lisp/emacs-lock.el

   1 ;;; emacs-lock.el --- prevents you from exiting emacs if a buffer is locked
   2
   3 ;; Copyright (C) 1994 Free Software Foundation, Inc
   4
   5 ;; Author: Tom Wurgler <twurgler@goodyear.com>
   6 ;; Created: 12/8/94
   7 ;; Version: 1.3
   8 ;; Keywords:
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software; you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation; either version 2, or (at your option)
  15 ;; any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  24 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  25 ;; Boston, MA 02111-1307, USA.
  26
  27 ;;; Commentary:
  28
  29 ;; This code sets a buffer-local variable to t if toggle-emacs-lock is run,
  30 ;; then if the user attempts to exit emacs, the locked buffer name will be
  31 ;; displayed and the exit aborted.  This is just a way of protecting
  32 ;; yourself from yourself.  For example, if you have a shell running a big
  33 ;; program and exiting emacs would abort that program, you may want to lock
  34 ;; that buffer, then if you forget about it after a while, you won't
  35 ;; accidentally exit emacs.  To unlock the buffer, just goto the buffer and
  36 ;; run toggle-emacs-lock again.
  37
  38 ;;; Code:
  39
  40 (defvar lock-emacs-from-exiting nil
  41   "Whether emacs is locked to prevent exiting.  See `check-emacs-lock'.")
  42 (make-variable-buffer-local 'lock-emacs-from-exiting)
  43
  44 (defun check-emacs-lock ()
  45   "Check if variable `lock-emacs-from-exiting' is t for any buffer.
  46 If any t is found, signal error and display the locked buffer name."
  47   (let ((buffers (buffer-list)))
  48     (save-excursion
  49       (while buffers
  50         (set-buffer (car buffers))
  51         (if lock-emacs-from-exiting
  52             (error "Emacs is locked from exit due to buffer: %s" (buffer-name))
  53           (setq buffers (cdr buffers)))))))
  54
  55 (defun toggle-emacs-lock ()
  56   "Toggle `lock-emacs-from-exiting' between t and nil for the current buffer.
  57 See `check-emacs-lock'."
  58   (interactive)
  59   (if lock-emacs-from-exiting
  60       (setq lock-emacs-from-exiting nil)
  61     (setq lock-emacs-from-exiting t))
  62   (if lock-emacs-from-exiting
  63       (message "Emacs is now locked from exiting.")
  64     (message "Emacs is now unlocked.")))
  65
  66 (add-hook 'kill-emacs-hook 'check-emacs-lock)
  67
  68 ;; emacs-lock.el ends here