src/os_unix.c:RealWaitForChar()
This function is over 400 lines and contains over 40 #ifdefs. Its job? To wait for keyboard input. Several factors caused this code to be so insane.
- Vim tries to be compatible with every OS, including dead ones such as BeOS, VMS, and Amiga.
- Features that drastically change behavior are enabled/disabled with preprocessor flags.
- Cross-platform libraries like libuv didn’t exist when Vim was created.
#ifndef VMS
/*
* Wait "msec" msec until a character is available from file descriptor "fd".
* "msec" == 0 will check for characters once.
* "msec" == -1 will block until a character is available.
* When a GUI is being used, this will not be used for input -- webb
* Returns also, when a request from Sniff is waiting -- toni.
* Or when a Linux GPM mouse event is waiting.
*/
#if defined(__BEOS__)
int
#else
static int
#endif
RealWaitForChar(fd, msec, check_for_gpm)
int fd;
long msec;
int *check_for_gpm UNUSED;
{
int ret;
#ifdef FEAT_NETBEANS_INTG
int nb_fd = netbeans_filedesc();
#endif
#if defined(FEAT_XCLIPBOARD) || defined(USE_XSMP) || defined(FEAT_MZSCHEME)
static int busy = FALSE;
/* May retry getting characters after an event was handled. */
# define MAY_LOOP
# if defined(HAVE_GETTIMEOFDAY) && defined(HAVE_SYS_TIME_H)
/* Remember at what time we started, so that we know how much longer we
* should wait after being interrupted. */
# define USE_START_TV
struct timeval start_tv;
if (msec > 0 && (
# ifdef FEAT_XCLIPBOARD
xterm_Shell != (Widget)0
# if defined(USE_XSMP) || defined(FEAT_MZSCHEME)
||
# endif
# endif
# ifdef USE_XSMP
xsmp_icefd != -1
# ifdef FEAT_MZSCHEME
||
# endif
# endif
# ifdef FEAT_MZSCHEME
(mzthreads_allowed() && p_mzq > 0)
# endif
))
gettimeofday(&start_tv, NULL);
# endif
/* Handle being called recursively. This may happen for the session
* manager stuff, it may save the file, which does a breakcheck. */
if (busy)
return 0;
#endif
#ifdef MAY_LOOP
for (;;)
#endif
{
#ifdef MAY_LOOP
int finished = TRUE; /* default is to 'loop' just once */
# ifdef FEAT_MZSCHEME
int mzquantum_used = FALSE;
# endif
#endif
#ifndef HAVE_SELECT
struct pollfd fds[6];
int nfd;
# ifdef FEAT_XCLIPBOARD
int xterm_idx = -1;
# endif
# ifdef FEAT_MOUSE_GPM
int gpm_idx = -1;
# endif
# ifdef USE_XSMP
int xsmp_idx = -1;
# endif
# ifdef FEAT_NETBEANS_INTG
int nb_idx = -1;
# endif
int towait = (int)msec;
# ifdef FEAT_MZSCHEME
mzvim_check_threads();
if (mzthreads_allowed() && p_mzq > 0 && (msec < 0 || msec > p_mzq))
{
towait = (int)p_mzq; /* don't wait longer than 'mzquantum' */
mzquantum_used = TRUE;
}
# endif
fds[0].fd = fd;
fds[0].events = POLLIN;
nfd = 1;
