lisp/emacs-lock.el

   1 ;;; emacs-lock.el --- prevents you from exiting Emacs if a buffer is locked
   2
   3 ;; Copyright (C) 1994, 1997, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc
   5
   6 ;; Author: Tom Wurgler <twurgler@goodyear.com>
   7 ;; Created: 12/8/94
   8 ;; Keywords: extensions, processes
   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 3, 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., 51 Franklin Street, Fifth Floor,
  25 ;; Boston, MA 02110-1301, 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 emacs-lock-from-exiting nil
  41   "Whether Emacs is locked to prevent exiting.  See `check-emacs-lock'.")
  42 (make-variable-buffer-local 'emacs-lock-from-exiting)
  43
  44 (defvar emacs-lock-buffer-locked nil
  45   "Whether a shell or telnet buffer was locked when its process was killed.")
  46 (make-variable-buffer-local 'emacs-lock-buffer-locked)
  47 (put 'emacs-lock-buffer-locked 'permanent-local t)
  48
  49 (defun check-emacs-lock ()
  50   "Check if variable `emacs-lock-from-exiting' is t for any buffer.
  51 If any locked buffer is found, signal error and display the buffer's name."
  52   (save-excursion
  53     (dolist (buffer (buffer-list))
  54       (set-buffer buffer)
  55       (when emacs-lock-from-exiting
  56         (error "Emacs is locked from exit due to buffer: %s" (buffer-name))))))
  57
  58 (defun toggle-emacs-lock ()
  59   "Toggle `emacs-lock-from-exiting' for the current buffer.
  60 See `check-emacs-lock'."
  61   (interactive)
  62   (setq emacs-lock-from-exiting (not emacs-lock-from-exiting))
  63   (if emacs-lock-from-exiting
  64       (message "Buffer is now locked")
  65     (message "Buffer is now unlocked")))
  66
  67 (defun emacs-lock-check-buffer-lock ()
  68   "Check if variable `emacs-lock-from-exiting' is t for a buffer.
  69 If the buffer is locked, signal error and display its name."
  70   (when emacs-lock-from-exiting
  71     (error "Buffer `%s' is locked, can't delete it" (buffer-name))))
  72
  73 ; These next defuns make it so if you exit a shell that is locked,  the lock
  74 ; is shut off for that shell so you can exit Emacs.  Same for telnet.
  75 ; Also, if a shell or a telnet buffer was locked and the process killed,
  76 ; turn the lock back on again if the process is restarted.
  77
  78 (defun emacs-lock-shell-sentinel ()
  79   (set-process-sentinel
  80    (get-buffer-process (buffer-name)) (function emacs-lock-clear-sentinel)))
  81
  82 (defun emacs-lock-clear-sentinel (proc str)
  83   (if emacs-lock-from-exiting
  84       (progn
  85         (setq emacs-lock-from-exiting nil)
  86         (setq emacs-lock-buffer-locked t)
  87         (message "Buffer is now unlocked"))
  88     (setq emacs-lock-buffer-locked nil)))
  89
  90 (defun emacs-lock-was-buffer-locked ()
  91   (if emacs-lock-buffer-locked
  92       (setq emacs-lock-from-exiting t)))
  93
  94 (add-hook 'kill-emacs-hook 'check-emacs-lock)
  95 (add-hook 'kill-buffer-hook 'emacs-lock-check-buffer-lock)
  96 (add-hook 'shell-mode-hook 'emacs-lock-was-buffer-locked)
  97 (add-hook 'shell-mode-hook 'emacs-lock-shell-sentinel)
  98 (add-hook 'telnet-mode-hook 'emacs-lock-was-buffer-locked)
  99 (add-hook 'telnet-mode-hook 'emacs-lock-shell-sentinel)
 100
 101 (provide 'emacs-lock)
 102
 103 ;;; arch-tag: 58e6cb43-7cf0-401a-bcb6-4902a0b8bdc1
 104 ;;; emacs-lock.el ends here