lisp/timer.el

   1 ;;; timer.el --- run a function with args at some time in future.
   2
   3 ;; Copyright (C) 1996 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 2, or (at your option)
  12 ;; any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  22 ;; Boston, MA 02111-1307, USA.
  23
  24 ;;; Commentary:
  25
  26 ;; This package gives you the capability to run Emacs Lisp commands at
  27 ;; specified times in the future, either as one-shots or periodically.
  28
  29 ;;; Code:
  30
  31 ;; Layout of a timer vector:
  32 ;; [triggered-p high-seconds low-seconds usecs repeat-delay
  33 ;;  function args idle-delay]
  34
  35 (defun timer-create ()
  36   "Create a timer object."
  37   (let ((timer (make-vector 8 nil)))
  38     (aset timer 0 t)
  39     timer))
  40
  41 (defun timerp (object)
  42   "Return t if OBJECT is a timer."
  43   (and (vectorp object) (= (length object) 8)))
  44
  45 (defun timer-set-time (timer time &optional delta)
  46   "Set the trigger time of TIMER to TIME.
  47 TIME must be in the internal format returned by, e.g., `current-time'.
  48 If optional third argument DELTA is a non-zero integer, make the timer
  49 fire repeatedly that many seconds apart."
  50   (or (timerp timer)
  51       (error "Invalid timer"))
  52   (aset timer 1 (car time))
  53   (aset timer 2 (if (consp (cdr time)) (car (cdr time)) (cdr time)))
  54   (aset timer 3 (or (and (consp (cdr time)) (consp (cdr (cdr time)))
  55                          (nth 2 time))
  56                     0))
  57   (aset timer 4 (and (numberp delta) (> delta 0) delta))
  58   timer)
  59
  60 (defun timer-set-idle-time (timer secs &optional repeat)
  61   "Set the trigger idle time of TIMER to SECS.
  62 If optional third argument REPEAT is non-nil, make the timer
  63 fire each time Emacs is idle for that many seconds."
  64   (or (timerp timer)
  65       (error "Invalid timer"))
  66   (aset timer 1 0)
  67   (aset timer 2 0)
  68   (aset timer 3 0)
  69   (timer-inc-time timer secs)
  70   (aset timer 4 repeat)
  71   timer)
  72
  73 (defun timer-next-integral-multiple-of-time (time secs)
  74   "Yield the next value after TIME that is an integral multiple of SECS.
  75 More precisely, the next value, after TIME, that is an integral multiple
  76 of SECS seconds since the epoch.  SECS may be a fraction."
  77   (let ((time-base (ash 1 16)))
  78     (if (fboundp 'atan)
  79         ;; Use floating point, taking care to not lose precision.
  80         (let* ((float-time-base (float time-base))
  81                (million 1000000.0)
  82                (time-usec (+ (* million
  83                                 (+ (* float-time-base (nth 0 time))
  84                                    (nth 1 time)))
  85                              (nth 2 time)))
  86                (secs-usec (* million secs))
  87                (mod-usec (mod time-usec secs-usec))
  88                (next-usec (+ (- time-usec mod-usec) secs-usec))
  89                (time-base-million (* float-time-base million)))
  90           (list (floor next-usec time-base-million)
  91                 (floor (mod next-usec time-base-million) million)
  92                 (floor (mod next-usec million))))
  93       ;; Floating point is not supported.
  94       ;; Use integer arithmetic, avoiding overflow if possible.
  95       (let* ((mod-sec (mod (+ (* (mod time-base secs)
  96                                  (mod (nth 0 time) secs))
  97                               (nth 1 time))
  98                            secs))
  99              (next-1-sec (+ (- (nth 1 time) mod-sec) secs)))
 100         (list (+ (nth 0 time) (floor next-1-sec time-base))
 101               (mod next-1-sec time-base)
 102               0)))))
 103
 104 (defun timer-relative-time (time secs &optional usecs)
 105   "Advance TIME by SECS seconds and optionally USECS microseconds.
