lisp/emacs-lock.el

   1 ;;; emacs-lock.el --- prevents you from exiting emacs if a buffer is locked
   2
   3 ;; Copyright (C) 1994, 1997, 2002, 2003, 2004,
   4 ;;   2005, 2006 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 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., 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 t is found, signal error and display the locked buffer name."
  52   (let ((buffers (buffer-list)))
  53     (save-excursion
  54       (while buffers
  55         (set-buffer (car buffers))
  56         (if emacs-lock-from-exiting
  57             (error "Emacs is locked from exit due to buffer: %s" (buffer-name))
  58           (setq buffers (cdr buffers)))))))
  59
  60 (defun toggle-emacs-lock ()
  61   "Toggle `emacs-lock-from-exiting' between t and nil for the current buffer.
  62 See `check-emacs-lock'."
  63   (interactive)
  64   (if emacs-lock-from-exiting
  65       (setq emacs-lock-from-exiting nil)
  66     (setq emacs-lock-from-exiting t))
  67   (if emacs-lock-from-exiting
  68       (message "Buffer is now locked")
  69     (message "Buffer is now unlocked")))
  70
  71 (defun emacs-lock-check-buffer-lock ()
  72   "Check if variable `emacs-lock-from-exiting' is t for a buffer.
  73 If t is found, signal error and display the locked buffer name."
  74   (if emacs-lock-from-exiting
  75       (error "Buffer `%s' is locked, can't delete it" (buffer-name))))
  76
  77 ; These next defuns make it so if you exit a shell that is locked,  the lock
  78 ; is shut off for that shell so you can exit emacs.  Same for telnet.
  79 ; Also, if a shell or a telnet buffer was locked and the process killed,
  80 ; turn the lock back on again if the process is restarted.
  81
  82 (defun emacs-lock-shell-sentinel ()
  83   (set-process-sentinel
  84    (get-buffer-process (buffer-name)) (function emacs-lock-clear-sentinel)))
  85
  86 (defun emacs-lock-clear-sentinel (proc str)
  87   (if emacs-lock-from-exiting
  88       (progn
  89         (setq emacs-lock-from-exiting nil)
  90         (setq emacs-lock-buffer-locked t)
  91         (message "Buffer is now unlocked"))
  92     (setq emacs-lock-buffer-locked nil)))
  93
  94 (defun emacs-lock-was-buffer-locked ()
  95   (if emacs-lock-buffer-locked
  96       (setq emacs-lock-from-exiting t)))
  97
  98 (add-hook 'kill-emacs-hook 'check-emacs-lock)
  99 (add-hook 'kill-buffer-hook 'emacs-lock-check-buffer-lock)
 100 (add-hook 'shell-mode-hook 'emacs-lock-was-buffer-locked)
 101 (add-hook 'shell-mode-hook 'emacs-lock-shell-sentinel)
 102 (add-hook 'telnet-mode-hook 'emacs-lock-was-buffer-locked)
 103 (add-hook 'telnet-mode-hook 'emacs-lock-shell-sentinel)
 104
 105 (provide 'emacs-lock)
 106
 107 ;;; arch-tag: 58e6cb43-7cf0-401a-bcb6-4902a0b8bdc1
 108 ;;; emacs-lock.el ends here