;;; autorevert.el --- revert buffers when files on disk change
-;; Copyright (C) 1997, 1998, 1999, 2001 Free Software Foundation, Inc.
+;; Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003, 2004,
+;; 2005, 2006, 2007 Free Software Foundation, Inc.
;; Author: Anders Lindgren <andersl@andersl.com>
;; Keywords: convenience
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to the
-;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
;;; Commentary:
;;
;; This package contains two minor modes: Global Auto-Revert Mode and
;; Auto-Revert Mode. Both modes automatically revert buffers
-;; whenever the corresponding files have been changed on disk.
+;; whenever the corresponding files have been changed on disk and the
+;; buffer contains no unsaved changes.
;;
;; Auto-Revert Mode can be activated for individual buffers. Global
;; Auto-Revert Mode applies to all file buffers. (If the user option
;; Just put point at the end of the buffer and it will stay there.
;; These rules apply to file buffers. For non-file buffers, the
;; behavior may be mode dependent.
+;;
+;; While you can use Auto Revert Mode to tail a file, this package
+;; contains a third minor mode, Auto Revert Tail Mode, which does so
+;; more efficiently, as long as you are sure that the file will only
+;; change by growing at the end. It only appends the new output,
+;; instead of reverting the entire buffer. It does so even if the
+;; buffer contains unsaved changes. (Because they will not be lost.)
;; Usage:
;;
-;; Go to the appropriate buffer and press:
+;; Go to the appropriate buffer and press either of:
;; M-x auto-revert-mode RET
+;; M-x auto-revert-tail-mode RET
;;
;; To activate Global Auto-Revert Mode, press:
;; M-x global-auto-revert-mode RET
;; Variables:
-;; Autoload for the benefit of `make-mode-line-mouse-sensitive'.
-;;;###autoload
+;;; What's this?: ;; Autoload for the benefit of `make-mode-line-mouse-sensitive'.
+;;; What's this?: ;;;###autoload
(defvar auto-revert-mode nil
"*Non-nil when Auto-Revert Mode is active.
Never set this variable directly, use the command `auto-revert-mode' instead.")
(put 'auto-revert-mode 'permanent-local t)
+(defvar auto-revert-tail-mode nil
+ "*Non-nil when Auto-Revert Tail Mode is active.
+Never set this variable directly, use the command
+`auto-revert-tail-mode' instead.")
+(put 'auto-revert-tail-mode 'permanent-local t)
+
(defvar auto-revert-timer nil
"Timer used by Auto-Revert Mode.")
(auto-revert-set-timer))))
(defcustom auto-revert-stop-on-user-input t
- "When non-nil Auto-Revert Mode stops checking files on user input."
+ "When non-nil, user input temporarily interrupts Auto-Revert Mode.
+With this setting, Auto-Revert Mode checks for user input after
+handling each buffer and does not process any further buffers
+\(until the next run of the timer) if user input is available.
+When nil, Auto-Revert Mode checks files and reverts buffers,
+with quitting disabled, without paying attention to user input.
+Thus, with this setting, Emacs might be non-responsive at times."
:group 'auto-revert
:type 'boolean)
(defcustom auto-revert-verbose t
- "When nil, Auto-Revert Mode will not generate any messages.
+ "When nil, Auto-Revert Mode does not generate any messages.
When non-nil, a message is generated whenever a file is reverted."
:group 'auto-revert
:type 'boolean)
:group 'auto-revert
:type 'string)
+(defcustom auto-revert-tail-mode-text " Tail"
+ "String to display in the mode line when Auto-Revert Tail Mode is active.
+
+\(When the string is not empty, make sure that it has a leading space.)"
+ :group 'auto-revert
+ :type 'string
+ :version "22.1")
+
(defcustom auto-revert-mode-hook nil
"Functions to run when Auto-Revert Mode is activated."
:tag "Auto Revert Mode Hook" ; To separate it from `global-...'
of files. You may still sometimes want to revert them manually.
Use this option with care since it could lead to excessive auto-reverts.