 106 SECS may be a fraction."
 107   (let ((high (car time))
 108         (low (if (consp (cdr time)) (nth 1 time) (cdr time)))
 109         (micro (if (numberp (car-safe (cdr-safe (cdr time))))
 110                    (nth 2 time)
 111                  0)))
 112     ;; Add
 113     (if usecs (setq micro (+ micro usecs)))
 114     (if (floatp secs)
 115         (setq micro (+ micro (floor (* 1000000 (- secs (floor secs)))))))
 116     (setq low (+ low (floor secs)))
 117
 118     ;; Normalize
 119     (setq low (+ low (/ micro 1000000)))
 120     (setq micro (mod micro 1000000))
 121     (setq high (+ high (/ low 65536)))
 122     (setq low (logand low 65535))
 123
 124     (list high low (and (/= micro 0) micro))))
 125
 126 (defun timer-inc-time (timer secs &optional usecs)
 127   "Increment the time set in TIMER by SECS seconds and USECS microseconds.
 128 SECS may be a fraction."
 129   (let ((time (timer-relative-time
 130                (list (aref timer 1) (aref timer 2) (aref timer 3))
 131                secs
 132                usecs)))
 133     (aset timer 1 (nth 0 time))
 134     (aset timer 2 (nth 1 time))
 135     (aset timer 3 (or (nth 2 time) 0))))
 136
 137 (defun timer-set-time-with-usecs (timer time usecs &optional delta)
 138   "Set the trigger time of TIMER to TIME.
 139 TIME must be in the internal format returned by, e.g., `current-time'.
 140 If optional third argument DELTA is a non-zero integer, make the timer
 141 fire repeatedly that many seconds apart."
 142   (or (timerp timer)
 143       (error "Invalid timer"))
 144   (aset timer 1 (car time))
 145   (aset timer 2 (if (consp (cdr time)) (car (cdr time)) (cdr time)))
 146   (aset timer 3 usecs)
 147   (aset timer 4 (and (numberp delta) (> delta 0) delta))
 148   timer)
 149
 150 (defun timer-set-function (timer function &optional args)
 151   "Make TIMER call FUNCTION with optional ARGS when triggering."
 152   (or (timerp timer)
 153       (error "Invalid timer"))
 154   (aset timer 5 function)
 155   (aset timer 6 args)
 156   timer)
 157 \f
 158 (defun timer-activate (timer)
 159   "Put TIMER on the list of active timers."
 160   (if (and (timerp timer)
 161            (integerp (aref timer 1))
 162            (integerp (aref timer 2))
 163            (integerp (aref timer 3))
 164            (aref timer 5))
 165       (let ((timers timer-list)
 166             last)
 167         ;; Skip all timers to trigger before the new one.
 168         (while (and timers
 169                     (or (> (aref timer 1) (aref (car timers) 1))
 170                         (and (= (aref timer 1) (aref (car timers) 1))
 171                              (> (aref timer 2) (aref (car timers) 2)))
 172                         (and (= (aref timer 1) (aref (car timers) 1))
 173                              (= (aref timer 2) (aref (car timers) 2))
 174                              (> (aref timer 3) (aref (car timers) 3)))))
 175           (setq last timers
 176                 timers (cdr timers)))
 177         ;; Insert new timer after last which possibly means in front of queue.
 178         (if last
 179             (setcdr last (cons timer timers))
 180           (setq timer-list (cons timer timers)))
 181         (aset timer 0 nil)
 182         (aset timer 7 nil)
 183         nil)
 184     (error "Invalid or uninitialized timer")))
 185
 186 (defun timer-activate-when-idle (timer &optional dont-wait)
 187   "Arrange to activate TIMER whenever Emacs is next idle.
 188 If optional argument DONT-WAIT is non-nil, then enable the
 189 timer to activate immediately, or at the right time, if Emacs
 190 is already idle."
 191   (if (and (timerp timer)
 192            (integerp (aref timer 1))
 193            (integerp (aref timer 2))
 194            (integerp (aref timer 3))
 195            (aref timer 5))
 196       (let ((timers timer-idle-list)
 197             last)
 198         ;; Skip all timers to trigger before the new one.
