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, 2009 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 of the License, or
  15 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; This code sets a buffer-local variable to t if toggle-emacs-lock is run,
  28 ;; then if the user attempts to exit Emacs, the locked buffer name will be
  29 ;; displayed and the exit aborted.  This is just a way of protecting
  30 ;; yourself from yourself.  For example, if you have a shell running a big
  31 ;; program and exiting Emacs would abort that program, you may want to lock
  32 ;; that buffer, then if you forget about it after a while, you won't
  33 ;; accidentally exit Emacs.  To unlock the buffer, just goto the buffer and
  34 ;; run toggle-emacs-lock again.
  35
  36 ;;; Code:
  37
  38 (defvar emacs-lock-from-exiting nil
  39   "Whether Emacs is locked to prevent exiting.  See `check-emacs-lock'.")
  40 (make-variable-buffer-local 'emacs-lock-from-exiting)
  41
  42 (defvar emacs-lock-buffer-locked nil
  43   "Whether a shell or telnet buffer was locked when its process was killed.")
  44 (make-variable-buffer-local 'emacs-lock-buffer-locked)
  45 (put 'emacs-lock-buffer-locked 'permanent-local t)
  46
  47 (defun check-emacs-lock ()
  48   "Check if variable `emacs-lock-from-exiting' is t for any buffer.
  49 If any locked buffer is found, signal error and display the buffer's name."
  50   (save-excursion
  51     (dolist (buffer (buffer-list))
  52       (set-buffer buffer)
  53       (when emacs-lock-from-exiting
  54         (error "Emacs is locked from exit due to buffer: %s" (buffer-name))))))
  55
  56 (defun toggle-emacs-lock ()
  57   "Toggle `emacs-lock-from-exiting' for the current buffer.
  58 See `check-emacs-lock'."
  59   (interactive)
  60   (setq emacs-lock-from-exiting (not emacs-lock-from-exiting))
  61   (if emacs-lock-from-exiting
  62       (message "Buffer is now locked")
  63     (message "Buffer is now unlocked")))
  64
  65 (defun emacs-lock-check-buffer-lock ()
  66   "Check if variable `emacs-lock-from-exiting' is t for a buffer.
  67 If the buffer is locked, signal error and display its name."
  68   (when emacs-lock-from-exiting
  69     (error "Buffer `%s' is locked, can't delete it" (buffer-name))))
  70
  71 ; These next defuns make it so if you exit a shell that is locked,  the lock
  72 ; is shut off for that shell so you can exit Emacs.  Same for telnet.
  73 ; Also, if a shell or a telnet buffer was locked and the process killed,
  74 ; turn the lock back on again if the process is restarted.
  75
  76 (defun emacs-lock-shell-sentinel ()
  77   (set-process-sentinel
  78    (get-buffer-process (buffer-name)) (function emacs-lock-clear-sentinel)))
  79
  80 (defun emacs-lock-clear-sentinel (proc str)
  81   (if emacs-lock-from-exiting
  82       (progn
  83         (setq emacs-lock-from-exiting nil)
  84         (setq emacs-lock-buffer-locked t)
  85         (message "Buffer is now unlocked"))
  86     (setq emacs-lock-buffer-locked nil)))
  87
  88 (defun emacs-lock-was-buffer-locked ()
  89   (if emacs-lock-buffer-locked
  90       (setq emacs-lock-from-exiting t)))
  91
  92 (add-hook 'kill-emacs-hook 'check-emacs-lock)
  93 (add-hook 'kill-buffer-hook 'emacs-lock-check-buffer-lock)
  94 (add-hook 'shell-mode-hook 'emacs-lock-was-buffer-locked)
  95 (add-hook 'shell-mode-hook 'emacs-lock-shell-sentinel)
  96 (add-hook 'telnet-mode-hook 'emacs-lock-was-buffer-locked)
  97 (add-hook 'telnet-mode-hook 'emacs-lock-shell-sentinel)
  98
  99 (provide 'emacs-lock)
 100
 101 ;; arch-tag: 58e6cb43-7cf0-401a-bcb6-4902a0b8bdc1
 102 ;;; emacs-lock.el ends here