-For more information, see Info node `(emacs-xtra)Autorevert'."
+For more information, see Info node `(emacs)Autorevert'."
:group 'auto-revert
:type 'boolean
- :link '(info-link "(emacs-xtra)Autorevert"))
+ :link '(info-link "(emacs)Autorevert"))
-(defcustom global-auto-revert-ignore-modes '()
+(defcustom global-auto-revert-ignore-modes ()
"List of major modes Global Auto-Revert Mode should not check."
:group 'auto-revert
:type '(repeat sexp))
control info every `auto-revert-interval' seconds. Nevertheless,
it should not cause excessive CPU usage on a reasonably fast
machine, if it does not apply to too many version controlled
-buffers. CPU usage depends on the version control system"
+buffers. CPU usage depends on the version control system."
:group 'auto-revert
:type 'boolean
- :version "21.4")
+ :version "22.1")
(defvar global-auto-revert-ignore-buffer nil
"*When non-nil, Global Auto-Revert Mode will not revert this buffer.
;; Internal variables:
-(defvar auto-revert-buffer-list '()
+(defvar auto-revert-buffer-list ()
"List of buffers in Auto-Revert Mode.
Note that only Auto-Revert Mode, never Global Auto-Revert Mode, adds
The timer function `auto-revert-buffers' is responsible for purging
the list of old buffers.")
-(defvar auto-revert-remaining-buffers '()
+(defvar auto-revert-remaining-buffers ()
"Buffers not checked when user input stopped execution.")
+(defvar auto-revert-tail-pos 0
+ "Position of last known end of file.")
+
+(add-hook 'find-file-hook
+ (lambda ()
+ (set (make-local-variable 'auto-revert-tail-pos)
+ (save-restriction (widen) (1- (point-max))))))
;; Functions:
With arg, turn Auto Revert mode on if and only if arg is positive.
This is a minor mode that affects only the current buffer.
-Use `global-auto-revert-mode' to automatically revert all buffers."
- nil auto-revert-mode-text nil
+Use `global-auto-revert-mode' to automatically revert all buffers.
+Use `auto-revert-tail-mode' if you know that the file will only grow
+without being changed in the part that is already in the buffer."
+ :group 'auto-revert :lighter auto-revert-mode-text
(if auto-revert-mode
(if (not (memq (current-buffer) auto-revert-buffer-list))
(push (current-buffer) auto-revert-buffer-list))
(delq (current-buffer) auto-revert-buffer-list)))
(auto-revert-set-timer)
(when auto-revert-mode
- (auto-revert-buffers)))
+ (auto-revert-buffers)
+ (setq auto-revert-tail-mode nil)))
;;;###autoload
(auto-revert-mode 1))
+;;;###autoload
+(define-minor-mode auto-revert-tail-mode
+ "Toggle reverting tail of buffer when file on disk grows.
+With arg, turn Tail mode on iff arg is positive.
+
+When Tail mode is enabled, the tail of the file is constantly
+followed, as with the shell command `tail -f'. This means that
+whenever the file grows on disk (presumably because some
+background process is appending to it from time to time), this is
+reflected in the current buffer.
+
+You can edit the buffer and turn this mode off and on again as
+you please. But make sure the background process has stopped
+writing before you save the file!
+
+Use `auto-revert-mode' for changes other than appends!"
+ :group 'find-file :lighter auto-revert-tail-mode-text
+ (when auto-revert-tail-mode
+ (unless buffer-file-name
+ (auto-revert-tail-mode 0)
+ (error "This buffer is not visiting a file"))
+ (if (and (buffer-modified-p)
+ (not auto-revert-tail-pos) ; library was loaded only after finding file
+ (not (y-or-n-p "Buffer is modified, so tail offset may be wrong. Proceed? ")))
+ (auto-revert-tail-mode 0)
+ ;; else we might reappend our own end when we save
+ (add-hook 'before-save-hook (lambda () (auto-revert-tail-mode 0)) nil t)
+ (or (local-variable-p 'auto-revert-tail-pos) ; don't lose prior position
+ (set (make-local-variable 'auto-revert-tail-pos)
+ (save-restriction (widen) (1- (point-max)))))
+ ;; let auto-revert-mode set up the mechanism for us if it isn't already
+ (or auto-revert-mode
+ (let ((auto-revert-tail-mode t))
+ (auto-revert-mode 1)))
+ (setq auto-revert-mode nil))))
+
+
+;;;###autoload
+(defun turn-on-auto-revert-tail-mode ()
+ "Turn on Auto-Revert Tail Mode.