 199         (while (and timers
 200                     (or (> (aref timer 1) (aref (car timers) 1))
 201                         (and (= (aref timer 1) (aref (car timers) 1))
 202                              (> (aref timer 2) (aref (car timers) 2)))
 203                         (and (= (aref timer 1) (aref (car timers) 1))
 204                              (= (aref timer 2) (aref (car timers) 2))
 205                              (> (aref timer 3) (aref (car timers) 3)))))
 206           (setq last timers
 207                 timers (cdr timers)))
 208         ;; Insert new timer after last which possibly means in front of queue.
 209         (if last
 210             (setcdr last (cons timer timers))
 211           (setq timer-idle-list (cons timer timers)))
 212         (aset timer 0 (not dont-wait))
 213         (aset timer 7 t)
 214         nil)
 215     (error "Invalid or uninitialized timer")))
 216
 217 ;;;###autoload
 218 (defalias 'disable-timeout 'cancel-timer)
 219 ;;;###autoload
 220 (defun cancel-timer (timer)
 221   "Remove TIMER from the list of active timers."
 222   (or (timerp timer)
 223       (error "Invalid timer"))
 224   (setq timer-list (delq timer timer-list))
 225   (setq timer-idle-list (delq timer timer-idle-list))
 226   nil)
 227
 228 ;;;###autoload
 229 (defun cancel-function-timers (function)
 230   "Cancel all timers scheduled by `run-at-time' which would run FUNCTION."
 231   (interactive "aCancel timers of function: ")
 232   (let ((tail timer-list))
 233     (while tail
 234       (if (eq (aref (car tail) 5) function)
 235           (setq timer-list (delq (car tail) timer-list)))
 236       (setq tail (cdr tail))))
 237   (let ((tail timer-idle-list))
 238     (while tail
 239       (if (eq (aref (car tail) 5) function)
 240           (setq timer-idle-list (delq (car tail) timer-idle-list)))
 241       (setq tail (cdr tail)))))
 242 \f
 243 ;; Record the last few events, for debugging.
 244 (defvar timer-event-last-2 nil)
 245 (defvar timer-event-last-1 nil)
 246 (defvar timer-event-last nil)
 247
 248 (defvar timer-max-repeats 10
 249   "*Maximum number of times to repeat a timer, if real time jumps.")
 250
 251 (defun timer-until (timer time)
 252   "Calculate number of seconds from when TIMER will run, until TIME.
 253 TIMER is a timer, and stands for the time when its next repeat is scheduled.
 254 TIME is a time-list."
 255   (let ((high (- (car time) (aref timer 1)))
 256         (low (- (nth 1 time) (aref timer 2))))
 257     (+ low (* high 65536))))
 258
 259 (defun timer-event-handler (timer)
 260   "Call the handler for the timer TIMER.
 261 This function is called, by name, directly by the C code."
 262   (setq timer-event-last-2 timer-event-last-1)
 263   (setq timer-event-last-1 timer-event-last)
 264   (setq timer-event-last timer)
 265   (let ((inhibit-quit t))
 266     (if (timerp timer)
 267         (progn
 268           ;; Delete from queue.
 269           (cancel-timer timer)
 270           ;; Re-schedule if requested.
 271           (if (aref timer 4)
 272               (if (aref timer 7)
 273                   (timer-activate-when-idle timer)
 274                 (timer-inc-time timer (aref timer 4) 0)
 275                 ;; If real time has jumped forward,
 276                 ;; perhaps because Emacs was suspended for a long time,
 277                 ;; limit how many times things get repeated.
 278                 (if (and (numberp timer-max-repeats)
 279                          (< 0 (timer-until timer (current-time))))
 280                     (let ((repeats (/ (timer-until timer (current-time))
 281                                       (aref timer 4))))
 282                       (if (> repeats timer-max-repeats)
 283                           (timer-inc-time timer (* (aref timer 4) repeats)))))
 284                 (timer-activate timer)))
 285           ;; Run handler.
 286           ;; We do this after rescheduling so that the handler function
 287           ;; can cancel its own timer successfully with cancel-timer.
 288           (condition-case nil
 289               (apply (aref timer 5) (aref timer 6))
 290             (error nil)))
 291       (error "Bogus timer event"))))
 292
 293 ;; This function is incompatible with the one in levents.el.
