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/* Asynchronous timers.
Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005,
2006, 2007 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA. */
#include <config.h>
#include <signal.h>
#include <stdio.h>
#include <lisp.h>
#include <syssignal.h>
#include <systime.h>
#include <blockinput.h>
#include <atimer.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
/* Free-list of atimer structures. */
static struct atimer *free_atimers;
/* List of currently not running timers due to a call to
lock_atimer. */
static struct atimer *stopped_atimers;
/* List of active atimers, sorted by expiration time. The timer that
will become ripe next is always at the front of this list. */
static struct atimer *atimers;
/* Non-zero means alarm_signal_handler has found ripe timers but
interrupt_input_blocked was non-zero. In this case, timer
functions are not called until the next UNBLOCK_INPUT because timer
functions are expected to call X, and X cannot be assumed to be
reentrant. */
int pending_atimers;
/* Block/unblock SIGALRM. */
#define BLOCK_ATIMERS sigblock (sigmask (SIGALRM))
#define UNBLOCK_ATIMERS sigunblock (sigmask (SIGALRM))
/* Function prototypes. */
static void set_alarm P_ ((void));
static void schedule_atimer P_ ((struct atimer *));
static struct atimer *append_atimer_lists P_ ((struct atimer *,
struct atimer *));
SIGTYPE alarm_signal_handler ();
/* Start a new atimer of type TYPE. TIME specifies when the timer is
ripe. FN is the function to call when the timer fires.
CLIENT_DATA is stored in the client_data member of the atimer
structure returned and so made available to FN when it is called.
If TYPE is ATIMER_ABSOLUTE, TIME is the absolute time at which the
timer fires.
If TYPE is ATIMER_RELATIVE, the timer is ripe TIME s/us in the
future.
In both cases, the timer is automatically freed after it has fired.
If TYPE is ATIMER_CONTINUOUS, the timer fires every TIME s/us.
Value is a pointer to the atimer started. It can be used in calls
to cancel_atimer; don't free it yourself. */
struct atimer *
start_atimer (type, time, fn, client_data)
enum atimer_type type;
EMACS_TIME time;
atimer_callback fn;
void *client_data;
{
struct atimer *t;
/* Round TIME up to the next full second if we don't have
itimers. */
#ifndef HAVE_SETITIMER
if (EMACS_USECS (time) != 0)
{
EMACS_SET_USECS (time, 0);
EMACS_SET_SECS (time, EMACS_SECS (time) + 1);
}
#endif /* not HAVE_SETITIMER */
/* Get an atimer structure from the free-list, or allocate
a new one. */
if (free_atimers)
{
t = free_atimers;
free_atimers = t->next;
}
else
t = (struct atimer *) xmalloc (sizeof *t);
/* Fill the atimer structure. */
bzero (t, sizeof *t);
t->type = type;
t->fn = fn;
t->client_data = client_data;
BLOCK_ATIMERS;
/* Compute the timer's expiration time. */
switch (type)
{
case ATIMER_ABSOLUTE:
t->expiration = time;
break;
case ATIMER_RELATIVE:
EMACS_GET_TIME (t->expiration);
EMACS_ADD_TIME (t->expiration, t->expiration, time);
break;
case ATIMER_CONTINUOUS:
EMACS_GET_TIME (t->expiration);
EMACS_ADD_TIME (t->expiration, t->expiration, time);
t->interval = time;
break;
}
/* Insert the timer in the list of active atimers. */
schedule_atimer (t);
UNBLOCK_ATIMERS;
/* Arrange for a SIGALRM at the time the next atimer is ripe. */
set_alarm ();
return t;
}
/* Cancel and free atimer TIMER. */
void
cancel_atimer (timer)
struct atimer *timer;
{
int i;
BLOCK_ATIMERS;
for (i = 0; i < 2; ++i)
{
struct atimer *t, *prev;
struct atimer **list = i ? &stopped_atimers : &atimers;
/* See if TIMER is active or stopped. */
for (t = *list, prev = NULL; t && t != timer; prev = t, t = t->next)
;
/* If it is, take it off the its list, and put in on the
free-list. We don't bother to arrange for setting a
different alarm time, since a too early one doesn't hurt. */
if (t)
{
if (prev)
prev->next = t->next;
else
*list = t->next;
t->next = free_atimers;
free_atimers = t;
break;
}
}
UNBLOCK_ATIMERS;
}
/* Append two lists of atimers LIST1 and LIST2 and return the
result list. */