# ifdef FEAT_SNIFF
# define SNIFF_IDX 1
if (want_sniff_request)
{
fds[SNIFF_IDX].fd = fd_from_sniff;
fds[SNIFF_IDX].events = POLLIN;
nfd++;
}
# endif
# ifdef FEAT_XCLIPBOARD
if (xterm_Shell != (Widget)0)
{
xterm_idx = nfd;
fds[nfd].fd = ConnectionNumber(xterm_dpy);
fds[nfd].events = POLLIN;
nfd++;
}
# endif
# ifdef FEAT_MOUSE_GPM
if (check_for_gpm != NULL && gpm_flag && gpm_fd >= 0)
{
gpm_idx = nfd;
fds[nfd].fd = gpm_fd;
fds[nfd].events = POLLIN;
nfd++;
}
# endif
# ifdef USE_XSMP
if (xsmp_icefd != -1)
{
xsmp_idx = nfd;
fds[nfd].fd = xsmp_icefd;
fds[nfd].events = POLLIN;
nfd++;
}
# endif
#ifdef FEAT_NETBEANS_INTG
if (nb_fd != -1)
{
nb_idx = nfd;
fds[nfd].fd = nb_fd;
fds[nfd].events = POLLIN;
nfd++;
}
#endif
ret = poll(fds, nfd, towait);
# ifdef FEAT_MZSCHEME
if (ret == 0 && mzquantum_used)
/* MzThreads scheduling is required and timeout occurred */
finished = FALSE;
# endif
# ifdef FEAT_SNIFF
if (ret < 0)
sniff_disconnect(1);
else if (want_sniff_request)
{
if (fds[SNIFF_IDX].revents & POLLHUP)
sniff_disconnect(1);
if (fds[SNIFF_IDX].revents & POLLIN)
sniff_request_waiting = 1;
}
# endif
# ifdef FEAT_XCLIPBOARD
if (xterm_Shell != (Widget)0 && (fds[xterm_idx].revents & POLLIN))
{
xterm_update(); /* Maybe we should hand out clipboard */
if (--ret == 0 && !input_available())
/* Try again */
finished = FALSE;
}
# endif
# ifdef FEAT_MOUSE_GPM
if (gpm_idx >= 0 && (fds[gpm_idx].revents & POLLIN))
{
*check_for_gpm = 1;
}
# endif
# ifdef USE_XSMP
if (xsmp_idx >= 0 && (fds[xsmp_idx].revents & (POLLIN | POLLHUP)))
{
if (fds[xsmp_idx].revents & POLLIN)
{
busy = TRUE;
xsmp_handle_requests();
busy = FALSE;
}
else if (fds[xsmp_idx].revents & POLLHUP)
{
if (p_verbose > 0)
verb_msg((char_u *)_("XSMP lost ICE connection"));
xsmp_close();
}
if (--ret == 0)
finished = FALSE; /* Try again */
}
# endif
#ifdef FEAT_NETBEANS_INTG
if (ret > 0 && nb_idx != -1 && fds[nb_idx].revents & POLLIN)
{
netbeans_read();
--ret;
}
#endif
#else /* HAVE_SELECT */
struct timeval tv;
struct timeval *tvp;
fd_set rfds, efds;
int maxfd;
long towait = msec;
# ifdef FEAT_MZSCHEME
mzvim_check_threads();
if (mzthreads_allowed() && p_mzq > 0 && (msec < 0 || msec > p_mzq))
{
towait = p_mzq; /* don't wait longer than 'mzquantum' */
mzquantum_used = TRUE;
}
# endif
# ifdef __EMX__
/* don't check for incoming chars if not in raw mode, because select()
* always returns TRUE then (in some version of emx.dll) */
if (curr_tmode != TMODE_RAW)
return 0;
# endif
if (towait >= 0)
{
tv.tv_sec = towait / 1000;
tv.tv_usec = (towait % 1000) * (1000000/1000);
tvp = &tv;
}
else
tvp = NULL;
/*
* Select on ready for reading and exceptional condition (end of file).
