| 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 | /* Free-list of atimer structures. */ |
| 39 | |
| 40 | static struct atimer *free_atimers; |
| 41 | |
| 42 | /* List of currently not running timers due to a call to |
| 43 | lock_atimer. */ |
| 44 | |
| 45 | static struct atimer *stopped_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 | static struct atimer *append_atimer_lists P_ ((struct atimer *, |
| 70 | struct atimer *)); |
| 71 | SIGTYPE alarm_signal_handler (); |
| 72 | |
| 73 | |
| 74 | /* Start a new atimer of type TYPE. TIME specifies when the timer is |
| 75 | ripe. FN is the function to call when the timer fires. |
| 76 | CLIENT_DATA is stored in the client_data member of the atimer |
| 77 | structure returned and so made available to FN when it is called. |
| 78 | |
| 79 | If TYPE is ATIMER_ABSOLUTE, TIME is the absolute time at which the |
| 80 | timer fires. |
| 81 | |
| 82 | If TYPE is ATIMER_RELATIVE, the timer is ripe TIME s/us in the |
| 83 | future. |
| 84 | |
| 85 | In both cases, the timer is automatically freed after it has fired. |
| 86 | |
| 87 | If TYPE is ATIMER_CONTINUOUS, the timer fires every TIME s/us. |
| 88 | |
| 89 | Value is a pointer to the atimer started. It can be used in calls |
| 90 | to cancel_atimer; don't free it yourself. */ |
| 91 | |
| 92 | struct atimer * |
| 93 | start_atimer (type, time, fn, client_data) |
| 94 | enum atimer_type type; |
| 95 | EMACS_TIME time; |
| 96 | atimer_callback fn; |
| 97 | void *client_data; |
| 98 | { |
| 99 | struct atimer *t; |
| 100 | |
| 101 | /* Round TIME up to the next full second if we don't have |
| 102 | itimers. */ |
| 103 | #ifndef HAVE_SETITIMER |
| 104 | if (EMACS_USECS (time) != 0) |
| 105 | { |
| 106 | EMACS_SET_USECS (time, 0); |
| 107 | EMACS_SET_SECS (time, EMACS_SECS (time) + 1); |
| 108 | } |
| 109 | #endif /* not HAVE_SETITIMER */ |
| 110 | |
| 111 | /* Get an atimer structure from the free-list, or allocate |
| 112 | a new one. */ |
| 113 | if (free_atimers) |
| 114 | { |
| 115 | t = free_atimers; |
| 116 | free_atimers = t->next; |
| 117 | } |
| 118 | else |
| 119 | t = (struct atimer *) xmalloc (sizeof *t); |
| 120 | |
| 121 | /* Fill the atimer structure. */ |
| 122 | bzero (t, sizeof *t); |
| 123 | t->type = type; |
| 124 | t->fn = fn; |
| 125 | t->client_data = client_data; |
| 126 | |
| 127 | BLOCK_ATIMERS; |
| 128 | |
| 129 | /* Compute the timer's expiration time. */ |
| 130 | switch (type) |
| 131 | { |
| 132 | case ATIMER_ABSOLUTE: |
| 133 | t->expiration = time; |
| 134 | break; |
| 135 | |
| 136 | case ATIMER_RELATIVE: |
| 137 | EMACS_GET_TIME (t->expiration); |
| 138 | EMACS_ADD_TIME (t->expiration, t->expiration, time); |
| 139 | break; |
| 140 | |
| 141 | case ATIMER_CONTINUOUS: |
| 142 | EMACS_GET_TIME (t->expiration); |
| 143 | EMACS_ADD_TIME (t->expiration, t->expiration, time); |
| 144 | t->interval = time; |
| 145 | break; |
| 146 | } |
| 147 | |
| 148 | /* Insert the timer in the list of active atimers. */ |
| 149 | schedule_atimer (t); |
| 150 | UNBLOCK_ATIMERS; |
| 151 | |
| 152 | /* Arrange for a SIGALRM at the time the next atimer is ripe. */ |
| 153 | set_alarm (); |
| 154 | |
| 155 | return t; |
| 156 | } |
| 157 | |
| 158 | |
| 159 | /* Cancel and free atimer TIMER. */ |
| 160 | |
| 161 | void |
| 162 | cancel_atimer (timer) |
| 163 | struct atimer *timer; |
| 164 | { |
| 165 | int i; |
| 166 | |
| 167 | BLOCK_ATIMERS; |
| 168 | |
| 169 | for (i = 0; i < 2; ++i) |
| 170 | { |
| 171 | struct atimer *t, *prev; |