 294 (defun timeout-event-p (event)
 295   "Non-nil if EVENT is a timeout event."
 296   (and (listp event) (eq (car event) 'timer-event)))
 297 \f
 298 ;;;###autoload
 299 (defun run-at-time (time repeat function &rest args)
 300   "Perform an action at time TIME.
 301 Repeat the action every REPEAT seconds, if REPEAT is non-nil.
 302 TIME should be a string like \"11:23pm\", nil meaning now, a number of seconds
 303 from now, a value from `current-time', or t (with non-nil REPEAT)
 304 meaning the next integral multiple of REPEAT.
 305 REPEAT may be an integer or floating point number.
 306 The action is to call FUNCTION with arguments ARGS.
 307
 308 This function returns a timer object which you can use in `cancel-timer'."
 309   (interactive "sRun at time: \nNRepeat interval: \naFunction: ")
 310
 311   (or (null repeat)
 312       (and (numberp repeat) (< 0 repeat))
 313       (error "Invalid repetition interval"))
 314
 315   ;; Special case: nil means "now" and is useful when repeating.
 316   (if (null time)
 317       (setq time (current-time)))
 318
 319   ;; Special case: t means the next integral multiple of REPEAT.
 320   (if (and (eq time t) repeat)
 321       (setq time (timer-next-integral-multiple-of-time (current-time) repeat)))
 322
 323   ;; Handle numbers as relative times in seconds.
 324   (if (numberp time)
 325       (setq time (timer-relative-time (current-time) time)))
 326
 327   ;; Handle relative times like "2 hours and 35 minutes"
 328   (if (stringp time)
 329       (let ((secs (timer-duration time)))
 330         (if secs
 331             (setq time (timer-relative-time (current-time) secs)))))
 332
 333   ;; Handle "11:23pm" and the like.  Interpret it as meaning today
 334   ;; which admittedly is rather stupid if we have passed that time
 335   ;; already.  (Though only Emacs hackers hack Emacs at that time.)
 336   (if (stringp time)
 337       (progn
 338         (require 'diary-lib)
 339         (let ((hhmm (diary-entry-time time))
 340               (now (decode-time)))
 341           (if (>= hhmm 0)
 342               (setq time
 343                     (encode-time 0 (% hhmm 100) (/ hhmm 100) (nth 3 now)
 344                                  (nth 4 now) (nth 5 now) (nth 8 now)))))))
 345
 346   (or (consp time)
 347       (error "Invalid time format"))
 348
 349   (let ((timer (timer-create)))
 350     (timer-set-time timer time repeat)
 351     (timer-set-function timer function args)
 352     (timer-activate timer)
 353     timer))
 354
 355 ;;;###autoload
 356 (defun run-with-timer (secs repeat function &rest args)
 357   "Perform an action after a delay of SECS seconds.
 358 Repeat the action every REPEAT seconds, if REPEAT is non-nil.
 359 SECS and REPEAT may be integers or floating point numbers.
 360 The action is to call FUNCTION with arguments ARGS.
 361
 362 This function returns a timer object which you can use in `cancel-timer'."
 363   (interactive "sRun after delay (seconds): \nNRepeat interval: \naFunction: ")
 364   (apply 'run-at-time secs repeat function args))
 365
 366 ;;;###autoload
 367 (defun add-timeout (secs function object &optional repeat)
 368   "Add a timer to run SECS seconds from now, to call FUNCTION on OBJECT.
 369 If REPEAT is non-nil, repeat the timer every REPEAT seconds.
 370 This function is for compatibility; see also `run-with-timer'."
 371   (run-with-timer secs repeat function object))
 372
 373 ;;;###autoload
 374 (defun run-with-idle-timer (secs repeat function &rest args)
 375   "Perform an action the next time Emacs is idle for SECS seconds.
 376 The action is to call FUNCTION with arguments ARGS.
 377 SECS may be an integer or a floating point number.
 378
 379 If REPEAT is non-nil, do the action each time Emacs has been idle for
 380 exactly SECS seconds (that is, only once for each time Emacs becomes idle).
