1;;; autorevert.el --- revert buffers when files on disk change 2 3;; Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003, 2004, 4;; 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Author: Anders Lindgren <andersl@andersl.com> 7;; Keywords: convenience 8;; Created: 1997-06-01 9;; Date: 1999-11-30 10 11;; This file is part of GNU Emacs. 12 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) 16;; any later version. 17 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. 22 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. 27 28;;; Commentary: 29 30;; Introduction: 31;; 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. 35;; 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. 40;; 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. 47;; 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). 53;; 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. 64;; 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.) 71 72;; Usage: 73;; 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 77;; 78;; To activate Global Auto-Revert Mode, press: 79;; M-x global-auto-revert-mode RET 80;; 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) 85;; 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: 90;; 91;; (add-hook 'c-mode-hook 'turn-on-auto-revert-mode) 92 93;;; Code: 94 95;; Dependencies: 96 97(require 'timer) 98 99(eval-when-compile (require 'cl)) 100 101 102;; Custom Group: 103;; 104;; The two modes will be placed next to Auto Save Mode under the 105;; Files group under Emacs. 106 107(defgroup auto-revert nil 108 "Revert individual buffers when files on disk change. 109 110Auto-Revert Mode can be activated for individual buffer. 111Global Auto-Revert Mode applies to all buffers." 112 :group 'files 113 :group 'convenience) 114 115 116;; Variables: 117 118;;; 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. 122Never set this variable directly, use the command `auto-revert-mode' instead.") 123(put 'auto-revert-mode 'permanent-local t) 124 125(defvar auto-revert-tail-mode nil 126 "*Non-nil when Auto-Revert Tail Mode is active. 127Never set this variable directly, use the command 128`auto-revert-tail-mode' instead.") 129(put 'auto-revert-tail-mode 'permanent-local t) 130 131(defvar auto-revert-timer nil 132 "Timer used by Auto-Revert Mode.") 133 134(defcustom auto-revert-interval 5 135 "Time, in seconds, between Auto-Revert Mode file checks. 136The value may be an integer or floating point number. 137 138If a timer is already active, there are two ways to make sure 139that the new value will take effect immediately. You can set 140this variable through Custom or you can call the command 141`auto-revert-set-timer' after setting the variable. Otherwise, 142the new value will take effect the first time Auto Revert Mode 143calls `auto-revert-set-timer' for internal reasons or in your 144next editing session." 145 :group 'auto-revert 146 :type 'number 147 :set (lambda (variable value) 148 (set-default variable value) 149 (and (boundp 'auto-revert-timer) 150 auto-revert-timer 151 (auto-revert-set-timer)))) 152 153(defcustom auto-revert-stop-on-user-input t 154 "When non-nil, user input temporarily interrupts Auto-Revert Mode. 155With this setting, Auto-Revert Mode checks for user input after 156handling each buffer and does not process any further buffers 157\(until the next run of the timer) if user input is available. 158When nil, Auto-Revert Mode checks files and reverts buffers, 159with quitting disabled, without paying attention to user input. 160Thus, with this setting, Emacs might be non-responsive at times." 161 :group 'auto-revert 162 :type 'boolean) 163 164(defcustom auto-revert-verbose t 165 "When nil, Auto-Revert Mode does not generate any messages. 166When non-nil, a message is generated whenever a file is reverted." 167 :group 'auto-revert 168 :type 'boolean) 169 170(defcustom auto-revert-mode-text " ARev" 171 "String to display in the mode line when Auto-Revert Mode is active. 172 173\(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-...' 175 :group 'auto-revert 176 :type 'string) 177 178(defcustom auto-revert-tail-mode-text " Tail" 179 "String to display in the mode line when Auto-Revert Tail Mode is active. 180 181\(When the string is not empty, make sure that it has a leading space.)" 182 :group 'auto-revert 183 :type 'string 184 :version "22.1") 185 186(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-...' 189 :group 'auto-revert 190 :type 'hook) 191 192(defcustom global-auto-revert-mode-text "" 193 "String to display when Global Auto-Revert Mode is active. 