+
+This function is designed to be added to hooks, for example:
+ (add-hook 'my-logfile-mode-hook 'turn-on-auto-revert-tail-mode)"
+ (auto-revert-tail-mode 1))
+
+
;;;###autoload
(define-minor-mode global-auto-revert-mode
"Revert any buffer when file on disk changes.
(if (or global-auto-revert-mode auto-revert-buffer-list)
(run-with-timer auto-revert-interval
auto-revert-interval
- 'auto-revert-buffers)
- nil)))
+ 'auto-revert-buffers))))
(defun auto-revert-active-p ()
"Check if auto-revert is active (in current buffer or globally)."
(or auto-revert-mode
+ auto-revert-tail-mode
(and
global-auto-revert-mode
(not global-auto-revert-ignore-buffer)
(defun auto-revert-handler ()
"Revert current buffer, if appropriate.
This is an internal function used by Auto-Revert Mode."
- (unless (buffer-modified-p)
- (let ((buffer (current-buffer)) revert eob eoblist)
- (or (and buffer-file-name
- (not (file-remote-p buffer-file-name))
- (file-readable-p buffer-file-name)
- (not (verify-visited-file-modtime buffer))
- (setq revert t))
- (and (or auto-revert-mode global-auto-revert-non-file-buffers)
- revert-buffer-function
- (boundp 'buffer-stale-function)
- (functionp buffer-stale-function)
- (setq revert (funcall buffer-stale-function t))))
+ (when (or auto-revert-tail-mode (not (buffer-modified-p)))
+ (let* ((buffer (current-buffer))
+ (revert
+ (or (and buffer-file-name
+ (not (file-remote-p buffer-file-name))
+ (file-readable-p buffer-file-name)
+ (not (verify-visited-file-modtime buffer)))
+ (and (or auto-revert-mode
+ global-auto-revert-non-file-buffers)
+ revert-buffer-function
+ (boundp 'buffer-stale-function)
+ (functionp buffer-stale-function)
+ (funcall buffer-stale-function t))))
+ eob eoblist)
(when revert
(when (and auto-revert-verbose
(not (eq revert 'fast)))
(= (window-point window) (point-max))
(push window eoblist)))
'no-mini t))
- (revert-buffer 'ignore-auto 'dont-ask 'preserve-modes)
+ (if auto-revert-tail-mode
+ (auto-revert-tail-handler)
+ ;; Bind buffer-read-only in case user has done C-x C-q,
+ ;; so as not to forget that. This gives undesirable results
+ ;; when the file's mode changes, but that is less common.
+ (let ((buffer-read-only buffer-read-only))
+ (revert-buffer 'ignore-auto 'dont-ask 'preserve-modes)))
(when buffer-file-name
(when eob (goto-char (point-max)))
(dolist (window eoblist)
(when (or revert auto-revert-check-vc-info)
(vc-find-file-hook)))))
+(defun auto-revert-tail-handler ()
+ (let ((size (nth 7 (file-attributes buffer-file-name)))
+ (modified (buffer-modified-p))
+ buffer-read-only ; ignore
+ (file buffer-file-name)
+ buffer-file-name) ; ignore that file has changed
+ (when (> size auto-revert-tail-pos)
+ (undo-boundary)
+ (save-restriction
+ (widen)
+ (save-excursion
+ (goto-char (point-max))
+ (insert-file-contents file nil auto-revert-tail-pos size)))
+ (undo-boundary)
+ (setq auto-revert-tail-pos size)
+ (set-buffer-modified-p modified)))
+ (set-visited-file-modtime))
+
(defun auto-revert-buffers ()
"Revert buffers as specified by Auto-Revert and Global Auto-Revert Mode.
