1 ;;; autorevert.el --- revert buffers when files on disk change
3 ;; Copyright (C) 1997-1999, 2001-2011 Free Software Foundation, Inc.
5 ;; Author: Anders Lindgren <andersl@andersl.com>
6 ;; Keywords: convenience
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 3 of the License, or
15 ;; (at your option) 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. If not, see <http://www.gnu.org/licenses/>.
29 ;; Whenever a file that Emacs is editing has been changed by another
30 ;; program the user normally has to execute the command `revert-buffer'
31 ;; to load the new content of the file into Emacs.
33 ;; This package contains two minor modes: Global Auto-Revert Mode and
34 ;; Auto-Revert Mode. Both modes automatically revert buffers
35 ;; whenever the corresponding files have been changed on disk and the
36 ;; buffer contains no unsaved changes.
38 ;; Auto-Revert Mode can be activated for individual buffers. Global
39 ;; Auto-Revert Mode applies to all file buffers. (If the user option
40 ;; `global-auto-revert-non-file-buffers' is non-nil, it also applies
41 ;; to some non-file buffers. This option is disabled by default.)
42 ;; Since checking a remote file is too slow, these modes do not check
43 ;; or revert remote files.
45 ;; Both modes operate by checking the time stamp of all files at
46 ;; intervals of `auto-revert-interval'. The default is every five
47 ;; seconds. The check is aborted whenever the user actually uses
48 ;; Emacs. You should never even notice that this package is active
49 ;; (except that your buffers will be reverted, of course).
51 ;; After reverting a file buffer, Auto Revert Mode normally puts point
52 ;; at the same position that a regular manual revert would. However,
53 ;; there is one exception to this rule. If point is at the end of the
54 ;; buffer before reverting, it stays at the end. Similarly if point
55 ;; is displayed at the end of a file buffer in any window, it will stay
56 ;; at the end of the buffer in that window, even if the window is not
57 ;; selected. This way, you can use Auto Revert Mode to `tail' a file.
58 ;; Just put point at the end of the buffer and it will stay there.
59 ;; These rules apply to file buffers. For non-file buffers, the
60 ;; behavior may be mode dependent.
62 ;; While you can use Auto Revert Mode to tail a file, this package
63 ;; contains a third minor mode, Auto Revert Tail Mode, which does so
64 ;; more efficiently, as long as you are sure that the file will only
65 ;; change by growing at the end. It only appends the new output,
66 ;; instead of reverting the entire buffer. It does so even if the
67 ;; buffer contains unsaved changes. (Because they will not be lost.)
68 ;; Auto Revert Tail Mode works also for remote files.
72 ;; Go to the appropriate buffer and press either of:
73 ;; M-x auto-revert-mode RET
74 ;; M-x auto-revert-tail-mode RET
76 ;; To activate Global Auto-Revert Mode, press:
77 ;; M-x global-auto-revert-mode RET
79 ;; To activate Global Auto-Revert Mode every time Emacs is started
80 ;; customise the option `global-auto-revert-mode' or the following
81 ;; line could be added to your ~/.emacs:
82 ;; (global-auto-revert-mode 1)
84 ;; The function `turn-on-auto-revert-mode' could be added to any major
85 ;; mode hook to activate Auto-Revert Mode for all buffers in that
86 ;; mode. For example, the following line will activate Auto-Revert
87 ;; Mode in all C mode buffers:
89 ;; (add-hook 'c-mode-hook 'turn-on-auto-revert-mode)
97 (eval-when-compile (require 'cl
))
102 ;; The two modes will be placed next to Auto Save Mode under the
103 ;; Files group under Emacs.
105 (defgroup auto-revert nil
106 "Revert individual buffers when files on disk change.
108 Auto-Revert Mode can be activated for individual buffer.
109 Global Auto-Revert Mode applies to all buffers."
116 ;;; What's this?: ;; Autoload for the benefit of `make-mode-line-mouse-sensitive'.
117 ;;; What's this?: ;;;###autoload
118 (defvar auto-revert-mode nil
119 "Non-nil when Auto-Revert Mode is active.
120 Never set this variable directly, use the command `auto-revert-mode' instead.")
121 (put 'auto-revert-mode
'permanent-local t
)
123 (defvar auto-revert-tail-mode nil
124 "Non-nil when Auto-Revert Tail Mode is active.
125 Never set this variable directly, use the command
126 `auto-revert-tail-mode' instead.")
127 (put 'auto-revert-tail-mode
'permanent-local t
)
129 (defvar auto-revert-timer nil
130 "Timer used by Auto-Revert Mode.")
132 (defcustom auto-revert-interval
5
133 "Time, in seconds, between Auto-Revert Mode file checks.
