;;; autorevert.el --- revert buffers when files on disk change
-;; Copyright (C) 1997-1999, 2001-2012 Free Software Foundation, Inc.
+;; Copyright (C) 1997-1999, 2001-2013 Free Software Foundation, Inc.
;; Author: Anders Lindgren <andersl@andersl.com>
;; Keywords: convenience
;; Emacs. You should never even notice that this package is active
;; (except that your buffers will be reverted, of course).
;;
+;; If Emacs is compiled with file watch support, notifications are
+;; used instead of checking the time stamp of the files. You can
+;; disable this by setting the user option `auto-revert-use-notify' to
+;; nil.
+;;
;; After reverting a file buffer, Auto Revert Mode normally puts point
;; at the same position that a regular manual revert would. However,
;; there is one exception to this rule. If point is at the end of the
;; Dependencies:
+(eval-when-compile (require 'cl-lib))
(require 'timer)
-(eval-when-compile (require 'cl))
-
-
;; Custom Group:
;;
;; The two modes will be placed next to Auto Save Mode under the
This variable becomes buffer local when set in any fashion.")
(make-variable-buffer-local 'global-auto-revert-ignore-buffer)
+(defconst auto-revert-notify-enabled
+ (or (featurep 'inotify) (featurep 'w32notify))
+ "Non-nil when Emacs has been compiled with file watch support.")
+
+(defcustom auto-revert-use-notify auto-revert-notify-enabled
+ "If non-nil Auto Revert Mode uses file watch functions.
+This requires Emacs being compiled with file watch support (see
+`auto-revert-notify-enabled'). You should set this variable
+through Custom only."
+ :group 'auto-revert
+ :type 'boolean
+ :set (lambda (variable value)
+ (set-default variable (and auto-revert-notify-enabled value))
+ (unless (symbol-value variable)
+ (when auto-revert-notify-enabled
+ (dolist (buf (buffer-list))
+ (with-current-buffer buf
+ (when (symbol-value 'auto-revert-notify-watch-descriptor)
+ (auto-revert-notify-rm-watch)))))))
+ :version "24.4")
+
;; Internal variables:
(defvar auto-revert-buffer-list ()
(set (make-local-variable 'auto-revert-tail-pos)
(nth 7 (file-attributes buffer-file-name)))))
+(defvar auto-revert-notify-watch-descriptor-hash-list
+ (make-hash-table :test 'equal)
+ "A hash table collecting all file watch descriptors.
+Hash key is a watch descriptor, hash value is the corresponding buffer.")
+
+(defvar auto-revert-notify-watch-descriptor nil
+ "The file watch descriptor active for the current buffer.")
+(put 'auto-revert-notify-watch-descriptor 'permanent-local t)
+
+(defvar auto-revert-notify-modified-p nil
+ "Non-nil when file has been modified on the file system.
+This has been reported by a file watch event.")
+(make-variable-buffer-local 'auto-revert-notify-modified-p)
+
;; Functions:
;;;###autoload
(if auto-revert-mode
(if (not (memq (current-buffer) auto-revert-buffer-list))
(push (current-buffer) auto-revert-buffer-list))
+ (when auto-revert-use-notify (auto-revert-notify-rm-watch))
(setq auto-revert-buffer-list
(delq (current-buffer) auto-revert-buffer-list)))
(auto-revert-set-timer)
specifies in the mode line."
:global t :group 'auto-revert :lighter global-auto-revert-mode-text
(auto-revert-set-timer)
- (when global-auto-revert-mode
- (auto-revert-buffers)))
-
+ (if global-auto-revert-mode
+ (auto-revert-buffers)
+ (when auto-revert-use-notify
+ (dolist (buf (buffer-list))
+ (with-current-buffer buf
+ (auto-revert-notify-rm-watch))))))
(defun auto-revert-set-timer ()
"Restart or cancel the timer used by Auto-Revert Mode.
auto-revert-interval
'auto-revert-buffers))))
+(defun auto-revert-notify-rm-watch ()
+ "Disable file watch for current buffer's associated file."
+ (when auto-revert-notify-watch-descriptor
+ (ignore-errors
+ (funcall (if (fboundp 'inotify-rm-watch)
+ 'inotify-rm-watch 'w32notify-rm-watch)
+ auto-revert-notify-watch-descriptor))
+ (remhash auto-revert-notify-watch-descriptor
+ auto-revert-notify-watch-descriptor-hash-list)
+ (remove-hook 'kill-buffer-hook 'auto-revert-notify-rm-watch))
+ (setq auto-revert-notify-watch-descriptor nil
+ auto-revert-notify-modified-p nil))
+
+(defun auto-revert-notify-add-watch ()
+ "Enable file watch for current buffer's associated file."
