lisp/time.el

   1 ;;; time.el --- display time and load in mode line of Emacs.
   2
   3 ;; Copyright (C) 1985, 1986, 1987, 1993 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
  21 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  22
  23 ;;; Commentary:
  24
  25 ;;; Facilities to display current time/date and a new-mail indicator
  26 ;;; in the Emacs mode line.  The single entry point is `display-time'.
  27
  28 ;;; Code:
  29
  30 (defvar display-time-mail-file nil
  31   "*File name of mail inbox file, for indicating existence of new mail.
  32 Default is system-dependent, and is the same as used by Rmail.")
  33
  34 ;;;###autoload
  35 (defvar display-time-day-and-date nil "\
  36 *Non-nil means \\[display-time] should display day and date as well as time.")
  37
  38 (defvar display-time-process nil)
  39
  40 (defvar display-time-interval 60
  41   "*Seconds between updates of time in the mode line.")
  42
  43 (defvar display-time-24hr-format nil
  44   "*Non-nill indicates time should be displayed as hh:mm, 0 <= hh <= 23.
  45 Nil means 1 <= hh <= 12, and an AM/PM suffix is used.")
  46
  47 (defvar display-time-string nil)
  48
  49 (defvar display-time-hook nil
  50   "* List of functions to be called when the time is updated on the mode line.")
  51
  52 (defvar display-time-server-down-time nil
  53    "Time when mail file's file system was recorded to be down.
  54 If that file system seems to be up, the value is nil.")
  55
  56 ;;;###autoload
  57 (defun display-time ()
  58   "Display current time, load level, and mail flag in mode line of each buffer.
  59 Updates automatically every minute.
  60 If `display-time-day-and-date' is non-nil, the current day and date
  61 are displayed as well.
  62 After each update, `display-time-hook' is run with `run-hooks'."
  63   (interactive)
  64   (let ((live (and display-time-process
  65                    (eq (process-status display-time-process) 'run))))
  66     (if (not live)
  67         (progn
  68           (if display-time-process
  69               (delete-process display-time-process))
  70           (or global-mode-string (setq global-mode-string '("")))
  71           (or (memq 'display-time-string global-mode-string)
  72               (setq global-mode-string
  73                     (append global-mode-string '(display-time-string))))
  74           (setq display-time-string "")
  75           (setq display-time-process
  76                 (start-process "display-time" nil
  77                                (concat exec-directory "wakeup")
  78                                (int-to-string display-time-interval)))
  79           (process-kill-without-query display-time-process)
  80           (set-process-sentinel display-time-process 'display-time-sentinel)
  81           (set-process-filter display-time-process 'display-time-filter)))))
  82
  83 (defun display-time-sentinel (proc reason)
  84   (or (eq (process-status proc) 'run)
  85       (setq display-time-string ""))
  86   ;; Force mode-line updates
  87   (save-excursion (set-buffer (other-buffer)))
  88   (set-buffer-modified-p (buffer-modified-p))
  89   (sit-for 0))
  90
  91 (defun display-time-filter (proc string)
  92   (let ((time (current-time-string))
  93         (load (condition-case ()
  94                   (if (zerop (car (load-average))) ""
  95                     (let ((str (format " %03d" (car (load-average)))))
  96                       (concat (substring str 0 -2) "." (substring str -2))))
  97                 (error "")))
  98         (mail-spool-file (or display-time-mail-file
  99                              (getenv "MAIL")
 100                              (concat rmail-spool-directory
 101                                      (or (getenv "LOGNAME")
 102                                          (getenv "USER")
 103                                          (user-login-name)))))
 104         hour am-pm-flag mail-flag)
 105     (setq hour (read (substring time 11 13)))
 106     (if (not display-time-24hr-format)
 107         (progn
 108           (setq am-pm-flag (if (>= hour 12) "pm" "am"))
 109           (if (> hour 12)
 110               (setq hour (- hour 12))
 111             (if (= hour 0)
 112                 (setq hour 12))))
 113       (setq am-pm-flag ""))
 114     (setq mail-flag
 115           (if (and (or (null display-time-server-down-time)
 116                        ;; If have been down for 20 min, try again.
 117                        (> (- (nth 1 (current-time))
 118                              display-time-server-down-time)
 119                           1200))
 120                    (let ((start-time (current-time)))
 121                      (prog1
 122                          (display-time-file-nonempty-p mail-spool-file)
 123                        (if (> (- (nth 1 (current-time)) (nth 1 start-time))
 124                               20)
 125                            ;; Record that mail file is not accessible.
 126                            (setq display-time-server-down-time
 127                                  (nth 1 (current-time)))
 128                          ;; Record that mail file is accessible.
 129                          (setq display-time-server-down-time nil))
 130                        )))
 131               " Mail"
 132             ""))
 133     (setq display-time-string
 134           (concat (format "%d" hour) (substring time 13 16)
 135                   am-pm-flag
 136                   load
 137                   mail-flag))
 138     ;; Append the date if desired.
 139     (if display-time-day-and-date
 140         (setq display-time-string
 141               (concat (substring time 0 11) display-time-string))))
 142   (run-hooks 'display-time-hook)
 143   ;; Force redisplay of all buffers' mode lines to be considered.
 144   (save-excursion (set-buffer (other-buffer)))
 145   (set-buffer-modified-p (buffer-modified-p))
 146   ;; Do redisplay right now, if no input pending.
 147   (sit-for 0))
 148
 149 (defun display-time-file-nonempty-p (file)
 150   (and (file-exists-p file)
 151        (< 0 (nth 7 (file-attributes (file-chase-links file))))))
 152
 153 ;;; time.el ends here