134 The value may be an integer or floating point number.
136 If a timer is already active, there are two ways to make sure
137 that the new value will take effect immediately. You can set
138 this variable through Custom or you can call the command
139 `auto-revert-set-timer' after setting the variable. Otherwise,
140 the new value will take effect the first time Auto Revert Mode
141 calls `auto-revert-set-timer' for internal reasons or in your
142 next editing session."
145 :set
(lambda (variable value
)
146 (set-default variable value
)
147 (and (boundp 'auto-revert-timer
)
149 (auto-revert-set-timer))))
151 (defcustom auto-revert-stop-on-user-input t
152 "When non-nil, user input temporarily interrupts Auto-Revert Mode.
153 With this setting, Auto-Revert Mode checks for user input after
154 handling each buffer and does not process any further buffers
155 \(until the next run of the timer) if user input is available.
156 When nil, Auto-Revert Mode checks files and reverts buffers,
157 with quitting disabled, without paying attention to user input.
158 Thus, with this setting, Emacs might be non-responsive at times."
162 (defcustom auto-revert-verbose t
163 "When nil, Auto-Revert Mode does not generate any messages.
164 When non-nil, a message is generated whenever a file is reverted."
168 (defcustom auto-revert-mode-text
" ARev"
169 "String to display in the mode line when Auto-Revert Mode is active.
171 \(When the string is not empty, make sure that it has a leading space.)"
172 :tag
"Auto Revert Mode Text" ; To separate it from `global-...'
176 (defcustom auto-revert-tail-mode-text
" Tail"
177 "String to display in the mode line when Auto-Revert Tail Mode is active.
179 \(When the string is not empty, make sure that it has a leading space.)"
184 (defcustom auto-revert-mode-hook nil
185 "Functions to run when Auto-Revert Mode is activated."
186 :tag
"Auto Revert Mode Hook" ; To separate it from `global-...'
190 (defcustom global-auto-revert-mode-text
""
191 "String to display when Global Auto-Revert Mode is active.
193 The default is nothing since when this mode is active this text doesn't
194 vary over time, or between buffers. Hence mode line text
195 would only waste precious space."
199 (defcustom global-auto-revert-mode-hook nil
200 "Hook called when Global Auto-Revert Mode is activated."
204 (defcustom global-auto-revert-non-file-buffers nil
205 "When nil, Global Auto-Revert mode operates only on file-visiting buffers.
207 When non-nil, both file buffers and buffers with a custom
208 `revert-buffer-function' and a `buffer-stale-function' are
209 reverted by Global Auto-Revert mode. These include the Buffer
210 List buffer displayed by `buffer-menu', and Dired buffers showing
211 complete local directories. The Buffer List buffer reverts every
212 `auto-revert-interval' seconds; Dired buffers when the file list of
213 the main directory changes. Dired buffers do not auto-revert as
214 a result of changes in subdirectories, or in the contents, size,
215 modes, etc., of files. You may still sometimes want to revert
218 Use this option with care since it could lead to excessive auto-reverts.
219 For more information, see Info node `(emacs)Autorevert'."
222 :link
'(info-link "(emacs)Autorevert"))
224 (defcustom global-auto-revert-ignore-modes
()
225 "List of major modes Global Auto-Revert Mode should not check."
227 :type
'(repeat sexp
))
229 (defcustom auto-revert-load-hook nil
230 "Functions to run when Auto-Revert Mode is first loaded."
235 (defcustom auto-revert-check-vc-info nil
236 "If non-nil Auto Revert Mode reliably updates version control info.
237 Auto Revert Mode updates version control info whenever the buffer
238 needs reverting, regardless of the value of this variable.
239 However, the version control state can change without changes to
240 the work file. If the change is made from the current Emacs
241 session, all info is updated. But if, for instance, a new
242 version is checked in from outside the current Emacs session, the
243 version control number in the mode line, as well as other version
244 control related information, may not be properly updated. If you
245 are worried about this, set this variable to a non-nil value.
247 This currently works by automatically updating the version
248 control info every `auto-revert-interval' seconds. Nevertheless,
249 it should not cause excessive CPU usage on a reasonably fast
250 machine, if it does not apply to too many version controlled
251 buffers. CPU usage depends on the version control system."
256 (defvar global-auto-revert-ignore-buffer nil
257 "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 (nth 7 (file-attributes buffer-file-name
)))))
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 if arg is positive, otherwise turn it off.