This function is also responsible for removing buffers no longer in
Auto-Revert mode from `auto-revert-buffer-list', and for canceling
the timer when no buffers need to be checked."
- (let ((bufs (if global-auto-revert-mode
- (buffer-list)
- auto-revert-buffer-list))
- (remaining '())
- (new '()))
- ;; Partition `bufs' into two halves depending on whether or not
- ;; the buffers are in `auto-revert-remaining-buffers'. The two
- ;; halves are then re-joined with the "remaining" buffers at the
- ;; head of the list.
- (dolist (buf auto-revert-remaining-buffers)
- (if (memq buf bufs)
- (push buf remaining)))
- (dolist (buf bufs)
- (if (not (memq buf remaining))
- (push buf new)))
- (setq bufs (nreverse (nconc new remaining)))
- (while (and bufs
- (not (and auto-revert-stop-on-user-input
- (input-pending-p))))
- (let ((buf (car bufs)))
- (if (buffer-name buf) ; Buffer still alive?
- (with-current-buffer buf
- ;; Test if someone has turned off Auto-Revert Mode in a
- ;; non-standard way, for example by changing major mode.
- (if (and (not auto-revert-mode)
- (memq buf auto-revert-buffer-list))
- (setq auto-revert-buffer-list
- (delq buf auto-revert-buffer-list)))
- (when (auto-revert-active-p) (auto-revert-handler)))
- ;; Remove dead buffer from `auto-revert-buffer-list'.
- (setq auto-revert-buffer-list
- (delq buf auto-revert-buffer-list))))
- (setq bufs (cdr bufs)))
- (setq auto-revert-remaining-buffers bufs)
- ;; Check if we should cancel the timer.
- (when (and (not global-auto-revert-mode)
- (null auto-revert-buffer-list))
- (cancel-timer auto-revert-timer)
- (setq auto-revert-timer nil))))
+ (save-match-data
+ (let ((bufs (if global-auto-revert-mode
+ (buffer-list)
+ auto-revert-buffer-list))
+ (remaining ())
+ (new ()))
+ ;; Partition `bufs' into two halves depending on whether or not
+ ;; the buffers are in `auto-revert-remaining-buffers'. The two
+ ;; halves are then re-joined with the "remaining" buffers at the
+ ;; head of the list.
+ (dolist (buf auto-revert-remaining-buffers)
+ (if (memq buf bufs)
+ (push buf remaining)))
+ (dolist (buf bufs)
+ (if (not (memq buf remaining))
+ (push buf new)))
+ (setq bufs (nreverse (nconc new remaining)))
+ (while (and bufs
+ (not (and auto-revert-stop-on-user-input
+ (input-pending-p))))
+ (let ((buf (car bufs)))
+ (if (buffer-name buf) ; Buffer still alive?
+ (with-current-buffer buf
+ ;; Test if someone has turned off Auto-Revert Mode in a
+ ;; non-standard way, for example by changing major mode.
+ (if (and (not auto-revert-mode)
+ (not auto-revert-tail-mode)
+ (memq buf auto-revert-buffer-list))
+ (setq auto-revert-buffer-list
+ (delq buf auto-revert-buffer-list)))
+ (when (auto-revert-active-p) (auto-revert-handler)))
+ ;; Remove dead buffer from `auto-revert-buffer-list'.
+ (setq auto-revert-buffer-list
+ (delq buf auto-revert-buffer-list))))
+ (setq bufs (cdr bufs)))
+ (setq auto-revert-remaining-buffers bufs)
+ ;; Check if we should cancel the timer.
+ (when (and (not global-auto-revert-mode)
+ (null auto-revert-buffer-list))
+ (cancel-timer auto-revert-timer)
+ (setq auto-revert-timer nil)))))
;; The end: