lisp/timer.el

   1 ;;; timers.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 ;; The single entry point is `run-at-time'.
  29
  30 ;;; Code:
  31
  32 ;; Layout of a timer vector:
  33 ;; [triggered-p trigger-high trigger-low delta-secs function args]
  34
  35 (defun timer-create ()
  36   "Create a timer object."
  37   (let ((timer (make-vector 7 nil)))
  38     (aset timer 0 (make-vector 1 'timer-event))
  39     timer))
  40
  41 (defun timerp (object)
  42   "Return t if OBJECT is a timer."
  43   (and (vectorp object) (= (length object) 7)))
  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 menu 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 (if (consp (cdr time)) (nth 2 time) 0))
  55   (aset timer 4 (and (integerp delta) (> delta 0) delta))
  56   timer)
  57
  58
  59 (defun timer-inc-time (timer secs &optional usecs)
  60   "Increment the time set in TIMER by SECS seconds and USECS microseconds.
  61 SECS may be a fraction."
  62   (or usecs (setq usecs 0))
  63   (if (floatp secs)
  64       (let* ((integer (floor secs))
  65              (fraction (floor (* 1000000 (- secs integer)))))
  66         (setq usecs fraction secs integer)))
  67   (let ((newusecs (+ (aref timer 3) usecs)))
  68     (aset timer 3 (mod newusecs 1000000))
  69     (setq secs (+ secs (/ newusecs 1000000))))
  70   (let ((newlow (+ (aref timer 2) secs))
  71         (newhigh (aref timer 1)))
  72     (setq newhigh (+ newhigh (/ newlow 65536))
  73           newlow (logand newlow 65535))
  74     (aset timer 1 newhigh)
  75     (aset timer 2 newlow)))
  76
  77 (defun timer-set-time-with-usecs (timer time usecs &optional delta)
  78   "Set the trigger time of TIMER to TIME.
  79 TIME must be in the internal format returned by, e.g., `current-time'
  80 If optional third argument DELTA is a non-zero integer make the timer
  81 fire repeatedly that menu seconds apart."
  82   (or (timerp timer)
  83       (error "Invalid timer"))
  84   (aset timer 1 (car time))
  85   (aset timer 2 (if (consp (cdr time)) (car (cdr time)) (cdr time)))
  86   (aset timer 3 usecs)
  87   (aset timer 4 (and (integerp delta) (> delta 0) delta))
  88   timer)
  89
  90 (defun timer-set-function (timer function &optional args)
  91   "Make TIMER call FUNCTION with optional ARGS when triggering."
  92   (or (timerp timer)
  93       (error "Invalid timer"))
  94   (aset timer 5 function)
  95   (aset timer 6 args)
  96   timer)
  97 \f
  98 (defun timer-activate (timer)
  99   "Put TIMER on the list of active timers."
 100   (if (and (timerp timer)
 101            (integerp (aref timer 1))
 102            (integerp (aref timer 2))
 103            (integerp (aref timer 3))
 104            (aref timer 5))
 105       (let ((timers timer-list)
 106             last)
 107         ;; Skip all timers to trigger before the new one.
 108         (while (and timers
 109                     (or (> (aref timer 1) (aref (car timers) 1))
 110                         (and (= (aref timer 1) (aref (car timers) 1))
 111                              (> (aref timer 2) (aref (car timers) 2)))
 112                         (and (= (aref timer 1) (aref (car timers) 1))
 113                              (= (aref timer 2) (aref (car timers) 2))
 114                              (> (aref timer 3) (aref (car timers) 3)))))
 115           (setq last timers
 116                 timers (cdr timers)))
 117         ;; Insert new timer after last which possibly means in front of queue.
 118         (if last
 119             (setcdr last (cons timer timers))
 120           (setq timer-list (cons timer timers)))
 121         (aset timer 0 nil)
 122         nil)
 123     (error "Invalid or uninitialized timer")))
 124
 125 (defun cancel-timer (timer)
 126   "Remove TIMER from the list of active timers."