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 (zerop 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 ;; a-r-tail-pos stores the size of the file at the time of the
341 ;; last revert. After this package loads, it adds a
342 ;; find-file-hook to set this variable every time a file is
343 ;; loaded. If the package is loaded only _after_ visiting the
344 ;; file to be reverted, then we have no idea what the value of
345 ;; a-r-tail-pos should have been when the file was visited. If
346 ;; the file has changed on disk in the meantime, all we can do
347 ;; is offer to revert the whole thing. If you choose not to
348 ;; revert, then you might miss some output then happened
349 ;; between visiting the file and activating a-r-t-mode.
350 (and (zerop auto-revert-tail-pos
)
351 (not (verify-visited-file-modtime (current-buffer)))
352 (y-or-n-p "File changed on disk, content may be missing. \
353 Perform a full revert? ")
354 ;; Use this (not just revert-buffer) for point-preservation.
355 (auto-revert-handler))
356 ;; else we might reappend our own end when we save
357 (add-hook 'before-save-hook
(lambda () (auto-revert-tail-mode 0)) nil t
)
358 (or (local-variable-p 'auto-revert-tail-pos
) ; don't lose prior position
359 (set (make-local-variable 'auto-revert-tail-pos
)
360 (nth 7 (file-attributes buffer-file-name
))))
361 ;; let auto-revert-mode set up the mechanism for us if it isn't already
363 (let ((auto-revert-tail-mode t
))
364 (auto-revert-mode 1)))
365 (setq auto-revert-mode nil
))))
369 (defun turn-on-auto-revert-tail-mode ()
370 "Turn on Auto-Revert Tail Mode.
372 This function is designed to be added to hooks, for example:
373 (add-hook 'my-logfile-mode-hook 'turn-on-auto-revert-tail-mode)"
374 (auto-revert-tail-mode 1))
378 (define-minor-mode global-auto-revert-mode
379 "Toggle Global Auto Revert mode.
380 With optional prefix argument ARG, enable Global Auto Revert Mode
381 if ARG > 0, else disable it.
383 This is a global minor mode that reverts any buffer associated
384 with a file when the file changes on disk. Use `auto-revert-mode'
385 to revert a particular buffer.
387 If `global-auto-revert-non-file-buffers' is non-nil, this mode
388 may also revert some non-file buffers, as described in the
389 documentation of that variable. It ignores buffers with modes
390 matching `global-auto-revert-ignore-modes', and buffers with a
391 non-nil vale of `global-auto-revert-ignore-buffer'.
393 This function calls the hook `global-auto-revert-mode-hook'.
394 It displays the text that `global-auto-revert-mode-text'
395 specifies in the mode line."
396 :global t
:group
'auto-revert
:lighter global-auto-revert-mode-text
397 (auto-revert-set-timer)
398 (when global-auto-revert-mode
399 (auto-revert-buffers)))
402 (defun auto-revert-set-timer ()
403 "Restart or cancel the timer used by Auto-Revert Mode.
404 If such a timer is active, cancel it. Start a new timer if
405 Global Auto-Revert Mode is active or if Auto-Revert Mode is active
406 in some buffer. Restarting the timer ensures that Auto-Revert Mode
407 will use an up-to-date value of `auto-revert-interval'"
409 (if (timerp auto-revert-timer
)
410 (cancel-timer auto-revert-timer
))
411 (setq auto-revert-timer
412 (if (or global-auto-revert-mode auto-revert-buffer-list
)
413 (run-with-timer auto-revert-interval
415 'auto-revert-buffers
))))
417 (defun auto-revert-active-p ()
418 "Check if auto-revert is active (in current buffer or globally)."
420 auto-revert-tail-mode
422 global-auto-revert-mode
423 (not global-auto-revert-ignore-buffer
)
424 (not (memq major-mode
425 global-auto-revert-ignore-modes
)))))
427 (defun auto-revert-handler ()
428 "Revert current buffer, if appropriate.
429 This is an internal function used by Auto-Revert Mode."
430 (when (or auto-revert-tail-mode
(not (buffer-modified-p)))
431 (let* ((buffer (current-buffer)) size
433 (or (and buffer-file-name
434 (file-readable-p buffer-file-name
)
435 (if auto-revert-tail-mode
436 ;; Tramp caches the file attributes. Setting
437 ;; `tramp-cache-inhibit' forces Tramp to
438 ;; reread the values.
