;;; winner.el --- Restore old window configurations
;; Copyright (C) 1997-1998, 2001-2013 Free Software Foundation, Inc.
;; Author: Ivar Rummelhoff <ivarru@math.uio.no>
;; Created: 27 Feb 1997
;; Keywords: convenience frames
;; 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:
;; Winner mode is a global minor mode that records the changes in the
;; window configuration (i.e. how the frames are partitioned into
;; windows) so that the changes can be "undone" using the command
;; `winner-undo'. By default this one is bound to the key sequence
;; ctrl-c left. If you change your mind (while undoing), you can
;; press ctrl-c right (calling `winner-redo'). Even though it uses
;; some features of Emacs20.3, winner.el should also work with
;; Emacs19.34 and XEmacs20, provided that the installed version of
;; custom is not obsolete.
;; Winner mode was improved August 1998.
;; Further improvements February 2002.
;;; Code:
(eval-when-compile (require 'cl-lib))
(defun winner-active-region ()
(declare (gv-setter (lambda (store)
(if (featurep 'xemacs)
`(if ,store (zmacs-activate-region)
(zmacs-deactivate-region))
`(if ,store (activate-mark) (deactivate-mark))))))
(region-active-p))
(defalias 'winner-edges
(if (featurep 'xemacs) 'window-pixel-edges 'window-edges))
(defalias 'winner-window-list
(if (featurep 'xemacs)
(lambda () (delq (minibuffer-window) (window-list nil 0)))
(lambda () (window-list nil 0))))
(require 'ring)
(defgroup winner nil
"Restoring window configurations."
:group 'windows)
(defcustom winner-dont-bind-my-keys nil
"Non-nil means do not bind keys in Winner mode."
:type 'boolean
:group 'winner)
(defcustom winner-ring-size 200
"Maximum number of stored window configurations per frame."
:type 'integer
:group 'winner)
(defcustom winner-boring-buffers '("*Completions*")
"List of buffer names whose windows `winner-undo' will not restore.
You may want to include buffer names such as *Help*, *Apropos*,
*Buffer List*, *info* and *Compile-Log*."
:type '(repeat string)
:group 'winner)
;;;; Saving old configurations (internal variables and subroutines)
;;; Current configuration
;; List the windows according to their edges.
(defun winner-sorted-window-list ()
(sort (winner-window-list)
(lambda (x y)
(cl-loop for a in (winner-edges x)
for b in (winner-edges y)
while (= a b)
finally return (< a b)))))
(defun winner-win-data ()
;; Essential properties of the windows in the selected frame.
(cl-loop for win in (winner-sorted-window-list)
collect (cons (winner-edges win) (window-buffer win))))
;; This variable is updated with the current window configuration
;; every time it changes.
(defvar winner-currents nil)
;; The current configuration (+ the buffers involved).
(defsubst winner-conf ()
(cons (current-window-configuration)
(winner-win-data)))
;; Save current configuration.
;; (Called below by `winner-save-old-configurations').
(defun winner-remember ()
(let ((entry (assq (selected-frame) winner-currents)))
(if entry (setcdr entry (winner-conf))
(push (cons (selected-frame) (winner-conf))
winner-currents))))
;; Consult `winner-currents'.
(defun winner-configuration (&optional frame)
(or (cdr (assq (or frame (selected-frame)) winner-currents))
(with-selected-frame frame
(winner-conf))))
;;; Saved configurations
;; This variable contains the window configuration rings.
;; The key in this alist is the frame.
(defvar winner-ring-alist nil)
;; Find the right ring. If it does not exist, create one.
(defsubst winner-ring (frame)
(or (cdr (assq frame winner-ring-alist))
(let ((ring (make-ring winner-ring-size)))
(ring-insert ring (winner-configuration frame))
(push (cons frame ring) winner-ring-alist)
ring)))
;; If the same command is called several times in a row,
;; we only save one window configuration.
(defvar winner-last-command nil)
;; Frames affected by the previous command.
(defvar winner-last-frames nil)
(defsubst winner-equal (a b)
"Check whether two Winner configurations (as produced by
`winner-conf') are equal."
(equal (cdr a) (cdr b)))
;; Save the current window configuration, if it has changed.
;; If so return frame, otherwise return nil.
