1 ;;; autorevert.el --- revert buffers when files on disk change
3 ;; Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003, 2004,
4 ;; 2005, 2006, 2007 Free Software Foundation, Inc.
6 ;; Author: Anders Lindgren <andersl@andersl.com>
7 ;; Keywords: convenience
11 ;; This file is part of GNU Emacs.
13 ;; GNU Emacs is free software; you can redistribute it and/or modify
14 ;; it under the terms of the GNU General Public License as published by
15 ;; the Free Software Foundation; either version 2, or (at your option)
18 ;; GNU Emacs is distributed in the hope that it will be useful,
19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 ;; GNU General Public License for more details.
23 ;; You should have received a copy of the GNU General Public License
24 ;; along with GNU Emacs; see the file COPYING. If not, write to the
25 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
26 ;; Boston, MA 02110-1301, USA.
32 ;; Whenever a file that Emacs is editing has been changed by another
33 ;; program the user normally has to execute the command `revert-buffer'
34 ;; to load the new content of the file into Emacs.
36 ;; This package contains two minor modes: Global Auto-Revert Mode and
37 ;; Auto-Revert Mode. Both modes automatically revert buffers
38 ;; whenever the corresponding files have been changed on disk and the
39 ;; buffer contains no unsaved changes.
41 ;; Auto-Revert Mode can be activated for individual buffers. Global
42 ;; Auto-Revert Mode applies to all file buffers. (If the user option
43 ;; `global-auto-revert-non-file-buffers' is non-nil, it also applies
44 ;; to some non-file buffers. This option is disabled by default.)
45 ;; Since checking a remote file is too slow, these modes do not check
46 ;; or revert remote files.
48 ;; Both modes operate by checking the time stamp of all files at
49 ;; intervals of `auto-revert-interval'. The default is every five
50 ;; seconds. The check is aborted whenever the user actually uses
51 ;; Emacs. You should never even notice that this package is active
52 ;; (except that your buffers will be reverted, of course).
54 ;; After reverting a file buffer, Auto Revert Mode normally puts point
55 ;; at the same position that a regular manual revert would. However,
56 ;; there is one exception to this rule. If point is at the end of the
57 ;; buffer before reverting, it stays at the end. Similarly if point
58 ;; is displayed at the end of a file buffer in any window, it will stay
59 ;; at the end of the buffer in that window, even if the window is not
60 ;; selected. This way, you can use Auto Revert Mode to `tail' a file.
61 ;; Just put point at the end of the buffer and it will stay there.
62 ;; These rules apply to file buffers. For non-file buffers, the
63 ;; behavior may be mode dependent.
65 ;; While you can use Auto Revert Mode to tail a file, this package
66 ;; contains a third minor mode, Auto Revert Tail Mode, which does so
67 ;; more efficiently, as long as you are sure that the file will only
68 ;; change by growing at the end. It only appends the new output,
69 ;; instead of reverting the entire buffer. It does so even if the
70 ;; buffer contains unsaved changes. (Because they will not be lost.)
74 ;; Go to the appropriate buffer and press either of:
75 ;; M-x auto-revert-mode RET
76 ;; M-x auto-revert-tail-mode RET
78 ;; To activate Global Auto-Revert Mode, press:
79 ;; M-x global-auto-revert-mode RET
81 ;; To activate Global Auto-Revert Mode every time Emacs is started
82 ;; customise the option `global-auto-revert-mode' or the following
83 ;; line could be added to your ~/.emacs:
84 ;; (global-auto-revert-mode 1)
86 ;; The function `turn-on-auto-revert-mode' could be added to any major
87 ;; mode hook to activate Auto-Revert Mode for all buffers in that
88 ;; mode. For example, the following line will activate Auto-Revert
89 ;; Mode in all C mode buffers:
91 ;; (add-hook 'c-mode-hook 'turn-on-auto-revert-mode)
99 (eval-when-compile (require 'cl
))
104 ;; The two modes will be placed next to Auto Save Mode under the
105 ;; Files group under Emacs.
