lisp/time.el

   1 ;;; time.el --- display time, load and mail indicator in mode line of Emacs
   2
   3 ;; Copyright (C) 1985-1987, 1993-1994, 1996, 2000-2017 Free Software
   4 ;; Foundation, Inc.
   5
   6 ;; Maintainer: emacs-devel@gnu.org
   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 3 of the License, or
  13 ;; (at your option) 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.  If not, see <https://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; Facilities to display current time/date and a new-mail indicator
  26 ;; in the Emacs mode line.  The entry point is `display-time'.
  27
  28 ;; Display time world in a buffer, the entry point is
  29 ;; `display-time-world'.
  30
  31 ;;; Code:
  32
  33 (defgroup display-time nil
  34   "Display time and load in mode line of Emacs."
  35   :group 'mode-line
  36   :group 'mail)
  37
  38
  39 (defcustom display-time-mail-file nil
  40   "File name of mail inbox file, for indicating existence of new mail.
  41 Non-nil and not a string means don't check for mail; nil means use
  42 default, which is system-dependent, and is the same as used by Rmail."
  43   :type '(choice (const :tag "None" none)
  44                  (const :tag "Default" nil)
  45                  (file :format "%v"))
  46   :group 'display-time)
  47
  48 (defcustom display-time-mail-directory nil
  49   "Name of mail inbox directory, for indicating existence of new mail.
  50 Any nonempty regular file in the directory is regarded as newly arrived mail.
  51 If nil, do not check a directory for arriving mail."
  52   :type '(choice (const :tag "None" nil)
  53                  (directory :format "%v"))
  54   :group 'display-time)
  55
  56 (defcustom display-time-mail-function nil
  57   "Function to call, for indicating existence of new mail.
  58 If nil, that means use the default method: check that the file
  59 specified by `display-time-mail-file' is nonempty or that the
  60 directory `display-time-mail-directory' contains nonempty files."
  61   :type '(choice (const :tag "Default" nil)
  62                  (function))
  63   :group 'display-time)
  64
  65 (defcustom display-time-default-load-average 0
  66   "Which load average value will be shown in the mode line.
  67 Almost every system can provide values of load for the past 1 minute,
  68 past 5 or past 15 minutes.  The default is to display 1-minute load average.
  69 The value can be one of:
  70
  71   0   => 1 minute load
  72   1   => 5 minutes load
  73   2   => 15 minutes load
  74   nil => None (do not display the load average)"
  75   :type '(choice (const :tag "1 minute load" 0)
  76                  (const :tag "5 minutes load" 1)
  77                  (const :tag "15 minutes load" 2)
  78                  (const :tag "None" nil))
  79   :group 'display-time)
  80
  81 (defvar display-time-load-average nil
  82   "Value of the system's load average currently shown on the mode line.
  83 See `display-time-default-load-average'.
  84
  85 This is an internal variable; setting it has no effect.")
  86
  87 (defcustom display-time-load-average-threshold 0.1
  88   "Load-average values below this value won't be shown in the mode line."
  89   :type 'number
  90   :group 'display-time)
  91
  92 ;;;###autoload
  93 (defcustom display-time-day-and-date nil "\
  94 Non-nil means \\[display-time] should display day and date as well as time."
  95   :type 'boolean
  96   :group 'display-time)
  97
  98 (defvar display-time-timer nil)
  99
 100 (defcustom display-time-interval 60
 101   "Seconds between updates of time in the mode line."
 102   :type 'integer
 103   :group 'display-time)
 104
 105 (defcustom display-time-24hr-format nil
 106   "Non-nil indicates time should be displayed as hh:mm, 0 <= hh <= 23.
 107 A value of nil means 1 <= hh <= 12, and an AM/PM suffix is used."
 108   :type 'boolean
 109   :group 'display-time)
 110
 111 (defvar display-time-string nil
 112   "String used in mode lines to display a time string.
 113 It should not be set directly, but is instead updated by the
 114 `display-time' function.")
 115 ;;;###autoload(put 'display-time-string 'risky-local-variable t)
 116
 117 (defcustom display-time-hook nil
 118   "List of functions to be called when the time is updated on the mode line."
