lisp/winner.el

   1 ;;; winner.el --- Restore old window configurations
   2
   3 ;; Copyright (C) 1997-1998, 2001-2017 Free Software Foundation, Inc.
   4
   5 ;; Author: Ivar Rummelhoff <ivarru@math.uio.no>
   6 ;; Created: 27 Feb 1997
   7 ;; Keywords: convenience frames
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Winner mode is a global minor mode that records the changes in the
  27 ;; window configuration (i.e. how the frames are partitioned into
  28 ;; windows) so that the changes can be "undone" using the command
  29 ;; `winner-undo'.  By default this one is bound to the key sequence
  30 ;; ctrl-c left.  If you change your mind (while undoing), you can
  31 ;; press ctrl-c right (calling `winner-redo').  Even though it uses
  32 ;; some features of Emacs20.3, winner.el should also work with
  33 ;; Emacs19.34 and XEmacs20, provided that the installed version of
  34 ;; custom is not obsolete.
  35
  36 ;; Winner mode was improved August 1998.
  37 ;; Further improvements February 2002.
  38
  39 ;;; Code:
  40
  41 (eval-when-compile (require 'cl-lib))
  42
  43 (defun winner-active-region ()
  44   (declare (gv-setter (lambda (store)
  45                         (if (featurep 'xemacs)
  46                             `(if ,store (zmacs-activate-region)
  47                                (zmacs-deactivate-region))
  48                           `(if ,store (activate-mark) (deactivate-mark))))))
  49   (region-active-p))
  50
  51 (defalias 'winner-edges
  52   (if (featurep 'xemacs) 'window-pixel-edges 'window-edges))
  53 (defalias 'winner-window-list
  54   (if (featurep 'xemacs)
  55       (lambda () (delq (minibuffer-window) (window-list nil 0)))
  56     (lambda () (window-list nil 0))))
  57
  58 (require 'ring)
  59
  60 (defgroup winner nil
  61   "Restoring window configurations."
  62   :group 'windows)
  63
  64 (defcustom winner-dont-bind-my-keys nil
  65   "Non-nil means do not bind keys in Winner mode."
  66   :type  'boolean
  67   :group 'winner)
  68
  69 (defcustom winner-ring-size 200
  70   "Maximum number of stored window configurations per frame."
  71   :type  'integer
  72   :group 'winner)
  73
  74 (defcustom winner-boring-buffers '("*Completions*")
  75   "List of buffer names whose windows `winner-undo' will not restore.
  76 You may want to include buffer names such as *Help*, *Apropos*,
  77 *Buffer List*, *info* and *Compile-Log*."
  78   :type '(repeat string)
  79   :group 'winner)
  80
  81
  82 \f
  83 ;;;; Saving old configurations (internal variables and subroutines)
  84
  85
  86 ;;; Current configuration
  87
  88 ;; List the windows according to their edges.
  89 (defun winner-sorted-window-list ()
  90   (sort (winner-window-list)
  91         (lambda (x y)
  92           (cl-loop for a in (winner-edges x)
  93                    for b in (winner-edges y)
  94                    while (= a b)
  95                    finally return (< a b)))))
  96
  97 (defun winner-win-data ()
  98   ;; Essential properties of the windows in the selected frame.
  99   (cl-loop for win in (winner-sorted-window-list)
 100            collect (cons (winner-edges win) (window-buffer win))))
 101
 102 ;; This variable is updated with the current window configuration
 103 ;; every time it changes.
 104 (defvar winner-currents nil)
 105
 106 ;; The current configuration (+ the buffers involved).
 107 (defsubst winner-conf ()
 108   (cons (current-window-configuration)
 109         (winner-win-data)))
 110
 111
 112 ;; Save current configuration.
 113 ;; (Called below by `winner-save-old-configurations').
 114 (defun winner-remember ()
 115   (setf (alist-get (selected-frame) winner-currents) (winner-conf)))
 116
 117 ;; Consult `winner-currents'.
 118 (defun winner-configuration (&optional frame)
 119   (or (cdr (assq (or frame (selected-frame)) winner-currents))
 120       (with-selected-frame frame
 121         (winner-conf))))
 122
 123
 124
 125 ;;; Saved configurations
 126
 127 ;; This variable contains the window configuration rings.
 128 ;; The key in this alist is the frame.