194 195The default is nothing since when this mode is active this text doesn't 196vary over time, or between buffers. Hence mode line text 197would only waste precious space." 198 :group 'auto-revert 199 :type 'string) 200 201(defcustom global-auto-revert-mode-hook nil 202 "Hook called when Global Auto-Revert Mode is activated." 203 :group 'auto-revert 204 :type 'hook) 205 206(defcustom global-auto-revert-non-file-buffers nil 207 "When nil, Global Auto-Revert mode operates only on file-visiting buffers. 208 209When non-nil, both file buffers and buffers with a custom 210`revert-buffer-function' and a `buffer-stale-function' are 211reverted by Global Auto-Revert mode. These include the Buffer 212List buffer, and Dired buffers showing complete local 213directories. Dired buffers do not auto-revert as a result of 214changes in subdirectories or in the contents, size, modes, etc., 215of files. You may still sometimes want to revert them manually. 216 217Use this option with care since it could lead to excessive auto-reverts. 218For more information, see Info node `(emacs)Autorevert'." 219 :group 'auto-revert 220 :type 'boolean 221 :link '(info-link "(emacs)Autorevert")) 222 223(defcustom global-auto-revert-ignore-modes () 224 "List of major modes Global Auto-Revert Mode should not check." 225 :group 'auto-revert 226 :type '(repeat sexp)) 227 228(defcustom auto-revert-load-hook nil 229 "Functions to run when Auto-Revert Mode is first loaded." 230 :tag "Load Hook" 231 :group 'auto-revert 232 :type 'hook) 233 234(defcustom auto-revert-check-vc-info nil 235 "If non-nil Auto Revert Mode reliably updates version control info. 236Auto Revert Mode updates version control info whenever the buffer 237needs reverting, regardless of the value of this variable. 238However, the version control state can change without changes to 239the work file. If the change is made from the current Emacs 240session, all info is updated. But if, for instance, a new 241version is checked in from outside the current Emacs session, the 242version control number in the mode line, as well as other version 243control related information, may not be properly updated. If you 244are worried about this, set this variable to a non-nil value. 245 246This currently works by automatically updating the version 247control info every `auto-revert-interval' seconds. Nevertheless, 248it should not cause excessive CPU usage on a reasonably fast 249machine, if it does not apply to too many version controlled 250buffers. CPU usage depends on the version control system." 251 :group 'auto-revert 252 :type 'boolean 253 :version "22.1") 254 255(defvar global-auto-revert-ignore-buffer nil 256 "*When non-nil, Global Auto-Revert Mode will not revert this buffer. 257 258This variable becomes buffer local when set in any fashion.") 259(make-variable-buffer-local 'global-auto-revert-ignore-buffer) 260 261;; Internal variables: 262 263(defvar auto-revert-buffer-list () 264 "List of buffers in Auto-Revert Mode. 265 266Note that only Auto-Revert Mode, never Global Auto-Revert Mode, adds 267buffers to this list. 268 269The timer function `auto-revert-buffers' is responsible for purging 270the list of old buffers.") 271 272(defvar auto-revert-remaining-buffers () 273 "Buffers not checked when user input stopped execution.") 274 275(defvar auto-revert-tail-pos 0 276 "Position of last known end of file.") 277 278(add-hook 'find-file-hook 279 (lambda () 280 (set (make-local-variable 'auto-revert-tail-pos) 281 (nth 7 (file-attributes buffer-file-name))))) 282 283;; Functions: 284 285;;;###autoload 286(define-minor-mode auto-revert-mode 287 "Toggle reverting buffer when file on disk changes. 288 289With arg, turn Auto Revert mode on if and only if arg is positive. 290This is a minor mode that affects only the current buffer. 291Use `global-auto-revert-mode' to automatically revert all buffers. 292Use `auto-revert-tail-mode' if you know that the file will only grow 293without being changed in the part that is already in the buffer." 294 :group 'auto-revert :lighter auto-revert-mode-text 295 (if auto-revert-mode 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))) 304 305 306;;;###autoload 307(defun turn-on-auto-revert-mode () 308 "Turn on Auto-Revert Mode. 309 310This 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)) 313 314 315;;;###autoload 316(define-minor-mode auto-revert-tail-mode 317 "Toggle reverting tail of buffer when file on disk grows. 318With arg, turn Tail mode on iff arg is positive. 319 320When Tail mode is enabled, the tail of the file is constantly 321followed, as with the shell command `tail -f'. This means that 322whenever the file grows on disk (presumably because some 323background process is appending to it from time to time), this is 324reflected in the current buffer. 