 119   :type 'hook
 120   :group 'display-time)
 121
 122 (defvar display-time-server-down-time nil
 123    "Time when mail file's file system was recorded to be down.
 124 If that file system seems to be up, the value is nil.")
 125
 126 (defcustom zoneinfo-style-world-list
 127   '(("America/Los_Angeles" "Seattle")
 128     ("America/New_York" "New York")
 129     ("Europe/London" "London")
 130     ("Europe/Paris" "Paris")
 131     ("Asia/Calcutta" "Bangalore")
 132     ("Asia/Tokyo" "Tokyo"))
 133   "Alist of zoneinfo-style time zones and places for `display-time-world'.
 134 Each element has the form (TIMEZONE LABEL).
 135 TIMEZONE should be a string of the form AREA/LOCATION, where AREA is
 136 the name of a region -- a continent or ocean, and LOCATION is the name
 137 of a specific location, e.g., a city, within that region.
 138 LABEL is a string to display as the label of that TIMEZONE's time."
 139   :group 'display-time
 140   :type '(repeat (list string string))
 141   :version "23.1")
 142
 143 (defcustom legacy-style-world-list
 144   '(("PST8PDT" "Seattle")
 145     ("EST5EDT" "New York")
 146     ("GMT0BST" "London")
 147     ("CET-1CDT" "Paris")
 148     ("IST-5:30" "Bangalore")
 149     ("JST-9" "Tokyo"))
 150   "Alist of traditional-style time zones and places for `display-time-world'.
 151 Each element has the form (TIMEZONE LABEL).
 152 TIMEZONE should be a string of the form:
 153
 154      std[+|-]offset[dst[offset][,date[/time],date[/time]]]
 155
 156 See the documentation of the TZ environment variable on your system,
 157 for more details about the format of TIMEZONE.
 158 LABEL is a string to display as the label of that TIMEZONE's time."
 159   :group 'display-time
 160   :type '(repeat (list string string))
 161   :version "23.1")
 162
 163 (defcustom display-time-world-list
 164   ;; Determine if zoneinfo style timezones are supported by testing that
 165   ;; America/New York and Europe/London return different timezones.
 166   (let ((nyt (format-time-string "%z" nil "America/New_York"))
 167         (gmt (format-time-string "%z" nil "Europe/London")))
 168     (if (string-equal nyt gmt)
 169         legacy-style-world-list
 170       zoneinfo-style-world-list))
 171   "Alist of time zones and places for `display-time-world' to display.
 172 Each element has the form (TIMEZONE LABEL).
 173 TIMEZONE should be in a format supported by your system.  See the
 174 documentation of `zoneinfo-style-world-list' and
 175 `legacy-style-world-list' for two widely used formats.  LABEL is
 176 a string to display as the label of that TIMEZONE's time."
 177   :group 'display-time
 178   :type '(repeat (list string string))
 179   :version "23.1")
 180
 181 (defcustom display-time-world-time-format "%A %d %B %R %Z"
 182   "Format of the time displayed, see `format-time-string'."
 183   :group 'display-time
 184   :type 'string
 185   :version "23.1")
 186
 187 (defcustom display-time-world-buffer-name "*wclock*"
 188   "Name of the world clock buffer."
 189   :group 'display-time
 190   :type 'string
 191   :version "23.1")
 192
 193 (defcustom display-time-world-timer-enable t
 194   "If non-nil, a timer will update the world clock."
 195   :group 'display-time
 196   :type 'boolean
 197   :version "23.1")
 198
 199 (defcustom display-time-world-timer-second 60
 200   "Interval in seconds for updating the world clock."
 201   :group 'display-time
 202   :type 'integer
 203   :version "23.1")
 204
 205 ;;;###autoload
 206 (defun display-time ()
 207   "Enable display of time, load level, and mail flag in mode lines.
 208 This display updates automatically every minute.
 209 If `display-time-day-and-date' is non-nil, the current day and date
 210 are displayed as well.
