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[emacs.git] / lisp / autorevert.el
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1 ;;; autorevert --- revert buffers when files on disk change
3 ;; Copyright (C) 1997, 1998, 1999 Free Software Foundation, Inc.
5 ;; Author: Anders Lindgren <andersl@andersl.com>
6 ;; Keywords: convenience
7 ;; Created: 1997-06-01
8 ;; Date: 1999-11-30
10 ;; This file is part of GNU Emacs.
12 ;; GNU Emacs is free software; you can redistribute it and/or modify
13 ;; it under the terms of the GNU General Public License as published by
14 ;; the Free Software Foundation; either version 2, or (at your option)
15 ;; any later version.
17 ;; GNU Emacs is distributed in the hope that it will be useful,
18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 ;; GNU General Public License for more details.
22 ;; You should have received a copy of the GNU General Public License
23 ;; along with GNU Emacs; see the file COPYING. If not, write to the
24 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
25 ;; Boston, MA 02111-1307, USA.
27 ;;; Commentary:
29 ;; Introduction:
31 ;; Whenever a file that Emacs is editing has been changed by another
32 ;; program the user normally has to execute the command `revert-buffer'
33 ;; to load the new content of the file into Emacs.
35 ;; This package contains two minor modes: Global Auto-Revert Mode and
36 ;; Auto-Revert Mode. Both modes automatically revert buffers
37 ;; whenever the corresponding files have been changed on disk.
39 ;; Auto-Revert Mode can be activated for individual buffers.
40 ;; Global Auto-Revert Mode applies to all file buffers.
42 ;; Both modes operate by checking the time stamp of all files at
43 ;; intervals of `auto-revert-interval'. The default is every five
44 ;; seconds. The check is aborted whenever the user actually uses
45 ;; Emacs. You should never even notice that this package is active
46 ;; (except that your buffers will be reverted, of course).
48 ;; Usage:
50 ;; Go to the appropriate buffer and press:
51 ;; M-x auto-revert-mode RET
53 ;; To activate Global Auto-Revert Mode, press:
54 ;; M-x global-auto-revert-mode RET
56 ;; To activate Global Auto-Revert Mode every time Emacs is started
57 ;; customise the option `global-auto-revert-mode' or the following
58 ;; line could be added to your ~/.emacs:
59 ;; (global-auto-revert-mode 1)
61 ;; The function `turn-on-auto-revert-mode' could be added to any major
62 ;; mode hook to activate Auto-Revert Mode for all buffers in that
63 ;; mode. For example, the following line will activate Auto-Revert
64 ;; Mode in all C mode buffers:
66 ;; (add-hook 'c-mode-hook 'turn-on-auto-revert-mode)
68 ;;; Code:
70 ;; Dependencies:
72 (require 'timer)
73 (eval-when-compile (require 'cl))
76 ;; Custom Group:
78 ;; The two modes will be placed next to Auto Save Mode under the
79 ;; Files group under Emacs.
81 (defgroup auto-revert nil
82 "Revert individual buffers when files on disk change.
84 Auto-Revert Mode can be activated for individual buffer.
85 Global Auto-Revert Mode applies to all buffers."
86 :group 'files
87 :group 'convenience)
90 ;; Variables:
92 ;; Autoload for the benefit of `make-mode-line-mouse-sensitive'.
93 ;;;###autoload
94 (defvar auto-revert-mode nil
95 "*Non-nil when Auto-Revert Mode is active.
97 Never set this variable directly, use the command `auto-revert-mode'
98 instead.")
100 ;;;###autoload
101 (defcustom global-auto-revert-mode nil
102 "When on, buffers are automatically reverted when files on disk change.
104 Set this variable using \\[customize] only. Otherwise, use the
105 command `global-auto-revert-mode'."
106 :group 'auto-revert
107 :initialize 'custom-initialize-default
108 :set '(lambda (symbol value)
109 (global-auto-revert-mode (or value 0)))
110 :type 'boolean
111 :require 'autorevert)
113 (defcustom auto-revert-interval 5
114 "Time, in seconds, between Auto-Revert Mode file checks."
115 :group 'auto-revert
116 :type 'integer)
118 (defcustom auto-revert-stop-on-user-input t
119 "When non-nil Auto-Revert Mode stops checking files on user input."
120 :group 'auto-revert
121 :type 'boolean)
123 (defcustom auto-revert-verbose t
124 "When nil, Auto-Revert Mode will not generate any messages.
126 Currently, messages are generated when the mode is activated or
127 deactivated, and whenever a file is reverted."
128 :group 'auto-revert
129 :type 'boolean)
131 (defcustom auto-revert-mode-text " ARev"
132 "String to display in the mode line when Auto-Revert Mode is active.
134 \(When the string is not empty, make sure that it has a leading space.)"
135 :tag "Auto Revert Mode Text" ; To separate it from `global-...'
136 :group 'auto-revert
137 :type 'string)
139 (defcustom auto-revert-mode-hook nil
140 "Functions to run when Auto-Revert Mode is activated."
141 :tag "Auto Revert Mode Hook" ; To separate it from `global-...'
142 :group 'auto-revert
143 :type 'hook)
145 (defcustom global-auto-revert-mode-text ""
146 "String to display when Global Auto-Revert Mode is active.
148 The default is nothing since when this mode is active this text doesn't
149 vary over time, or between buffers. Hence mode line text
150 would only waste precious space."
151 :group 'auto-revert
152 :type 'string)
154 (defcustom global-auto-revert-mode-hook nil
155 "Hook called when Global Auto-Revert Mode is activated."
156 :group 'auto-revert
157 :type 'hook)
159 (defcustom global-auto-revert-non-file-buffers nil
160 "*When nil only file buffers are reverted by Global Auto-Revert Mode.
162 When non-nil, both file buffers and buffers with a custom
163 `revert-buffer-function' are reverted by Global Auto-Revert Mode."
164 :group 'auto-revert
165 :type 'boolean)
167 (defcustom global-auto-revert-non-file-buffers nil
168 "When nil only file buffers are reverted by Global Auto-Revert Mode.
170 When non-nil, both file buffers and buffers with a custom
171 `revert-buffer-function' are reverted by Global Auto-Revert Mode.
173 Use this option with care since it could lead to excessive reverts."
174 :group 'auto-revert
175 :type 'boolean)
177 (defcustom global-auto-revert-ignore-modes '()
178 "List of major modes Global Auto-Revert Mode should not check."
179 :group 'auto-revert
180 :type '(repeat sexp))
182 (defcustom auto-revert-load-hook nil
183 "Functions to run when Auto-Revert Mode is first loaded."
184 :tag "Load Hook"
185 :group 'auto-revert
186 :type 'hook)
188 (defvar global-auto-revert-ignore-buffer nil
189 "*When non-nil, Global Auto-Revert Mode will not revert this buffer.
191 This variable becomes buffer local when set in any fashion.")
192 (make-variable-buffer-local 'global-auto-revert-ignore-buffer)
195 ;; Internal variables:
197 (defvar auto-revert-buffer-list '()
198 "List of buffers in Auto-Revert Mode.
200 Note that only Auto-Revert Mode, never Global Auto-Revert Mode, adds
201 buffers to this list.
203 The timer function `auto-revert-buffers' is responsible for purging
204 the list of old buffers.")
206 (defvar auto-revert-timer nil
207 "Timer used by Auto-Revert Mode.")
209 (defvar auto-revert-remaining-buffers '()
210 "Buffers not checked when user input stopped execution.")
213 ;; Functions:
215 ;;;###autoload
216 (defun auto-revert-mode (&optional arg)
217 "Toggle reverting buffer when file on disk changes.
219 With arg, turn Auto Revert mode on if and only if arg is positive.
220 This is a minor mode that affects only the current buffer.
221 Use `global-auto-revert-mode' to automatically revert all buffers."
222 (interactive "P")
223 (make-local-variable 'auto-revert-mode)
224 (put 'auto-revert-mode 'permanent-local t)
225 (setq auto-revert-mode
226 (if (null arg)
227 (not auto-revert-mode)
228 (> (prefix-numeric-value arg) 0)))
229 (if (and auto-revert-verbose
230 (interactive-p))
231 (message "Auto-Revert Mode is now %s."
232 (if auto-revert-mode "on" "off")))
233 (if auto-revert-mode
234 (if (not (memq (current-buffer) auto-revert-buffer-list))
235 (push (current-buffer) auto-revert-buffer-list))
236 (setq auto-revert-buffer-list
237 (delq (current-buffer) auto-revert-buffer-list)))
238 (auto-revert-set-timer)
239 (when auto-revert-mode
240 (auto-revert-buffers)
241 (run-hooks 'auto-revert-mode-hook))
242 auto-revert-mode)
245 ;;;###autoload
246 (defun turn-on-auto-revert-mode ()
247 "Turn on Auto-Revert Mode.
249 This function is designed to be added to hooks, for example:
250 (add-hook 'c-mode-hook 'turn-on-auto-revert-mode)"
251 (auto-revert-mode 1))
254 ;;;###autoload
255 (defun global-auto-revert-mode (&optional arg)
256 "Revert any buffer when file on disk change.
258 With arg, turn Auto Revert mode on globally if and only if arg is positive.
259 This is a minor mode that affects all buffers.
260 Use `auto-revert-mode' to revert a particular buffer."
261 (interactive "P")
262 (setq global-auto-revert-mode
263 (if (null arg)
264 (not global-auto-revert-mode)
265 (> (prefix-numeric-value arg) 0)))
266 (if (and auto-revert-verbose
267 (interactive-p))
268 (message "Global Auto-Revert Mode is now %s."
