(diff-show-trailing-whitespaces): Remove function.

Move setting up whitepace-mode ...
(diff-mode): ... here.
(diff-mode-menu): Add a menu entry for showing trailing whitespace.

3 files changed, 18 insertions, 9 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 143342b5ad6..98d3d216b6f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -781,8 +781,8 @@ diff-auto-refine-mode.  It is bound to `C-c C-b'.
 buffer and tries to create ChangeLog entries for each change.
 It is bound to `C-x 4 A'.
 +++
-*** The new function `diff-show-trailing-whitespaces' shows
-trailing whitespace problems in the modified lines of a diff buffer.
+*** Turning on `whitespace-mode' in a diff buffer will show trailing
+whitespace problems in the modified lines.
 
 ** Dired
 +++
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 7e07d87f753..a94006499ad 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,10 @@
+2009-01-10  Dan Nicolaescu  <dann@ics.uci.edu>
+
+        * diff-mode.el (diff-show-trailing-whitespaces): Remove function.
+        Move setting up whitepace-mode ...
+        (diff-mode): ... here.
+        (diff-mode-menu): Add a menu entry for showing trailing whitespace.
+
 2009-01-10  Chong Yidong  <cyd@stupidchicken.com>
 
         * faces.el (x-font-family-list): Remove entirely.
diff --git a/lisp/diff-mode.el b/lisp/diff-mode.el
index cbd1aaf48b2..7eddf3b37e7 100644
--- a/lisp/diff-mode.el
+++ b/lisp/diff-mode.el
@@ -183,6 +183,9 @@ when editing big diffs)."
     ["Unified -> Context"       diff-unified->context
      :help "Convert unified diffs to context diffs"]
     ;;["Fixup Headers"          diff-fixup-modifs       (not buffer-read-only)]
+    ["Show trailing whitespace" whitespace-mode
+     :style toggle :selected whitespace-mode
+     :help "Show trailing whitespace in modified lines"]
     "-----"
     ["Split hunk"               diff-split-hunk
      :active (diff-splittable-p)
@@ -1264,6 +1267,12 @@ a diff with \\[diff-reverse-direction].
   (set (make-local-variable 'end-of-defun-function)
        'diff-end-of-file)
 
+  ;; Set up `whitespace-mode' so that turning it on will show trailing
+  ;; whitespace problems on the modified lines of the diff.
+  (set (make-local-variable 'whitespace-style) '(trailing))
+  (set (make-local-variable 'whitespace-trailing-regexp)
+       "^[-\+!<>].*?\\([\t ]+\\)$")
+
   (setq buffer-read-only diff-default-read-only)
   ;; setup change hooks
   (if (not diff-update-on-the-fly)
@@ -1885,13 +1894,6 @@ I.e. like `add-change-log-entry-other-window' but applied to all hunks."
         ;; When there's no more hunks, diff-hunk-next signals an error.
         (error nil)))))
 
-(defun diff-show-trailing-whitespaces ()
-  "Show trailing whitespaces in modified lines for diff-mode."
-  (interactive)
-  (let ((whitespace-style '(trailing))
-        (whitespace-trailing-regexp "^[-+!<>].*?\\([\t ]+\\)$"))
-    (whitespace-mode 1)))     ; display trailing whitespace in diff buffer
-
 ;; provide the package
 (provide 'diff-mode)