 211 This runs the normal hook `display-time-hook' after each update."
 212   (interactive)
 213   (display-time-mode 1))
 214
 215 ;; This business used to be simpler when all mode lines had the same
 216 ;; face and the image could just be pbm.  Now we try to rely on an xpm
 217 ;; image with a transparent background.  Otherwise, set the background
 218 ;; for pbm.
 219
 220 (defcustom display-time-mail-face nil
 221   "Face to use for `display-time-mail-string'.
 222 If `display-time-use-mail-icon' is non-nil, the image's
 223 background color is the background of this face.  Set this to
 224 make the mail indicator stand out on a color display."
 225   :group 'mode-line-faces
 226   :group 'display-time
 227   :version "22.1"
 228   :type '(choice (const :tag "None" nil) face))
 229
 230 (defvar display-time-mail-icon
 231   (find-image '((:type xpm :file "letter.xpm" :ascent center)
 232                 (:type pbm :file "letter.pbm" :ascent center)))
 233   "Image specification to offer as the mail indicator on a graphic display.
 234 See `display-time-use-mail-icon' and `display-time-mail-face'.")
 235
 236 ;; Fixme: Default to icon on graphical display?
 237 (defcustom display-time-use-mail-icon nil
 238   "Non-nil means use an icon as mail indicator on a graphic display.
 239 Otherwise use `display-time-mail-string'.  The icon may consume less
 240 of the mode line.  It is specified by `display-time-mail-icon'."
 241   :group 'display-time
 242   :type 'boolean)
 243
 244 ;; Fixme: maybe default to the character if we can display Unicode.
 245 (defcustom display-time-mail-string "Mail"
 246   "String to use as the mail indicator in `display-time-string-forms'.
 247 This can use the Unicode letter character if you can display it."
 248   :group 'display-time
 249   :version "22.1"
 250   :type '(choice (const "Mail")
 251                  ;; Use :tag here because the Lucid menu won't display
 252                  ;; multibyte text.
 253                  (const :tag "Unicode letter character" "✉")
 254                  string))
 255
 256 (defcustom display-time-format nil
 257   "String specifying format for displaying the time in the mode line.
 258 See the function `format-time-string' for an explanation of
 259 how to write this string.  If this is nil, the defaults
 260 depend on `display-time-day-and-date' and `display-time-24hr-format'."
 261   :type '(choice (const :tag "Default" nil)
 262                  string)
 263   :group 'display-time)
 264
 265 (defcustom display-time-string-forms
 266   '((if (and (not display-time-format) display-time-day-and-date)
 267         (format-time-string "%a %b %e " now)
 268       "")
 269     (propertize
 270      (format-time-string (or display-time-format
 271                              (if display-time-24hr-format "%H:%M" "%-I:%M%p"))
 272                          now)
 273      'help-echo (format-time-string "%a %b %e, %Y" now))
 274     load
 275     (if mail
 276         ;; Build the string every time to act on customization.
 277         ;; :set-after doesn't help for `customize-option'.  I think it
 278         ;; should.
 279         (concat
 280          " "
 281          (propertize
 282           display-time-mail-string
 283           'display `(when (and display-time-use-mail-icon
 284                                (display-graphic-p))
 285                       ,@display-time-mail-icon
 286                       ,@(if (and display-time-mail-face
 287                                  (memq (plist-get (cdr display-time-mail-icon)
 288                                                   :type)
 289                                        '(pbm xbm)))
 290                             (let ((bg (face-attribute display-time-mail-face
 291                                                       :background)))
 292                               (if (stringp bg)
 293                                   (list :background bg)))))
 294           'face display-time-mail-face
 295           'help-echo "You have new mail; mouse-2: Read mail"
 296           'mouse-face 'mode-line-highlight
 297           'local-map (make-mode-line-mouse-map 'mouse-2
 298                                                read-mail-command)))
 299       ""))
 300   "List of expressions governing display of the time in the mode line.
 301 For most purposes, you can control the time format using `display-time-format'
 302 which is a more standard interface.
 303
 304 This expression is a list of expressions that can involve the keywords
 305 `load', `day', `month', and `year', `12-hours', `24-hours', `minutes',
 306 `seconds', all numbers in string form, and `monthname', `dayname', `am-pm',
 307 and `time-zone' all alphabetic strings, and `mail' a true/nil value.
