Commit | Line | Data |
---|---|---|
e12489f9 GM |
1 | /* Asynchronous timers. |
2 | Copyright (C) 2000 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GNU Emacs. | |
5 | ||
6 | GNU Emacs is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GNU Emacs is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GNU Emacs; see the file COPYING. If not, write to | |
18 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | #include <config.h> | |
22 | #include <lisp.h> | |
23 | #include <signal.h> | |
24 | #include <syssignal.h> | |
25 | #include <systime.h> | |
26 | #include <blockinput.h> | |
27 | #include <atimer.h> | |
28 | #include <stdio.h> | |
29 | ||
30 | #ifdef HAVE_UNISTD_H | |
31 | #include <unistd.h> | |
32 | #endif | |
33 | ||
34 | #ifdef HAVE_SYS_TIME_H | |
35 | #include <sys/time.h> | |
36 | #endif | |
37 | ||
38 | /* The ubiquitous min/max macros. */ | |
39 | ||
40 | #define max(X, Y) ((X) > (Y) ? (X) : (Y)) | |
41 | #define min(X, Y) ((X) < (Y) ? (X) : (Y)) | |
42 | ||
43 | /* Free-list of atimer structures. */ | |
44 | ||
45 | static struct atimer *free_atimers; | |
46 | ||
47 | /* List of active atimers, sorted by expiration time. The timer that | |
48 | will become ripe next is always at the front of this list. */ | |
49 | ||
50 | static struct atimer *atimers; | |
51 | ||
52 | /* Non-zero means alarm_signal_handler has found ripe timers but | |
53 | interrupt_input_blocked was non-zero. In this case, timer | |
54 | functions are not called until the next UNBLOCK_INPUT because timer | |
55 | functions are expected to call X, and X cannot be assumed to be | |
56 | reentrant. */ | |
57 | ||
58 | int pending_atimers; | |
59 | ||
60 | /* Block/unblock SIGALRM.. */ | |
61 | ||
62 | #define BLOCK_ATIMERS sigblock (sigmask (SIGALRM)) | |
63 | #define UNBLOCK_ATIMERS sigunblock (sigmask (SIGALRM)) | |
64 | ||
65 | /* Function prototypes. */ | |
66 | ||
67 | static void set_alarm P_ ((void)); | |
68 | static void schedule_atimer P_ ((struct atimer *)); | |
69 | ||
70 | ||
71 | /* Start a new atimer of type TYPE. TIME specifies when the timer is | |
72 | ripe. FN is the function to call when the timer fires. | |
73 | CLIENT_DATA is stored in the client_data member of the atimer | |
74 | structure returned and so made available to FN when it is called. | |
75 | ||
76 | If TYPE is ATIMER_ABSOLUTE, TIME is the absolute time at which the | |
77 | timer fires. | |
78 | ||
79 | If TYPE is ATIMER_RELATIVE, the timer is ripe TIME s/us in the | |
80 | future. | |
81 | ||
82 | In both cases, the timer is automatically freed after it has fired. | |
83 | ||
84 | If TYPE is ATIMER_CONTINUOUS, the timer fires every TIME s/us. | |
85 | ||
86 | Value is a pointer to the atimer started. It can be used in calls | |
87 | to cancel_atimer; don't free it yourself. */ | |
88 | ||
89 | struct atimer * | |
90 | start_atimer (type, time, fn, client_data) | |
91 | enum atimer_type type; | |
92 | EMACS_TIME time; | |
93 | atimer_callback fn; | |
94 | void *client_data; | |
95 | { | |
96 | struct atimer *t; | |
97 | ||
98 | /* Round TIME up to the next full second if we don't have | |
99 | itimers. */ | |
100 | #ifndef HAVE_SETITIMER | |
