lisp/time.el

   1 ;;; time.el --- display time, load and mail indicator in mode line of Emacs.
   2
   3 ;; Copyright (C) 1985, 86, 87, 93, 94, 96, 2000 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 (defgroup display-time nil
  32   "Display time and load in mode line of Emacs."
  33   :group 'modeline
  34   :group 'mail)
  35
  36
  37 (defcustom display-time-mail-file nil
  38   "*File name of mail inbox file, for indicating existence of new mail.
  39 Non-nil and not a string means don't check for mail.  nil means use
  40 default, which is system-dependent, and is the same as used by Rmail."
  41   :type '(choice (const :tag "(None)" none)
  42                  (const :tag "Default" nil)
  43                  (file :format "%v"))
  44   :group 'display-time)
  45
  46 (defcustom display-time-mail-function nil
  47   "*Function to call, for indicating existence of new mail.
  48 nil means use the default method of checking `display-time-mail-file'."
  49   :type '(choice (const :tag "Default" nil)
  50                  (function))
  51   :group 'display-time)
  52
  53 ;;;###autoload
  54 (defcustom display-time-day-and-date nil "\
  55 *Non-nil means \\[display-time] should display day and date as well as time."
  56   :type 'boolean
  57   :group 'display-time)
  58
  59 (defvar display-time-timer nil)
  60
  61 (defcustom display-time-interval 60
  62   "*Seconds between updates of time in the mode line."
  63   :type 'integer
  64   :group 'display-time)
  65
  66 (defcustom display-time-24hr-format nil
  67   "*Non-nil indicates time should be displayed as hh:mm, 0 <= hh <= 23.
  68 Nil means 1 <= hh <= 12, and an AM/PM suffix is used."
  69   :type 'boolean
  70   :group 'display-time)
  71
  72 (defvar display-time-string nil)
  73
  74 (defcustom display-time-hook nil
  75   "*List of functions to be called when the time is updated on the mode line."
  76   :type 'hook
  77   :group 'display-time)
  78
  79 (defvar display-time-server-down-time nil
  80    "Time when mail file's file system was recorded to be down.
  81 If that file system seems to be up, the value is nil.")
  82
  83 ;;;###autoload
  84 (defun display-time ()
  85   "Enable display of time, load level, and mail flag in mode lines.
  86 This display updates automatically every minute.
  87 If `display-time-day-and-date' is non-nil, the current day and date
  88 are displayed as well.
  89 This runs the normal hook `display-time-hook' after each update."
  90   (interactive)
  91   (display-time-mode 1))
  92
  93 (defcustom display-time-mail-face 'mode-line
  94   "Face to use for `display-time-mail-string'.
  95 If `display-time-use-mail-icon' is non-nil, the image's background
  96 colour is the background of this face.  Set this to a face other than
  97 `mode-line' to make the mail indicator stand out on a suitable
  98 display."
  99   :group 'faces
 100   :group 'display-time
 101   :type 'face)
 102
 103 (defvar display-time-mail-icon
 104   (find-image '((:type xbm :file "letter.xbm" :ascent center)))
 105   "Image specification to offer as the mail indicator on a graphic
 106 display.  See `display-time-use-mail-icon' and
 107 `display-time-mail-face'.")
 108
 109 (defcustom display-time-use-mail-icon nil
 110   "Non-nil means use an icon as the mail indicator on a graphic display.
 111 Otherwise use the string \"Mail\".  The icon may consume less of the
 112 mode line.  It is specified by `display-time-mail-icon'."
 113   :group 'display-time
 114   :type 'boolean)
 115
 116 (defcustom display-time-format nil
 117   "*A string specifying the format for displaying the time in the mode line.
 118 See the function `format-time-string' for an explanation of
 119 how to write this string.  If this is nil, the defaults
 120 depend on `display-time-day-and-date' and `display-time-24hr-format'."