 308
 309 For example:
 310
 311    ((substring year -2) \"/\" month \"/\" day
 312     \" \" 24-hours \":\" minutes \":\" seconds
 313     (if time-zone \" (\") time-zone (if time-zone \")\")
 314     (if mail \" Mail\" \"\"))
 315
 316 would give mode line times like `94/12/30 21:07:48 (UTC)'."
 317   :type '(repeat sexp)
 318   :group 'display-time)
 319
 320 (defun display-time-event-handler ()
 321   (display-time-update)
 322   (let* ((current (current-time))
 323          (timer display-time-timer)
 324          ;; Compute the time when this timer will run again, next.
 325          (next-time (timer-relative-time
 326                      (list (aref timer 1) (aref timer 2) (aref timer 3))
 327                      (* 5 (aref timer 4)) 0)))
 328     ;; If the activation time is far in the past,
 329     ;; skip executions until we reach a time in the future.
 330     ;; This avoids a long pause if Emacs has been suspended for hours.
 331     (or (> (nth 0 next-time) (nth 0 current))
 332         (and (= (nth 0 next-time) (nth 0 current))
 333              (> (nth 1 next-time) (nth 1 current)))
 334         (and (= (nth 0 next-time) (nth 0 current))
 335              (= (nth 1 next-time) (nth 1 current))
 336              (> (nth 2 next-time) (nth 2 current)))
 337         (progn
 338           (timer-set-time timer (timer-next-integral-multiple-of-time
 339                                  current display-time-interval)
 340                           display-time-interval)
 341           (timer-activate timer)))))
 342
 343 (defun display-time-next-load-average ()
 344   "Switch between different load averages in the mode line.
 345 Switches from the 1 to 5 to 15 minute load average, and then back to 1."
 346   (interactive)
 347   (if (= 3 (setq display-time-load-average (1+ display-time-load-average)))
 348       (setq display-time-load-average 0))
 349   (display-time-update))
 350
 351 (defun display-time-mail-check-directory ()
 352   (let ((mail-files (directory-files display-time-mail-directory t))
 353         (size 0))
 354     (while (and mail-files (= size 0))
 355       ;; Count size of regular files only.
 356       (setq size (+ size (or (and (file-regular-p (car mail-files))
 357                                   (nth 7 (file-attributes (car mail-files))))
 358                              0)))
 359       (setq mail-files (cdr mail-files)))
 360     (if (> size 0)
 361         size
 362       nil)))
 363
 364 (with-no-warnings
 365   ;; Warnings are suppressed to avoid "global/dynamic var `X' lacks a prefix".
 366   (defvar now)
 367   (defvar time)
 368   (defvar load)
 369   (defvar mail)
 370   (defvar 24-hours)
 371   (defvar hour)
 372   (defvar 12-hours)
 373   (defvar am-pm)
 374   (defvar minutes)
 375   (defvar seconds)
 376   (defvar time-zone)
 377   (defvar day)
 378   (defvar year)
 379   (defvar monthname)
 380   (defvar month)
 381   (defvar dayname))
 382
 383 (defun display-time-update ()
 384   "Update the display-time info for the mode line.
 385 However, don't redisplay right now.
 386
 387 This is used for things like Rmail `g' that want to force an
 388 update which can wait for the next redisplay."
 389   (let* ((now (current-time))
 390          (time (current-time-string now))
 391          (load (if (null display-time-load-average)
 392                    ""
 393                  (condition-case ()
 394                      ;; Do not show values less than
 395                      ;; `display-time-load-average-threshold'.
 396                      (if (> (* display-time-load-average-threshold 100)
 397                             (nth display-time-load-average (load-average)))
 398                          ""
 399                        ;; The load average number is mysterious, so
 400                        ;; provide some help.
 401                        (let ((str (format " %03d"
 402                                           (nth display-time-load-average
 403                                                (load-average)))))
 404                          (propertize
 405                           (concat (substring str 0 -2) "." (substring str -2))
 406                           'local-map (make-mode-line-mouse-map
 407                                       'mouse-2 'display-time-next-load-average)
 408                           'mouse-face 'mode-line-highlight
 409                           'help-echo (concat
 410                                       "System load average for past "
 411                                       (if (= 0 display-time-load-average)
 412                                           "1 minute"
 413                                         (if (= 1 display-time-load-average)
 414                                             "5 minutes"
 415                                           "15 minutes"))
 416                                       "; mouse-2: next"))))
 417                    (error ""))))
 418          (mail-spool-file (or display-time-mail-file
 419                               (getenv "MAIL")
 420                               (concat rmail-spool-directory
 421                                       (user-login-name))))
 422          (mail (cond
 423                 (display-time-mail-function
 424                  (funcall display-time-mail-function))
 425                 (display-time-mail-directory
 426                  (display-time-mail-check-directory))
 427                 ((and (stringp mail-spool-file)
 428                       (or (null display-time-server-down-time)
 429                           ;; If have been down for 20 min, try again.
 430                           (> (- (nth 1 now) display-time-server-down-time)
 431                              1200)
 432                           (and (< (nth 1 now) display-time-server-down-time)
 433                                (> (- (nth 1 now)
 434                                      display-time-server-down-time)
 435                                   -64336))))
 436                  (let ((start-time (current-time)))
 437                    (prog1
 438                        (display-time-file-nonempty-p mail-spool-file)
 439                      (if (> (- (nth 1 (current-time))
 440                                (nth 1 start-time))
 441                             20)
 442                          ;; Record that mail file is not accessible.
 443                          (setq display-time-server-down-time
 444                                (nth 1 (current-time)))
 445                        ;; Record that mail file is accessible.
 446                        (setq display-time-server-down-time nil)))))))
 447          (24-hours (substring time 11 13))
 448          (hour (string-to-number 24-hours))
 449          (12-hours (int-to-string (1+ (% (+ hour 11) 12))))
 450          (am-pm (if (>= hour 12) "pm" "am"))
 451          (minutes (substring time 14 16))
 452          (seconds (substring time 17 19))
 453          (time-zone (car (cdr (current-time-zone now))))
 454          (day (substring time 8 10))
 455          (year (format-time-string "%Y" now))
 456          (monthname (substring time 4 7))
 457          (month
 458           (cdr
 459            (assoc
 460             monthname
 461             '(("Jan" . "1") ("Feb" . "2") ("Mar" . "3") ("Apr" . "4")
 462               ("May" . "5") ("Jun" . "6") ("Jul" . "7") ("Aug" . "8")
 463               ("Sep" . "9") ("Oct" . "10") ("Nov" . "11") ("Dec" . "12")))))
 464          (dayname (substring time 0 3)))
 465     (setq display-time-string
 466           (mapconcat 'eval display-time-string-forms ""))
 467     ;; This is inside the let binding, but we are not going to document
 468     ;; what variables are available.
 469     (run-hooks 'display-time-hook))
 470   (force-mode-line-update 'all))
 471
 472 (defun display-time-file-nonempty-p (file)
 473   (let ((remote-file-name-inhibit-cache (- display-time-interval 5)))
 474     (and (file-exists-p file)
 475          (< 0 (nth 7 (file-attributes (file-chase-links file)))))))
 476
 477 ;;;###autoload
 478 (define-minor-mode display-time-mode
 479   "Toggle display of time, load level, and mail flag in mode lines.
 480 With a prefix argument ARG, enable Display Time mode if ARG is
 481 positive, and disable it otherwise.  If called from Lisp, enable
 482 it if ARG is omitted or nil.
 483
 484 When Display Time mode is enabled, it updates every minute (you
 485 can control the number of seconds between updates by customizing
 486 `display-time-interval').  If `display-time-day-and-date' is
 487 non-nil, the current day and date are displayed as well.  This
 488 runs the normal hook `display-time-hook' after each update."
 489   :global t :group 'display-time
 490   (and display-time-timer (cancel-timer display-time-timer))
 491   (setq display-time-timer nil)
 492   (setq display-time-string "")
 493   (or global-mode-string (setq global-mode-string '("")))
 494   (setq display-time-load-average display-time-default-load-average)
 495   (if display-time-mode
 496       (progn
 497         (or (memq 'display-time-string global-mode-string)
 498             (setq global-mode-string
 499                   (append global-mode-string '(display-time-string))))
 500         ;; Set up the time timer.