325 326You can edit the buffer and turn this mode off and on again as 327you please. But make sure the background process has stopped 328writing before you save the file! 329 330Use `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 (nth 7 (file-attributes buffer-file-name)))) 345 ;; let auto-revert-mode set up the mechanism for us if it isn't already 346 (or auto-revert-mode 347 (let ((auto-revert-tail-mode t)) 348 (auto-revert-mode 1))) 349 (setq auto-revert-mode nil)))) 350 351 352;;;###autoload 353(defun turn-on-auto-revert-tail-mode () 354 "Turn on Auto-Revert Tail Mode. 355 356This 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)) 359 360 361;;;###autoload 362(define-minor-mode global-auto-revert-mode 363 "Revert any buffer when file on disk changes. 364 365With arg, turn Auto Revert mode on globally if and only if arg is positive. 366This is a minor mode that affects all buffers. 367Use `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))) 372 373 374(defun auto-revert-set-timer () 375 "Restart or cancel the timer used by Auto-Revert Mode. 376If such a timer is active, cancel it. Start a new timer if 377Global Auto-Revert Mode is active or if Auto-Revert Mode is active 378in some buffer. Restarting the timer ensures that Auto-Revert Mode 379will use an up-to-date value of `auto-revert-interval'" 380 (interactive) 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 386 auto-revert-interval 387 'auto-revert-buffers)))) 388 389(defun auto-revert-active-p () 390 "Check if auto-revert is active (in current buffer or globally)." 391 (or auto-revert-mode 392 auto-revert-tail-mode 393 (and 394 global-auto-revert-mode 395 (not global-auto-revert-ignore-buffer) 396 (not (memq major-mode 397 global-auto-revert-ignore-modes))))) 398 399(defun auto-revert-handler () 400 "Revert current buffer, if appropriate. 401This 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)) 404 (revert 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)))) 415 eob eoblist) 416 (when revert 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 422 ;; to tail a file. 423 (when buffer-file-name 424 (setq eob (eobp)) 425 (walk-windows 426 #'(lambda (window) 427 (and (eq (window-buffer window) buffer) 428 (= (window-point window) (point-max)) 429 (push window eoblist))) 430 'no-mini t)) 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))))) 446 447(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) 454 (undo-boundary) 455 (save-restriction 456 (widen) 457 (save-excursion 458 (goto-char (point-max)) 459 (insert-file-contents file nil auto-revert-tail-pos size))) 460 (run-mode-hooks 'after-revert-hook) 461 (undo-boundary) 462 (setq auto-revert-tail-pos size) 463 (set-buffer-modified-p modified))) 464 (set-visited-file-modtime)) 465 466(defun auto-revert-buffers () 467 "Revert buffers as specified by Auto-Revert and Global Auto-Revert Mode. 468 469Should `global-auto-revert-mode' be active all file buffers are checked. 470 471Should `auto-revert-mode' be active in some buffers, those buffers 472are checked. 473 474Non-file buffers that have a custom `revert-buffer-function' and 475a `buffer-stale-function' are reverted either when Auto-Revert 476Mode is active in that buffer, or when the variable 477`global-auto-revert-non-file-buffers' is non-nil and Global 478Auto-Revert Mode is active. 479 480This function stops whenever there is user input. The buffers not 481checked are stored in the variable `auto-revert-remaining-buffers'. 482 483To avoid starvation, the buffers in `auto-revert-remaining-buffers' 484are checked first the next time this function is called. 485 486This function is also responsible for removing buffers no longer in 487Auto-Revert mode from `auto-revert-buffer-list', and for canceling 488the timer when no buffers need to be checked." 489 (save-match-data 490 (let ((bufs (if global-auto-revert-mode 491 (buffer-list) 492 auto-revert-buffer-list)) 493 (remaining ()) 494 (new ())) 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 498 ;; head of the list. 499 (dolist (buf auto-revert-remaining-buffers) 500 (if (memq buf bufs) 501 (push buf remaining))) 502 (dolist (buf bufs) 503 (if (not (memq buf remaining)) 504 (push buf new))) 505 (setq bufs (nreverse (nconc new remaining))) 506 (while (and bufs 507 (not (and auto-revert-stop-on-user-input 508 (input-pending-p)))) 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))))) 530 531 532;; The end: 533(provide 'autorevert) 534 535(run-hooks 'auto-revert-load-hook) 536 537;;; arch-tag: f6bcb07b-4841-477e-9e44-b18678e58876 538;;; autorevert.el ends here 539