269 (if global-auto-revert-mode "on" "off")))
270 (auto-revert-set-timer)
271 (when global-auto-revert-mode
272 (auto-revert-buffers)
273 (run-hooks 'global-auto-revert-mode-hook)))
276 (defun auto-revert-set-timer ()
277 "Restart or cancel the timer."
278 (if (timerp auto-revert-timer)
279 (cancel-timer auto-revert-timer))
280 (if (or global-auto-revert-mode auto-revert-buffer-list)
281 (setq auto-revert-timer (run-with-timer auto-revert-interval
282 auto-revert-interval
283 'auto-revert-buffers))
284 (setq auto-revert-timer nil)))
287 (defun auto-revert-buffers ()
288 "Revert buffers as specified by Auto-Revert and Global Auto-Revert Mode.
290 Should `global-auto-revert-mode' be active all file buffers are checked.
292 Should `auto-revert-mode' be active in some buffers, those buffers
293 are checked.
295 Non-file buffers that have a custom `revert-buffer-function' are
296 reverted either when Auto-Revert Mode is active in that buffer, or
297 when the variable `global-auto-revert-non-file-buffers' is non-nil
298 and Global Auto-Revert Mode is active.
300 This function stops whenever there is user input. The buffers not
301 checked are stored in the variable `auto-revert-remaining-buffers'.
303 To avoid starvation, the buffers in `auto-revert-remaining-buffers'
304 are checked first the next time this function is called.
306 This function is also responsible for removing buffers no longer in
307 Auto-Revert mode from `auto-revert-buffer-list', and for canceling
308 the timer when no buffers need to be checked."
309 (let ((bufs (if global-auto-revert-mode
310 (buffer-list)
311 auto-revert-buffer-list))
312 (remaining '())
313 (new '()))
314 ;; Partition `bufs' into two halves depending on whether or not
315 ;; the buffers are in `auto-revert-remaining-buffers'. The two
316 ;; halves are then re-joined with the "remaining" buffers at the
317 ;; head of the list.
318 (dolist (buf auto-revert-remaining-buffers)
319 (if (memq buf bufs)
320 (push buf remaining)))
321 (dolist (buf bufs)
322 (if (not (memq buf remaining))
323 (push buf new)))
324 (setq bufs (nreverse (nconc new remaining)))
325 (while (and bufs
326 (not (and auto-revert-stop-on-user-input
327 (input-pending-p))))
328 (let ((buf (car bufs)))
329 (if (buffer-name buf) ; Buffer still alive?
330 (save-excursion
331 (set-buffer buf)
332 ;; Test if someone has turned off Auto-Revert Mode in a
333 ;; non-standard way, for example by changing major mode.
334 (if (and (not auto-revert-mode)
335 (memq buf auto-revert-buffer-list))
336 (setq auto-revert-buffer-list
337 (delq buf auto-revert-buffer-list)))
338 (when (and
339 (or auto-revert-mode
340 (and
341 global-auto-revert-mode
342 (not global-auto-revert-ignore-buffer)
343 (not (memq major-mode
344 global-auto-revert-ignore-modes))))
345 (not (buffer-modified-p))
346 (if (buffer-file-name)
347 (and (file-readable-p (buffer-file-name))
348 (not (verify-visited-file-modtime buf)))
349 (and revert-buffer-function
350 (or (and global-auto-revert-mode
351 global-auto-revert-non-file-buffers)
352 auto-revert-mode))))
353 (if auto-revert-verbose
354 (message "Reverting buffer `%s'." buf))
355 (revert-buffer t t t)))
356 ;; Remove dead buffer from `auto-revert-buffer-list'.
357 (setq auto-revert-buffer-list
358 (delq buf auto-revert-buffer-list))))
359 (setq bufs (cdr bufs)))
360 (setq auto-revert-remaining-buffers bufs)
361 ;; Check if we should cancel the timer.
362 (when (and (not global-auto-revert-mode)
363 (null auto-revert-buffer-list))
364 (cancel-timer auto-revert-timer)
365 (setq auto-revert-timer nil))))
368 ;; The end:
370 (unless (assq 'auto-revert-mode minor-mode-alist)
371 (push '(auto-revert-mode auto-revert-mode-text)
372 minor-mode-alist))
373 (unless (assq 'global-auto-revert-mode minor-mode-alist)
374 (push '(global-auto-revert-mode global-auto-revert-mode-text)
375 minor-mode-alist))
377 (provide 'autorevert)
379 (run-hooks 'auto-revert-load-hook)
381 ;; This makes it possible to set Global Auto-Revert Mode from
382 ;; Customize.
383 (if global-auto-revert-mode
384 (global-auto-revert-mode 1))
386 ;; autorevert.el ends here.