101 | if (EMACS_USECS (time) != 0) | |
102 | { | |
103 | EMACS_USECS (time) = 0; | |
104 | ++EMACS_SECS (time); | |
105 | } | |
106 | #endif /* not HAVE_SETITIMER */ | |
107 | ||
108 | /* Get an atimer structure from the free-list, or allocate | |
109 | a new one. */ | |
110 | if (free_atimers) | |
111 | { | |
112 | t = free_atimers; | |
113 | free_atimers = t->next; | |
114 | } | |
115 | else | |
116 | t = (struct atimer *) xmalloc (sizeof *t); | |
117 | ||
118 | /* Fill the atimer structure. */ | |
119 | bzero (t, sizeof *t); | |
120 | t->type = type; | |
121 | t->fn = fn; | |
122 | t->client_data = client_data; | |
123 | ||
124 | BLOCK_ATIMERS; | |
125 | ||
126 | /* Compute the timer's expiration time. */ | |
127 | switch (type) | |
128 | { | |
129 | case ATIMER_ABSOLUTE: | |
130 | t->expiration = time; | |
131 | break; | |
132 | ||
133 | case ATIMER_RELATIVE: | |
134 | EMACS_GET_TIME (t->expiration); | |
135 | EMACS_ADD_TIME (t->expiration, t->expiration, time); | |
136 | break; | |
137 | ||
138 | case ATIMER_CONTINUOUS: | |
139 | EMACS_GET_TIME (t->expiration); | |
140 | EMACS_ADD_TIME (t->expiration, t->expiration, time); | |
141 | t->interval = time; | |
142 | break; | |
143 | } | |
144 | ||
145 | /* Insert the timer in the list of active atimers. */ | |
146 | schedule_atimer (t); | |
147 | UNBLOCK_ATIMERS; | |
148 | ||
149 | /* Arrange for a SIGALRM at the time the next atimer is ripe. */ | |
150 | set_alarm (); | |
151 | ||
152 | return t; | |
153 | } | |
154 | ||
155 | ||
156 | /* Cancel and free atimer TIMER. */ | |
157 | ||
158 | void | |
159 | cancel_atimer (timer) | |
160 | struct atimer *timer; | |
161 | { | |
162 | struct atimer *t, *prev; | |
163 | ||
164 | BLOCK_ATIMERS; | |
165 | ||
166 | /* See if TIMER is active. */ | |
167 | for (t = atimers, prev = 0; t && t != timer; t = t->next) | |
168 | ; | |
169 | ||
170 | /* If it is, take it off the list of active timers, put in on the | |
171 | free-list. We don't bother to arrange for setting a different | |
172 | alarm time, since a too early one doesn't hurt. */ | |
173 | if (t) | |
174 | { | |
175 | if (prev) | |
176 | prev->next = t->next; | |
177 | else | |
178 | atimers = t->next; | |
179 | ||
180 | t->next = free_atimers; | |
181 | free_atimers = t; | |
182 | } | |
183 | ||
184 | UNBLOCK_ATIMERS; | |
185 | } | |
186 | ||
187 | ||
188 | /* Arrange for a SIGALRM to arrive when the next timer is ripe. */ | |
189 | ||
190 | static void | |
191 | set_alarm () | |
192 | { | |
193 | ||
194 | #if defined (USG) && !defined (POSIX_SIGNALS) | |
195 | /* USG systems forget handlers when they are used; | |
196 | must reestablish each time. */ | |
197 | signal (SIGALRM, alarm_signal_handler); | |
198 | #endif /* USG */ | |
199 | ||
200 | if (atimers) | |
201 | { | |
202 | EMACS_TIME now, time; | |
203 | #ifdef HAVE_SETITIMER | |
204 | struct itimerval it; | |
205 | #endif | |
206 | ||
207 | /* Determine s/us till the next timer is ripe. */ | |
208 | EMACS_GET_TIME (now); | |
209 | EMACS_SUB_TIME (time, atimers->expiration, now); | |
210 | ||
211 | #ifdef HAVE_SETITIMER | |
212 | /* Don't set the interval to 0; this disables the timer. */ | |
213 | if (EMACS_TIME_LE (atimers->expiration, now)) | |
