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, 2001
   4 ;;   Free Software Foundation, Inc.
   5
   6 ;; Maintainer: FSF
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;;; Commentary:
  26
  27 ;; Facilities to display current time/date and a new-mail indicator
  28 ;; in the Emacs mode line.  The single entry point is `display-time'.
  29
  30 ;;; Code:
  31
  32 (defgroup display-time nil
  33   "Display time and load in mode line of Emacs."
  34   :group 'modeline
  35   :group 'mail)
  36
  37
  38 (defcustom display-time-mail-file nil
  39   "*File name of mail inbox file, for indicating existence of new mail.
  40 Non-nil and not a string means don't check for mail.  nil means use
  41 default, which is system-dependent, and is the same as used by Rmail."
  42   :type '(choice (const :tag "(None)" none)
  43                  (const :tag "Default" nil)
  44                  (file :format "%v"))
  45   :group 'display-time)
  46
  47 (defcustom display-time-mail-function nil
  48   "*Function to call, for indicating existence of new mail.
  49 nil means use the default method of checking `display-time-mail-file'."
  50   :type '(choice (const :tag "Default" nil)
  51                  (function))
  52   :group 'display-time)
  53
  54 ;;;###autoload
  55 (defcustom display-time-day-and-date nil "\
  56 *Non-nil means \\[display-time] should display day and date as well as time."
  57   :type 'boolean
  58   :group 'display-time)
  59
  60 (defvar display-time-timer nil)
  61
  62 (defcustom display-time-interval 60
  63   "*Seconds between updates of time in the mode line."
  64   :type 'integer
  65   :group 'display-time)
  66
  67 (defcustom display-time-24hr-format nil
  68   "*Non-nil indicates time should be displayed as hh:mm, 0 <= hh <= 23.
  69 Nil means 1 <= hh <= 12, and an AM/PM suffix is used."
  70   :type 'boolean
  71   :group 'display-time)
  72
  73 (defvar display-time-string nil)
  74
  75 (defcustom display-time-hook nil
  76   "*List of functions to be called when the time is updated on the mode line."
  77   :type 'hook
  78   :group 'display-time)
  79
  80 (defvar display-time-server-down-time nil
  81    "Time when mail file's file system was recorded to be down.
  82 If that file system seems to be up, the value is nil.")
  83
  84 ;;;###autoload
  85 (defun display-time ()
  86   "Enable display of time, load level, and mail flag in mode lines.
  87 This display updates automatically every minute.
  88 If `display-time-day-and-date' is non-nil, the current day and date
  89 are displayed as well.
  90 This runs the normal hook `display-time-hook' after each update."
  91   (interactive)
  92   (display-time-mode 1))
  93
  94 (defcustom display-time-mail-face 'mode-line
  95   "Face to use for `display-time-mail-string'.
  96 If `display-time-use-mail-icon' is non-nil, the image's background
  97 colour is the background of this face.  Set this to a face other than
  98 `mode-line' to make the mail indicator stand out on a suitable
  99 display."
 100   :group 'faces
 101   :group 'display-time
 102   :type 'face)
 103
 104 (defvar display-time-mail-icon
 105   (find-image '((:type xbm :file "letter.xbm" :ascent center)))
 106   "Image specification to offer as the mail indicator on a graphic
 107 display.  See `display-time-use-mail-icon' and
 108 `display-time-mail-face'.")
 109
 110 (defcustom display-time-use-mail-icon nil
 111   "Non-nil means use an icon as the mail indicator on a graphic display.
 112 Otherwise use the string \"Mail\".  The icon may consume less of the
 113 mode line.  It is specified by `display-time-mail-icon'."
 114   :group 'display-time
 115   :type 'boolean)
 116
 117 (defcustom display-time-format nil
 118   "*A string specifying the format for displaying the time in the mode line.
 119 See the function `format-time-string' for an explanation of
 120 how to write this string.  If this is nil, the defaults
 121 depend on `display-time-day-and-date' and `display-time-24hr-format'."