*/
select_eintr:
FD_ZERO(&rfds);
FD_ZERO(&efds);
FD_SET(fd, &rfds);
# if !defined(__QNX__) && !defined(__CYGWIN32__)
/* For QNX select() always returns 1 if this is set. Why? */
FD_SET(fd, &efds);
# endif
maxfd = fd;
# ifdef FEAT_SNIFF
if (want_sniff_request)
{
FD_SET(fd_from_sniff, &rfds);
FD_SET(fd_from_sniff, &efds);
if (maxfd < fd_from_sniff)
maxfd = fd_from_sniff;
}
# endif
# ifdef FEAT_XCLIPBOARD
if (xterm_Shell != (Widget)0)
{
FD_SET(ConnectionNumber(xterm_dpy), &rfds);
if (maxfd < ConnectionNumber(xterm_dpy))
maxfd = ConnectionNumber(xterm_dpy);
/* An event may have already been read but not handled. In
* particulary, XFlush may cause this. */
xterm_update();
}
# endif
# ifdef FEAT_MOUSE_GPM
if (check_for_gpm != NULL && gpm_flag && gpm_fd >= 0)
{
FD_SET(gpm_fd, &rfds);
FD_SET(gpm_fd, &efds);
if (maxfd < gpm_fd)
maxfd = gpm_fd;
}
# endif
# ifdef USE_XSMP
if (xsmp_icefd != -1)
{
FD_SET(xsmp_icefd, &rfds);
FD_SET(xsmp_icefd, &efds);
if (maxfd < xsmp_icefd)
maxfd = xsmp_icefd;
}
# endif
# ifdef FEAT_NETBEANS_INTG
if (nb_fd != -1)
{
FD_SET(nb_fd, &rfds);
if (maxfd < nb_fd)
maxfd = nb_fd;
}
# endif
ret = select(maxfd + 1, &rfds, NULL, &efds, tvp);
# ifdef EINTR
if (ret == -1 && errno == EINTR)
{
/* Check whether window has been resized, EINTR may be caused by
* SIGWINCH. */
if (do_resize)
handle_resize();
/* Interrupted by a signal, need to try again. We ignore msec
* here, because we do want to check even after a timeout if
* characters are available. Needed for reading output of an
* external command after the process has finished. */
goto select_eintr;
}
# endif
# ifdef __TANDEM
if (ret == -1 && errno == ENOTSUP)
{
FD_ZERO(&rfds);
FD_ZERO(&efds);
ret = 0;
}
# endif
# ifdef FEAT_MZSCHEME
if (ret == 0 && mzquantum_used)
/* loop if MzThreads must be scheduled and timeout occurred */
finished = FALSE;
# endif
# ifdef FEAT_SNIFF
if (ret < 0 )
sniff_disconnect(1);
else if (ret > 0 && want_sniff_request)
{
if (FD_ISSET(fd_from_sniff, &efds))
sniff_disconnect(1);
if (FD_ISSET(fd_from_sniff, &rfds))
sniff_request_waiting = 1;
}
# endif
# ifdef FEAT_XCLIPBOARD
if (ret > 0 && xterm_Shell != (Widget)0
&& FD_ISSET(ConnectionNumber(xterm_dpy), &rfds))
{
xterm_update(); /* Maybe we should hand out clipboard */
/* continue looping when we only got the X event and the input
* buffer is empty */
if (--ret == 0 && !input_available())
{
/* Try again */
finished = FALSE;
}
}
# endif
# ifdef FEAT_MOUSE_GPM
if (ret > 0 && gpm_flag && check_for_gpm != NULL && gpm_fd >= 0)
{
if (FD_ISSET(gpm_fd, &efds))
gpm_close();
else if (FD_ISSET(gpm_fd, &rfds))
*check_for_gpm = 1;
}
# endif
# ifdef USE_XSMP
if (ret > 0 && xsmp_icefd != -1)
{
if (FD_ISSET(xsmp_icefd, &efds))
{
if (p_verbose > 0)
verb_msg((char_u *)_("XSMP lost ICE connection"));
xsmp_close();
if (--ret == 0)
finished = FALSE; /* keep going if event was only one */
}
else if (FD_ISSET(xsmp_icefd, &rfds))
{
busy = TRUE;
xsmp_handle_requests();
busy = FALSE;
if (--ret == 0)
finished = FALSE; /* keep going if event was only one */
}
}
# endif
#ifdef FEAT_NETBEANS_INTG
if (ret > 0 && nb_fd != -1 && FD_ISSET(nb_fd, &rfds))
{
netbeans_read();
--ret;
}
#endif
#endif /* HAVE_SELECT */
#ifdef MAY_LOOP
if (finished || msec == 0)
break;
/* We're going to loop around again, find out for how long */
if (msec > 0)
{
# ifdef USE_START_TV
struct timeval mtv;
/* Compute remaining wait time. */
gettimeofday(&mtv, NULL);
msec -= (mtv.tv_sec - start_tv.tv_sec) * 1000L
+ (mtv.tv_usec - start_tv.tv_usec) / 1000L;
# else
/* Guess we got interrupted halfway. */
msec = msec / 2;
# endif
if (msec <= 0)
break; /* waited long enough */
}
#endif
}
return (ret > 0);
}