 = time((time_t *) 0);
    if (first) {
      t0 = t1;
    }
    res = (t1 - t0) * 1000;
#endif
    TR(TRACE_IEVENT, ("%s time: %ld msec", first ? "get" : "elapsed", res));
    return res;
}

#ifdef NCURSES_WGETCH_EVENTS
NCURSES_EXPORT(int)
_nc_eventlist_timeout(_nc_eventlist * evl)
{
    _nc_event **ev, **last;
    int event_delay = -1;

    if (evl != 0) {

      ev = evl->events;
      last = ev + evl->count;

      while (ev < last) {
          if ((*ev)->type == _NC_EVENT_TIMEOUT_MSEC) {
            event_delay = (*ev)->data.timeout_msec;
            if (event_delay < 0)
                event_delay = LONG_MAX;   /* FIXME Is this defined? */
          }
      }
    }
    return event_delay;
}
#endif /* NCURSES_WGETCH_EVENTS */

/*
 * Wait a specified number of milliseconds, returning nonzero if the timer
 * didn't expire before there is activity on the specified file descriptors.
 * The file-descriptors are specified by the mode:
 *    0 - none (absolute time)
 *    1 - ncurses' normal input-descriptor
 *    2 - mouse descriptor, if any
 *    3 - either input or mouse.
 *
 * Experimental:  if NCURSES_WGETCH_EVENTS is defined, (mode & 4) determines
 * whether to pay attention to evl argument.  If set, the smallest of
 * millisecond and of timeout of evl is taken.
 *
 * We return a mask that corresponds to the mode (e.g., 2 for mouse activity).
 *
 * If the milliseconds given are -1, the wait blocks until activity on the
 * descriptors.
 */
NCURSES_EXPORT(int)
_nc_timed_wait(int mode,
             int milliseconds,
             int *timeleft
             EVENTLIST_2nd(_nc_eventlist * evl))
{
    int fd;
    int count;
    int result;

#ifdef NCURSES_WGETCH_EVENTS
    int timeout_is_event = 0;
#endif

#if USE_FUNC_POLL
    struct pollfd fd_list[2];
    struct pollfd *fds = fd_list;
#elif defined(__BEOS__)
#elif HAVE_SELECT
    static fd_set set;
#endif

    long starttime, returntime;

    TR(TRACE_IEVENT, ("start twait: %d milliseconds, mode: %d",
                  milliseconds, mode));

#ifdef NCURSES_WGETCH_EVENTS
    if (mode & 4) {
      int event_delay = _nc_eventlist_timeout(evl);

      if (event_delay >= 0
          && (milliseconds >= event_delay || milliseconds < 0)) {
          milliseconds = event_delay;
          timeout_is_event = 1;
      }
    }
#endif

#if PRECISE_GETTIME
  retry:
#endif
    starttime = _nc_gettime(TRUE);

    count = 0;

#ifdef NCURSES_WGETCH_EVENTS
    if ((mode & 4) && evl)
      evl->result_flags = 0;
#endif

#if USE_FUNC_POLL
    memset(fd_list, 0, sizeof(fd_list));

#ifdef NCURSES_WGETCH_EVENTS
    if ((mode & 4) && evl)
      fds = typeMalloc(struct pollfd, 2 + evl->count);
#endif

    if (mode & 1) {
      fds[count].fd = SP->_ifd;
      fds[count].events = POLLIN;
      count++;
    }
    if ((mode & 2)
      && (fd = SP->_mouse_fd) >= 0) {
      fds[count].fd = fd;
      fds[count].events = POLLIN;
      count++;
    }
#ifdef NCURSES_WGETCH_EVENTS
    if ((mode & 4) && evl) {
      _nc_event **ev = evl->events;
      _nc_event **last = ev + evl->count;

      while (ev < last) {
          if ((*ev)->type == _NC_EVENT_FILE
            && ((*ev)->data.fev.flags & _NC_EVENT_FILE_READABLE)) {
            fds[count].fd = (*ev)->data.fev.fd;
            fds[count].events = POLLIN;
            count++;
          }
      }
    }
#endif

    result = poll(fds, count, milliseconds);

#ifdef NCURSES_WGETCH_EVENTS
    if ((mode & 4) && evl) {
      _nc_event **ev = evl->events;
      _nc_event **last = ev + evl->count;
      int c;

      if (!result)
          count = 0;
      while (ev < last) {
          if ((*ev)->type == _NC_EVENT_FILE
            && ((*ev)->data.fev.flags & _NC_EVENT_FILE_READABLE)) {
            (*ev)->data.fev.result = 0;
            for (c = 0; c < count; c++)
                if (fds[c].fd == (*ev)->data.fev.fd
                  && fds[c].revents & POLLIN) {
                  (*ev)->data.fev.result |= _NC_EVENT_FILE_READABLE;
                  evl->result_flags |= _NC_EVENT_FILE_READABLE;
                }
          } else if ((*ev)->type == _NC_EVENT_TIMEOUT_MSEC
                   && !result && timeout_is_event) {
            evl->result_flags |= _NC_EVENT_TIMEOUT_MSEC;
          }
      }
    }

    if (fds != fd_list)
      free((char *) fds);

