lisp/emacs-lock.el

   1 ;; emacs-lock.el --- Prevents you from exiting emacs if a buffer is locked
   2 ;; Copyright (C) 1994 Free Software Foundation, Inc
   3 ;;
   4 ;; Author: Tom Wurgler <twurgler@goodyear.com>
   5 ;; Created: 12/8/94
   6 ;; Version: 1.3
   7 ;; Keywords:
   8 ;;
   9 ;; This program is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 2 of the License, or
  12 ;; (at your option) any later version.
  13 ;;
  14 ;; This program is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18 ;;
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; if not, write to the Free Software
  21 ;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22
  23 ;;; Commentary:
  24 ;;
  25 ;; This code sets a buffer-local variable to t if toggle-emacs-lock is run,
  26 ;; then if the user attempts to exit emacs, the locked buffer name will be
  27 ;; displayed and the exit aborted.  This is just a way of protecting
  28 ;; yourself from yourself.  For example, if you have a shell running a big
  29 ;; program and exiting emacs would abort that program, you may want to lock
  30 ;; that buffer, then if you forget about it after a while, you won't
  31 ;; accidently exit emacs.  To unlock the buffer, just goto the buffer and
  32 ;; run toggle-emacs-lock again.
  33
  34 (defvar lock-emacs-from-exiting nil
  35   "Whether emacs is locked to prevent exiting.  See `check-emacs-lock'.")
  36 (make-variable-buffer-local 'lock-emacs-from-exiting)
  37
  38 (defun check-emacs-lock ()
  39   "Check if variable `lock-emacs-from-exiting' is t for any buffer.
  40 If any t is found, signal error and display the locked buffer name."
  41   (let ((buffers (buffer-list)))
  42     (save-excursion
  43       (while buffers
  44         (set-buffer (car buffers))
  45         (if lock-emacs-from-exiting
  46             (error "Emacs is locked from exit due to buffer: %s" (buffer-name))
  47           (setq buffers (cdr buffers)))))))
  48
  49 (defun toggle-emacs-lock ()
  50   "Toggle `lock-emacs-from-exiting' between t and nil for the current buffer.
  51 See `check-emacs-lock'."
  52   (interactive)
  53   (if lock-emacs-from-exiting
  54       (setq lock-emacs-from-exiting nil)
  55     (setq lock-emacs-from-exiting t))
  56   (if lock-emacs-from-exiting
  57       (message "Emacs is now locked from exiting.")
  58     (message "Emacs is now unlocked.")))
  59
  60 (add-hook 'kill-emacs-hook 'check-emacs-lock)
  61
  62 ;; emacs-lock.el ends here