 121   :type '(choice (const :tag "Default" nil)
 122                  string)
 123   :group 'display-time)
 124
 125 (defcustom display-time-string-forms
 126   '((if (and (not display-time-format) display-time-day-and-date)
 127         (format-time-string "%a %b %e " now)
 128       "")
 129     (format-time-string (or display-time-format
 130                             (if display-time-24hr-format "%H:%M" "%-I:%M%p"))
 131                         now)
 132     load
 133     (if mail
 134         ;; Build the string every time to act on customization.
 135         (concat " "
 136                 (propertize
 137                  "Mail"
 138                  'display `(when (and display-time-use-mail-icon
 139                                       (display-graphic-p))
 140                              ,@display-time-mail-icon
 141                              ,@(list :background (face-attribute
 142                                                   display-time-mail-face
 143                                                   :background)))
 144                  'help-echo "mouse-2: Read mail"
 145                  'local-map (make-mode-line-mouse2-map read-mail-command)))
 146       ""))
 147   "*A list of expressions governing display of the time in the mode line.
 148 For most purposes, you can control the time format using `display-time-format'
 149 which is a more standard interface.
 150
 151 This expression is a list of expressions that can involve the keywords
 152 `load', `day', `month', and `year', `12-hours', `24-hours', `minutes',
 153 `seconds', all numbers in string form, and `monthname', `dayname', `am-pm',
 154 and `time-zone' all alphabetic strings, and `mail' a true/nil value.
 155
 156 For example, the form
 157
 158   '((substring year -2) \"/\" month \"/\" day
 159     \" \" 24-hours \":\" minutes \":\" seconds
 160     (if time-zone \" (\") time-zone (if time-zone \")\")
 161     (if mail \" Mail\" \"\"))
 162
 163 would give mode line times like `94/12/30 21:07:48 (UTC)'."
 164   :type 'sexp
 165   :group 'display-time)
 166
 167 (defun display-time-event-handler ()
 168   (display-time-update)
 169   ;; Do redisplay right now, if no input pending.
 170   (sit-for 0)
 171   (let* ((current (current-time))
 172          (timer display-time-timer)
 173          ;; Compute the time when this timer will run again, next.
 174          (next-time (timer-relative-time
 175                      (list (aref timer 1) (aref timer 2) (aref timer 3))
 176                      (* 5 (aref timer 4)) 0)))
 177     ;; If the activation time is far in the past,
 178     ;; skip executions until we reach a time in the future.
 179     ;; This avoids a long pause if Emacs has been suspended for hours.
 180     (or (> (nth 0 next-time) (nth 0 current))
 181         (and (= (nth 0 next-time) (nth 0 current))
 182              (> (nth 1 next-time) (nth 1 current)))
 183         (and (= (nth 0 next-time) (nth 0 current))
 184              (= (nth 1 next-time) (nth 1 current))
 185              (> (nth 2 next-time) (nth 2 current)))
 186         (progn
 187           (timer-set-time timer (timer-next-integral-multiple-of-time
 188                                  current display-time-interval)
 189                           display-time-interval)
 190           (timer-activate timer)))))
 191
 192 ;; Update the display-time info for the mode line
 193 ;; but don't redisplay right now.  This is used for
 194 ;; things like Rmail `g' that want to force an update
 195 ;; which can wait for the next redisplay.
 196 (defun display-time-update ()
 197   (let* ((now (current-time))
 198          (time (current-time-string now))
 199          (load (condition-case ()
 200                    (if (zerop (car (load-average))) ""
 201                      ;; The load average number is mysterious, so
 202                      ;; propvide some help.
 203                      (let ((str (format " %03d" (car (load-average)))))
 204                        (propertize
 205                         (concat (substring str 0 -2) "." (substring str -2))
 206                         'help-echo "System load average")))
 207                  (error "")))
 208          (mail-spool-file (or display-time-mail-file
 209                               (getenv "MAIL")
 210                               (concat rmail-spool-directory
 211                                       (user-login-name))))
 212          (mail (or (and display-time-mail-function
 213                         (funcall display-time-mail-function))
 214                    (and (stringp mail-spool-file)
 215                         (or (null display-time-server-down-time)
 216                             ;; If have been down for 20 min, try again.