static struct atimer *
append_atimer_lists (list1, list2)
struct atimer *list1, *list2;
{
if (list1 == NULL)
return list2;
else if (list2 == NULL)
return list1;
else
{
struct atimer *p;
for (p = list1; p->next; p = p->next)
;
p->next = list2;
return list1;
}
}
/* Stop all timers except timer T. T null means stop all timers. */
void
stop_other_atimers (t)
struct atimer *t;
{
BLOCK_ATIMERS;
if (t)
{
struct atimer *p, *prev;
/* See if T is active. */
for (p = atimers, prev = NULL; p && p != t; prev = p, p = p->next)
;
if (p == t)
{
if (prev)
prev->next = t->next;
else
atimers = t->next;
t->next = NULL;
}
else
/* T is not active. Let's handle this like T == 0. */
t = NULL;
}
stopped_atimers = append_atimer_lists (atimers, stopped_atimers);
atimers = t;
UNBLOCK_ATIMERS;
}
/* Run all timers again, if some have been stopped with a call to
stop_other_atimers. */
void
run_all_atimers ()
{
if (stopped_atimers)
{
struct atimer *t = atimers;
struct atimer *next;
BLOCK_ATIMERS;
atimers = stopped_atimers;
stopped_atimers = NULL;
while (t)
{
next = t->next;
schedule_atimer (t);
t = next;
}
UNBLOCK_ATIMERS;
}
}
/* A version of run_all_timers suitable for a record_unwind_protect. */
Lisp_Object
unwind_stop_other_atimers (dummy)
Lisp_Object dummy;
{
run_all_atimers ();
return Qnil;
}
/* Arrange for a SIGALRM to arrive when the next timer is ripe. */
static void
set_alarm ()
{
#if defined (USG) && !defined (POSIX_SIGNALS)
/* USG systems forget handlers when they are used;
must reestablish each time. */
signal (SIGALRM, alarm_signal_handler);
#endif /* USG */
if (atimers)
{
EMACS_TIME now, time;
#ifdef HAVE_SETITIMER
struct itimerval it;
#endif
/* Determine s/us till the next timer is ripe. */
EMACS_GET_TIME (now);
EMACS_SUB_TIME (time, atimers->expiration, now);
#ifdef HAVE_SETITIMER
/* Don't set the interval to 0; this disables the timer. */
if (EMACS_TIME_LE (atimers->expiration, now))
{
EMACS_SET_SECS (time, 0);
EMACS_SET_USECS (time, 1000);
}
bzero (&it, sizeof it);
it.it_value = time;
setitimer (ITIMER_REAL, &it, 0);
#else /* not HAVE_SETITIMER */
alarm (max (EMACS_SECS (time), 1));
#endif /* not HAVE_SETITIMER */
}
}
/* Insert timer T into the list of active atimers `atimers', keeping
the list sorted by expiration time. T must not be in this list
already. */
static void
schedule_atimer (t)
struct atimer *t;
{
struct atimer *a = atimers, *prev = NULL;
/* Look for the first atimer that is ripe after T. */
while (a && EMACS_TIME_GT (t->expiration, a->expiration))
prev = a, a = a->next;
/* Insert T in front of the atimer found, if any. */
if (prev)
prev->next = t;
else
atimers = t;
t->next = a;
}
/* Signal handler for SIGALRM. SIGNO is the signal number, i.e.
SIGALRM. */
SIGTYPE
alarm_signal_handler (signo)
int signo;
{
EMACS_TIME now;
SIGNAL_THREAD_CHECK (signo);
EMACS_GET_TIME (now);
pending_atimers = 0;
while (atimers
&& (pending_atimers = interrupt_input_blocked) == 0
&& EMACS_TIME_LE (atimers->expiration, now))
{
struct atimer *t;
t = atimers;
atimers = atimers->next;
#ifndef MAC_OSX
t->fn (t);
#endif
if (t->type == ATIMER_CONTINUOUS)
{
EMACS_ADD_TIME (t->expiration, now, t->interval);
schedule_atimer (t);
}
else
{
t->next = free_atimers;
free_atimers = t;
}
#ifdef MAC_OSX
/* Fix for Ctrl-G. Perhaps this should apply to all platforms. */
t->fn (t);
#endif
EMACS_GET_TIME (now);
}
if (! pending_atimers)
set_alarm ();
}
/* Call alarm_signal_handler for pending timers. */
void
do_pending_atimers ()
{
if (pending_atimers)
{
BLOCK_ATIMERS;
alarm_signal_handler (SIGALRM);
UNBLOCK_ATIMERS;
}
}
/* Turn alarms on/off. This seems to be temporarily necessary on
some systems like HPUX (see process.c). */
void
turn_on_atimers (on)
int on;
{
if (on)
{
signal (SIGALRM, alarm_signal_handler);
set_alarm ();
}
else
alarm (0);
}
void
init_atimer ()
{
free_atimers = atimers = NULL;
pending_atimers = 0;
signal (SIGALRM, alarm_signal_handler);
}
/* arch-tag: e6308261-eec6-404b-89fb-6e5909518d70
(do not change this comment) */
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