(defun winner-insert-if-new (frame)
(unless (or (memq frame winner-last-frames)
(eq this-command 'winner-redo))
(let ((conf (winner-configuration frame))
(ring (winner-ring frame)))
(when (and (not (ring-empty-p ring))
(winner-equal conf (ring-ref ring 0)))
;; When the previous configuration was very similar,
;; keep only the latest.
(ring-remove ring 0))
(ring-insert ring conf)
(push frame winner-last-frames)
frame)))
;;; Hooks
;; Frames affected by the current command.
(defvar winner-modified-list nil)
;; Called whenever the window configuration changes
;; (a `window-configuration-change-hook').
(defun winner-change-fun ()
(unless (or (memq (selected-frame) winner-modified-list)
(/= 0 (minibuffer-depth)))
(push (selected-frame) winner-modified-list)))
;; A `post-command-hook' for emacsen with
;; `window-configuration-change-hook'.
(defun winner-save-old-configurations ()
(when (zerop (minibuffer-depth))
(unless (eq this-command winner-last-command)
(setq winner-last-frames nil)
(setq winner-last-command this-command))
(dolist (frame winner-modified-list)
(winner-insert-if-new frame))
(setq winner-modified-list nil)
(winner-remember)))
;; A `minibuffer-setup-hook'.
(defun winner-save-unconditionally ()
(unless (eq this-command winner-last-command)
(setq winner-last-frames nil)
(setq winner-last-command this-command))
(winner-insert-if-new (selected-frame))
(winner-remember))
;; A `post-command-hook' for other emacsen.
;; Also called by `winner-undo' before "undoing".
(defun winner-save-conditionally ()
(when (zerop (minibuffer-depth))
(winner-save-unconditionally)))
;;;; Restoring configurations
;; Works almost as `set-window-configuration',
;; but does not change the contents or the size of the minibuffer,
;; and tries to preserve the selected window.
(defun winner-set-conf (winconf)
(let* ((miniwin (minibuffer-window))
(chosen (selected-window))
(minisize (window-height miniwin)))
(cl-letf (((window-buffer miniwin))
((window-point miniwin)))
(set-window-configuration winconf))
(cond
((window-live-p chosen) (select-window chosen))
((window-minibuffer-p) (other-window 1)))
(when (/= minisize (window-height miniwin))
(with-selected-window miniwin
(setf (window-height) minisize)))))
(defvar winner-point-alist nil)
;; `set-window-configuration' restores old points and marks. This is
;; not what we want, so we make a list of the "real" (i.e. new) points
;; and marks before undoing window configurations.
;;
;; Format of entries: (buffer (mark . mark-active) (window . point) ..)
(defun winner-make-point-alist ()
(save-current-buffer
(cl-loop with alist
for win in (winner-window-list)
for entry =
(or (assq (window-buffer win) alist)
(car (push (list (set-buffer (window-buffer win))
(cons (mark t) (winner-active-region)))
alist)))
do (push (cons win (window-point win))
(cddr entry))
finally return alist)))
(defun winner-get-point (buf win)
;; Consult (and possibly extend) `winner-point-alist'.
;; Returns nil if buf no longer exists.
(when (buffer-name buf)
(let ((entry (assq buf winner-point-alist)))
(cond
(entry
(or (cdr (assq win (cddr entry)))
(cdr (assq nil (cddr entry)))
(with-current-buffer buf
(push (cons nil (point)) (cddr entry))
(point))))
(t (with-current-buffer buf
(push (list buf
(cons (mark t) (winner-active-region))
(cons nil (point)))
winner-point-alist)
(point)))))))
;; Make sure point does not end up in the minibuffer and delete
;; windows displaying dead or boring buffers
;; (c.f. `winner-boring-buffers'). Return nil if all the windows
;; should be deleted. Preserve correct points and marks.
(defun winner-set (conf)
;; For the format of `conf', see `winner-conf'.
(let* ((buffers nil)
(alive
;; Possibly update `winner-point-alist'
(cl-loop for buf in (mapcar 'cdr (cdr conf))
for pos = (winner-get-point buf nil)
if (and pos (not (memq buf buffers)))
do (push buf buffers)
collect pos)))
(winner-set-conf (car conf))
(let (xwins) ; to be deleted
;; Restore points
(dolist (win (winner-sorted-window-list))
(unless (and (pop alive)
(setf (window-point win)
(winner-get-point (window-buffer win) win))
(not (member (buffer-name (window-buffer win))
winner-boring-buffers)))
(push win xwins))) ; delete this window
;; Restore marks
(save-current-buffer
(cl-loop for buf in buffers
for entry = (cadr (assq buf winner-point-alist))
do (progn (set-buffer buf)
(set-mark (car entry))
(setf (winner-active-region) (cdr entry)))))
;; Delete windows, whose buffers are dead or boring.
