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mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-11-30 08:09:04 +00:00
emacs/lisp/timer.el
1992-08-19 03:54:46 +00:00

101 lines
4.4 KiB
EmacsLisp

;;; timer.el --- run a function with args at some time in future
;; Copyright (C) 1990 Free Software Foundation, Inc.
;; Maintainer: FSF
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
;;; Code:
(defvar timer-process nil)
(defvar timer-alist ())
(defvar timer-out "")
(defvar timer-dont-exit nil
;; this is useful for functions which will be doing their own erratic
;; rescheduling or people who otherwise expect to use the process frequently
"If non-nil, don't exit the timer process when no more events are pending.")
;;;###autoload
(defun run-at-time (time repeat function &rest args)
"Run a function at a time, and optionally on a regular interval.
Arguments are TIME, REPEAT, FUNCTION &rest ARGS.
TIME, a string, can be specified absolutely or relative to now.
REPEAT, an integer number of seconds, is the interval on which to repeat
the call to the function."
(interactive "sRun at time: \nNRepeat interval: \naFunction: ")
(cond ((or (not timer-process)
(memq (process-status timer-process) '(exit signal nil)))
(if timer-process (delete-process timer-process))
(setq timer-process (start-process "timer" nil "timer")
timer-alist nil)
(set-process-filter timer-process 'timer-process-filter)
(set-process-sentinel timer-process 'timer-process-sentinel)
(process-kill-without-query timer-process))
((eq (process-status timer-process) 'stop)
(continue-process timer-process)))
;; There should be a living, breathing timer process now
(let ((token (concat (current-time-string) "-" (length timer-alist))))
(send-string timer-process (concat time "@" token "\n"))
(setq timer-alist (cons (list token repeat function args) timer-alist))))
(defun timer-process-filter (proc str)
(setq timer-out (concat timer-out str))
(let (do token error)
(while (string-match "\n" timer-out)
(setq token (substring timer-out 0 (match-beginning 0))
do (assoc token timer-alist)
timer-out (substring timer-out (match-end 0)))
(cond
(do (apply (nth 2 do) (nth 3 do)) ; do it
(if (natnump (nth 1 do)) ; reschedule it
(send-string proc (concat (nth 1 do) " sec@" (car do) "\n"))
(setq timer-alist (delq do timer-alist))))
((string-match "timer: \\([^:]+\\): \\([^@]*\\)@\\(.*\\)$" token)
(setq error (substring token (match-beginning 1) (match-end 1))
do (substring token (match-beginning 2) (match-end 2))
token (assoc (substring token (match-beginning 3) (match-end 3))
timer-alist)
timer-alist (delq token timer-alist))
(ding 'no-terminate) ; using error function in process filters is rude
(message "%s for %s; couldn't set at \"%s\"" error (nth 2 token) do))))
(or timer-alist timer-dont-exit (process-send-eof proc))))
(defun timer-process-sentinel (proc str)
(let ((stat (process-status proc)))
(if (eq stat 'stop) (continue-process proc)
;; if it exited normally, presumably it was intentional.
;; if there were no pending events, who cares that it exited?
(if (or (not timer-alist) (eq stat 'exit)) ()
(ding 'no-terminate)
(message "Timer exited abnormally. All events cancelled."))
(setq timer-process nil timer-alist nil timer-scratch ""))))
(defun cancel-timer (function)
"Cancel all events scheduled by ``run-at-time'' which would run FUNCTION."
(interactive "aCancel function: ")
(let ((alist timer-alist))
(while alist
(if (eq (nth 2 (car alist)) function)
(setq timer-alist (delq (car alist) timer-alist)))
(setq alist (cdr alist))))
(or timer-alist timer-dont-exit (process-send-eof timer-process)))
(provide 'timer)
;;; timer.el ends here