| 172 | struct atimer **list = i ? &stopped_atimers : &atimers; |
| 173 | |
| 174 | /* See if TIMER is active or stopped. */ |
| 175 | for (t = *list, prev = NULL; t && t != timer; prev = t, t = t->next) |
| 176 | ; |
| 177 | |
| 178 | /* If it is, take it off the its list, and put in on the |
| 179 | free-list. We don't bother to arrange for setting a |
| 180 | different alarm time, since a too early one doesn't hurt. */ |
| 181 | if (t) |
| 182 | { |
| 183 | if (prev) |
| 184 | prev->next = t->next; |
| 185 | else |
| 186 | *list = t->next; |
| 187 | |
| 188 | t->next = free_atimers; |
| 189 | free_atimers = t; |
| 190 | break; |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | UNBLOCK_ATIMERS; |
| 195 | } |
| 196 | |
| 197 | |
| 198 | /* Append two lists of atimers LIST1 and LIST2 and return the |
| 199 | result list. */ |
| 200 | |
| 201 | static struct atimer * |
| 202 | append_atimer_lists (list1, list2) |
| 203 | struct atimer *list1, *list2; |
| 204 | { |
| 205 | if (list1 == NULL) |
| 206 | return list2; |
| 207 | else if (list2 == NULL) |
| 208 | return list1; |
| 209 | else |
| 210 | { |
| 211 | struct atimer *p; |
| 212 | |
| 213 | for (p = list1; p->next; p = p->next) |
| 214 | ; |
| 215 | p->next = list2; |
| 216 | return list1; |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | |
| 221 | /* Stop all timers except timer T. T null means stop all timers. */ |
| 222 | |
| 223 | void |
| 224 | stop_other_atimers (t) |
| 225 | struct atimer *t; |
| 226 | { |
| 227 | BLOCK_ATIMERS; |
| 228 | |
| 229 | if (t) |
| 230 | { |
| 231 | struct atimer *p, *prev; |
| 232 | |
| 233 | /* See if T is active. */ |
| 234 | for (p = atimers, prev = 0; p && p != t; p = p->next) |
| 235 | ; |
| 236 | |
| 237 | if (p == t) |
| 238 | { |
| 239 | if (prev) |
| 240 | prev->next = t->next; |
| 241 | else |
| 242 | atimers = t->next; |
| 243 | t->next = NULL; |
| 244 | } |
| 245 | else |
| 246 | /* T is not active. Let's handle this like T == 0. */ |
| 247 | t = NULL; |
| 248 | } |
| 249 | |
| 250 | stopped_atimers = append_atimer_lists (atimers, stopped_atimers); |
| 251 | atimers = t; |
| 252 | UNBLOCK_ATIMERS; |
| 253 | } |
| 254 | |
| 255 | |
| 256 | /* Run all timers again, if some have been stopped with a call to |
| 257 | stop_other_atimers. */ |
| 258 | |
| 259 | void |
| 260 | run_all_atimers () |
| 261 | { |
| 262 | if (stopped_atimers) |
| 263 | { |
| 264 | struct atimer *t = atimers; |
| 265 | struct atimer *next; |
| 266 | |
| 267 | BLOCK_ATIMERS; |
| 268 | atimers = stopped_atimers; |
| 269 | stopped_atimers = NULL; |
| 270 | |
| 271 | while (t) |
| 272 | { |
| 273 | next = t->next; |
| 274 | schedule_atimer (t); |
| 275 | t = next; |
| 276 | } |
| 277 | |
| 278 | UNBLOCK_ATIMERS; |
| 279 | } |
| 280 | } |
| 281 | |
| 282 | |
| 283 | /* A version of run_all_timers suitable for a record_unwind_protect. */ |
| 284 | |
| 285 | Lisp_Object |
| 286 | unwind_stop_other_atimers (dummy) |
| 287 | Lisp_Object dummy; |
| 288 | { |
| 289 | run_all_atimers (); |
| 290 | return Qnil; |
| 291 | } |
| 292 | |
| 293 | |
| 294 | /* Arrange for a SIGALRM to arrive when the next timer is ripe. */ |
| 295 | |
| 296 | static void |
| 297 | set_alarm () |
| 298 | { |
| 299 | #if defined (USG) && !defined (POSIX_SIGNALS) |
| 300 | /* USG systems forget handlers when they are used; |
| 301 | must reestablish each time. */ |
| 302 | signal (SIGALRM, alarm_signal_handler); |
| 303 | #endif /* USG */ |
| 304 | |
| 305 | if (atimers) |
| 306 | { |
| 307 | EMACS_TIME now, time; |
