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;;; emacs-lock.el --- prevents you from exiting Emacs if a buffer is locked
;; Copyright (C) 1994, 1997, 2001, 2002, 2003, 2004,
;; 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc
;; Author: Tom Wurgler <twurgler@goodyear.com>
;; Created: 12/8/94
;; Keywords: extensions, processes
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;; This code sets a buffer-local variable to t if toggle-emacs-lock is run,
;; then if the user attempts to exit Emacs, the locked buffer name will be
;; displayed and the exit aborted. This is just a way of protecting
;; yourself from yourself. For example, if you have a shell running a big
;; program and exiting Emacs would abort that program, you may want to lock
;; that buffer, then if you forget about it after a while, you won't
;; accidentally exit Emacs. To unlock the buffer, just goto the buffer and
;; run toggle-emacs-lock again.
;;; Code:
(defvar emacs-lock-from-exiting nil
"Whether Emacs is locked to prevent exiting. See `check-emacs-lock'.")
(make-variable-buffer-local 'emacs-lock-from-exiting)
(defvar emacs-lock-buffer-locked nil
"Whether a shell or telnet buffer was locked when its process was killed.")
(make-variable-buffer-local 'emacs-lock-buffer-locked)
(put 'emacs-lock-buffer-locked 'permanent-local t)
(defun check-emacs-lock ()
"Check if variable `emacs-lock-from-exiting' is t for any buffer.
If any locked buffer is found, signal error and display the buffer's name."
(save-excursion
(dolist (buffer (buffer-list))
(set-buffer buffer)
(when emacs-lock-from-exiting
(error "Emacs is locked from exit due to buffer: %s" (buffer-name))))))
(defun toggle-emacs-lock ()
"Toggle `emacs-lock-from-exiting' for the current buffer.
See `check-emacs-lock'."
(interactive)
(setq emacs-lock-from-exiting (not emacs-lock-from-exiting))
(if emacs-lock-from-exiting
(message "Buffer is now locked")
(message "Buffer is now unlocked")))
(defun emacs-lock-check-buffer-lock ()
"Check if variable `emacs-lock-from-exiting' is t for a buffer.
If the buffer is locked, signal error and display its name."
(when emacs-lock-from-exiting
(error "Buffer `%s' is locked, can't delete it" (buffer-name))))
; These next defuns make it so if you exit a shell that is locked, the lock
; is shut off for that shell so you can exit Emacs. Same for telnet.
; Also, if a shell or a telnet buffer was locked and the process killed,
; turn the lock back on again if the process is restarted.
(defun emacs-lock-shell-sentinel ()
(set-process-sentinel
(get-buffer-process (buffer-name)) (function emacs-lock-clear-sentinel)))
(defun emacs-lock-clear-sentinel (proc str)
(if emacs-lock-from-exiting
(progn
(setq emacs-lock-from-exiting nil)
(setq emacs-lock-buffer-locked t)
(message "Buffer is now unlocked"))
(setq emacs-lock-buffer-locked nil)))
(defun emacs-lock-was-buffer-locked ()
(if emacs-lock-buffer-locked
(setq emacs-lock-from-exiting t)))
(add-hook 'kill-emacs-hook 'check-emacs-lock)
(add-hook 'kill-buffer-hook 'emacs-lock-check-buffer-lock)
(add-hook 'shell-mode-hook 'emacs-lock-was-buffer-locked)
(add-hook 'shell-mode-hook 'emacs-lock-shell-sentinel)
(add-hook 'telnet-mode-hook 'emacs-lock-was-buffer-locked)
(add-hook 'telnet-mode-hook 'emacs-lock-shell-sentinel)
(provide 'emacs-lock)
;; arch-tag: 58e6cb43-7cf0-401a-bcb6-4902a0b8bdc1
;;; emacs-lock.el ends here