 127   (or (timerp timer)
 128       (error "Invalid timer"))
 129   (setq timer-list (delq timer timer-list))
 130   nil)
 131
 132 (defun cancel-function-timers (function)
 133   "Cancel all timers scheduled by `run-at-time' which would run FUNCTION."
 134   (interactive "aCancel timers of function: ")
 135   (let ((tail timer-list))
 136     (while tail
 137       (if (eq (aref (car tail) 5) function)
 138           (setq timer-list (delq (car tail) timer-list)))
 139       (setq tail (cdr tail)))))
 140 \f
 141 ;; Set up the common handler for all timer events.  Since the event has
 142 ;; the timer as parameter we can still distinguish.  Note that using
 143 ;; special-event-map ensures that event timer events that arrive in the
 144 ;; middle of a key sequence being entered are still handled correctly.
 145 (define-key special-event-map [timer-event] 'timer-event-handler)
 146 (defun timer-event-handler (event)
 147   "Call the handler for the timer in the event EVENT."
 148   (interactive "e")
 149   (let ((timer (cdr-safe event)))
 150     (if (timerp timer)
 151         (progn
 152           ;; Delete from queue.
 153           (cancel-timer timer)
 154           ;; Run handler
 155           (apply (aref timer 5) (aref timer 6))
 156           ;; Re-schedule if requested.
 157           (if (aref timer 4)
 158               (progn
 159                 (timer-inc-time timer (aref timer 4) 0)
 160                 (timer-activate timer))))
 161       (error "Bogus timer event"))))
 162 \f
 163 ;;;###autoload
 164 (defun run-at-time (time repeat function &rest args)
 165   "Run a function at a time, and optionally on a regular interval.
 166 Arguments are TIME, REPEAT, FUNCTION &rest ARGS.
 167 TIME is a string like \"11:23pm\" or a value from `encode-time'.
 168 REPEAT, an integer number of seconds, is the interval on which to repeat
 169 the call to the function.  If REPEAT is nil or 0, call it just once."
 170   (interactive "sRun at time: \nNRepeat interval: \naFunction: ")
 171
 172   ;; Handle "11:23pm" and the like.  Interpret it as meaning today
 173   ;; which admittedly is rather stupid if we have passed that time
 174   ;; already.  Unfortunately we don't have a `parse-time' function
 175   ;; to do the right thing.
 176   (if (stringp time)
 177       (progn
 178         (require 'diary-lib)
 179         (let ((hhmm (diary-entry-time time))
 180               (now (decode-time)))
 181           (if (< hhmm 0)
 182               (setq time 'bad)
 183             (setq time
 184                   (encode-time 0 (% hhmm 100) (/ hhmm 100) (nth 3 now)
 185                                (nth 4 now) (nth 5 now) (nth 8 now)))))))
 186
 187   ;; Special case: nil means "now" and is useful when repeting.
 188   (if (null time)
 189       (setq time (current-time)))
 190
 191   (or (consp time)
 192       (error "Invalid time format"))
 193
 194   (or (null repeat)
 195       (natnump repeat)
 196       (error "Invalid repetition interval"))
 197
 198   (let ((timer (timer-create)))
 199     (timer-set-time timer time repeat)
 200     (timer-set-function timer function args)
 201     (timer-activate timer)))
 202
 203 ;;;###autoload
 204 (defun run-after-delay (secs repeat function &rest args)
 205   "Perform an action after a delay of SECS seconds.
 206 Repeat the action every REPEAT seconds, if REPEAT is non-nil.
 207 SECS and REPEAT need not be integers.
 208 The action is to call FUNCTION with arguments ARGS."
 209   (interactive "sRun after delay (seconds): \nNRepeat interval: \naFunction: ")
 210
 211   (or (null repeat)
 212       (and (numberp repeat) (>= repeat 0))
 213       (error "Invalid repetition interval"))
 214
 215   (let ((timer (timer-create)))
 216     (timer-set-time timer (current-time))
 217     (timer-inc-time timer secs)
 218     (timer-set-function timer function args)
 219     (timer-activate timer)))
 220 \f
 221 (provide 'timers)
 222
 223 ;;; timers.el ends here