-;;; emacs-lock.el --- prevents you from exiting Emacs if a buffer is locked
+;;; emacs-lock.el --- protect buffers against killing or exiting -*- lexical-binding: t -*-
-;; Copyright (C) 1994, 1997, 2001, 2002, 2003, 2004,
-;; 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
+;; Copyright (C) 2011-2016 Free Software Foundation, Inc.
-;; Author: Tom Wurgler <twurgler@goodyear.com>
-;; Created: 12/8/94
+;; Author: Juanma Barranquero <lekktu@gmail.com>
+;; Inspired by emacs-lock.el by Tom Wurgler <twurgler@goodyear.com>
+;; Maintainer: emacs-devel@gnu.org
;; Keywords: extensions, processes
;; This file is part of GNU Emacs.
;;; 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.
+;; This package defines a minor mode Emacs Lock to mark a buffer as
+;; protected against accidental killing, or exiting Emacs, or both.
+;; Buffers associated with inferior modes, like shell or telnet, can
+;; be treated specially, by auto-unlocking them if their inferior
+;; processes are dead.
;;; 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
+(defgroup emacs-lock nil
+ "Emacs-Lock mode."
+ :version "24.1"
+ :group 'convenience)
+
+(defcustom emacs-lock-default-locking-mode 'all
+ "Default locking mode of Emacs-Locked buffers.
+
+Its value is used as the default for `emacs-lock-mode' (which
+see) the first time that Emacs Lock mode is turned on in a buffer
+without passing an explicit locking mode.
+
+Possible values are:
+ exit -- Emacs cannot exit while the buffer is locked
+ kill -- the buffer cannot be killed, but Emacs can exit as usual
+ all -- the buffer is locked against both actions
+ nil -- the buffer is not locked"
+ :type '(choice
+ (const :tag "Do not allow Emacs to exit" exit)
+ (const :tag "Do not allow killing the buffer" kill)
+ (const :tag "Do not allow killing the buffer or exiting Emacs" all)
+ (const :tag "Do not lock the buffer" nil))
+ :group 'emacs-lock
+ :version "24.1")
+
+;; Note: as auto-unlocking can lead to data loss, it would be better
+;; to default to nil; but the value below is for compatibility with
+;; the old emacs-lock.el.
+(defcustom emacs-lock-unlockable-modes '((shell-mode . all)
+ (telnet-mode . all))
+ "Alist of auto-unlockable modes.
+Each element is a pair (MAJOR-MODE . ACTION), where ACTION is
+one of `kill', `exit' or `all'. Buffers with matching major
+modes are auto-unlocked for the specific action if their
+inferior processes are not alive. If this variable is t, all
+buffers associated to inferior processes are auto-unlockable
+for both actions (NOT RECOMMENDED)."
+ :type '(choice
+ (const :tag "All buffers with inferior processes" t)
+ (repeat :tag "Selected modes"
+ (cons :tag "Set auto-unlock for"
+ (symbol :tag "Major mode")
+ (radio
+ (const :tag "Allow exiting" exit)
+ (const :tag "Allow killing" kill)
+ (const :tag "Allow both" all)))))
+ :group 'emacs-lock
+ :version "24.1")
+
+(defcustom emacs-lock-locked-buffer-functions nil
+ "Abnormal hook run when Emacs Lock prevents exiting Emacs, or killing a buffer.
+The functions get one argument, the first locked buffer found."
+ :type 'hook
+ :group 'emacs-lock
+ :version "24.3")
+
+(defvar-local emacs-lock-mode nil
+ "If non-nil, the current buffer is locked.
+It can be one of the following values:
+ exit -- Emacs cannot exit while the buffer is locked
+ kill -- the buffer cannot be killed, but Emacs can exit as usual
+ all -- the buffer is locked against both actions
+ nil -- the buffer is not locked")
+(put 'emacs-lock-mode 'permanent-local t)
+
+(defvar-local emacs-lock--old-mode nil
+ "Most recent locking mode set on the buffer.
+Internal use only.")
+(put 'emacs-lock--old-mode 'permanent-local t)
+
+(defvar-local emacs-lock--try-unlocking nil
+ "Non-nil if current buffer should be checked for auto-unlocking.
+Internal use only.")
+(put 'emacs-lock--try-unlocking 'permanent-local t)
+
+(defun emacs-lock-live-process-p (buffer-or-name)
+ "Return t if BUFFER-OR-NAME is associated with a live process."
+ (process-live-p (get-buffer-process buffer-or-name)))
+
+(defun emacs-lock--can-auto-unlock (action)
+ "Return t if the current buffer can auto-unlock for ACTION.
+ACTION must be one of `kill' or `exit'.
+See `emacs-lock-unlockable-modes'."
+ (and emacs-lock--try-unlocking
+ (not (emacs-lock-live-process-p (current-buffer)))
+ (or (eq emacs-lock-unlockable-modes t)
+ (let ((unlock (cdr (assq major-mode emacs-lock-unlockable-modes))))
+ (or (eq unlock 'all) (eq unlock action))))))
+
+(defun emacs-lock--exit-locked-buffer ()
+ "Return the first exit-locked buffer found."
+ (save-current-buffer
+ (catch :found
+ (dolist (buffer (buffer-list))
+ (set-buffer buffer)
+ (unless (or (emacs-lock--can-auto-unlock 'exit)
+ (memq emacs-lock-mode '(nil kill)))
+ (throw :found buffer)))
+ nil)))
+
+(defun emacs-lock--kill-emacs-hook ()
+ "Signal an error if any buffer is exit-locked.