| 308 | #ifdef HAVE_SETITIMER |
| 309 | struct itimerval it; |
| 310 | #endif |
| 311 | |
| 312 | /* Determine s/us till the next timer is ripe. */ |
| 313 | EMACS_GET_TIME (now); |
| 314 | EMACS_SUB_TIME (time, atimers->expiration, now); |
| 315 | |
| 316 | #ifdef HAVE_SETITIMER |
| 317 | /* Don't set the interval to 0; this disables the timer. */ |
| 318 | if (EMACS_TIME_LE (atimers->expiration, now)) |
| 319 | { |
| 320 | EMACS_SET_SECS (time, 0); |
| 321 | EMACS_SET_USECS (time, 1000); |
| 322 | } |
| 323 | |
| 324 | bzero (&it, sizeof it); |
| 325 | it.it_value = time; |
| 326 | setitimer (ITIMER_REAL, &it, 0); |
| 327 | #else /* not HAVE_SETITIMER */ |
| 328 | alarm (max (EMACS_SECS (time), 1)); |
| 329 | #endif /* not HAVE_SETITIMER */ |
| 330 | } |
| 331 | } |
| 332 | |
| 333 | |
| 334 | /* Insert timer T into the list of active atimers `atimers', keeping |
| 335 | the list sorted by expiration time. T must not be in this list |
| 336 | already. */ |
| 337 | |
| 338 | static void |
| 339 | schedule_atimer (t) |
| 340 | struct atimer *t; |
| 341 | { |
| 342 | struct atimer *a = atimers, *prev = NULL; |
| 343 | |
| 344 | /* Look for the first atimer that is ripe after T. */ |
| 345 | while (a && EMACS_TIME_GT (t->expiration, a->expiration)) |
| 346 | prev = a, a = a->next; |
| 347 | |
| 348 | /* Insert T in front of the atimer found, if any. */ |
| 349 | if (prev) |
| 350 | prev->next = t; |
| 351 | else |
| 352 | atimers = t; |
| 353 | |
| 354 | t->next = a; |
| 355 | } |
| 356 | |
| 357 | |
| 358 | /* Signal handler for SIGALRM. SIGNO is the signal number, i.e. |
| 359 | SIGALRM. */ |
| 360 | |
| 361 | SIGTYPE |
| 362 | alarm_signal_handler (signo) |
| 363 | int signo; |
| 364 | { |
| 365 | EMACS_TIME now; |
| 366 | |
| 367 | EMACS_GET_TIME (now); |
| 368 | pending_atimers = 0; |
| 369 | |
| 370 | while (atimers |
| 371 | && (pending_atimers = interrupt_input_blocked) == 0 |
| 372 | && EMACS_TIME_LE (atimers->expiration, now)) |
| 373 | { |
| 374 | struct atimer *t; |
| 375 | |
| 376 | t = atimers; |
| 377 | atimers = atimers->next; |
| 378 | t->fn (t); |
| 379 | |
| 380 | if (t->type == ATIMER_CONTINUOUS) |
| 381 | { |
| 382 | EMACS_ADD_TIME (t->expiration, now, t->interval); |
| 383 | schedule_atimer (t); |
| 384 | } |
| 385 | else |
| 386 | { |
| 387 | t->next = free_atimers; |
| 388 | free_atimers = t; |
| 389 | } |
| 390 | |
| 391 | EMACS_GET_TIME (now); |
| 392 | } |
| 393 | |
| 394 | set_alarm (); |
| 395 | } |
| 396 | |
| 397 | |
| 398 | /* Call alarm_signal_handler for pending timers. */ |
| 399 | |
| 400 | void |
| 401 | do_pending_atimers () |
| 402 | { |
| 403 | if (pending_atimers) |
| 404 | { |
| 405 | BLOCK_ATIMERS; |
| 406 | alarm_signal_handler (SIGALRM); |
| 407 | UNBLOCK_ATIMERS; |
| 408 | } |
| 409 | } |
| 410 | |
| 411 | |
| 412 | /* Turn alarms on/off. This seems to be temporarily necessary on |
| 413 | some systems like HPUX (see process.c). */ |
| 414 | |
| 415 | void |
| 416 | turn_on_atimers (on) |
| 417 | int on; |
| 418 | { |
| 419 | if (on) |
| 420 | { |
| 421 | signal (SIGALRM, alarm_signal_handler); |
| 422 | set_alarm (); |
| 423 | } |
| 424 | else |
| 425 | alarm (0); |
| 426 | } |
| 427 | |
| 428 | |
| 429 | void |
| 430 | init_atimer () |
| 431 | { |
| 432 | free_atimers = atimers = NULL; |
| 433 | pending_atimers = 0; |
| 434 | signal (SIGALRM, alarm_signal_handler); |
| 435 | } |
| 436 | |
| 437 | /* arch-tag: e6308261-eec6-404b-89fb-6e5909518d70 |
| 438 | (do not change this comment) */ |