 501         (setq display-time-timer
 502               (run-at-time t display-time-interval
 503                            'display-time-event-handler))
 504         ;; Make the time appear right away.
 505         (display-time-update)
 506         ;; When you get new mail, clear "Mail" from the mode line.
 507         (add-hook 'rmail-after-get-new-mail-hook
 508                   'display-time-event-handler))
 509     (remove-hook 'rmail-after-get-new-mail-hook
 510                  'display-time-event-handler)))
 511
 512
 513 (define-derived-mode display-time-world-mode special-mode "World clock"
 514   "Major mode for buffer that displays times in various time zones.
 515 See `display-time-world'."
 516   (setq show-trailing-whitespace nil))
 517
 518 (defun display-time-world-display (alist)
 519   "Replace current buffer text with times in various zones, based on ALIST."
 520   (let ((inhibit-read-only t)
 521         (buffer-undo-list t)
 522         (now (current-time))
 523         (max-width 0)
 524         result fmt)
 525     (erase-buffer)
 526     (dolist (zone alist)
 527       (let* ((label (cadr zone))
 528              (width (string-width label)))
 529         (push (cons label
 530                     (format-time-string display-time-world-time-format
 531                                         now (car zone)))
 532               result)
 533         (when (> width max-width)
 534           (setq max-width width))))
 535     (setq fmt (concat "%-" (int-to-string max-width) "s %s\n"))
 536     (dolist (timedata (nreverse result))
 537       (insert (format fmt (car timedata) (cdr timedata))))
 538     (delete-char -1))
 539   (goto-char (point-min)))
 540
 541 ;;;###autoload
 542 (defun display-time-world ()
 543   "Enable updating display of times in various time zones.
 544 `display-time-world-list' specifies the zones.
 545 To turn off the world time display, go to that window and type `q'."
 546   (interactive)
 547   (when (and display-time-world-timer-enable
 548              (not (get-buffer display-time-world-buffer-name)))
 549     (run-at-time t display-time-world-timer-second 'display-time-world-timer))
 550   (with-current-buffer (get-buffer-create display-time-world-buffer-name)
 551     (display-time-world-display display-time-world-list)
 552     (display-buffer display-time-world-buffer-name
 553                     (cons nil '((window-height . fit-window-to-buffer))))
 554     (display-time-world-mode)))
 555
 556 (defun display-time-world-timer ()
 557   (if (get-buffer display-time-world-buffer-name)
 558       (with-current-buffer (get-buffer display-time-world-buffer-name)
 559         (display-time-world-display display-time-world-list))
 560     ;; cancel timer
 561     (let ((list timer-list))
 562       (while list
 563         (let ((elt (pop list)))
 564           (when (equal (symbol-name (timer--function elt))
 565                        "display-time-world-timer")
 566             (cancel-timer elt)))))))
 567
 568 ;;;###autoload
 569 (defun emacs-uptime (&optional format)
 570   "Return a string giving the uptime of this instance of Emacs.
 571 FORMAT is a string to format the result, using `format-seconds'.
 572 For example, the Unix uptime command format is \"%D, %z%2h:%.2m\"."
 573   (interactive)
 574   (let ((str
 575          (format-seconds (or format "%Y, %D, %H, %M, %z%S")
 576                          (float-time
 577                           (time-subtract (current-time) before-init-time)))))
 578     (if (called-interactively-p 'interactive)
 579         (message "%s" str)
 580       str)))
 581
 582 ;;;###autoload
 583 (defun emacs-init-time ()
 584   "Return a string giving the duration of the Emacs initialization."
 585   (interactive)
 586   (let ((str
 587          (format "%.1f seconds"
 588                  (float-time
 589                   (time-subtract after-init-time before-init-time)))))
 590     (if (called-interactively-p 'interactive)
 591         (message "%s" str)
 592       str)))
 593
 594 (provide 'time)
 595
 596 ;;; time.el ends here