 122   :type '(choice (const :tag "Default" nil)
 123                  string)
 124   :group 'display-time)
 125
 126 (defcustom display-time-string-forms
 127   '((if (and (not display-time-format) display-time-day-and-date)
 128         (format-time-string "%a %b %e " now)
 129       "")
 130     (format-time-string (or display-time-format
 131                             (if display-time-24hr-format "%H:%M" "%-I:%M%p"))
 132                         now)
 133     load
 134     (if mail
 135         ;; Build the string every time to act on customization.
 136         (concat " "
 137                 (propertize
 138                  "Mail"
 139                  'display `(when (and display-time-use-mail-icon
 140                                       (display-graphic-p))
 141                              ,@display-time-mail-icon
 142                              ,@(list :background (face-attribute
 143                                                   display-time-mail-face
 144                                                   :background)))
 145                  'help-echo "mouse-2: Read mail"
 146                  'local-map (make-mode-line-mouse-map 'mouse-2
 147                                                       read-mail-command)))
 148       ""))
 149   "*A list of expressions governing display of the time in the mode line.
 150 For most purposes, you can control the time format using `display-time-format'
 151 which is a more standard interface.
 152
 153 This expression is a list of expressions that can involve the keywords
 154 `load', `day', `month', and `year', `12-hours', `24-hours', `minutes',
 155 `seconds', all numbers in string form, and `monthname', `dayname', `am-pm',
 156 and `time-zone' all alphabetic strings, and `mail' a true/nil value.
 157
 158 For example, the form
 159
 160   '((substring year -2) \"/\" month \"/\" day
 161     \" \" 24-hours \":\" minutes \":\" seconds
 162     (if time-zone \" (\") time-zone (if time-zone \")\")
 163     (if mail \" Mail\" \"\"))
 164
 165 would give mode line times like `94/12/30 21:07:48 (UTC)'."
 166   :type 'sexp
 167   :group 'display-time)
 168
 169 (defun display-time-event-handler ()
 170   (display-time-update)
 171   ;; Do redisplay right now, if no input pending.
 172   (sit-for 0)
 173   (let* ((current (current-time))
 174          (timer display-time-timer)
 175          ;; Compute the time when this timer will run again, next.
 176          (next-time (timer-relative-time
 177                      (list (aref timer 1) (aref timer 2) (aref timer 3))
 178                      (* 5 (aref timer 4)) 0)))
 179     ;; If the activation time is far in the past,
 180     ;; skip executions until we reach a time in the future.
 181     ;; This avoids a long pause if Emacs has been suspended for hours.
 182     (or (> (nth 0 next-time) (nth 0 current))
 183         (and (= (nth 0 next-time) (nth 0 current))
 184              (> (nth 1 next-time) (nth 1 current)))
 185         (and (= (nth 0 next-time) (nth 0 current))
 186              (= (nth 1 next-time) (nth 1 current))
 187              (> (nth 2 next-time) (nth 2 current)))
 188         (progn
 189           (timer-set-time timer (timer-next-integral-multiple-of-time
 190                                  current display-time-interval)
 191                           display-time-interval)
 192           (timer-activate timer)))))
 193
 194 ;; Update the display-time info for the mode line
 195 ;; but don't redisplay right now.  This is used for
 196 ;; things like Rmail `g' that want to force an update
 197 ;; which can wait for the next redisplay.
 198 (defun display-time-update ()
 199   (let* ((now (current-time))
 200          (time (current-time-string now))
 201          (load (condition-case ()
 202                    (if (zerop (car (load-average))) ""
 203                      ;; The load average number is mysterious, so
 204                      ;; propvide some help.