 129 (defvar winner-ring-alist nil)
 130
 131 ;; Find the right ring.  If it does not exist, create one.
 132 (defsubst winner-ring (frame)
 133   (or (cdr (assq frame winner-ring-alist))
 134       (let ((ring (make-ring winner-ring-size)))
 135         (ring-insert ring (winner-configuration frame))
 136         (push (cons frame ring) winner-ring-alist)
 137         ring)))
 138
 139 \f
 140 ;; If the same command is called several times in a row,
 141 ;; we only save one window configuration.
 142 (defvar winner-last-command nil)
 143
 144 ;; Frames affected by the previous command.
 145 (defvar winner-last-frames nil)
 146
 147
 148 (defsubst winner-equal (a b)
 149   "Check whether two Winner configurations (as produced by
 150 `winner-conf') are equal."
 151   (equal (cdr a) (cdr b)))
 152
 153
 154 ;; Save the current window configuration, if it has changed.
 155 ;; If so return frame, otherwise return nil.
 156 (defun winner-insert-if-new (frame)
 157   (unless (or (memq frame winner-last-frames)
 158               (eq this-command 'winner-redo))
 159     (let ((conf (winner-configuration frame))
 160           (ring (winner-ring frame)))
 161       (when (and (not (ring-empty-p ring))
 162                  (winner-equal conf (ring-ref ring 0)))
 163         ;; When the previous configuration was very similar,
 164         ;; keep only the latest.
 165         (ring-remove ring 0))
 166       (ring-insert ring conf)
 167       (push frame winner-last-frames)
 168       frame)))
 169
 170
 171
 172 ;;; Hooks
 173
 174 ;; Frames affected by the current command.
 175 (defvar winner-modified-list nil)
 176
 177 ;; Called whenever the window configuration changes
 178 ;; (a `window-configuration-change-hook').
 179 (defun winner-change-fun ()
 180
 181   ;; Cull dead frames.
 182   (setq winner-modified-list
 183         (cl-loop for frame in winner-modified-list
 184              if (frame-live-p frame) collect frame))
 185
 186   (unless (or (memq (selected-frame) winner-modified-list)
 187               (/= 0 (minibuffer-depth)))
 188     (push (selected-frame) winner-modified-list)))
 189
 190 ;; A `post-command-hook' for emacsen with
 191 ;; `window-configuration-change-hook'.
 192 (defun winner-save-old-configurations ()
 193   (when (zerop (minibuffer-depth))
 194     (unless (eq this-command winner-last-command)
 195       (setq winner-last-frames nil)
 196       (setq winner-last-command this-command))
 197     (dolist (frame winner-modified-list)
 198       (winner-insert-if-new frame))
 199     (setq winner-modified-list nil)
 200     (winner-remember)))
 201
 202 ;; A `minibuffer-setup-hook'.
 203 (defun winner-save-unconditionally ()
 204   (unless (eq this-command winner-last-command)
 205     (setq winner-last-frames nil)
 206     (setq winner-last-command this-command))
 207   (winner-insert-if-new (selected-frame))
 208   (winner-remember))
 209
 210 ;; A `post-command-hook' for other emacsen.
 211 ;; Also called by `winner-undo' before "undoing".
 212 (defun winner-save-conditionally ()
 213   (when (zerop (minibuffer-depth))
 214     (winner-save-unconditionally)))
 215
 216
 217
 218 \f
 219 ;;;; Restoring configurations
 220
 221 ;; Works almost as `set-window-configuration',
 222 ;; but does not change the contents or the size of the minibuffer,
 223 ;; and tries to preserve the selected window.
 224 (defun winner-set-conf (winconf)
 225   (let* ((miniwin  (minibuffer-window))
 226          (chosen   (selected-window))
 227          (minisize (window-height miniwin)))
 228     (cl-letf (((window-buffer miniwin))
 229               ((window-point  miniwin)))
 230       (set-window-configuration winconf))
 231     (cond
 232      ((window-live-p chosen) (select-window chosen))
 233      ((window-minibuffer-p) (other-window 1)))
 234     (when (/= minisize (window-height miniwin))
 235       (with-selected-window miniwin
 236         (setf (window-height) minisize)))))
 237
 238
 239
 240 (defvar winner-point-alist nil)
 241 ;; `set-window-configuration' restores old points and marks.  This is
 242 ;; not what we want, so we make a list of the "real" (i.e. new) points
 243 ;; and marks before undoing window configurations.