214 | { | |
215 | EMACS_SET_SECS (time, 0); | |
216 | EMACS_SET_USECS (time, 1000); | |
217 | } | |
218 | ||
219 | bzero (&it, sizeof it); | |
220 | it.it_value = time; | |
221 | setitimer (ITIMER_REAL, &it, 0); | |
222 | #else /* not HAVE_SETITIMER */ | |
223 | alarm (max (EMACS_SECS (time), 1)); | |
224 | #endif /* not HAVE_SETITIMER */ | |
225 | } | |
226 | } | |
227 | ||
228 | ||
229 | /* Insert timer T into the list of active atimers `atimers', keeping | |
230 | the list sorted by expiration time. T must not be in this list | |
231 | already. */ | |
232 | ||
233 | static void | |
234 | schedule_atimer (t) | |
235 | struct atimer *t; | |
236 | { | |
237 | struct atimer *a = atimers, *prev = NULL; | |
238 | ||
239 | /* Look for the first atimer that is ripe after T. */ | |
240 | while (a && EMACS_TIME_GT (t->expiration, a->expiration)) | |
241 | prev = a, a = a->next; | |
242 | ||
243 | /* Insert T in front of the atimer found, if any. */ | |
244 | if (prev) | |
245 | prev->next = t; | |
246 | else | |
247 | atimers = t; | |
248 | ||
249 | t->next = a; | |
250 | } | |
251 | ||
252 | ||
253 | /* Signal handler for SIGALRM. SIGNO is the signal number, i.e. | |
254 | SIGALRM. */ | |
255 | ||
256 | SIGTYPE | |
257 | alarm_signal_handler (signo) | |
258 | int signo; | |
259 | { | |
260 | EMACS_TIME now; | |
261 | ||
262 | EMACS_GET_TIME (now); | |
263 | pending_atimers = 0; | |
264 | ||
265 | while (atimers | |
266 | && (pending_atimers = interrupt_input_blocked) == 0 | |
267 | && EMACS_TIME_LE (atimers->expiration, now)) | |
268 | { | |
269 | struct atimer *t; | |
270 | ||
271 | t = atimers; | |
272 | atimers = atimers->next; | |
273 | t->fn (t); | |
274 | ||
275 | if (t->type == ATIMER_CONTINUOUS) | |
276 | { | |
277 | EMACS_ADD_TIME (t->expiration, now, t->interval); | |
278 | schedule_atimer (t); | |
279 | } | |
280 | else | |
281 | { | |
282 | t->next = free_atimers; | |
283 | free_atimers = t; | |
284 | } | |
285 | ||
286 | EMACS_GET_TIME (now); | |
287 | } | |
288 | ||
289 | #if defined (USG) && !defined (POSIX_SIGNALS) | |
290 | /* USG systems forget handlers when they are used; | |
291 | must reestablish each time. */ | |
292 | signal (SIGALRM, alarm_signal_handler); | |
293 | #endif /* USG */ | |
294 | ||
295 | set_alarm (); | |
296 | } | |
297 | ||
298 | ||
299 | /* Call alarm_signal_handler for pending timers. */ | |
300 | ||
301 | void | |
302 | do_pending_atimers () | |
303 | { | |
304 | if (pending_atimers) | |
305 | { | |
306 | BLOCK_ATIMERS; | |
307 | alarm_signal_handler (SIGALRM); | |
308 | UNBLOCK_ATIMERS; | |
309 | } | |
310 | } | |
311 | ||
312 | ||
313 | /* Turn alarms on/off. This seems to be temporarily necessary on | |
314 | some systems like HPUX (see process.c). */ | |
315 | ||
316 | void | |
317 | turn_on_atimers (on) | |
318 | int on; | |
319 | { | |
320 | if (on) | |
321 | { | |
322 | signal (SIGALRM, alarm_signal_handler); | |
323 | set_alarm (); | |
324 | } | |
325 | else | |
326 | alarm (0); | |
327 | } | |
328 | ||
329 | ||
330 | void | |
331 | init_atimer () | |
332 | { | |
333 | free_atimers = atimers = NULL; | |
334 | pending_atimers = 0; | |
335 | signal (SIGALRM, alarm_signal_handler); | |
336 | } |