 205                      (let ((str (format " %03d" (car (load-average)))))
 206                        (propertize
 207                         (concat (substring str 0 -2) "." (substring str -2))
 208                         'help-echo "System load average")))
 209                  (error "")))
 210          (mail-spool-file (or display-time-mail-file
 211                               (getenv "MAIL")
 212                               (concat rmail-spool-directory
 213                                       (user-login-name))))
 214          (mail (or (and display-time-mail-function
 215                         (funcall display-time-mail-function))
 216                    (and (stringp mail-spool-file)
 217                         (or (null display-time-server-down-time)
 218                             ;; If have been down for 20 min, try again.
 219                             (> (- (nth 1 now) display-time-server-down-time)
 220                                1200)
 221                             (and (< (nth 1 now) display-time-server-down-time)
 222                                  (> (- (nth 1 now) display-time-server-down-time)
 223                                     -64336)))
 224                         (let ((start-time (current-time)))
 225                           (prog1
 226                               (display-time-file-nonempty-p mail-spool-file)
 227                             (if (> (- (nth 1 (current-time)) (nth 1 start-time))
 228                                    20)
 229                                 ;; Record that mail file is not accessible.
 230                                 (setq display-time-server-down-time
 231                                       (nth 1 (current-time)))
 232                               ;; Record that mail file is accessible.
 233                               (setq display-time-server-down-time nil)))))))
 234          (24-hours (substring time 11 13))
 235          (hour (string-to-int 24-hours))
 236          (12-hours (int-to-string (1+ (% (+ hour 11) 12))))
 237          (am-pm (if (>= hour 12) "pm" "am"))
 238          (minutes (substring time 14 16))
 239          (seconds (substring time 17 19))
 240          (time-zone (car (cdr (current-time-zone now))))
 241          (day (substring time 8 10))
 242          (year (substring time 20 24))
 243          (monthname (substring time 4 7))
 244          (month
 245           (cdr
 246            (assoc
 247             monthname
 248             '(("Jan" . "1") ("Feb" . "2") ("Mar" . "3") ("Apr" . "4")
 249               ("May" . "5") ("Jun" . "6") ("Jul" . "7") ("Aug" . "8")
 250               ("Sep" . "9") ("Oct" . "10") ("Nov" . "11") ("Dec" . "12")))))
 251          (dayname (substring time 0 3)))
 252     (setq display-time-string
 253           (mapconcat 'eval display-time-string-forms ""))
 254     ;; This is inside the let binding, but we are not going to document
 255     ;; what variables are available.
 256     (run-hooks 'display-time-hook))
 257   (force-mode-line-update))
 258
 259 (defun display-time-file-nonempty-p (file)
 260   (and (file-exists-p file)
 261        (< 0 (nth 7 (file-attributes (file-chase-links file))))))
 262
 263 ;;;###autoload
 264 (define-minor-mode display-time-mode
 265   "Toggle display of time, load level, and mail flag in mode lines.
 266 With a numeric arg, enable this display if arg is positive.
 267
 268 When this display is enabled, it updates automatically every minute.
 269 If `display-time-day-and-date' is non-nil, the current day and date
 270 are displayed as well.
 271 This runs the normal hook `display-time-hook' after each update."
 272   :global t :group 'display-time
 273     (and display-time-timer (cancel-timer display-time-timer))
 274     (setq display-time-timer nil)
 275     (setq display-time-string "")
 276     (or global-mode-string (setq global-mode-string '("")))
 277     (if display-time-mode
 278         (progn
 279           (or (memq 'display-time-string global-mode-string)
 280               (setq global-mode-string
 281                     (append global-mode-string '(display-time-string))))
 282           ;; Set up the time timer.
 283           (setq display-time-timer
 284                 (run-at-time t display-time-interval
 285                              'display-time-event-handler))
 286           ;; Make the time appear right away.
 287           (display-time-update)
 288           ;; When you get new mail, clear "Mail" from the mode line.
 289           (add-hook 'rmail-after-get-new-mail-hook
 290                     'display-time-event-handler))
 291       (remove-hook 'rmail-after-get-new-mail-hook
 292                    'display-time-event-handler)))
 293
 294 (provide 'time)
 295
 296 ;;; time.el ends here