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[bpt/emacs.git] / lisp / autorevert.el
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e8af40ee 1;;; autorevert.el --- revert buffers when files on disk change
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bf2150fa 3;; Copyright (C) 1997, 1998, 1999, 2001 Free Software Foundation, Inc.
4a35aff3 4
a468671a 5;; Author: Anders Lindgren <andersl@andersl.com>
f5f727f8 6;; Keywords: convenience
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7;; Created: 1997-06-01
8;; Date: 1999-11-30
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9
10;; This file is part of GNU Emacs.
11
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.
16
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.
21
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.
26
27;;; Commentary:
28
29;; Introduction:
30;;
31;; Whenever a file that Emacs is editing has been changed by another
48764ae2 32;; program the user normally has to execute the command `revert-buffer'
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33;; to load the new content of the file into Emacs.
34;;
35;; This package contains two minor modes: Global Auto-Revert Mode and
48764ae2 36;; Auto-Revert Mode. Both modes automatically revert buffers
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37;; whenever the corresponding files have been changed on disk.
38;;
39;; Auto-Revert Mode can be activated for individual buffers.
40;; Global Auto-Revert Mode applies to all file buffers.
41;;
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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).
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47
48;; Usage:
49;;
50;; Go to the appropriate buffer and press:
51;; M-x auto-revert-mode RET
52;;
53;; To activate Global Auto-Revert Mode, press:
54;; M-x global-auto-revert-mode RET
55;;
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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:
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59;; (global-auto-revert-mode 1)
60;;
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:
65;;
66;; (add-hook 'c-mode-hook 'turn-on-auto-revert-mode)
67
68;;; Code:
69
70;; Dependencies:
71
72(require 'timer)
73(eval-when-compile (require 'cl))
74
75
76;; Custom Group:
77;;
78;; The two modes will be placed next to Auto Save Mode under the
79;; Files group under Emacs.
80
81(defgroup auto-revert nil
48764ae2 82 "Revert individual buffers when files on disk change.
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83
84Auto-Revert Mode can be activated for individual buffer.
85Global Auto-Revert Mode applies to all buffers."
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86 :group 'files
87 :group 'convenience)
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88
89
90;; Variables:
91
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92;; Autoload for the benefit of `make-mode-line-mouse-sensitive'.
93;;;###autoload
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94(defvar auto-revert-mode nil
95 "*Non-nil when Auto-Revert Mode is active.
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96Never set this variable directly, use the command `auto-revert-mode' instead.")
97(put 'auto-revert-mode 'permanent-local t)
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98
99(defcustom auto-revert-interval 5
100 "Time, in seconds, between Auto-Revert Mode file checks."
101 :group 'auto-revert
102 :type 'integer)
103
104(defcustom auto-revert-stop-on-user-input t
105 "When non-nil Auto-Revert Mode stops checking files on user input."
106 :group 'auto-revert
107 :type 'boolean)
108
109(defcustom auto-revert-verbose t
110 "When nil, Auto-Revert Mode will not generate any messages.
111
112Currently, messages are generated when the mode is activated or
113deactivated, and whenever a file is reverted."
114 :group 'auto-revert
115 :type 'boolean)
116
117(defcustom auto-revert-mode-text " ARev"
118 "String to display in the mode line when Auto-Revert Mode is active.
119
120\(When the string is not empty, make sure that it has a leading space.)"
121 :tag "Auto Revert Mode Text" ; To separate it from `global-...'
122 :group 'auto-revert
123 :type 'string)
124
125(defcustom auto-revert-mode-hook nil
126 "Functions to run when Auto-Revert Mode is activated."
127 :tag "Auto Revert Mode Hook" ; To separate it from `global-...'
128 :group 'auto-revert
129 :type 'hook)
130
131(defcustom global-auto-revert-mode-text ""
132 "String to display when Global Auto-Revert Mode is active.
133
134The default is nothing since when this mode is active this text doesn't
48764ae2 135vary over time, or between buffers. Hence mode line text
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136would only waste precious space."