107 (defgroup auto-revert nil
108 "Revert individual buffers when files on disk change.
110 Auto-Revert Mode can be activated for individual buffer.
111 Global Auto-Revert Mode applies to all buffers."
118 ;;; What's this?: ;; Autoload for the benefit of `make-mode-line-mouse-sensitive'.
119 ;;; What's this?: ;;;###autoload
120 (defvar auto-revert-mode nil
121 "*Non-nil when Auto-Revert Mode is active.
122 Never set this variable directly, use the command `auto-revert-mode' instead.")
123 (put 'auto-revert-mode
'permanent-local t
)
125 (defvar auto-revert-tail-mode nil
126 "*Non-nil when Auto-Revert Tail Mode is active.
127 Never set this variable directly, use the command
128 `auto-revert-tail-mode' instead.")
129 (put 'auto-revert-tail-mode
'permanent-local t
)
131 (defvar auto-revert-timer nil
132 "Timer used by Auto-Revert Mode.")
134 (defcustom auto-revert-interval
5
135 "Time, in seconds, between Auto-Revert Mode file checks.
136 The value may be an integer or floating point number.
138 If a timer is already active, there are two ways to make sure
139 that the new value will take effect immediately. You can set
140 this variable through Custom or you can call the command
141 `auto-revert-set-timer' after setting the variable. Otherwise,
142 the new value will take effect the first time Auto Revert Mode
143 calls `auto-revert-set-timer' for internal reasons or in your
144 next editing session."
147 :set
(lambda (variable value
)
148 (set-default variable value
)
149 (and (boundp 'auto-revert-timer
)
151 (auto-revert-set-timer))))
153 (defcustom auto-revert-stop-on-user-input t
154 "When non-nil, user input temporarily interrupts Auto-Revert Mode.
155 With this setting, Auto-Revert Mode checks for user input after
156 handling each buffer and does not process any further buffers
157 \(until the next run of the timer) if user input is available.
158 When nil, Auto-Revert Mode checks files and reverts buffers,
159 with quitting disabled, without paying attention to user input.
160 Thus, with this setting, Emacs might be non-responsive at times."
164 (defcustom auto-revert-verbose t
165 "When nil, Auto-Revert Mode does not generate any messages.
166 When non-nil, a message is generated whenever a file is reverted."
170 (defcustom auto-revert-mode-text
" ARev"
171 "String to display in the mode line when Auto-Revert Mode is active.
173 \(When the string is not empty, make sure that it has a leading space.)"
174 :tag
"Auto Revert Mode Text" ; To separate it from `global-...'
178 (defcustom auto-revert-tail-mode-text
" Tail"
179 "String to display in the mode line when Auto-Revert Tail Mode is active.
181 \(When the string is not empty, make sure that it has a leading space.)"
186 (defcustom auto-revert-mode-hook nil
187 "Functions to run when Auto-Revert Mode is activated."
188 :tag
"Auto Revert Mode Hook" ; To separate it from `global-...'
192 (defcustom global-auto-revert-mode-text
""
193 "String to display when Global Auto-Revert Mode is active.
195 The default is nothing since when this mode is active this text doesn't
196 vary over time, or between buffers. Hence mode line text
197 would only waste precious space."
201 (defcustom global-auto-revert-mode-hook nil
202 "Hook called when Global Auto-Revert Mode is activated."
206 (defcustom global-auto-revert-non-file-buffers nil
207 "When nil, Global Auto-Revert mode operates only on file-visiting buffers.
209 When non-nil, both file buffers and buffers with a custom
210 `revert-buffer-function' and a `buffer-stale-function' are
211 reverted by Global Auto-Revert mode. These include the Buffer
212 List buffer, and Dired buffers showing complete local
213 directories. Dired buffers do not auto-revert as a result of
214 changes in subdirectories or in the contents, size, modes, etc.,
215 of files. You may still sometimes want to revert them manually.
217 Use this option with care since it could lead to excessive auto-reverts.
218 For more information, see Info node `(emacs)Autorevert'."
221 :link
'(info-link "(emacs)Autorevert"))
223 (defcustom global-auto-revert-ignore-modes
()
224 "List of major modes Global Auto-Revert Mode should not check."