439 (let ((tramp-cache-inhibit-cache t
))
440 (/= auto-revert-tail-pos
442 (nth 7 (file-attributes
443 buffer-file-name
)))))
444 (and (not (file-remote-p buffer-file-name
))
445 (not (verify-visited-file-modtime buffer
)))))
446 (and (or auto-revert-mode
447 global-auto-revert-non-file-buffers
)
448 revert-buffer-function
449 (boundp 'buffer-stale-function
)
450 (functionp buffer-stale-function
)
451 (funcall buffer-stale-function t
))))
454 (when (and auto-revert-verbose
455 (not (eq revert
'fast
)))
456 (message "Reverting buffer `%s'." (buffer-name)))
457 ;; If point (or a window point) is at the end of the buffer,
458 ;; we want to keep it at the end after reverting. This allows
460 (when buffer-file-name
464 (and (eq (window-buffer window
) buffer
)
465 (= (window-point window
) (point-max))
466 (push window eoblist
)))
468 (if auto-revert-tail-mode
469 (auto-revert-tail-handler size
)
470 ;; Bind buffer-read-only in case user has done C-x C-q,
471 ;; so as not to forget that. This gives undesirable results
472 ;; when the file's mode changes, but that is less common.
473 (let ((buffer-read-only buffer-read-only
))
474 (revert-buffer 'ignore-auto
'dont-ask
'preserve-modes
)))
475 (when buffer-file-name
476 (when eob
(goto-char (point-max)))
477 (dolist (window eoblist
)
478 (set-window-point window
(point-max)))))
479 ;; `preserve-modes' avoids changing the (minor) modes. But we
480 ;; do want to reset the mode for VC, so we do it manually.
481 (when (or revert auto-revert-check-vc-info
)
482 (vc-find-file-hook)))))
484 (defun auto-revert-tail-handler (size)
485 (let ((modified (buffer-modified-p))
486 (inhibit-read-only t
) ; Ignore.
487 (file buffer-file-name
)
488 (buffer-file-name nil
)) ; Ignore that file has changed.
489 (when (/= auto-revert-tail-pos size
)
490 (run-hooks 'before-revert-hook
)
495 (goto-char (point-max))
496 (insert-file-contents file nil
497 (and (< auto-revert-tail-pos size
)
498 auto-revert-tail-pos
)
500 (run-hooks 'after-revert-hook
)
502 (setq auto-revert-tail-pos size
)
503 (restore-buffer-modified-p modified
)))
504 (set-visited-file-modtime))
506 (defun auto-revert-buffers ()
507 "Revert buffers as specified by Auto-Revert and Global Auto-Revert Mode.
509 Should `global-auto-revert-mode' be active all file buffers are checked.
511 Should `auto-revert-mode' be active in some buffers, those buffers
514 Non-file buffers that have a custom `revert-buffer-function' and
515 a `buffer-stale-function' are reverted either when Auto-Revert
516 Mode is active in that buffer, or when the variable
517 `global-auto-revert-non-file-buffers' is non-nil and Global
518 Auto-Revert Mode is active.
520 This function stops whenever there is user input. The buffers not
521 checked are stored in the variable `auto-revert-remaining-buffers'.
523 To avoid starvation, the buffers in `auto-revert-remaining-buffers'
524 are checked first the next time this function is called.
526 This function is also responsible for removing buffers no longer in
527 Auto-Revert mode from `auto-revert-buffer-list', and for canceling
528 the timer when no buffers need to be checked."
530 (let ((bufs (if global-auto-revert-mode
532 auto-revert-buffer-list
))
535 ;; Partition `bufs' into two halves depending on whether or not
536 ;; the buffers are in `auto-revert-remaining-buffers'. The two
537 ;; halves are then re-joined with the "remaining" buffers at the
539 (dolist (buf auto-revert-remaining-buffers
)
541 (push buf remaining
)))
543 (if (not (memq buf remaining
))
545 (setq bufs
(nreverse (nconc new remaining
)))
547 (not (and auto-revert-stop-on-user-input
549 (let ((buf (car bufs
)))
550 (if (buffer-live-p buf
)
551 (with-current-buffer buf
552 ;; Test if someone has turned off Auto-Revert Mode in a
553 ;; non-standard way, for example by changing major mode.
554 (if (and (not auto-revert-mode
)
555 (not auto-revert-tail-mode
)
556 (memq buf auto-revert-buffer-list
))
557 (setq auto-revert-buffer-list
558 (delq buf auto-revert-buffer-list
)))
559 (when (auto-revert-active-p) (auto-revert-handler)))
560 ;; Remove dead buffer from `auto-revert-buffer-list'.
561 (setq auto-revert-buffer-list
562 (delq buf auto-revert-buffer-list
))))
563 (setq bufs
(cdr bufs
)))
564 (setq auto-revert-remaining-buffers bufs
)
565 ;; Check if we should cancel the timer.
566 (when (and (not global-auto-revert-mode
)
567 (null auto-revert-buffer-list
))
568 (cancel-timer auto-revert-timer
)
569 (setq auto-revert-timer nil
)))))
573 (provide 'autorevert
)
575 (run-hooks 'auto-revert-load-hook
)
577 ;;; autorevert.el ends here