Refactor rotate-windows, add utility swap-windows

Changes to rotate-windows:
- rename to spacemacs/rotate-windows-forward
- direction of rotation matches window numbers
- COUNT argument now rotates all windows by COUNT steps
- all window parameters are saved, not only buffer and window-start

swap-windows is not used for now, but could be helpful in the future.

layers/+distributions/spacemacs-base/funcs.el

@@ -148,41 +148,48 @@ automatically applied to."
   "Determines if a buffer is useless."
   (not (spacemacs/useful-buffer-p buffer)))
 
-;; from magnars modified by ffevotte for dedicated windows support
+
-(defun spacemacs/rotate-windows (count)
+(defun spacemacs/swap-windows (window1 window2)
+  "Swap two windows.
+WINDOW1 and WINDOW2 must be valid windows. They may contain child
+windows."
+  (let ((state1 (window-state-get window1))
+        (state2 (window-state-get window2)))
+    ;; to put state into dedicated windows, we must undedicate them first (not
+    ;; needed with Emacs 25.1)
+    (dolist (win (list window1 window2))
+      (if (window-live-p win)
+          (set-window-dedicated-p win nil)
+        ;; win has sub-windows, undedicate all of them
+        (walk-window-subtree (lambda (leaf-window)
+                               (set-window-dedicated-p leaf-window nil))
+                             win)))
+    (window-state-put state1 window2)
+    (window-state-put state2 window1)))
+
+;; originally from magnars and modified by ffevotte for dedicated windows
+;; support, it has quite diverged by now
+(defun spacemacs/rotate-windows-forward (count)
   "Rotate each window forwards.
 A negative prefix argument rotates each window backwards.
 Dedicated (locked) windows are left untouched."
   (interactive "p")
-  (let* ((non-dedicated-windows (remove-if 'window-dedicated-p (window-list)))
+  (let* ((non-dedicated-windows (cl-remove-if 'window-dedicated-p (window-list)))
+         (states (mapcar #'window-state-get non-dedicated-windows))
          (num-windows (length non-dedicated-windows))
-         (i 0)
          (step (+ num-windows count)))
-    (cond ((not (> num-windows 1))
+    (if (< num-windows 2)
-           (message "You can't rotate a single window!"))
+        (error "You can't rotate a single window!")
-          (t
+      (dotimes (i num-windows)
-           (dotimes (counter (- num-windows 1))
+        (window-state-put
-             (let* ((next-i (% (+ step i) num-windows))
+         (elt states i)
-
+         (elt non-dedicated-windows (% (+ step i) num-windows)))))))
-                    (w1 (elt non-dedicated-windows i))
-                    (w2 (elt non-dedicated-windows next-i))
-
-                    (b1 (window-buffer w1))
-                    (b2 (window-buffer w2))
-
-                    (s1 (window-start w1))
-                    (s2 (window-start w2)))
-               (set-window-buffer w1 b2)
-               (set-window-buffer w2 b1)
-               (set-window-start w1 s2)
-               (set-window-start w2 s1)
-               (setq i next-i)))))))
 
 (defun spacemacs/rotate-windows-backward (count)
   "Rotate each window backwards.
 Dedicated (locked) windows are left untouched."
   (interactive "p")
-  (spacemacs/rotate-windows (* -1 count)))
+  (spacemacs/rotate-windows-forward (* -1 count)))
 
 ;; Note that this duplicates code from select-window-by-number, ideally should
 ;; upstream this function into windows.el

layers/+distributions/spacemacs-base/keybindings.el

@@ -392,7 +392,7 @@
   "wc"  'spacemacs/toggle-centered-buffer-mode
   "wC"  'spacemacs/centered-buffer-mode-full-width
   "wo"  'other-frame
-  "wr"  'spacemacs/rotate-windows
+  "wr"  'spacemacs/rotate-windows-forward
   "wR"  'spacemacs/rotate-windows-backward
   "ws"  'split-window-below
   "wS"  'split-window-below-and-focus
@@ -541,7 +541,7 @@
   ("L" evil-window-move-far-right)
   ("<S-right>" evil-window-move-far-right)
   ("o" other-frame)
-  ("r" spacemacs/rotate-windows)
+  ("r" spacemacs/rotate-windows-forward)
   ("R" spacemacs/rotate-windows-backward)
   ("s" split-window-below)
   ("S" split-window-below-and-focus)