1;;; winner.el --- Restore old window configurations
2
3;; Copyright (C) 1997, 1998, 2001, 2002, 2003, 2004,
4;;   2005, 2006, 2007 Free Software Foundation. Inc.
5
6;; Author: Ivar Rummelhoff <ivarru@math.uio.no>
7;; Created: 27 Feb 1997
8;; Time-stamp: <2006-02-06 15:13:57 ttn>
9;; Keywords: convenience frames
10
11;; This file is part of GNU Emacs.
12
13;; GNU Emacs is free software; you can redistribute it and/or modify
14;; it under the terms of the GNU General Public License as published by
15;; the Free Software Foundation; either version 2, or (at your option)
16;; any later version.
17
18;; GNU Emacs is distributed in the hope that it will be useful,
19;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21;; GNU General Public License for more details.
22
23;; You should have received a copy of the GNU General Public License
24;; along with GNU Emacs; see the file COPYING.  If not, write to the
25;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
26;; Boston, MA 02110-1301, USA.
27
28;;; Commentary:
29
30;; Winner mode is a global minor mode that records the changes in the
31;; window configuration (i.e. how the frames are partitioned into
32;; windows) so that the changes can be "undone" using the command
33;; `winner-undo'.  By default this one is bound to the key sequence
34;; ctrl-c left.  If you change your mind (while undoing), you can
35;; press ctrl-c right (calling `winner-redo').  Even though it uses
36;; some features of Emacs20.3, winner.el should also work with
37;; Emacs19.34 and XEmacs20, provided that the installed version of
38;; custom is not obsolete.
39
40;; Winner mode was improved August 1998.
41;; Further improvements February 2002.
42
43;;; Code:
44
45(eval-when-compile
46  (require 'cl))
47
48
49(defmacro winner-active-region ()
50  (if (fboundp 'region-active-p)
51      '(region-active-p)
52    'mark-active))
53
54(defsetf winner-active-region () (store)
55  (if (fboundp 'zmacs-activate-region)
56      `(if ,store (zmacs-activate-region)
57	 (zmacs-deactivate-region))
58    `(setq mark-active ,store)))
59
60(defalias 'winner-edges
61  (if (featurep 'xemacs) 'window-pixel-edges 'window-edges))
62(defalias 'winner-window-list
63  (if (featurep 'xemacs)
64      (lambda () (delq (minibuffer-window) (window-list nil 0)))
65    (lambda () (window-list nil 0))))
66
67(require 'ring)
68
69(unless (fboundp 'defgroup)
70  (defmacro defgroup (&rest rest)))
71
72(defgroup winner nil
73  "Restoring window configurations."
74  :group 'windows)
75
76(unless (fboundp 'defcustom)
77  (defmacro defcustom (symbol &optional initvalue docs &rest rest)
78    (list 'defvar symbol initvalue docs)))
79
80;;;###autoload
81(defcustom winner-mode nil
82  "Toggle Winner mode.
83Setting this variable directly does not take effect;
84use either \\[customize] or the function `winner-mode'."
85  :set #'(lambda (symbol value) (funcall symbol (or value 0)))
86  :initialize 'custom-initialize-default
87  :type    'boolean
88  :group   'winner
89  :require 'winner)
90
91(defcustom winner-dont-bind-my-keys nil
92  "If non-nil: Do not use `winner-mode-map' in Winner mode."
93  :type  'boolean
94  :group 'winner)
95
96(defcustom winner-ring-size 200
97  "Maximum number of stored window configurations per frame."
98  :type  'integer
99  :group 'winner)
100
101(defcustom winner-boring-buffers '("*Completions*")
102  "`winner-undo' will not restore windows displaying any of these buffers.
103You may want to include buffer names such as *Help*, *Apropos*,
104*Buffer List*, *info* and *Compile-Log*."
105  :type '(repeat string)
106  :group 'winner)
107
108
109
110
111
112;;;; Saving old configurations (internal variables and subroutines)
113
114
115;;; Current configuration
116
117;; List the windows according to their edges.
118(defun winner-sorted-window-list ()
119  (sort (winner-window-list)
120        (lambda (x y)
121          (loop for a in (winner-edges x)
122                for b in (winner-edges y)
123                while (= a b)
124                finally return (< a b)))))
125
126(defun winner-win-data ()
127  ;; Essential properties of the windows in the selected frame.