+ (when (and buffer-file-name auto-revert-use-notify
+ (not auto-revert-notify-watch-descriptor))
+ (let ((func (if (fboundp 'inotify-add-watch)
+ 'inotify-add-watch 'w32notify-add-watch))
+ (aspect (if (fboundp 'inotify-add-watch)
+ '(modify) '(size last-write-time))))
+ (setq auto-revert-notify-watch-descriptor
+ (ignore-errors
+ (funcall
+ func buffer-file-name aspect 'auto-revert-notify-handler)))
+ (if auto-revert-notify-watch-descriptor
+ (progn
+ (puthash auto-revert-notify-watch-descriptor
+ (current-buffer)
+ auto-revert-notify-watch-descriptor-hash-list)
+ (add-hook (make-local-variable 'kill-buffer-hook)
+ 'auto-revert-notify-rm-watch))
+ ;; Fallback to file checks.
+ (set (make-local-variable 'auto-revert-use-notify) nil)))))
+
+(defun auto-revert-notify-event-p (event)
+ "Check that event is a file watch event."
+ (cond ((featurep 'inotify)
+ (and (listp event) (= (length event) 4)))
+ ((featurep 'w32notify)
+ (and (listp event) (= (length event) 3) (stringp (nth 2 event))))))
+
+(defun auto-revert-notify-event-descriptor (event)
+ "Return watch descriptor of notification event, or nil."
+ (and (auto-revert-notify-event-p event) (car event)))
+
+(defun auto-revert-notify-event-action (event)
+ "Return action of notification event, or nil."
+ (and (auto-revert-notify-event-p event) (nth 1 event)))
+
+(defun auto-revert-notify-event-file-name (event)
+ "Return file name of notification event, or nil."
+ (and (auto-revert-notify-event-p event)
+ (cond ((featurep 'inotify) (nth 3 event))
+ ((featurep 'w32notify) (nth 2 event)))))
+
+(defun auto-revert-notify-handler (event)
+ "Handle an event returned from file watch."
+ (when (auto-revert-notify-event-p event)
+ (let* ((descriptor (auto-revert-notify-event-descriptor event))
+ (action (auto-revert-notify-event-action event))
+ (file (auto-revert-notify-event-file-name event))
+ (buffer (gethash descriptor
+ auto-revert-notify-watch-descriptor-hash-list)))
+ (ignore-errors
+ ;; Check, that event is meant for us.
+ ;; TODO: Filter events which stop watching, like `move' or `removed'.
+ (cl-assert descriptor)
+ (when (featurep 'inotify) (cl-assert (memq 'modify action)))
+ (when (featurep 'w32notify) (cl-assert (eq 'modified action)))
+ (cl-assert (bufferp buffer))
+ (with-current-buffer buffer
+ (when (and (stringp file) (stringp buffer-file-name))
+ ;; w32notify returns the basename of the file without its
+ ;; leading directories; inotify returns its full absolute
+ ;; file name.
+ (cl-assert (file-equal-p file buffer-file-name)))
+
+ ;; Mark buffer modified.
+ (setq auto-revert-notify-modified-p t))))))
+
(defun auto-revert-active-p ()
"Check if auto-revert is active (in current buffer or globally)."
(or auto-revert-mode
(let* ((buffer (current-buffer)) size
(revert
(or (and buffer-file-name
+ (or (not auto-revert-use-notify)
+ auto-revert-notify-modified-p)
(if auto-revert-tail-mode
;; Tramp caches the file attributes. Setting
;; `remote-file-name-inhibit-cache' forces Tramp
(funcall buffer-stale-function t))))
eob eoblist)
(when revert
+ (setq auto-revert-notify-modified-p nil)
(when (and auto-revert-verbose
(not (eq revert 'fast)))
(message "Reverting buffer `%s'." (buffer-name)))
(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)))
+ (when (auto-revert-active-p)
+ ;; Enable file watches.
+ (when (and auto-revert-use-notify buffer-file-name
+ (not auto-revert-notify-watch-descriptor)
+ (auto-revert-notify-add-watch)))
+ (auto-revert-handler)))
;; Remove dead buffer from `auto-revert-buffer-list'.
(setq auto-revert-buffer-list
(delq buf auto-revert-buffer-list))))