 217                             (> (- (nth 1 now) display-time-server-down-time)
 218                                1200)
 219                             (and (< (nth 1 now) display-time-server-down-time)
 220                                  (> (- (nth 1 now) display-time-server-down-time)
 221                                     -64336)))
 222                         (let ((start-time (current-time)))
 223                           (prog1
 224                               (display-time-file-nonempty-p mail-spool-file)
 225                             (if (> (- (nth 1 (current-time)) (nth 1 start-time))
 226                                    20)
 227                                 ;; Record that mail file is not accessible.
 228                                 (setq display-time-server-down-time
 229                                       (nth 1 (current-time)))
 230                               ;; Record that mail file is accessible.
 231                               (setq display-time-server-down-time nil)))))))
 232          (24-hours (substring time 11 13))
 233          (hour (string-to-int 24-hours))
 234          (12-hours (int-to-string (1+ (% (+ hour 11) 12))))
 235          (am-pm (if (>= hour 12) "pm" "am"))
 236          (minutes (substring time 14 16))
 237          (seconds (substring time 17 19))
 238          (time-zone (car (cdr (current-time-zone now))))
 239          (day (substring time 8 10))
 240          (year (substring time 20 24))
 241          (monthname (substring time 4 7))
 242          (month
 243           (cdr
 244            (assoc
 245             monthname
 246             '(("Jan" . "1") ("Feb" . "2") ("Mar" . "3") ("Apr" . "4")
 247               ("May" . "5") ("Jun" . "6") ("Jul" . "7") ("Aug" . "8")
 248               ("Sep" . "9") ("Oct" . "10") ("Nov" . "11") ("Dec" . "12")))))
 249          (dayname (substring time 0 3)))
 250     (setq display-time-string
 251           (mapconcat 'eval display-time-string-forms ""))
 252     ;; This is inside the let binding, but we are not going to document
 253     ;; what variables are available.
 254     (run-hooks 'display-time-hook))
 255   (force-mode-line-update))
 256
 257 (defun display-time-file-nonempty-p (file)
 258   (and (file-exists-p file)
 259        (< 0 (nth 7 (file-attributes (file-chase-links file))))))
 260
 261 ;;;###autoload
 262 (define-minor-mode display-time-mode
 263   "Toggle display of time, load level, and mail flag in mode lines.
 264 With a numeric arg, enable this display if arg is positive.
 265
 266 When this display is enabled, it updates automatically every minute.
 267 If `display-time-day-and-date' is non-nil, the current day and date
 268 are displayed as well.
 269 This runs the normal hook `display-time-hook' after each update."
 270   :global t :group 'display-time
 271     (and display-time-timer (cancel-timer display-time-timer))
 272     (setq display-time-timer nil)
 273     (setq display-time-string "")
 274     (or global-mode-string (setq global-mode-string '("")))
 275     (if display-time-mode
 276         (progn
 277           (or (memq 'display-time-string global-mode-string)
 278               (setq global-mode-string
 279                     (append global-mode-string '(display-time-string))))
 280           ;; Set up the time timer.
 281           (setq display-time-timer
 282                 (run-at-time t display-time-interval
 283                              'display-time-event-handler))
 284           ;; Make the time appear right away.
 285           (display-time-update)
 286           ;; When you get new mail, clear "Mail" from the mode line.
 287           (add-hook 'rmail-after-get-new-mail-hook
 288                     'display-time-event-handler))
 289       (remove-hook 'rmail-after-get-new-mail-hook
 290                    'display-time-event-handler)))
 291
 292 (provide 'time)
 293
 294 ;;; time.el ends here