+Used from `kill-emacs-hook' (which see)."
+ (let ((locked (emacs-lock--exit-locked-buffer)))
+ (when locked
+ (run-hook-with-args 'emacs-lock-locked-buffer-functions locked)
+ (error "Emacs cannot exit because buffer %S is locked"
+ (buffer-name locked)))))
+
+(defun emacs-lock--kill-emacs-query-functions ()
+ "Display a message if any buffer is exit-locked.
+Return a value appropriate for `kill-emacs-query-functions' (which see)."
+ (let ((locked (emacs-lock--exit-locked-buffer)))
+ (if (not locked)
+ t
+ (run-hook-with-args 'emacs-lock-locked-buffer-functions locked)
+ (message "Emacs cannot exit because buffer %S is locked"
+ (buffer-name locked))
+ nil)))
+
+(defun emacs-lock--kill-buffer-query-functions ()
+ "Display a message if the current buffer is kill-locked.
+Return a value appropriate for `kill-buffer-query-functions' (which see)."
+ (if (or (emacs-lock--can-auto-unlock 'kill)
+ (memq emacs-lock-mode '(nil exit)))
+ t
+ (run-hook-with-args 'emacs-lock-locked-buffer-functions (current-buffer))
+ (message "Buffer %S is locked and cannot be killed" (buffer-name))
+ nil))
+
+(defun emacs-lock--set-mode (mode arg)
+ "Setter function for `emacs-lock-mode'."
+ (setq emacs-lock-mode
+ (cond ((memq arg '(all exit kill))
+ ;; explicit locking mode arg, use it
+ arg)
+ ((and (eq arg current-prefix-arg) (consp current-prefix-arg))
+ ;; called with C-u M-x emacs-lock-mode, so ask the user
+ (intern (completing-read "Locking mode: "
+ '("all" "exit" "kill")
+ nil t nil nil
+ (symbol-name
+ emacs-lock-default-locking-mode))))
+ ((eq mode t)
+ ;; turn on, so use previous setting, or customized default
+ (or emacs-lock--old-mode emacs-lock-default-locking-mode))
+ (t
+ ;; anything else (turn off)
+ mode))))
+
+(define-obsolete-variable-alias 'emacs-lock-from-exiting
+ 'emacs-lock-mode "24.1")
+
+;;;###autoload
+(define-minor-mode emacs-lock-mode
+ "Toggle Emacs Lock mode in the current buffer.
+If called with a plain prefix argument, ask for the locking mode
+to be used. With any other prefix ARG, turn mode on if ARG is
+positive, off otherwise. If called from Lisp, enable the mode if
+ARG is omitted or nil.
+
+Initially, if the user does not pass an explicit locking mode, it
+defaults to `emacs-lock-default-locking-mode' (which see);
+afterwards, the locking mode most recently set on the buffer is
+used instead.
+
+When called from Elisp code, ARG can be any locking mode:
+
+ exit -- Emacs cannot exit while the buffer is locked
+ kill -- the buffer cannot be killed, but Emacs can exit as usual
+ all -- the buffer is locked against both actions
+
+Other values are interpreted as usual."
+ :init-value nil
+ :lighter (""
+ (emacs-lock--try-unlocking " locked:" " Locked:")
+ (:eval (symbol-name emacs-lock-mode)))
+ :group 'emacs-lock
+ :variable (emacs-lock-mode .
+ (lambda (mode)
+ (emacs-lock--set-mode mode arg)))
+ (when emacs-lock-mode
+ (setq emacs-lock--old-mode emacs-lock-mode)
+ (setq emacs-lock--try-unlocking
+ (and (if (eq emacs-lock-unlockable-modes t)
+ (emacs-lock-live-process-p (current-buffer))
+ (assq major-mode emacs-lock-unlockable-modes))
+ t))))
+
+(unless noninteractive
+ (add-hook 'kill-buffer-query-functions 'emacs-lock--kill-buffer-query-functions)
+ ;; We set a hook in both kill-emacs-hook and kill-emacs-query-functions because
+ ;; we really want to use k-e-q-f to stop as soon as possible, but don't want to
+ ;; be caught by surprise if someone calls `kill-emacs' instead.
+ (add-hook 'kill-emacs-hook 'emacs-lock--kill-emacs-hook)
+ (add-hook 'kill-emacs-query-functions 'emacs-lock--kill-emacs-query-functions))
+
+(defun emacs-lock-unload-function ()
+ "Unload the Emacs Lock library."
+ (catch :continue
(dolist (buffer (buffer-list))
(set-buffer buffer)
- (when emacs-lock-from-exiting
- (error "Emacs is locked from exit due to buffer: %s" (buffer-name))))))
+ (when emacs-lock-mode
+ (if (y-or-n-p (format "Buffer %S is locked, unlock it? " (buffer-name)))
+ (emacs-lock-mode -1)
+ (message "Unloading of feature `emacs-lock' aborted.")
+ (throw :continue t))))
+ ;; continue standard unloading
+ nil))
+
+;;; Compatibility
(defun toggle-emacs-lock ()
- "Toggle `emacs-lock-from-exiting' for the current buffer.
-See `check-emacs-lock'."
+ "Toggle `emacs-lock-from-exiting' for the current buffer."
+ (declare (obsolete emacs-lock-mode "24.1"))
(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)
+ (call-interactively 'emacs-lock-mode))
(provide 'emacs-lock)
-;; arch-tag: 58e6cb43-7cf0-401a-bcb6-4902a0b8bdc1
;;; emacs-lock.el ends here