128  (loop for win in (winner-sorted-window-list)
129        collect (cons (winner-edges win) (window-buffer win))))
130
131;; This variable is updated with the current window configuration
132;; every time it changes.
133(defvar winner-currents nil)
134
135;; The current configuration (+ the buffers involved).
136(defsubst winner-conf ()
137  (cons (current-window-configuration)
138        (winner-win-data)))
139
140
141;; Save current configuration.
142;; (Called below by `winner-save-old-configurations').
143(defun winner-remember ()
144  (let ((entry (assq (selected-frame) winner-currents)))
145    (if entry (setcdr entry (winner-conf))
146      (push (cons (selected-frame) (winner-conf))
147	    winner-currents))))
148
149;; Consult `winner-currents'.
150(defun winner-configuration (&optional frame)
151  (or (cdr (assq (or frame (selected-frame)) winner-currents))
152      (letf (((selected-frame) frame))
153	(winner-conf))))
154
155
156
157;;; Saved configurations
158
159;; This variable contains the window cofiguration rings.
160;; The key in this alist is the frame.
161(defvar winner-ring-alist nil)
162
163;; Find the right ring.  If it does not exist, create one.
164(defsubst winner-ring (frame)
165  (or (cdr (assq frame winner-ring-alist))
166      (let ((ring (make-ring winner-ring-size)))
167        (ring-insert ring (winner-configuration frame))
168        (push (cons frame ring) winner-ring-alist)
169        ring)))
170
171
172;; If the same command is called several times in a row,
173;; we only save one window configuration.
174(defvar winner-last-command nil)
175
176;; Frames affected by the previous command.
177(defvar winner-last-frames nil)
178
179
180(defsubst winner-equal (a b)
181  "Check whether two Winner configurations (as produced by
182`winner-conf') are equal."
183  (equal (cdr a) (cdr b)))
184
185
186;; Save the current window configuration, if it has changed.
187;; If so return frame, otherwise return nil.
188(defun winner-insert-if-new (frame)
189  (unless (or (memq frame winner-last-frames)
190	      (eq this-command 'winner-redo))
191    (let ((conf (winner-configuration frame))
192	  (ring (winner-ring frame)))
193      (when (and (not (ring-empty-p ring))
194		 (winner-equal conf (ring-ref ring 0)))
195        ;; When the previous configuration was very similar,
196        ;; keep only the latest.
197	(ring-remove ring 0))
198      (ring-insert ring conf)
199      (push frame winner-last-frames)
200      frame)))
201
202
203
204;;; Hooks
205
206;; Frames affected by the current command.
207(defvar winner-modified-list nil)
208
209;; Called whenever the window configuration changes
210;; (a `window-configuration-change-hook').
211(defun winner-change-fun ()
212  (unless (or (memq (selected-frame) winner-modified-list)
213              (/= 0 (minibuffer-depth)))
214    (push (selected-frame) winner-modified-list)))
215
216;; A `post-command-hook' for emacsen with
217;; `window-configuration-change-hook'.
218(defun winner-save-old-configurations ()
219  (when (zerop (minibuffer-depth))
220    (unless (eq this-command winner-last-command)
221      (setq winner-last-frames nil)
222      (setq winner-last-command this-command))
223    (dolist (frame winner-modified-list)
224      (winner-insert-if-new frame))
225    (setq winner-modified-list nil)
226    (winner-remember)))
227
228;; A `minibuffer-setup-hook'.
229(defun winner-save-unconditionally ()
230  (unless (eq this-command winner-last-command)
231    (setq winner-last-frames nil)
232    (setq winner-last-command this-command))
233  (winner-insert-if-new (selected-frame))
234  (winner-remember))
235
236;; A `post-command-hook' for other emacsen.
237;; Also called by `winner-undo' before "undoing".
238(defun winner-save-conditionally ()
239  (when (zerop (minibuffer-depth))
240    (winner-save-unconditionally)))
241
242
243
244
245;;;; Restoring configurations
246
247;; Works almost as `set-window-configuration',
248;; but does not change the contents or the size of the minibuffer,
249;; and tries to preserve the selected window.