 244 ;;
 245 ;; Format of entries: (buffer (mark . mark-active) (window . point) ..)
 246
 247 (defun winner-make-point-alist ()
 248   (save-current-buffer
 249     (cl-loop with alist
 250              for win in (winner-window-list)
 251              for entry =
 252              (or (assq (window-buffer win) alist)
 253                  (car (push (list (set-buffer (window-buffer win))
 254                                   (cons (mark t) (winner-active-region)))
 255                             alist)))
 256              do (push (cons win (window-point win))
 257                       (cddr entry))
 258              finally return alist)))
 259
 260 (defun winner-get-point (buf win)
 261   ;; Consult (and possibly extend) `winner-point-alist'.
 262   ;; Returns nil if buf no longer exists.
 263   (when (buffer-name buf)
 264     (let ((entry (assq buf winner-point-alist)))
 265       (cond
 266        (entry
 267         (or (cdr (assq win (cddr entry)))
 268             (cdr (assq nil (cddr entry)))
 269             (with-current-buffer buf
 270               (push (cons nil (point)) (cddr entry))
 271               (point))))
 272        (t (with-current-buffer buf
 273             (push (list buf
 274                         (cons (mark t) (winner-active-region))
 275                         (cons nil (point)))
 276                   winner-point-alist)
 277             (point)))))))
 278
 279 \f
 280 ;; Make sure point does not end up in the minibuffer and delete
 281 ;; windows displaying dead or boring buffers
 282 ;; (c.f. `winner-boring-buffers').  Return nil if all the windows
 283 ;; should be deleted.  Preserve correct points and marks.
 284 (defun winner-set (conf)
 285   ;; For the format of `conf', see `winner-conf'.
 286   (let* ((buffers nil)
 287          (alive
 288           ;; Possibly update `winner-point-alist'
 289           (cl-loop for buf in (mapcar 'cdr (cdr conf))
 290                    for pos = (winner-get-point buf nil)
 291                    if (and pos (not (memq buf buffers)))
 292                    do (push buf buffers)
 293                    collect pos)))
 294     (winner-set-conf (car conf))
 295     (let (xwins)                        ; to be deleted
 296
 297       ;; Restore points
 298       (dolist (win (winner-sorted-window-list))
 299         (unless (and (pop alive)
 300                      (setf (window-point win)
 301                            (winner-get-point (window-buffer win) win))
 302                      (not (member (buffer-name (window-buffer win))
 303                                   winner-boring-buffers)))
 304           (push win xwins)))            ; delete this window
 305
 306       ;; Restore marks
 307       ;; `winner-undo' shouldn't update the selection (Bug#28631) when
 308       ;; select-enable-primary is non-nil.
 309       (unless select-enable-primary
 310         (save-current-buffer
 311           (cl-loop for buf in buffers
 312                    for entry = (cadr (assq buf winner-point-alist))
 313                    do (progn (set-buffer buf)
 314                              (set-mark (car entry))
 315                              (setf (winner-active-region) (cdr entry))))))
 316       ;; Delete windows, whose buffers are dead or boring.
 317       ;; Return t if this is still a possible configuration.
 318       (or (null xwins)
 319           (progn
 320             (mapc 'delete-window (cdr xwins)) ; delete all but one
 321             (unless (one-window-p t)
 322               (delete-window (car xwins))
 323               t))))))
 324
 325
 326
 327 ;;;; Winner mode  (a minor mode)
 328
 329 (defcustom winner-mode-hook nil
 330   "Functions to run whenever Winner mode is turned on or off."
 331   :type 'hook
 332   :group 'winner)
 333
 334 (define-obsolete-variable-alias 'winner-mode-leave-hook
 335   'winner-mode-off-hook "24.3")
 336
 337 (defcustom winner-mode-off-hook nil
 338   "Functions to run whenever Winner mode is turned off."
 339   :type 'hook
 340   :group 'winner)
 341
 342 (defvar winner-mode-map
 343   (let ((map (make-sparse-keymap)))
 344     (unless winner-dont-bind-my-keys
 345       (define-key map [(control c) left] 'winner-undo)
 346       (define-key map [(control c) right] 'winner-redo))
 347     map)
 348   "Keymap for Winner mode.")
