summaryrefslogtreecommitdiff
path: root/lisp/time.el
blob: 8f798fa08a26827a8d4b2ff9081169f805a4bfef (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
;;; time.el --- display time and load in mode line of Emacs.

;; Copyright (C) 1985, 86, 87, 93, 94, 1996 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; Facilities to display current time/date and a new-mail indicator
;; in the Emacs mode line.  The single entry point is `display-time'.

;;; Code:

(defvar display-time-mail-file nil
  "*File name of mail inbox file, for indicating existence of new mail.
Non-nil and not a string means don't check for mail.  nil means use
default, which is system-dependent, and is the same as used by Rmail.")

;;;###autoload
(defvar display-time-day-and-date nil "\
*Non-nil means \\[display-time] should display day and date as well as time.")

(defvar display-time-timer nil)

(defvar display-time-interval 60
  "*Seconds between updates of time in the mode line.")

(defvar display-time-24hr-format nil
  "*Non-nil indicates time should be displayed as hh:mm, 0 <= hh <= 23.
Nil means 1 <= hh <= 12, and an AM/PM suffix is used.")

(defvar display-time-string nil)

(defvar display-time-hook nil
  "* List of functions to be called when the time is updated on the mode line.")

(defvar display-time-server-down-time nil
   "Time when mail file's file system was recorded to be down.
If that file system seems to be up, the value is nil.")

;;;###autoload
(defun display-time ()
  "Enable display of time, load level, and mail flag in mode lines.
This display updates automatically every minute.
If `display-time-day-and-date' is non-nil, the current day and date
are displayed as well.
This runs the normal hook `display-time-hook' after each update."
  (interactive)
  (display-time-mode 1))

;;;###autoload
(defun display-time-mode (arg)
  "Toggle display of time, load level, and mail flag in mode lines.
With a numeric arg, enable this display if arg is positive.

When this display is enabled, it updates automatically every minute.
If `display-time-day-and-date' is non-nil, the current day and date
are displayed as well.
This runs the normal hook `display-time-hook' after each update."
  (interactive "P")
  (let ((on (if (null arg)
		(not display-time-timer)
	      (> (prefix-numeric-value arg) 0))))
    (and display-time-timer (cancel-timer display-time-timer))
    (setq display-time-timer nil)
    (setq display-time-string "")
    (or global-mode-string (setq global-mode-string '("")))
    (if on
	(progn
	  (or (memq 'display-time-string global-mode-string)
	      (setq global-mode-string
		    (append global-mode-string '(display-time-string))))
	  ;; Set up the time timer.
	  (setq display-time-timer
		(run-at-time t display-time-interval
			     'display-time-event-handler))
	  ;; Make the time appear right away.
	  (display-time-update)
	  ;; When you get new mail, clear "Mail" from the mode line.
	  (add-hook 'rmail-after-get-new-mail-hook
		    'display-time-event-handler))
      (remove-hook 'rmail-after-get-new-mail-hook
		   'display-time-event-handler))))


(defvar display-time-format
  (concat 
   (if display-time-day-and-date
       "%a %b %e" "")
   (if display-time-24hr-format "%H:%m" "%-I:%M%p"))
  "*A string specifying the format for displaying the time in the mode line.
See the function `format-time-string' for an explanation of
how to write this string.")

(defvar display-time-string-forms
  '((format-time-string display-time-format now)
    load
    (if mail " Mail" ""))
  "*A list of expressions governing display of the time in the mode line.
For most purposes, you can control the time format using `display-time-format'
which is a more standard interface.

This expression is a list of expressions that can involve the keywords
`load', `day', `month', and `year', `12-hours', `24-hours', `minutes',
`seconds', all numbers in string form, and `monthname', `dayname', `am-pm',
and `time-zone' all alphabetic strings, and `mail' a true/nil value.