;; Return t if this is still a possible configuration.
(or (null xwins)
(progn
(mapc 'delete-window (cdr xwins)) ; delete all but one
(unless (one-window-p t)
(delete-window (car xwins))
t))))))
;;;; Winner mode (a minor mode)
(defcustom winner-mode-hook nil
"Functions to run whenever Winner mode is turned on or off."
:type 'hook
:group 'winner)
(define-obsolete-variable-alias 'winner-mode-leave-hook
'winner-mode-off-hook "24.3")
(defcustom winner-mode-off-hook nil
"Functions to run whenever Winner mode is turned off."
:type 'hook
:group 'winner)
(defvar winner-mode-map
(let ((map (make-sparse-keymap)))
(unless winner-dont-bind-my-keys
(define-key map [(control c) left] 'winner-undo)
(define-key map [(control c) right] 'winner-redo))
map)
"Keymap for Winner mode.")
;;;###autoload
(define-minor-mode winner-mode nil :global t ; let d-m-m make the doc
(if winner-mode
(progn
(add-hook 'window-configuration-change-hook 'winner-change-fun)
(add-hook 'post-command-hook 'winner-save-old-configurations)
(add-hook 'minibuffer-setup-hook 'winner-save-unconditionally)
(setq winner-modified-list (frame-list))
(winner-save-old-configurations))
(remove-hook 'window-configuration-change-hook 'winner-change-fun)
(remove-hook 'post-command-hook 'winner-save-old-configurations)
(remove-hook 'minibuffer-setup-hook 'winner-save-unconditionally)))
;; Inspired by undo (simple.el)
(defvar winner-undo-frame nil)
(defvar winner-pending-undo-ring nil
"The ring currently used by `winner-undo'.")
(defvar winner-undo-counter nil)
(defvar winner-undone-data nil) ; There confs have been passed.
(defun winner-undo ()
"Switch back to an earlier window configuration saved by Winner mode.
In other words, \"undo\" changes in window configuration."
(interactive)
(cond
((not winner-mode) (error "Winner mode is turned off"))
(t (unless (and (eq last-command 'winner-undo)
(eq winner-undo-frame (selected-frame)))
(winner-save-conditionally) ; current configuration->stack
(setq winner-undo-frame (selected-frame))
(setq winner-point-alist (winner-make-point-alist))
(setq winner-pending-undo-ring (winner-ring (selected-frame)))
(setq winner-undo-counter 0)
(setq winner-undone-data (list (winner-win-data))))
(cl-incf winner-undo-counter) ; starting at 1
(when (and (winner-undo-this)
(not (window-minibuffer-p)))
(message "Winner undo (%d / %d)"
winner-undo-counter
(1- (ring-length winner-pending-undo-ring)))))))
(defun winner-undo-this () ; The heart of winner undo.
(cl-loop
(cond
((>= winner-undo-counter (ring-length winner-pending-undo-ring))
(message "No further window configuration undo information")
(cl-return nil))
((and ; If possible configuration
(winner-set (ring-ref winner-pending-undo-ring
winner-undo-counter))
; .. and new configuration
(let ((data (winner-win-data)))
(and (not (member data winner-undone-data))
(push data winner-undone-data))))
(cl-return t)) ; .. then everything is fine.
(t ;; Otherwise, discharge it (and try the next one).
(ring-remove winner-pending-undo-ring winner-undo-counter)))))
(defun winner-redo () ; If you change your mind.
"Restore a more recent window configuration saved by Winner mode."
(interactive)
(cond
((eq last-command 'winner-undo)
(winner-set
(if (zerop (minibuffer-depth))
(ring-remove winner-pending-undo-ring 0)
(ring-ref winner-pending-undo-ring 0)))
(unless (eq (selected-window) (minibuffer-window))
(message "Winner undid undo")))
(t (error "Previous command was not a `winner-undo'"))))
(provide 'winner)
;;; winner.el ends here