250(defun winner-set-conf (winconf)
251  (let* ((miniwin  (minibuffer-window))
252         (chosen   (selected-window))
253         (minisize (window-height miniwin)))
254    (letf (((window-buffer miniwin))
255           ((window-point  miniwin)))
256      (set-window-configuration winconf))
257    (cond
258     ((window-live-p chosen) (select-window chosen))
259     ((window-minibuffer-p (selected-window))
260      (other-window 1)))
261    (when (/= minisize (window-height miniwin))
262      (letf (((selected-window) miniwin) )
263        (setf (window-height) minisize)))))
264
265
266
267(defvar winner-point-alist nil)
268;; `set-window-configuration' restores old points and marks.  This is
269;; not what we want, so we make a list of the "real" (i.e. new) points
270;; and marks before undoing window configurations.
271;;
272;; Format of entries: (buffer (mark . mark-active) (window . point) ..)
273
274(defun winner-make-point-alist ()
275  (letf (((current-buffer)))
276    (loop with alist
277	  for win in (winner-window-list)
278	  for entry =
279          (or (assq (window-buffer win) alist)
280              (car (push (list (set-buffer (window-buffer win))
281                               (cons (mark t) (winner-active-region)))
282                         alist)))
283	  do (push (cons win (window-point win))
284                   (cddr entry))
285	  finally return alist)))
286
287(defun winner-get-point (buf win)
288  ;; Consult (and possibly extend) `winner-point-alist'.
289  ;; Returns nil iff buf no longer exists.
290  (when (buffer-name buf)
291    (let ((entry (assq buf winner-point-alist)))
292      (cond
293       (entry
294	(or (cdr (assq win (cddr entry)))
295	    (cdr (assq nil (cddr entry)))
296	    (letf (((current-buffer) buf))
297	      (push (cons nil (point)) (cddr entry))
298	      (point))))
299       (t (letf (((current-buffer) buf))
300	    (push (list buf
301			(cons (mark t) (winner-active-region))
302			(cons nil (point)))
303		  winner-point-alist)
304	    (point)))))))
305
306
307;; Make sure point does not end up in the minibuffer and delete
308;; windows displaying dead or boring buffers
309;; (c.f. `winner-boring-buffers').  Return nil iff all the windows
310;; should be deleted.  Preserve correct points and marks.
311(defun winner-set (conf)
312  ;; For the format of `conf', see `winner-conf'.
313  (let* ((buffers nil)
314	 (alive
315          ;; Possibly update `winner-point-alist'
316	  (loop for buf in (mapcar 'cdr (cdr conf))
317		for pos = (winner-get-point buf nil)
318		if (and pos (not (memq buf buffers)))
319		do (push buf buffers)
320		collect pos)))
321    (winner-set-conf (car conf))
322    (let (xwins)                        ; to be deleted
323
324      ;; Restore points
325      (dolist (win (winner-sorted-window-list))
326        (unless (and (pop alive)
327                     (setf (window-point win)
328                           (winner-get-point (window-buffer win) win))
329                     (not (member (buffer-name (window-buffer win))
330                                  winner-boring-buffers)))
331          (push win xwins)))            ; delete this window
332
333      ;; Restore marks
334      (letf (((current-buffer)))
335	(loop for buf in buffers
336	      for entry = (cadr (assq buf winner-point-alist))
337	      do (progn (set-buffer buf)
338			(set-mark (car entry))
339			(setf (winner-active-region) (cdr entry)))))
340      ;; Delete windows, whose buffers are dead or boring.
341      ;; Return t if this is still a possible configuration.
342      (or (null xwins)
343	  (progn
344            (mapc 'delete-window (cdr xwins)) ; delete all but one
345            (unless (one-window-p t)
346              (delete-window (car xwins))
347              t))))))
348
349
350
351;;;; Winner mode  (a minor mode)
352
353(defcustom winner-mode-hook nil
354  "Functions to run whenever Winner mode is turned on."
355  :type 'hook
356  :group 'winner)
357
358(defcustom winner-mode-leave-hook nil
359  "Functions to run whenever Winner mode is turned off."
360  :type 'hook
361  :group 'winner)
362
363(defvar winner-mode-map
364  (let ((map (make-sparse-keymap)))
365    (define-key map [(control c) left] 'winner-undo)
366    (define-key map [(control c) right] 'winner-redo)
367    map)
368  "Keymap for Winner mode.")
369
370;; Check if `window-configuration-change-hook' is working.
371(defun winner-hook-installed-p ()
372  (save-window-excursion
373    (let ((winner-var nil)
374	  (window-configuration-change-hook
375	   '((lambda () (setq winner-var t)))))
376      (split-window)
377      winner-var)))
378
379
380;;;###autoload
381(defun winner-mode (&optional arg)
382  "Toggle Winner mode.