137 :group 'auto-revert
138 :type 'string)
139
140(defcustom global-auto-revert-mode-hook nil
141 "Hook called when Global Auto-Revert Mode is activated."
142 :group 'auto-revert
143 :type 'hook)
144
145(defcustom global-auto-revert-non-file-buffers nil
0e4f9468 146 "When nil only file buffers are reverted by Global Auto-Revert Mode.
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147
148When non-nil, both file buffers and buffers with a custom
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149`revert-buffer-function' are reverted by Global Auto-Revert Mode.
150
151Use this option with care since it could lead to excessive reverts."
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152 :group 'auto-revert
153 :type 'boolean)
154
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155(defcustom global-auto-revert-ignore-modes '()
156 "List of major modes Global Auto-Revert Mode should not check."
157 :group 'auto-revert
158 :type '(repeat sexp))
159
160(defcustom auto-revert-load-hook nil
161 "Functions to run when Auto-Revert Mode is first loaded."
162 :tag "Load Hook"
163 :group 'auto-revert
164 :type 'hook)
165
166(defvar global-auto-revert-ignore-buffer nil
f1e3ff80 167 "*When non-nil, Global Auto-Revert Mode will not revert this buffer.
4a35aff3 168
48764ae2 169This variable becomes buffer local when set in any fashion.")
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170(make-variable-buffer-local 'global-auto-revert-ignore-buffer)
171
172
173;; Internal variables:
174
175(defvar auto-revert-buffer-list '()
176 "List of buffers in Auto-Revert Mode.
177
178Note that only Auto-Revert Mode, never Global Auto-Revert Mode, adds
179buffers to this list.
180
181The timer function `auto-revert-buffers' is responsible for purging
182the list of old buffers.")
183
184(defvar auto-revert-timer nil
185 "Timer used by Auto-Revert Mode.")
186
187(defvar auto-revert-remaining-buffers '()
188 "Buffers not checked when user input stopped execution.")
189
190
191;; Functions:
192
193;;;###autoload
0e4f9468 194(define-minor-mode auto-revert-mode
48764ae2 195 "Toggle reverting buffer when file on disk changes.
4a35aff3 196
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197With arg, turn Auto Revert mode on if and only if arg is positive.
198This is a minor mode that affects only the current buffer.
4a35aff3 199Use `global-auto-revert-mode' to automatically revert all buffers."
0e4f9468 200 nil auto-revert-mode-text nil
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201 (if auto-revert-mode
202 (if (not (memq (current-buffer) auto-revert-buffer-list))
203 (push (current-buffer) auto-revert-buffer-list))
204 (setq auto-revert-buffer-list
205 (delq (current-buffer) auto-revert-buffer-list)))
206 (auto-revert-set-timer)
207 (when auto-revert-mode
0e4f9468 208 (auto-revert-buffers)))
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209
210
211;;;###autoload
212(defun turn-on-auto-revert-mode ()
213 "Turn on Auto-Revert Mode.
214
215This function is designed to be added to hooks, for example:
216 (add-hook 'c-mode-hook 'turn-on-auto-revert-mode)"
217 (auto-revert-mode 1))
218
219
220;;;###autoload
0e4f9468 221(define-minor-mode global-auto-revert-mode
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222 "Revert any buffer when file on disk change.
223
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224With arg, turn Auto Revert mode on globally if and only if arg is positive.
225This is a minor mode that affects all buffers.
4a35aff3 226Use `auto-revert-mode' to revert a particular buffer."
0e4f9468 227 :global t :group 'auto-revert :lighter global-auto-revert-mode-text
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228 (auto-revert-set-timer)
229 (when global-auto-revert-mode
0e4f9468 230 (auto-revert-buffers)))
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231
232
233(defun auto-revert-set-timer ()
234 "Restart or cancel the timer."
235 (if (timerp auto-revert-timer)
236 (cancel-timer auto-revert-timer))
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237 (setq auto-revert-timer
238 (if (or global-auto-revert-mode auto-revert-buffer-list)
239 (run-with-timer auto-revert-interval
240 auto-revert-interval
241 'auto-revert-buffers)
242 nil)))
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243
244(defun auto-revert-buffers ()
245 "Revert buffers as specified by Auto-Revert and Global Auto-Revert Mode.