For example, the form

  '((substring year -2) \"/\" month \"/\" day
    \" \" 24-hours \":\" minutes \":\" seconds
    (if time-zone \" (\") time-zone (if time-zone \")\")
    (if mail \" Mail\" \"\"))

would give mode line times like `94/12/30 21:07:48 (UTC)'.")

(defun display-time-event-handler ()
  (display-time-update)
  ;; Do redisplay right now, if no input pending.
  (sit-for 0)
  (let* ((current (current-time))
	 (timer display-time-timer)
	 ;; Compute the time when this timer will run again, next.
	 (next-time (timer-relative-time
		     (list (aref timer 1) (aref timer 2) (aref timer 3))
		     (* 5 (aref timer 4)) 0)))
    ;; If the activation time is far in the past,
    ;; skip executions until we reach a time in the future.
    ;; This avoids a long pause if Emacs has been suspended for hours.
    (or (> (nth 0 next-time) (nth 0 current))
	(and (= (nth 0 next-time) (nth 0 current))
	     (> (nth 1 next-time) (nth 1 current)))
	(and (= (nth 0 next-time) (nth 0 current))
	     (= (nth 1 next-time) (nth 1 current))
	     (> (nth 2 next-time) (nth 2 current)))
	(progn
	  (timer-set-time timer (timer-next-integral-multiple-of-time
				 current display-time-interval)
			  display-time-interval)
	  (timer-activate timer)))))

;; Update the display-time info for the mode line
;; but don't redisplay right now.  This is used for
;; things like Rmail `g' that want to force an update
;; which can wait for the next redisplay.
(defun display-time-update ()
  (let* ((now (current-time))
	 (time (current-time-string now))
         (load (condition-case ()
                   (if (zerop (car (load-average))) ""
                     (let ((str (format " %03d" (car (load-average)))))
                       (concat (substring str 0 -2) "." (substring str -2))))
                 (error "")))
         (mail-spool-file (or display-time-mail-file
                              (getenv "MAIL")
                              (concat rmail-spool-directory
                                      (user-login-name))))
	 (mail (and (stringp mail-spool-file)
		    (or (null display-time-server-down-time)
			;; If have been down for 20 min, try again.
			(> (- (nth 1 (current-time))
			      display-time-server-down-time)
			   1200))
		    (let ((start-time (current-time)))
		      (prog1
			  (display-time-file-nonempty-p mail-spool-file)
			(if (> (- (nth 1 (current-time)) (nth 1 start-time))
			       20)
			    ;; Record that mail file is not accessible.
			    (setq display-time-server-down-time 
				  (nth 1 (current-time)))
			  ;; Record that mail file is accessible.
			  (setq display-time-server-down-time nil))))))
         (24-hours (substring time 11 13))
         (hour (string-to-int 24-hours))
         (12-hours (int-to-string (1+ (% (+ hour 11) 12))))
         (am-pm (if (>= hour 12) "pm" "am"))
         (minutes (substring time 14 16))
         (seconds (substring time 17 19))
         (time-zone (car (cdr (current-time-zone now))))
         (day (substring time 8 10))
         (year (substring time 20 24))
         (monthname (substring time 4 7))
         (month
          (cdr
           (assoc
            monthname
            '(("Jan" . "1") ("Feb" . "2") ("Mar" . "3") ("Apr" . "4")
              ("May" . "5") ("Jun" . "6") ("Jul" . "7") ("Aug" . "8")
              ("Sep" . "9") ("Oct" . "10") ("Nov" . "11") ("Dec" . "12")))))
         (dayname (substring time 0 3)))
    (setq display-time-string
          (mapconcat 'eval display-time-string-forms ""))
    ;; This is inside the let binding, but we are not going to document
    ;; what variables are available.
    (run-hooks 'display-time-hook))
  (force-mode-line-update))

(defun display-time-file-nonempty-p (file)
  (and (file-exists-p file)
       (< 0 (nth 7 (file-attributes (file-chase-links file))))))

;;; time.el ends here