383With arg, turn Winner mode on if and only if arg is positive."
384  (interactive "P")
385  (let ((on-p (if arg (> (prefix-numeric-value arg) 0)
386		(not winner-mode))))
387    (cond
388     ;; Turn mode on
389     (on-p
390      (setq winner-mode t)
391      (cond
392       ((winner-hook-installed-p)
393	(add-hook 'window-configuration-change-hook 'winner-change-fun)
394      (add-hook 'post-command-hook 'winner-save-old-configurations))
395       (t (add-hook 'post-command-hook 'winner-save-conditionally)))
396      (add-hook 'minibuffer-setup-hook 'winner-save-unconditionally)
397      (setq winner-modified-list (frame-list))
398      (winner-save-old-configurations)
399      (run-hooks 'winner-mode-hook)
400      (when (interactive-p) (message "Winner mode enabled")))
401     ;; Turn mode off
402     (winner-mode
403      (setq winner-mode nil)
404      (remove-hook 'window-configuration-change-hook 'winner-change-fun)
405      (remove-hook 'post-command-hook 'winner-save-old-configurations)
406      (remove-hook 'post-command-hook 'winner-save-conditionally)
407      (remove-hook 'minibuffer-setup-hook 'winner-save-unconditionally)
408      (run-hooks 'winner-mode-leave-hook)
409      (when (interactive-p) (message "Winner mode disabled"))))))
410
411;; Inspired by undo (simple.el)
412
413(defvar winner-undo-frame nil)
414
415(defvar winner-pending-undo-ring nil
416  "The ring currently used by `winner-undo'.")
417(defvar winner-undo-counter nil)
418(defvar winner-undone-data  nil) ; There confs have been passed.
419
420(defun winner-undo ()
421  "Switch back to an earlier window configuration saved by Winner mode.
422In other words, \"undo\" changes in window configuration."
423  (interactive)
424  (cond
425   ((not winner-mode) (error "Winner mode is turned off"))
426   (t (unless (and (eq last-command 'winner-undo)
427 		   (eq winner-undo-frame (selected-frame)))
428	(winner-save-conditionally)     ; current configuration->stack
429 	(setq winner-undo-frame (selected-frame))
430 	(setq winner-point-alist (winner-make-point-alist))
431 	(setq winner-pending-undo-ring (winner-ring (selected-frame)))
432 	(setq winner-undo-counter 0)
433 	(setq winner-undone-data (list (winner-win-data))))
434      (incf winner-undo-counter)	; starting at 1
435      (when (and (winner-undo-this)
436 		 (not (window-minibuffer-p (selected-window))))
437 	(message "Winner undo (%d / %d)"
438 		 winner-undo-counter
439 		 (1- (ring-length winner-pending-undo-ring)))))))
440
441
442
443
444(defun winner-undo-this ()		; The heart of winner undo.
445  (loop
446   (cond
447    ((>= winner-undo-counter (ring-length winner-pending-undo-ring))
448     (message "No further window configuration undo information")
449     (return nil))
450
451    ((and				; If possible configuration
452      (winner-set (ring-ref winner-pending-undo-ring
453 			    winner-undo-counter))
454                                        ; .. and new configuration
455      (let ((data (winner-win-data)))
456 	(and (not (member data winner-undone-data))
457 	     (push data winner-undone-data))))
458     (return t))			; .. then everything is fine.
459    (t ;; Otherwise, discharge it (and try the next one).
460     (ring-remove winner-pending-undo-ring winner-undo-counter)))))
461
462
463(defun winner-redo ()			; If you change your mind.
464  "Restore a more recent window configuration saved by Winner mode."
465  (interactive)
466  (cond
467   ((eq last-command 'winner-undo)
468    (winner-set
469     (if (zerop (minibuffer-depth))
470         (ring-remove winner-pending-undo-ring 0)
471       (ring-ref winner-pending-undo-ring 0)))
472    (unless (eq (selected-window) (minibuffer-window))
473      (message "Winner undid undo")))
474   (t (error "Previous command was not a `winner-undo'"))))
475
476;;; To be evaluated when the package is loaded:
477
478(unless (or (assq 'winner-mode minor-mode-map-alist)
479	    winner-dont-bind-my-keys)
480  (push (cons 'winner-mode winner-mode-map)
481	minor-mode-map-alist))
482
483(provide 'winner)
484;; arch-tag: 686d1c1b-010e-42ca-a192-b5685112418f
485;;; winner.el ends here
486