#endif

#elif defined(__BEOS__)
    /*
     * BeOS's select() is declared in socket.h, so the configure script does
     * not see it.  That's just as well, since that function works only for
     * sockets.  This (using snooze and ioctl) was distilled from Be's patch
     * for ncurses which uses a separate thread to simulate select().
     *
     * FIXME: the return values from the ioctl aren't very clear if we get
     * interrupted.
     *
     * FIXME: this assumes mode&1 if milliseconds < 0 (see lib_getch.c).
     */
    result = 0;
    if (mode & 1) {
      int step = (milliseconds < 0) ? 0 : 5000;
      bigtime_t d;
      bigtime_t useconds = milliseconds * 1000;
      int n, howmany;

      if (useconds <= 0)      /* we're here to go _through_ the loop */
          useconds = 1;

      for (d = 0; d < useconds; d += step) {
          n = 0;
          howmany = ioctl(0, 'ichr', &n);
          if (howmany >= 0 && n > 0) {
            result = 1;
            break;
          }
          if (useconds > 1 && step > 0) {
            snooze(step);
            milliseconds -= (step / 1000);
            if (milliseconds <= 0) {
                milliseconds = 0;
                break;
            }
          }
      }
    } else if (milliseconds > 0) {
      snooze(milliseconds * 1000);
      milliseconds = 0;
    }
#elif HAVE_SELECT
    /*
     * select() modifies the fd_set arguments; do this in the
     * loop.
     */
    FD_ZERO(&set);

    if (mode & 1) {
      FD_SET(SP->_ifd, &set);
      count = SP->_ifd + 1;
    }
    if ((mode & 2)
      && (fd = SP->_mouse_fd) >= 0) {
      FD_SET(fd, &set);
      count = max(fd, count) + 1;
    }
#ifdef NCURSES_WGETCH_EVENTS
    if ((mode & 4) && evl) {
      _nc_event **ev = evl->events;
      _nc_event **last = ev + evl->count;

      while (ev < last) {
          if ((*ev)->type == _NC_EVENT_FILE
            && ((*ev)->data.fev.flags & _NC_EVENT_FILE_READABLE)) {
            FD_SET((*ev)->data.fev.fd, &set);
            count = max((*ev)->data.fev.fd + 1, count);
          }
      }
    }
#endif

    if (milliseconds >= 0) {
      struct timeval ntimeout;
      ntimeout.tv_sec = milliseconds / 1000;
      ntimeout.tv_usec = (milliseconds % 1000) * 1000;
      result = select(count, &set, NULL, NULL, &ntimeout);
    } else {
      result = select(count, &set, NULL, NULL, NULL);
    }

#ifdef NCURSES_WGETCH_EVENTS
    if ((mode & 4) && evl) {
      _nc_event **ev = evl->events;
      _nc_event **last = ev + evl->count;

      evl->result_flags = 0;
      while (ev < last) {
          if ((*ev)->type == _NC_EVENT_FILE
            && ((*ev)->data.fev.flags & _NC_EVENT_FILE_READABLE)) {
            (*ev)->data.fev.result = 0;
            if (FD_ISSET((*ev)->data.fev.fd, &set)) {
                (*ev)->data.fev.result |= _NC_EVENT_FILE_READABLE;
                evl->result_flags |= _NC_EVENT_FILE_READABLE;
            }
          } else if ((*ev)->type == _NC_EVENT_TIMEOUT_MSEC
                   && !result && timeout_is_event)
            evl->result_flags |= _NC_EVENT_TIMEOUT_MSEC;
      }
    }
#endif

#endif /* USE_FUNC_POLL, etc */

    returntime = _nc_gettime(FALSE);

    if (milliseconds >= 0)
      milliseconds -= (returntime - starttime);

#ifdef NCURSES_WGETCH_EVENTS
    if (evl) {
      _nc_event **ev = evl->events;
      _nc_event **last = ev + evl->count;

      evl->result_flags = 0;
      while (ev < last) {
          if ((*ev)->type == _NC_EVENT_TIMEOUT_MSEC) {
            long diff = (returntime - starttime);
            if ((*ev)->data.timeout_msec <= diff)
                (*ev)->data.timeout_msec = 0;
            else
                (*ev)->data.timeout_msec -= diff;
          }

      }
    }
#endif

#if PRECISE_GETTIME && HAVE_NANOSLEEP
    /*
     * If the timeout hasn't expired, and we've gotten no data,
     * this is probably a system where 'select()' needs to be left
     * alone so that it can complete.  Make this process sleep,
     * then come back for more.
     */
    if (result == 0 && milliseconds > 100) {
      napms(100);       /* FIXME: this won't be right if I recur! */
      milliseconds -= 100;
      goto retry;
    }
#endif

    /* return approximate time left in milliseconds */
    if (timeleft)
      *timeleft = milliseconds;

    TR(TRACE_IEVENT, ("end twait: returned %d (%d), remaining time %d msec",
                  result, errno, milliseconds));

    /*
     * Both 'poll()' and 'select()' return the number of file descriptors
     * that are active.  Translate this back to the mask that denotes which
     * file-descriptors, so that we don't need all of this system-specific
     * code everywhere.
     */
    if (result != 0) {
      if (result > 0) {
          result = 0;
#if USE_FUNC_POLL
          for (count = 0; count < 2; count++) {
            if ((mode & (1 << count))
                && (fds[count].revents & POLLIN)) {
                result |= (1 << count);
            }
          }
#elif defined(__BEOS__)
          result = 1;         /* redundant, but simple */
#elif HAVE_SELECT
          if ((mode & 2)
            && (fd = SP->_mouse_fd) >= 0
            && FD_ISSET(fd, &set))
            result |= 2;
          if ((mode & 1)
            && FD_ISSET(SP->_ifd, &set))
            result |= 1;
#endif
      } else
          result = 0;
    }
#ifdef NCURSES_WGETCH_EVENTS
    if ((mode & 4) && evl && evl->result_flags)
      result |= 4;
#endif

    return (result);
}

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