bug#4880: point moves in other dired windows

["Per Starbäck" <per@starback.se>]

I have done this in 23.1 and in the current cvs version:

emacs -q /tmp
C-x 2 g

Point in the *other* window now goes to the beginning of the buffer,
which was unexpected for me.

dired-revert saves the old point, but only for the current window. The
enclosed patch fixes it so that
dired-revert saves and restores the point in all windows showing that
dired buffer.

$ diff -c dired.el.~1.436~ dired.el
*** dired.el.~1.436~	2009-11-06 13:29:08.000000000 +0100
--- dired.el	2009-11-06 15:35:29.000000000 +0100
***************
*** 1103,1110 ****
  Preserves old cursor, marks/flags, hidden-p."
    (widen)				; just in case user narrowed
    (let ((modflag (buffer-modified-p))
! 	(opoint (point))
! 	(ofile (dired-get-filename nil t))
  	(mark-alist nil)		; save marked files
  	(hidden-subdirs (dired-remember-hidden))
  	(old-subdir-alist (cdr (reverse dired-subdir-alist))) ; except pwd
--- 1103,1109 ----
  Preserves old cursor, marks/flags, hidden-p."
    (widen)				; just in case user narrowed
    (let ((modflag (buffer-modified-p))
! 	(positions (dired-save-positions))
  	(mark-alist nil)		; save marked files
  	(hidden-subdirs (dired-remember-hidden))
  	(old-subdir-alist (cdr (reverse dired-subdir-alist))) ; except pwd
***************
*** 1124,1132 ****
      ;; ... run the hook for the whole buffer, and only after markers
      ;; have been reinserted (else omitting in dired-x would omit marked files)
      (run-hooks 'dired-after-readin-hook)	; no need to narrow
!     (or (and ofile (dired-goto-file ofile)) ; move cursor to where it
! 	(goto-char opoint))		; was before
!     (dired-move-to-filename)
      (save-excursion			; hide subdirs that were hidden
        (dolist (dir hidden-subdirs)
  	(if (dired-goto-subdir dir)
--- 1123,1129 ----
      ;; ... run the hook for the whole buffer, and only after markers
      ;; have been reinserted (else omitting in dired-x would omit marked files)
      (run-hooks 'dired-after-readin-hook)	; no need to narrow
!     (dired-restore-positions positions)
      (save-excursion			; hide subdirs that were hidden
        (dolist (dir hidden-subdirs)
  	(if (dired-goto-subdir dir)
***************
*** 1140,1145 ****
--- 1137,1161 ----
  ;; Subroutines of dired-revert
  ;; Some of these are also used when inserting subdirs.

+ (defun dired-save-positions ()
+   "Store the current positions in all windows displaying this dired buffer.
+ Store both filename (if any) and point."
+   (mapcar (lambda (w)
+ 	    (list w
+ 		  (with-selected-window w
+ 		    (dired-get-filename nil t))
+ 		  (window-point w)))
+ 	  (get-buffer-window-list nil 0 t)))
+
+ (defun dired-restore-positions (positions)
+   "Restore POSITIONS saved with `dired-save-positions'."
+   (dolist (win-file-pos positions)
+     (with-selected-window (car win-file-pos)
+       (unless (and (nth 1 win-file-pos)
+ 		   (dired-goto-file (nth 1 win-file-pos)))
+ 	(goto-char (nth 2 win-file-pos))
+ 	(dired-move-to-filename)))))
+
  (defun dired-remember-marks (beg end)
    "Return alist of files and their marks, from BEG to END."
    (if selective-display			; must unhide to make this work.