246
247Should `global-auto-revert-mode' be active all file buffers are checked.
248
249Should `auto-revert-mode' be active in some buffers, those buffers
250are checked.
251
252Non-file buffers that have a custom `revert-buffer-function' are
253reverted either when Auto-Revert Mode is active in that buffer, or
254when the variable `global-auto-revert-non-file-buffers' is non-nil
255and Global Auto-Revert Mode is active.
256
48764ae2 257This function stops whenever there is user input. The buffers not
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258checked are stored in the variable `auto-revert-remaining-buffers'.
259
260To avoid starvation, the buffers in `auto-revert-remaining-buffers'
261are checked first the next time this function is called.
262
48764ae2 263This function is also responsible for removing buffers no longer in
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264Auto-Revert mode from `auto-revert-buffer-list', and for canceling
265the timer when no buffers need to be checked."
266 (let ((bufs (if global-auto-revert-mode
267 (buffer-list)
268 auto-revert-buffer-list))
269 (remaining '())
270 (new '()))
271 ;; Partition `bufs' into two halves depending on whether or not
272 ;; the buffers are in `auto-revert-remaining-buffers'. The two
273 ;; halves are then re-joined with the "remaining" buffers at the
274 ;; head of the list.
275 (dolist (buf auto-revert-remaining-buffers)
276 (if (memq buf bufs)
277 (push buf remaining)))
278 (dolist (buf bufs)
279 (if (not (memq buf remaining))
280 (push buf new)))
281 (setq bufs (nreverse (nconc new remaining)))
282 (while (and bufs
283 (not (and auto-revert-stop-on-user-input
284 (input-pending-p))))
285 (let ((buf (car bufs)))
286 (if (buffer-name buf) ; Buffer still alive?
0e4f9468 287 (with-current-buffer buf
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288 ;; Test if someone has turned off Auto-Revert Mode in a
289 ;; non-standard way, for example by changing major mode.
290 (if (and (not auto-revert-mode)
291 (memq buf auto-revert-buffer-list))
292 (setq auto-revert-buffer-list
293 (delq buf auto-revert-buffer-list)))
294 (when (and
295 (or auto-revert-mode
296 (and
297 global-auto-revert-mode
298 (not global-auto-revert-ignore-buffer)
299 (not (memq major-mode
300 global-auto-revert-ignore-modes))))
301 (not (buffer-modified-p))
302 (if (buffer-file-name)
303 (and (file-readable-p (buffer-file-name))
304 (not (verify-visited-file-modtime buf)))
305 (and revert-buffer-function
306 (or (and global-auto-revert-mode
307 global-auto-revert-non-file-buffers)
308 auto-revert-mode))))
309 (if auto-revert-verbose
310 (message "Reverting buffer `%s'." buf))
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311 (revert-buffer 'ignore-auto 'dont-ask 'preserve-modes)
312 ;; `preserve-modes' avoids changing the (minor) modes. But we
313 ;; do want to reset the mode for VC, so we do it explicitly.
314 (vc-find-file-hook)))
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315 ;; Remove dead buffer from `auto-revert-buffer-list'.
316 (setq auto-revert-buffer-list
317 (delq buf auto-revert-buffer-list))))
318 (setq bufs (cdr bufs)))
319 (setq auto-revert-remaining-buffers bufs)
320 ;; Check if we should cancel the timer.
321 (when (and (not global-auto-revert-mode)
322 (null auto-revert-buffer-list))
323 (cancel-timer auto-revert-timer)
324 (setq auto-revert-timer nil))))
325
326
327;; The end:
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328(provide 'autorevert)
329
330(run-hooks 'auto-revert-load-hook)
331
ab5796a9 332;;; arch-tag: f6bcb07b-4841-477e-9e44-b18678e58876
e8af40ee 333;;; autorevert.el ends here