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[emacs.git] / lisp / emacs-lisp / timer.el
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1 ;;; timer.el --- run a function with args at some time in future
3 ;; Copyright (C) 1996, 2001-2015 Free Software Foundation, Inc.
5 ;; Maintainer: emacs-devel@gnu.org
6 ;; Package: emacs
8 ;; This file is part of GNU Emacs.
10 ;; GNU Emacs is free software: you can redistribute it and/or modify
11 ;; it under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation, either version 3 of the License, or
13 ;; (at your option) any later version.
15 ;; GNU Emacs is distributed in the hope that it will be useful,
16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;; GNU General Public License for more details.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
23 ;;; Commentary:
25 ;; This package gives you the capability to run Emacs Lisp commands at
26 ;; specified times in the future, either as one-shots or periodically.
28 ;;; Code:
30 (eval-when-compile (require 'cl-lib))
32 (cl-defstruct (timer
33 (:constructor nil)
34 (:copier nil)
35 (:constructor timer-create ())
36 (:type vector)
37 (:conc-name timer--))
38 ;; nil if the timer is active (waiting to be triggered),
39 ;; non-nil if it is inactive ("already triggered", in theory).
40 (triggered t)
41 ;; Time of next trigger: for normal timers, absolute time, for idle timers,
42 ;; time relative to idle-start.
43 high-seconds low-seconds usecs
44 ;; For normal timers, time between repetitions, or nil. For idle timers,
45 ;; non-nil iff repeated.
46 repeat-delay
47 function args ;What to do when triggered.
48 idle-delay ;If non-nil, this is an idle-timer.
49 psecs)
51 (defun timerp (object)
52 "Return t if OBJECT is a timer."
53 (and (vectorp object) (= (length object) 9)))
55 (defsubst timer--check (timer)
56 (or (timerp timer) (signal 'wrong-type-argument (list #'timerp timer))))
58 (defun timer--time-setter (timer time)
59 (timer--check timer)
60 (setf (timer--high-seconds timer) (pop time))
61 (let ((low time) (usecs 0) (psecs 0))
62 (when (consp time)
63 (setq low (pop time))
64 (when time
65 (setq usecs (pop time))
66 (when time
67 (setq psecs (car time)))))
68 (setf (timer--low-seconds timer) low)
69 (setf (timer--usecs timer) usecs)
70 (setf (timer--psecs timer) psecs)
71 time))
73 ;; Pseudo field `time'.
74 (defun timer--time (timer)
75 (declare (gv-setter timer--time-setter))
76 (list (timer--high-seconds timer)
77 (timer--low-seconds timer)
78 (timer--usecs timer)
79 (timer--psecs timer)))
81 (defun timer-set-time (timer time &optional delta)
82 "Set the trigger time of TIMER to TIME.
83 TIME must be in the internal format returned by, e.g., `current-time'.
84 If optional third argument DELTA is a positive number, make the timer
85 fire repeatedly that many seconds apart."
86 (setf (timer--time timer) time)
87 (setf (timer--repeat-delay timer) (and (numberp delta) (> delta 0) delta))
88 timer)
90 (defun timer-set-idle-time (timer secs &optional repeat)
91 ;; FIXME: Merge with timer-set-time.
92 "Set the trigger idle time of TIMER to SECS.
93 SECS may be an integer, floating point number, or the internal
94 time format returned by, e.g., `current-idle-time'.
95 If optional third argument REPEAT is non-nil, make the timer
96 fire each time Emacs is idle for that many seconds."
97 (setf (timer--time timer) (if (consp secs) secs (seconds-to-time secs)))
98 (setf (timer--repeat-delay timer) repeat)
99 timer)
101 (defun timer-next-integral-multiple-of-time (time secs)
102 "Yield the next value after TIME that is an integral multiple of SECS.
103 More precisely, the next value, after TIME, that is an integral multiple
104 of SECS seconds since the epoch. SECS may be a fraction."
