lisp/time.el

   1 ;;; time.el --- display time and load in mode line of Emacs.
   2
   3 ;; Copyright (C) 1985, 86, 87, 93, 94, 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 ;; Facilities to display current time/date and a new-mail indicator
  27 ;; in the Emacs mode line.  The single entry point is `display-time'.
  28
  29 ;;; Code:
  30
  31 (defvar display-time-mail-file nil
  32   "*File name of mail inbox file, for indicating existence of new mail.
  33 Non-nil and not a string means don't check for mail.  nil means use
  34 default, which is system-dependent, and is the same as used by Rmail.")
  35
  36 ;;;###autoload
  37 (defvar display-time-day-and-date nil "\
  38 *Non-nil means \\[display-time] should display day and date as well as time.")
  39
  40 (defvar display-time-timer nil)
  41
  42 (defvar display-time-interval 60
  43   "*Seconds between updates of time in the mode line.")
  44
  45 (defvar display-time-24hr-format nil
  46   "*Non-nil indicates time should be displayed as hh:mm, 0 <= hh <= 23.
  47 Nil means 1 <= hh <= 12, and an AM/PM suffix is used.")
  48
  49 (defvar display-time-string nil)
  50
  51 (defvar display-time-hook nil
  52   "* List of functions to be called when the time is updated on the mode line.")
  53
  54 (defvar display-time-server-down-time nil
  55    "Time when mail file's file system was recorded to be down.
  56 If that file system seems to be up, the value is nil.")
  57
  58 ;;;###autoload
  59 (defun display-time ()
  60   "Display current time, load level, and mail flag in mode line of each buffer.
  61 Updates automatically every minute.
  62 If `display-time-day-and-date' is non-nil, the current day and date
  63 are displayed as well.
  64 After each update, `display-time-hook' is run with `run-hooks'."
  65   (interactive)
  66   (setq display-time-string "")
  67   (or global-mode-string (setq global-mode-string '("")))
  68   (or (memq 'display-time-string global-mode-string)
  69       (setq global-mode-string
  70             (append global-mode-string '(display-time-string))))
  71   ;; Setup the time timer.
  72   (and display-time-timer (cancel-timer display-time-timer))
  73   (setq display-time-timer
  74         ;; Start timer at the beginning of the next minute.
  75         (run-at-time (apply 'encode-time 60 (cdr (decode-time)))
  76                      display-time-interval 'display-time-event-handler))
  77   ;; Make the time appear right away.
  78   (display-time-update)
  79   ;; When you get new mail, clear "Mail" from the mode line.
  80   (add-hook 'rmail-after-get-new-mail-hook 'display-time-event-handler))
  81
  82 (defvar display-time-string-forms
  83   '((if display-time-day-and-date
  84         (format "%s %s %s " dayname monthname day)
  85       "")
  86     (format "%s:%s%s"
  87             (if display-time-24hr-format 24-hours 12-hours)
  88             minutes
  89             (if display-time-24hr-format "" am-pm))
  90     load
  91     (if mail " Mail" ""))
  92   "*A list of expressions governing display of the time in the mode line.
  93 This expression is a list of expressions that can involve the keywords
  94 `load', `day', `month', and `year', `12-hours', `24-hours', `minutes',
  95 `seconds', all numbers in string form, and `monthname', `dayname', `am-pm',
  96 and `time-zone' all alphabetic strings, and `mail' a true/nil value.
  97
  98 For example, the form
  99
 100   '((substring year -2) \"/\" month \"/\" day
 101     \" \" 24-hours \":\" minutes \":\" seconds
 102     (if time-zone \" (\") time-zone (if time-zone \")\")
 103     (if mail \" Mail\" \"\"))
 104
 105 would give mode line times like `94/12/30 21:07:48 (UTC)'.")
 106
 107 (defun display-time-event-handler ()
 108   (display-time-update)
 109   ;; Do redisplay right now, if no input pending.
 110   (sit-for 0))
 111
 112 ;; Update the display-time info for the mode line
 113 ;; but don't redisplay right now.  This is used for
 114 ;; things like Rmail `g' that want to force an update
 115 ;; which can wait for the next redisplay.
 116 (defun display-time-update ()
 117   (let* ((now (current-time))
 118          (time (current-time-string now))
 119          (load (condition-case ()
 120                    (if (zerop (car (load-average))) ""
 121                      (let ((str (format " %03d" (car (load-average)))))
 122                        (concat (substring str 0 -2) "." (substring str -2))))
 123                  (error "")))
 124          (mail-spool-file (or display-time-mail-file
 125                               (getenv "MAIL")
 126                               (concat rmail-spool-directory
 127                                       (user-login-name))))
 128          (mail (and (stringp mail-spool-file)
 129                     (or (null display-time-server-down-time)
 130                         ;; If have been down for 20 min, try again.
 131                         (> (- (nth 1 (current-time))
 132                               display-time-server-down-time)
 133                            1200))
 134                     (let ((start-time (current-time)))
 135                       (prog1
 136                           (display-time-file-nonempty-p mail-spool-file)
 137                         (if (> (- (nth 1 (current-time)) (nth 1 start-time))
 138                                20)
 139                             ;; Record that mail file is not accessible.
 140                             (setq display-time-server-down-time
 141                                   (nth 1 (current-time)))
 142                           ;; Record that mail file is accessible.
 143                           (setq display-time-server-down-time nil))))))
 144          (24-hours (substring time 11 13))
 145          (hour (string-to-int 24-hours))
 146          (12-hours (int-to-string (1+ (% (+ hour 11) 12))))
 147          (am-pm (if (>= hour 12) "pm" "am"))
 148          (minutes (substring time 14 16))
 149          (seconds (substring time 17 19))
 150          (time-zone (car (cdr (current-time-zone now))))
 151          (day (substring time 8 10))
 152          (year (substring time 20 24))
 153          (monthname (substring time 4 7))
 154          (month
 155           (cdr
 156            (assoc
 157             monthname
 158             '(("Jan" . "1") ("Feb" . "2") ("Mar" . "3") ("Apr" . "4")
 159               ("May" . "5") ("Jun" . "6") ("Jul" . "7") ("Aug" . "8")
 160               ("Sep" . "9") ("Oct" . "10") ("Nov" . "11") ("Dec" . "12")))))
 161          (dayname (substring time 0 3)))
 162     (setq display-time-string
 163           (mapconcat 'eval display-time-string-forms ""))
 164     ;; This is inside the let binding, but we are not going to document
 165     ;; what variables are available.
 166     (run-hooks 'display-time-hook))
 167   (force-mode-line-update))
 168
 169 (defun display-time-file-nonempty-p (file)
 170   (and (file-exists-p file)
 171        (< 0 (nth 7 (file-attributes (file-chase-links file))))))
 172
 173 ;;; time.el ends here