226 :type
'(repeat sexp
))
228 (defcustom auto-revert-load-hook nil
229 "Functions to run when Auto-Revert Mode is first loaded."
234 (defcustom auto-revert-check-vc-info nil
235 "If non-nil Auto Revert Mode reliably updates version control info.
236 Auto Revert Mode updates version control info whenever the buffer
237 needs reverting, regardless of the value of this variable.
238 However, the version control state can change without changes to
239 the work file. If the change is made from the current Emacs
240 session, all info is updated. But if, for instance, a new
241 version is checked in from outside the current Emacs session, the
242 version control number in the mode line, as well as other version
243 control related information, may not be properly updated. If you
244 are worried about this, set this variable to a non-nil value.
246 This currently works by automatically updating the version
247 control info every `auto-revert-interval' seconds. Nevertheless,
248 it should not cause excessive CPU usage on a reasonably fast
249 machine, if it does not apply to too many version controlled
250 buffers. CPU usage depends on the version control system."
255 (defvar global-auto-revert-ignore-buffer nil
256 "*When non-nil, Global Auto-Revert Mode will not revert this buffer.
258 This variable becomes buffer local when set in any fashion.")
259 (make-variable-buffer-local 'global-auto-revert-ignore-buffer
)
261 ;; Internal variables:
263 (defvar auto-revert-buffer-list
()
264 "List of buffers in Auto-Revert Mode.
266 Note that only Auto-Revert Mode, never Global Auto-Revert Mode, adds
267 buffers to this list.
269 The timer function `auto-revert-buffers' is responsible for purging
270 the list of old buffers.")
272 (defvar auto-revert-remaining-buffers
()
273 "Buffers not checked when user input stopped execution.")
275 (defvar auto-revert-tail-pos
0
276 "Position of last known end of file.")
278 (add-hook 'find-file-hook
280 (set (make-local-variable 'auto-revert-tail-pos
)
281 (save-restriction (widen) (1- (point-max))))))
286 (define-minor-mode auto-revert-mode
287 "Toggle reverting buffer when file on disk changes.
289 With arg, turn Auto Revert mode on if and only if arg is positive.
290 This is a minor mode that affects only the current buffer.
291 Use `global-auto-revert-mode' to automatically revert all buffers.
292 Use `auto-revert-tail-mode' if you know that the file will only grow
293 without being changed in the part that is already in the buffer."
294 :group
'auto-revert
:lighter auto-revert-mode-text
296 (if (not (memq (current-buffer) auto-revert-buffer-list
))
297 (push (current-buffer) auto-revert-buffer-list
))
298 (setq auto-revert-buffer-list
299 (delq (current-buffer) auto-revert-buffer-list
)))
300 (auto-revert-set-timer)
301 (when auto-revert-mode
302 (auto-revert-buffers)
303 (setq auto-revert-tail-mode nil
)))
307 (defun turn-on-auto-revert-mode ()
308 "Turn on Auto-Revert Mode.
310 This function is designed to be added to hooks, for example:
311 (add-hook 'c-mode-hook 'turn-on-auto-revert-mode)"
312 (auto-revert-mode 1))
316 (define-minor-mode auto-revert-tail-mode
317 "Toggle reverting tail of buffer when file on disk grows.
318 With arg, turn Tail mode on iff arg is positive.
320 When Tail mode is enabled, the tail of the file is constantly
321 followed, as with the shell command `tail -f'. This means that
322 whenever the file grows on disk (presumably because some
323 background process is appending to it from time to time), this is
324 reflected in the current buffer.
326 You can edit the buffer and turn this mode off and on again as
327 you please. But make sure the background process has stopped
328 writing before you save the file!