105 (let* ((trillion 1e12)
106 (time-sec (+ (nth 1 time)
107 (* 65536.0 (nth 0 time))))
108 (delta-sec (mod (- time-sec) secs))
109 (next-sec (+ time-sec (ffloor delta-sec)))
110 (next-sec-psec (ffloor (* trillion (mod delta-sec 1))))
111 (sub-time-psec (+ (or (nth 3 time) 0)
112 (* 1e6 (nth 2 time))))
113 (psec-diff (- sub-time-psec next-sec-psec)))
114 (if (and (<= next-sec time-sec) (< 0 psec-diff))
115 (setq next-sec-psec (+ sub-time-psec
116 (mod (- psec-diff) (* trillion secs)))))
117 (setq next-sec (+ next-sec (floor next-sec-psec trillion)))
118 (setq next-sec-psec (mod next-sec-psec trillion))
119 (list (floor next-sec 65536)
120 (floor (mod next-sec 65536))
121 (floor next-sec-psec 1000000)
122 (floor (mod next-sec-psec 1000000)))))
124 (defun timer-relative-time (time secs &optional usecs psecs)
125 "Advance TIME by SECS seconds and optionally USECS microseconds
126 and PSECS picoseconds. SECS may be either an integer or a
127 floating point number."
128 (let ((delta secs))
129 (if (or usecs psecs)
130 (setq delta (time-add delta (list 0 0 (or usecs 0) (or psecs 0)))))
131 (time-add time delta)))
133 (defun timer--time-less-p (t1 t2)
134 "Say whether time value T1 is less than time value T2."
135 (time-less-p (timer--time t1) (timer--time t2)))
137 (defun timer-inc-time (timer secs &optional usecs psecs)
138 "Increment the time set in TIMER by SECS seconds, USECS microseconds,
139 and PSECS picoseconds. SECS may be a fraction. If USECS or PSECS are
140 omitted, they are treated as zero."
141 (setf (timer--time timer)
142 (timer-relative-time (timer--time timer) secs usecs psecs)))
144 (defun timer-set-time-with-usecs (timer time usecs &optional delta)
145 "Set the trigger time of TIMER to TIME plus USECS.
146 TIME must be in the internal format returned by, e.g., `current-time'.
147 The microsecond count from TIME is ignored, and USECS is used instead.
148 If optional fourth argument DELTA is a positive number, make the timer
149 fire repeatedly that many seconds apart."
150 (declare (obsolete "use `timer-set-time' and `timer-inc-time' instead."
151 "22.1"))
152 (setf (timer--time timer) time)
153 (setf (timer--usecs timer) usecs)
154 (setf (timer--psecs timer) 0)
155 (setf (timer--repeat-delay timer) (and (numberp delta) (> delta 0) delta))
156 timer)
158 (defun timer-set-function (timer function &optional args)
159 "Make TIMER call FUNCTION with optional ARGS when triggering."
160 (timer--check timer)
161 (setf (timer--function timer) function)
162 (setf (timer--args timer) args)
163 timer)
165 (defun timer--activate (timer &optional triggered-p reuse-cell idle)
166 (if (and (timerp timer)
167 (integerp (timer--high-seconds timer))
168 (integerp (timer--low-seconds timer))
169 (integerp (timer--usecs timer))
170 (integerp (timer--psecs timer))
171 (timer--function timer))
172 (let ((timers (if idle timer-idle-list timer-list))
173 last)
174 ;; Skip all timers to trigger before the new one.
175 (while (and timers (timer--time-less-p (car timers) timer))
176 (setq last timers
177 timers (cdr timers)))
178 (if reuse-cell
179 (progn
180 (setcar reuse-cell timer)
181 (setcdr reuse-cell timers))
182 (setq reuse-cell (cons timer timers)))
183 ;; Insert new timer after last which possibly means in front of queue.
184 (setf (cond (last (cdr last))
185 (idle timer-idle-list)
186 (t timer-list))
187 reuse-cell)
188 (setf (timer--triggered timer) triggered-p)
189 (setf (timer--idle-delay timer) idle)
190 nil)
191 (error "Invalid or uninitialized timer")))
193 (defun timer-activate (timer &optional triggered-p reuse-cell)
194 "Insert TIMER into `timer-list'.