 381
 382 This function returns a timer object which you can use in `cancel-timer'."
 383   (interactive
 384    (list (read-from-minibuffer "Run after idle (seconds): " nil nil t)
 385          (y-or-n-p "Repeat each time Emacs is idle? ")
 386          (intern (completing-read "Function: " obarray 'fboundp t))))
 387   (let ((timer (timer-create)))
 388     (timer-set-function timer function args)
 389     (timer-set-idle-time timer secs repeat)
 390     (timer-activate-when-idle timer)
 391     timer))
 392 \f
 393 (defun with-timeout-handler (tag)
 394   (throw tag 'timeout))
 395
 396 ;;;###autoload (put 'with-timeout 'lisp-indent-function 1)
 397
 398 ;;;###autoload
 399 (defmacro with-timeout (list &rest body)
 400   "Run BODY, but if it doesn't finish in SECONDS seconds, give up.
 401 If we give up, we run the TIMEOUT-FORMS and return the value of the last one.
 402 The call should look like:
 403  (with-timeout (SECONDS TIMEOUT-FORMS...) BODY...)
 404 The timeout is checked whenever Emacs waits for some kind of external
 405 event \(such as keyboard input, input from subprocesses, or a certain time);
 406 if the program loops without waiting in any way, the timeout will not
 407 be detected."
 408   (let ((seconds (car list))
 409         (timeout-forms (cdr list)))
 410     `(let ((with-timeout-tag (cons nil nil))
 411            with-timeout-value with-timeout-timer)
 412        (if (catch with-timeout-tag
 413              (progn
 414                (setq with-timeout-timer
 415                      (run-with-timer ,seconds nil
 416                                       'with-timeout-handler
 417                                       with-timeout-tag))
 418                (setq with-timeout-value (progn . ,body))
 419                nil))
 420            (progn . ,timeout-forms)
 421          (cancel-timer with-timeout-timer)
 422          with-timeout-value))))
 423
 424 (defun y-or-n-p-with-timeout (prompt seconds default-value)
 425   "Like (y-or-n-p PROMPT), with a timeout.
 426 If the user does not answer after SECONDS seconds, return DEFAULT-VALUE."
 427   (with-timeout (seconds default-value)
 428     (y-or-n-p prompt)))
 429 \f
 430 (defvar timer-duration-words
 431   (list (cons "microsec" 0.000001)
 432         (cons "microsecond" 0.000001)
 433         (cons "millisec" 0.001)
 434         (cons "millisecond" 0.001)
 435         (cons "sec" 1)
 436         (cons "second" 1)
 437         (cons "min" 60)
 438         (cons "minute" 60)
 439         (cons "hour" (* 60 60))
 440         (cons "day" (* 24 60 60))
 441         (cons "week" (* 7 24 60 60))
 442         (cons "fortnight" (* 14 24 60 60))
 443         (cons "month" (* 30 24 60 60))    ; Approximation
 444         (cons "year" (* 365.25 24 60 60)) ; Approximation
 445         )
 446   "Alist mapping temporal words to durations in seconds")
 447
 448 (defun timer-duration (string)
 449   "Return number of seconds specified by STRING, or nil if parsing fails."
 450   (let ((secs 0)
 451         (start 0)
 452         (case-fold-search t))
 453     (while (string-match
 454             "[ \t]*\\([0-9.]+\\)?[ \t]*\\([a-z]+[a-rt-z]\\)s?[ \t]*"
 455             string start)
 456       (let ((count (if (match-beginning 1)
 457                        (string-to-number (match-string 1 string))
 458                      1))
 459             (itemsize (cdr (assoc (match-string 2 string)
 460                                   timer-duration-words))))
 461         (if itemsize
 462             (setq start (match-end 0)
 463                   secs (+ secs (* count itemsize)))
 464           (setq secs nil
 465                 start (length string)))))
 466     (if (= start (length string))
 467         secs
 468       (if (string-match "\\`[0-9.]+\\'" string)
 469           (string-to-number string)))))
 470 \f
 471 (provide 'timer)
 472
 473 ;;; timer.el ends here