330 Use `auto-revert-mode' for changes other than appends!"
331 :group
'find-file
:lighter auto-revert-tail-mode-text
332 (when auto-revert-tail-mode
333 (unless buffer-file-name
334 (auto-revert-tail-mode 0)
335 (error "This buffer is not visiting a file"))
336 (if (and (buffer-modified-p)
337 (not auto-revert-tail-pos
) ; library was loaded only after finding file
338 (not (y-or-n-p "Buffer is modified, so tail offset may be wrong. Proceed? ")))
339 (auto-revert-tail-mode 0)
340 ;; else we might reappend our own end when we save
341 (add-hook 'before-save-hook
(lambda () (auto-revert-tail-mode 0)) nil t
)
342 (or (local-variable-p 'auto-revert-tail-pos
) ; don't lose prior position
343 (set (make-local-variable 'auto-revert-tail-pos
)
344 (save-restriction (widen) (1- (point-max)))))
345 ;; let auto-revert-mode set up the mechanism for us if it isn't already
347 (let ((auto-revert-tail-mode t
))
348 (auto-revert-mode 1)))
349 (setq auto-revert-mode nil
))))
353 (defun turn-on-auto-revert-tail-mode ()
354 "Turn on Auto-Revert Tail Mode.
356 This function is designed to be added to hooks, for example:
357 (add-hook 'my-logfile-mode-hook 'turn-on-auto-revert-tail-mode)"
358 (auto-revert-tail-mode 1))
362 (define-minor-mode global-auto-revert-mode
363 "Revert any buffer when file on disk changes.
365 With arg, turn Auto Revert mode on globally if and only if arg is positive.
366 This is a minor mode that affects all buffers.
367 Use `auto-revert-mode' to revert a particular buffer."
368 :global t
:group
'auto-revert
:lighter global-auto-revert-mode-text
369 (auto-revert-set-timer)
370 (when global-auto-revert-mode
371 (auto-revert-buffers)))
374 (defun auto-revert-set-timer ()
375 "Restart or cancel the timer used by Auto-Revert Mode.
376 If such a timer is active, cancel it. Start a new timer if
377 Global Auto-Revert Mode is active or if Auto-Revert Mode is active
378 in some buffer. Restarting the timer ensures that Auto-Revert Mode
379 will use an up-to-date value of `auto-revert-interval'"
381 (if (timerp auto-revert-timer
)
382 (cancel-timer auto-revert-timer
))
383 (setq auto-revert-timer
384 (if (or global-auto-revert-mode auto-revert-buffer-list
)
385 (run-with-timer auto-revert-interval
387 'auto-revert-buffers
))))
389 (defun auto-revert-active-p ()
390 "Check if auto-revert is active (in current buffer or globally)."
392 auto-revert-tail-mode
394 global-auto-revert-mode
395 (not global-auto-revert-ignore-buffer
)
396 (not (memq major-mode
397 global-auto-revert-ignore-modes
)))))
399 (defun auto-revert-handler ()
400 "Revert current buffer, if appropriate.
401 This is an internal function used by Auto-Revert Mode."
402 (when (or auto-revert-tail-mode
(not (buffer-modified-p)))
403 (let* ((buffer (current-buffer))
405 (or (and buffer-file-name
406 (not (file-remote-p buffer-file-name
))
407 (file-readable-p buffer-file-name
)
408 (not (verify-visited-file-modtime buffer
)))
409 (and (or auto-revert-mode
410 global-auto-revert-non-file-buffers
)
411 revert-buffer-function
412 (boundp 'buffer-stale-function
)
413 (functionp buffer-stale-function
)
414 (funcall buffer-stale-function t
))))
417 (when (and auto-revert-verbose
418 (not (eq revert
'fast
)))
419 (message "Reverting buffer `%s'." (buffer-name)))
420 ;; If point (or a window point) is at the end of the buffer,
421 ;; we want to keep it at the end after reverting. This allows
423 (when buffer-file-name
427 (and (eq (window-buffer window
) buffer
)
428 (= (window-point window
) (point-max))
429 (push window eoblist
)))
431 (if auto-revert-tail-mode
432 (auto-revert-tail-handler)
433 ;; Bind buffer-read-only in case user has done C-x C-q,
434 ;; so as not to forget that. This gives undesirable results
435 ;; when the file's mode changes, but that is less common.
