* ibuffer.el: Update autoload checksum.

[gnu-emacs] / lisp / dired-aux.el

diff --git a/lisp/dired-aux.el b/lisp/dired-aux.el
index 4976d2cd68391f690c32c2d893ab870c181d92e1..62d6928c024594a08501eaa8adde838d5137c442 100644 (file)
--- a/lisp/dired-aux.el
+++ b/lisp/dired-aux.el
@@ -1,7 +1,7 @@
 ;;; dired-aux.el --- less commonly used parts of dired
 
 ;; Copyright (C) 1985, 1986, 1992, 1994, 1998, 2000, 2001, 2002, 2003,
-;;   2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+;;   2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
 
 ;; Author: Sebastian Kremer <sk@thp.uni-koeln.de>.
 ;; Maintainer: FSF
@@ -60,27 +60,44 @@ With prefix arg, prompt for second argument SWITCHES,
 which is options for `diff'."
   (interactive
    (let* ((current (dired-get-filename t))
-         (target-dir (dired-dwim-target-directory))
-         (marked (and (mark t) (save-excursion
-                                 (goto-char (mark t))
-                                 (dired-get-filename nil t))))
-         (defaults
-           (append (dired-dwim-target-defaults nil target-dir)
-                   ;; Additional file with the mark.
-                   (and marked (list marked)))))
+         ;; Get the file at the mark.
+         (file-at-mark (if (mark t)
+                           (save-excursion (goto-char (mark t))
+                                           (dired-get-filename t t))))
+         ;; Use it as default if it's not the same as the current file,
+         ;; and the target dir is the current dir or the mark is active.
+         (default (if (and (not (equal file-at-mark current))
+                           (or (equal (dired-dwim-target-directory)
+                                      (dired-current-directory))
+                               mark-active))
+                      file-at-mark))
+         (target-dir (if default
+                         (dired-current-directory)
+                       (dired-dwim-target-directory)))
+         (defaults (dired-dwim-target-defaults (list current) target-dir)))
      (require 'diff)
      (list
       (minibuffer-with-setup-hook
          (lambda ()
            (set (make-local-variable 'minibuffer-default-add-function) nil)
            (setq minibuffer-default defaults))
-       (read-file-name (format "Diff %s with: " current) target-dir nil t))
+       (read-file-name
+        (format "Diff %s with%s: " current
+                (if default (format " (default %s)" default) ""))
+        target-dir default t))
       (if current-prefix-arg
          (read-string "Options for diff: "
                       (if (stringp diff-switches)
                           diff-switches
                         (mapconcat 'identity diff-switches " ")))))))
-  (diff file (dired-get-filename t) switches))
+  (let ((current (dired-get-filename t)))
+    (when (or (equal (expand-file-name file)
+                    (expand-file-name current))
+             (and (file-directory-p file)
+                  (equal (expand-file-name current file)
+                         (expand-file-name current))))
+      (error "Attempt to compare the file to itself"))
+    (diff file current switches)))
 
 ;;;###autoload
 (defun dired-backup-diff (&optional switches)
@@ -2291,7 +2308,7 @@ Use \\[dired-hide-all] to (un)hide all directories."
     (restore-buffer-modified-p modflag)))
 
 ;;;###autoload
-(defun dired-hide-all (arg)
+(defun dired-hide-all (&optional ignored)
   "Hide all subdirectories, leaving only their header lines.
 If there is already something hidden, make everything visible again.
 Use \\[dired-hide-subdir] to (un)hide a particular subdirectory."