+;;; userlock.el --- handle file access contention between multiple users
+
;; Copyright (C) 1985, 1986 Free Software Foundation, inc.
+;; Maintainer: FSF
+;; Keywords: internal
+
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
-;; the Free Software Foundation; either version 1, or (at your option)
+;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; GNU General Public License for more details.
;; 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, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; 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.
+;;; Commentary:
-;; This file is autloaded to handle certain conditions
+;; This file is autoloaded to handle certain conditions
;; detected by the file-locking code within Emacs.
;; The two entry points are `ask-user-about-lock' and
;; `ask-user-about-supersession-threat'.
+;;; Code:
(put 'file-locked 'error-conditions '(file-locked file-error error))
+;;;###autoload
(defun ask-user-about-lock (fn opponent)
"Ask user what to do when he wants to edit FILE but it is locked by USER.
This function has a choice of three things to do:
You can <s>teal the file; The other user becomes the
intruder if (s)he ever unmodifies the file and then changes it again.
You can <p>roceed; you edit at your own (and the other user's) risk.
-You can <q>uit; don't modify this file.")))
+You can <q>uit; don't modify this file.")
+ (save-excursion
+ (set-buffer standard-output)
+ (help-mode))))
(put
'file-supersession 'error-conditions '(file-supersession file-error error))
+;;;###autoload
(defun ask-user-about-supersession-threat (fn)
"Ask a user who is about to modify an obsolete buffer what to do.
This function has two choices: it can return, in which case the modification
(save-window-excursion
(let (answer)
(while (null answer)
- (message "File has changed on disk; really want to edit the buffer? (y, n or C-h) ")
+ (message "%s changed on disk; really edit the buffer? (y, n, r or C-h) "
+ (file-name-nondirectory fn))
(let ((tem (downcase (let ((cursor-in-echo-area t))
(read-char)))))
(setq answer
(cdr (assoc tem '((?n . yield)
(?\C-g . yield)
(?y . proceed)
+ (?r . revert)
(?? . help))))))
(cond ((null answer)
(beep)
- (message "Please type y or n; or ? for help")
+ (message "Please type y, n or r; or ? for help")
(sit-for 3))
((eq answer 'help)
(ask-user-about-supersession-help)
(setq answer nil))
+ ((eq answer 'revert)
+ (revert-buffer nil (not (buffer-modified-p)))
+ ; ask confirmation iff buffer modified
+ (signal 'file-supersession
+ (list "File reverted" fn)))
((eq answer 'yield)
(signal 'file-supersession
(list "File changed on disk" fn))))))
If you say `y' to go ahead and modify this buffer,
you risk ruining the work of whoever rewrote the file.
+If you say `r' to revert, the contents of the buffer are refreshed
+from the file on disk.
If you say `n', the change you started to make will be aborted.
Usually, you should type `n' and then `M-x revert-buffer',
-to get the latest version of the file, then make the change again.")))
-
+to get the latest version of the file, then make the change again.")
+ (save-excursion
+ (set-buffer standard-output)
+ (help-mode))))
+;;; userlock.el ends here