195 If TRIGGERED-P is t, make TIMER inactive (put it on the list, but
196 mark it as already triggered). To remove it, use `cancel-timer'.
198 REUSE-CELL, if non-nil, is a cons cell to reuse when inserting
199 TIMER into `timer-list' (usually a cell removed from that list by
200 `cancel-timer-internal'; using this reduces consing for repeat
201 timers). If nil, allocate a new cell."
202 (timer--activate timer triggered-p reuse-cell nil))
204 (defun timer-activate-when-idle (timer &optional dont-wait reuse-cell)
205 "Insert TIMER into `timer-idle-list'.
206 This arranges to activate TIMER whenever Emacs is next idle.
207 If optional argument DONT-WAIT is non-nil, set TIMER to activate
208 immediately \(see below\), or at the right time, if Emacs is
209 already idle.
211 REUSE-CELL, if non-nil, is a cons cell to reuse when inserting
212 TIMER into `timer-idle-list' (usually a cell removed from that
213 list by `cancel-timer-internal'; using this reduces consing for
214 repeat timers). If nil, allocate a new cell.
216 Using non-nil DONT-WAIT is not recommended when activating an
217 idle timer from an idle timer handler, if the timer being
218 activated has an idleness time that is smaller or equal to
219 the time of the current timer. That's because the activated
220 timer will fire right away."
221 (timer--activate timer (not dont-wait) reuse-cell 'idle))
223 (defalias 'disable-timeout 'cancel-timer)
225 (defun cancel-timer (timer)
226 "Remove TIMER from the list of active timers."
227 (timer--check timer)
228 (setq timer-list (delq timer timer-list))
229 (setq timer-idle-list (delq timer timer-idle-list))
230 nil)
232 (defun cancel-timer-internal (timer)
233 "Remove TIMER from the list of active timers or idle timers.
234 Only to be used in this file. It returns the cons cell
235 that was removed from the timer list."
236 (let ((cell1 (memq timer timer-list))
237 (cell2 (memq timer timer-idle-list)))
238 (if cell1
239 (setq timer-list (delq timer timer-list)))
240 (if cell2
241 (setq timer-idle-list (delq timer timer-idle-list)))
242 (or cell1 cell2)))
244 (defun cancel-function-timers (function)
245 "Cancel all timers which would run FUNCTION.
246 This affects ordinary timers such as are scheduled by `run-at-time',
247 and idle timers such as are scheduled by `run-with-idle-timer'."
248 (interactive "aCancel timers of function: ")
249 (dolist (timer timer-list)
250 (if (eq (timer--function timer) function)
251 (setq timer-list (delq timer timer-list))))
252 (dolist (timer timer-idle-list)
253 (if (eq (timer--function timer) function)
254 (setq timer-idle-list (delq timer timer-idle-list)))))
256 ;; Record the last few events, for debugging.
257 (defvar timer-event-last nil
258 "Last timer that was run.")
259 (defvar timer-event-last-1 nil
260 "Next-to-last timer that was run.")
261 (defvar timer-event-last-2 nil
262 "Third-to-last timer that was run.")
264 (defcustom timer-max-repeats 10
265 "Maximum number of times to repeat a timer, if many repeats are delayed.
266 Timer invocations can be delayed because Emacs is suspended or busy,
267 or because the system's time changes. If such an occurrence makes it
268 appear that many invocations are overdue, this variable controls
269 how many will really happen."
270 :type 'integer
271 :group 'internal)
273 (defun timer-until (timer time)
274 "Calculate number of seconds from when TIMER will run, until TIME.
275 TIMER is a timer, and stands for the time when its next repeat is scheduled.
276 TIME is a time-list."
277 (- (float-time time) (float-time (timer--time timer))))
279 (defun timer-event-handler (timer)
280 "Call the handler for the timer TIMER.
281 This function is called, by name, directly by the C code."
282 (setq timer-event-last-2 timer-event-last-1)
283 (setq timer-event-last-1 timer-event-last)
284 (setq timer-event-last timer)
285 (let ((inhibit-quit t))
286 (timer--check timer)
287 (let ((retrigger nil)
288 (cell
289 ;; Delete from queue. Record the cons cell that was used.
290 (cancel-timer-internal timer)))
291 ;; If `cell' is nil, it means the timer was already canceled, so we
292 ;; shouldn't be running it at all. This can happen for example with the
293 ;; following scenario (bug#17392):
294 ;; - we run timers, starting with A (and remembering the rest as (B C)).
295 ;; - A runs and a does a sit-for.
296 ;; - during sit-for we run timer D which cancels timer B.
297 ;; - timer A finally finishes, so we move on to timers B and C.
298 (when cell
299 ;; Re-schedule if requested.
300 (if (timer--repeat-delay timer)
301 (if (timer--idle-delay timer)
302 (timer-activate-when-idle timer nil cell)
303 (timer-inc-time timer (timer--repeat-delay timer) 0)
304 ;; If real time has jumped forward,
305 ;; perhaps because Emacs was suspended for a long time,
306 ;; limit how many times things get repeated.
307 (if (and (numberp timer-max-repeats)
308 (< 0 (timer-until timer nil)))
309 (let ((repeats (/ (timer-until timer nil)
310 (timer--repeat-delay timer))))
311 (if (> repeats timer-max-repeats)
312 (timer-inc-time timer (* (timer--repeat-delay timer)
313 repeats)))))
314 ;; Place it back on the timer-list before running
315 ;; timer--function, so it can cancel-timer itself.
316 (timer-activate timer t cell)
317 (setq retrigger t)))
318 ;; Run handler.
319 (condition-case-unless-debug err
320 ;; Timer functions should not change the current buffer.
321 ;; If they do, all kinds of nasty surprises can happen,
322 ;; and it can be hellish to track down their source.
323 (save-current-buffer
324 (apply (timer--function timer) (timer--args timer)))
325 (error (message "Error running timer%s: %S"
326 (if (symbolp (timer--function timer))
327 (format " `%s'" (timer--function timer)) "")
328 err)))
329 (when (and retrigger
330 ;; If the timer's been canceled, don't "retrigger" it
331 ;; since it might still be in the copy of timer-list kept
332 ;; by keyboard.c:timer_check (bug#14156).
333 (memq timer timer-list))
334 (setf (timer--triggered timer) nil))))))
336 ;; This function is incompatible with the one in levents.el.
337 (defun timeout-event-p (event)
338 "Non-nil if EVENT is a timeout event."
339 (and (listp event) (eq (car event) 'timer-event)))
342 (declare-function diary-entry-time "diary-lib" (s))
344 (defun run-at-time (time repeat function &rest args)
345 "Perform an action at time TIME.
346 Repeat the action every REPEAT seconds, if REPEAT is non-nil.
347 TIME should be one of: a string giving an absolute time like
348 \"11:23pm\" (the acceptable formats are those recognized by
349 `diary-entry-time'; note that such times are interpreted as times
350 today, even if in the past); a string giving a relative time like
351 \"2 hours 35 minutes\" (the acceptable formats are those
352 recognized by `timer-duration'); nil meaning now; a number of
353 seconds from now; a value from `encode-time'; or t (with non-nil
354 REPEAT) meaning the next integral multiple of REPEAT. REPEAT may
355 be an integer or floating point number. The action is to call
356 FUNCTION with arguments ARGS.
358 This function returns a timer object which you can use in `cancel-timer'."
359 (interactive "sRun at time: \nNRepeat interval: \naFunction: ")
361 (or (null repeat)
362 (and (numberp repeat) (< 0 repeat))
363 (error "Invalid repetition interval"))
365 ;; Special case: nil means "now" and is useful when repeating.
366 (if (null time)
367 (setq time (current-time)))
369 ;; Special case: t means the next integral multiple of REPEAT.
