Initial revision

lisp/emacs-lock.el

+;; emacs-lock.el --- Prevents you from exiting emacs if a buffer is locked
+;; Copyright (C) 1994 Free Software Foundation, Inc
+;;
+;; Author: Tom Wurgler <twurgler@goodyear.com>
+;; Created: 12/8/94
+;; Version: 1.3
+;; Keywords: 
+;;
+;; This program 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 2 of the License, or
+;; (at your option) any later version.
+;;
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; if not, write to the Free Software
+;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+;;; Commentary:
+;;
+;; This code sets a buffer-local variable to t if toggle-emacs-lock is run,
+;; then if the user attempts to exit emacs, the locked buffer name will be
+;; displayed and the exit aborted.  This is just a way of protecting
+;; yourself from yourself.  For example, if you have a shell running a big
+;; program and exiting emacs would abort that program, you may want to lock
+;; that buffer, then if you forget about it after a while, you won't
+;; accidently exit emacs.  To unlock the buffer, just goto the buffer and
+;; run toggle-emacs-lock again.
+
+(defvar lock-emacs-from-exiting nil
+  "Whether emacs is locked to prevent exiting.  See `check-emacs-lock'.")
+(make-variable-buffer-local 'lock-emacs-from-exiting)
+
+(defun check-emacs-lock ()
+  "Check if variable `lock-emacs-from-exiting' is t for any buffer.
+If any t is found, signal error and display the locked buffer name."
+  (let ((buffers (buffer-list)))
+    (save-excursion
+      (while buffers 
+	(set-buffer (car buffers))
+	(if lock-emacs-from-exiting
+	    (error "Emacs is locked from exit due to buffer: %s" (buffer-name))
+	  (setq buffers (cdr buffers)))))))
+
+(defun toggle-emacs-lock ()
+  "Toggle `lock-emacs-from-exiting' between t and nil for the current buffer.
+See `check-emacs-lock'."
+  (interactive)
+  (if lock-emacs-from-exiting
+      (setq lock-emacs-from-exiting nil)
+    (setq lock-emacs-from-exiting t))
+  (if lock-emacs-from-exiting
+      (message "Emacs is now locked from exiting.")
+    (message "Emacs is now unlocked.")))
+
+(add-hook 'kill-emacs-hook 'check-emacs-lock)
+
+;; emacs-lock.el ends here