 349
 350 \f
 351 ;;;###autoload
 352 (define-minor-mode winner-mode
 353   "Toggle Winner mode on or off.
 354 With a prefix argument ARG, enable Winner mode if ARG is
 355 positive, and disable it otherwise.  If called from Lisp, enable
 356 the mode if ARG is omitted or nil, and toggle it if ARG is ‘toggle’.
 357
 358 Winner mode is a global minor mode that records the changes in
 359 the window configuration (i.e. how the frames are partitioned
 360 into windows) so that the changes can be \"undone\" using the
 361 command `winner-undo'.  By default this one is bound to the key
 362 sequence `C-c <left>'.  If you change your mind (while undoing),
 363 you can press `C-c <right>' (calling `winner-redo')."
 364   :global t
 365   (if winner-mode
 366       (progn
 367         (add-hook 'window-configuration-change-hook 'winner-change-fun)
 368         (add-hook 'post-command-hook 'winner-save-old-configurations)
 369         (add-hook 'minibuffer-setup-hook 'winner-save-unconditionally)
 370         (setq winner-modified-list (frame-list))
 371         (winner-save-old-configurations))
 372     (remove-hook 'window-configuration-change-hook 'winner-change-fun)
 373     (remove-hook 'post-command-hook 'winner-save-old-configurations)
 374     (remove-hook 'minibuffer-setup-hook 'winner-save-unconditionally)))
 375
 376 ;; Inspired by undo (simple.el)
 377
 378 (defvar winner-undo-frame nil)
 379
 380 (defvar winner-pending-undo-ring nil
 381   "The ring currently used by `winner-undo'.")
 382 (defvar winner-undo-counter nil)
 383 (defvar winner-undone-data  nil) ; There confs have been passed.
 384
 385 (defun winner-undo ()
 386   "Switch back to an earlier window configuration saved by Winner mode.
 387 In other words, \"undo\" changes in window configuration."
 388   (interactive)
 389   (cond
 390    ((not winner-mode) (error "Winner mode is turned off"))
 391    (t (unless (and (eq last-command 'winner-undo)
 392                    (eq winner-undo-frame (selected-frame)))
 393         (winner-save-conditionally)     ; current configuration->stack
 394         (setq winner-undo-frame (selected-frame))
 395         (setq winner-point-alist (winner-make-point-alist))
 396         (setq winner-pending-undo-ring (winner-ring (selected-frame)))
 397         (setq winner-undo-counter 0)
 398         (setq winner-undone-data (list (winner-win-data))))
 399       (cl-incf winner-undo-counter)     ; starting at 1
 400       (when (and (winner-undo-this)
 401                  (not (window-minibuffer-p)))
 402         (message "Winner undo (%d / %d)"
 403                  winner-undo-counter
 404                  (1- (ring-length winner-pending-undo-ring)))))))
 405
 406
 407
 408 \f
 409 (defun winner-undo-this ()              ; The heart of winner undo.
 410   (cl-loop
 411    (cond
 412     ((>= winner-undo-counter (ring-length winner-pending-undo-ring))
 413      (message "No further window configuration undo information")
 414      (cl-return nil))
 415
 416     ((and                               ; If possible configuration
 417       (winner-set (ring-ref winner-pending-undo-ring
 418                             winner-undo-counter))
 419                                         ; .. and new configuration
 420       (let ((data (winner-win-data)))
 421         (and (not (member data winner-undone-data))
 422              (push data winner-undone-data))))
 423      (cl-return t))                     ; .. then everything is fine.
 424     (t ;; Otherwise, discharge it (and try the next one).
 425      (ring-remove winner-pending-undo-ring winner-undo-counter)))))
 426
 427
 428 (defun winner-redo ()                   ; If you change your mind.
 429   "Restore a more recent window configuration saved by Winner mode."
 430   (interactive)
 431   (cond
 432    ((eq last-command 'winner-undo)
 433     (winner-set
 434      (if (zerop (minibuffer-depth))
 435          (ring-remove winner-pending-undo-ring 0)
 436        (ring-ref winner-pending-undo-ring 0)))
 437     (unless (eq (selected-window) (minibuffer-window))
 438       (message "Winner undid undo")))
 439    (t (user-error "Previous command was not a `winner-undo'"))))
 440
 441 (provide 'winner)
 442 ;;; winner.el ends here