370 (if (and (eq time t) repeat)
371 (setq time (timer-next-integral-multiple-of-time (current-time) repeat)))
373 ;; Handle numbers as relative times in seconds.
374 (if (numberp time)
375 (setq time (timer-relative-time nil time)))
377 ;; Handle relative times like "2 hours 35 minutes"
378 (if (stringp time)
379 (let ((secs (timer-duration time)))
380 (if secs
381 (setq time (timer-relative-time nil secs)))))
383 ;; Handle "11:23pm" and the like. Interpret it as meaning today
384 ;; which admittedly is rather stupid if we have passed that time
385 ;; already. (Though only Emacs hackers hack Emacs at that time.)
386 (if (stringp time)
387 (progn
388 (require 'diary-lib)
389 (let ((hhmm (diary-entry-time time))
390 (now (decode-time)))
391 (if (>= hhmm 0)
392 (setq time
393 (encode-time 0 (% hhmm 100) (/ hhmm 100) (nth 3 now)
394 (nth 4 now) (nth 5 now) (nth 8 now)))))))
396 (or (consp time)
397 (error "Invalid time format"))
399 (let ((timer (timer-create)))
400 (timer-set-time timer time repeat)
401 (timer-set-function timer function args)
402 (timer-activate timer)
403 timer))
405 (defun run-with-timer (secs repeat function &rest args)
406 "Perform an action after a delay of SECS seconds.
407 Repeat the action every REPEAT seconds, if REPEAT is non-nil.
408 SECS and REPEAT may be integers or floating point numbers.
409 The action is to call FUNCTION with arguments ARGS.
411 This function returns a timer object which you can use in `cancel-timer'."
412 (interactive "sRun after delay (seconds): \nNRepeat interval: \naFunction: ")
413 (apply 'run-at-time secs repeat function args))
415 (defun add-timeout (secs function object &optional repeat)
416 "Add a timer to run SECS seconds from now, to call FUNCTION on OBJECT.
417 If REPEAT is non-nil, repeat the timer every REPEAT seconds.
418 This function is for compatibility; see also `run-with-timer'."
419 (run-with-timer secs repeat function object))
421 (defun run-with-idle-timer (secs repeat function &rest args)
422 "Perform an action the next time Emacs is idle for SECS seconds.
423 The action is to call FUNCTION with arguments ARGS.
424 SECS may be an integer, a floating point number, or the internal
425 time format returned by, e.g., `current-idle-time'.
426 If Emacs is currently idle, and has been idle for N seconds (N < SECS),
427 then it will call FUNCTION in SECS - N seconds from now. Using
428 SECS <= N is not recommended if this function is invoked from an idle
429 timer, because FUNCTION will then be called immediately.
431 If REPEAT is non-nil, do the action each time Emacs has been idle for
432 exactly SECS seconds (that is, only once for each time Emacs becomes idle).
434 This function returns a timer object which you can use in `cancel-timer'."
435 (interactive
436 (list (read-from-minibuffer "Run after idle (seconds): " nil nil t)
437 (y-or-n-p "Repeat each time Emacs is idle? ")
438 (intern (completing-read "Function: " obarray 'fboundp t))))
439 (let ((timer (timer-create)))
440 (timer-set-function timer function args)
441 (timer-set-idle-time timer secs repeat)
442 (timer-activate-when-idle timer t)
443 timer))
445 (defvar with-timeout-timers nil
446 "List of all timers used by currently pending `with-timeout' calls.")
448 (defmacro with-timeout (list &rest body)
449 "Run BODY, but if it doesn't finish in SECONDS seconds, give up.
450 If we give up, we run the TIMEOUT-FORMS and return the value of the last one.
451 The timeout is checked whenever Emacs waits for some kind of external
452 event (such as keyboard input, input from subprocesses, or a certain time);
453 if the program loops without waiting in any way, the timeout will not
454 be detected.