436 (let ((buffer-read-only buffer-read-only
))
437 (revert-buffer 'ignore-auto
'dont-ask
'preserve-modes
)))
438 (when buffer-file-name
439 (when eob
(goto-char (point-max)))
440 (dolist (window eoblist
)
441 (set-window-point window
(point-max)))))
442 ;; `preserve-modes' avoids changing the (minor) modes. But we
443 ;; do want to reset the mode for VC, so we do it manually.
444 (when (or revert auto-revert-check-vc-info
)
445 (vc-find-file-hook)))))
447 (defun auto-revert-tail-handler ()
448 (let ((size (nth 7 (file-attributes buffer-file-name
)))
449 (modified (buffer-modified-p))
450 buffer-read-only
; ignore
451 (file buffer-file-name
)
452 buffer-file-name
) ; ignore that file has changed
453 (when (> size auto-revert-tail-pos
)
458 (goto-char (point-max))
459 (insert-file-contents file nil auto-revert-tail-pos size
)))
460 (run-mode-hooks 'after-revert-hook
)
462 (setq auto-revert-tail-pos size
)
463 (set-buffer-modified-p modified
)))
464 (set-visited-file-modtime))
466 (defun auto-revert-buffers ()
467 "Revert buffers as specified by Auto-Revert and Global Auto-Revert Mode.
469 Should `global-auto-revert-mode' be active all file buffers are checked.
471 Should `auto-revert-mode' be active in some buffers, those buffers
474 Non-file buffers that have a custom `revert-buffer-function' and
475 a `buffer-stale-function' are reverted either when Auto-Revert
476 Mode is active in that buffer, or when the variable
477 `global-auto-revert-non-file-buffers' is non-nil and Global
478 Auto-Revert Mode is active.
480 This function stops whenever there is user input. The buffers not
481 checked are stored in the variable `auto-revert-remaining-buffers'.
483 To avoid starvation, the buffers in `auto-revert-remaining-buffers'
484 are checked first the next time this function is called.
486 This function is also responsible for removing buffers no longer in
487 Auto-Revert mode from `auto-revert-buffer-list', and for canceling
488 the timer when no buffers need to be checked."
490 (let ((bufs (if global-auto-revert-mode
492 auto-revert-buffer-list
))
495 ;; Partition `bufs' into two halves depending on whether or not
496 ;; the buffers are in `auto-revert-remaining-buffers'. The two
497 ;; halves are then re-joined with the "remaining" buffers at the
499 (dolist (buf auto-revert-remaining-buffers
)
501 (push buf remaining
)))
503 (if (not (memq buf remaining
))
505 (setq bufs
(nreverse (nconc new remaining
)))
507 (not (and auto-revert-stop-on-user-input
509 (let ((buf (car bufs
)))
510 (if (buffer-name buf
) ; Buffer still alive?
511 (with-current-buffer buf
512 ;; Test if someone has turned off Auto-Revert Mode in a
513 ;; non-standard way, for example by changing major mode.
514 (if (and (not auto-revert-mode
)
515 (not auto-revert-tail-mode
)
516 (memq buf auto-revert-buffer-list
))
517 (setq auto-revert-buffer-list
518 (delq buf auto-revert-buffer-list
)))
519 (when (auto-revert-active-p) (auto-revert-handler)))
520 ;; Remove dead buffer from `auto-revert-buffer-list'.
521 (setq auto-revert-buffer-list
522 (delq buf auto-revert-buffer-list
))))
523 (setq bufs
(cdr bufs
)))
524 (setq auto-revert-remaining-buffers bufs
)
525 ;; Check if we should cancel the timer.
526 (when (and (not global-auto-revert-mode
)
527 (null auto-revert-buffer-list
))
528 (cancel-timer auto-revert-timer
)
529 (setq auto-revert-timer nil
)))))
533 (provide 'autorevert
)
535 (run-hooks 'auto-revert-load-hook
)
537 ;;; arch-tag: f6bcb07b-4841-477e-9e44-b18678e58876
538 ;;; autorevert.el ends here