455 \n(fn (SECONDS TIMEOUT-FORMS...) BODY)"
456 (declare (indent 1) (debug ((form body) body)))
457 (let ((seconds (car list))
458 (timeout-forms (cdr list))
459 (timeout (make-symbol "timeout")))
460 `(let ((-with-timeout-value-
461 (catch ',timeout
462 (let* ((-with-timeout-timer-
463 (run-with-timer ,seconds nil
464 (lambda () (throw ',timeout ',timeout))))
465 (with-timeout-timers
466 (cons -with-timeout-timer- with-timeout-timers)))
467 (unwind-protect
468 (progn ,@body)
469 (cancel-timer -with-timeout-timer-))))))
470 ;; It is tempting to avoid the `if' altogether and instead run
471 ;; timeout-forms in the timer, just before throwing `timeout'.
472 ;; But that would mean that timeout-forms are run in the deeper
473 ;; dynamic context of the timer, with inhibit-quit set etc...
474 (if (eq -with-timeout-value- ',timeout)
475 (progn ,@timeout-forms)
476 -with-timeout-value-))))
478 (defun with-timeout-suspend ()
479 "Stop the clock for `with-timeout'. Used by debuggers.
480 The idea is that the time you spend in the debugger should not
481 count against these timeouts.
483 The value is a list that the debugger can pass to `with-timeout-unsuspend'
484 when it exits, to make these timers start counting again."
485 (mapcar (lambda (timer)
486 (cancel-timer timer)
487 (list timer (time-subtract (timer--time timer) nil)))
488 with-timeout-timers))
490 (defun with-timeout-unsuspend (timer-spec-list)
491 "Restart the clock for `with-timeout'.
492 The argument should be a value previously returned by `with-timeout-suspend'."
493 (dolist (elt timer-spec-list)
494 (let ((timer (car elt))
495 (delay (cadr elt)))
496 (timer-set-time timer (time-add nil delay))
497 (timer-activate timer))))
499 (defun y-or-n-p-with-timeout (prompt seconds default-value)
500 "Like (y-or-n-p PROMPT), with a timeout.
501 If the user does not answer after SECONDS seconds, return DEFAULT-VALUE."
502 (with-timeout (seconds default-value)
503 (y-or-n-p prompt)))
505 (defconst timer-duration-words
506 (list (cons "microsec" 0.000001)
507 (cons "microsecond" 0.000001)
508 (cons "millisec" 0.001)
509 (cons "millisecond" 0.001)
510 (cons "sec" 1)
511 (cons "second" 1)
512 (cons "min" 60)
513 (cons "minute" 60)
514 (cons "hour" (* 60 60))
515 (cons "day" (* 24 60 60))
516 (cons "week" (* 7 24 60 60))
517 (cons "fortnight" (* 14 24 60 60))
518 (cons "month" (* 30 24 60 60)) ; Approximation
519 (cons "year" (* 365.25 24 60 60)) ; Approximation
521 "Alist mapping temporal words to durations in seconds.")
523 (defun timer-duration (string)
524 "Return number of seconds specified by STRING, or nil if parsing fails."
525 (let ((secs 0)
526 (start 0)
527 (case-fold-search t))
528 (while (string-match
529 "[ \t]*\\([0-9.]+\\)?[ \t]*\\([a-z]+[a-rt-z]\\)s?[ \t]*"
530 string start)
531 (let ((count (if (match-beginning 1)
532 (string-to-number (match-string 1 string))
534 (itemsize (cdr (assoc (match-string 2 string)
535 timer-duration-words))))
536 (if itemsize
537 (setq start (match-end 0)
538 secs (+ secs (* count itemsize)))
539 (setq secs nil
540 start (length string)))))
541 (if (= start (length string))
542 secs
543 (if (string-match-p "\\`[0-9.]+\\'" string)
544 (string-to-number string)))))
546 (defun internal-timer-start-idle ()
547 "Mark all idle-time timers as once again candidates for running."
548 (dolist (timer timer-idle-list)
549 (if (timerp timer) ;; FIXME: Why test?
550 (setf (timer--triggered timer) nil))))
552 (provide 'timer)
554 ;;; timer.el ends here