New commands for browsing diffs easily

[Lars Magne Ingebrigtsen]

I use `C-x v =' a lot, and one thing I've missed for ages is the
ability to just walk through the diff history.  That is, after seeing
that the diff in question wasn't really the one I was looking for, I
just want to see the diffs that comes before or after.

So this diff adds that.  I'm not quite sure that this is the best
implementation -- calling vc functions from diff mode might be a bit
naughty.  Or perhaps not.

I bound the commands to `M-C-n' and `M-C-p' as all the more likely key
strokes were already taken.

Index: ChangeLog
===================================================================
RCS file: /sources/emacs/emacs/lisp/ChangeLog,v
retrieving revision 1.9381
diff --unified -r1.9381 ChangeLog
--- ChangeLog   11 Apr 2006 00:08:56 -0000      1.9381
+++ ChangeLog   11 Apr 2006 08:13:24 -0000
@@ -1,3 +1,11 @@
+2006-04-11  Lars Magne Ingebrigtsen  <address@hidden>
+
+       * vc.el (vc-buffer-revisions): New variable.
+       (vc-version-diff): Record the revisions.
+
+       * diff-mode.el (diff-display-previous-diff)
+       (diff-display-next-diff, diff-display-new-diff): New commands. 
+
 2006-04-10  Bill Wohler  <address@hidden>
 
        * custom.el (defcustom, custom-handle-keyword): Add
Index: diff-mode.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/diff-mode.el,v
retrieving revision 1.85
diff --unified -r1.85 diff-mode.el
--- diff-mode.el        21 Mar 2006 10:15:39 -0000      1.85
+++ diff-mode.el        11 Apr 2006 08:13:24 -0000
@@ -135,6 +135,8 @@
     ("R" . diff-reverse-direction)
     ("U" . diff-context->unified)
     ("C" . diff-unified->context)
+    ("\C-p" . diff-display-previous-diff)
+    ("\C-n" . diff-display-next-diff)
     ("q" . quit-window))
   "Basic keymap for `diff-mode', bound to various prefix keys.")
 
@@ -1376,6 +1378,30 @@
       (delete-file file1)
       (delete-file file2))))
 
+(defun diff-display-previous-diff ()
+  "Display the the diff between the two previous revisions."
+  (interactive)
+  (diff-display-new-diff vc-parent-buffer
+                        (vc-call previous-version
+                                 (buffer-file-name vc-parent-buffer)
+                                 (car vc-buffer-revisions))
+                        (car vc-buffer-revisions)))
+
+(defun diff-display-next-diff ()
+  "Display the the diff between the two next revisions."
+  (interactive)
+  (when (zerop (length (cadr vc-buffer-revisions)))
+    (error "At the end of the revision list"))
+  (diff-display-new-diff vc-parent-buffer
+                        (cadr vc-buffer-revisions)
+                        (vc-call next-version
+                                 (buffer-file-name vc-parent-buffer)
+                                 (cadr vc-buffer-revisions))))
+
+(defun diff-display-new-diff (parent-buffer rev1 rev2)
+  (set-buffer parent-buffer)
+  (vc-version-diff (buffer-file-name (current-buffer)) rev1 rev2))
+
 ;; provide the package
 (provide 'diff-mode)
 
Index: vc.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/vc.el,v
retrieving revision 1.414
diff --unified -r1.414 vc.el
--- vc.el       7 Feb 2006 16:59:01 -0000       1.414
+++ vc.el       11 Apr 2006 08:13:25 -0000
@@ -716,6 +716,8 @@
 (put 'vc-parent-buffer 'permanent-local t)
 (defvar vc-parent-buffer-name nil)
 (put 'vc-parent-buffer-name 'permanent-local t)
+(defvar vc-buffer-revisions nil)
+(put 'vc-buffer-revisions 'permanent-local t)
 
 (defvar vc-disable-async-diff nil
   "VC sets this to t locally to disable some async diff operations.
@@ -1755,6 +1757,8 @@
     ;; buffer should affect the diff command.
     (vc-diff-internal file rev1 rev2))
   (set-buffer "*vc-diff*")
+  ;; Record the revisions used to create this buffer
+  (set (make-local-variable 'vc-buffer-revisions) (list rev1 rev2))
   (if (and (zerop (buffer-size))
           (not (get-buffer-process (current-buffer))))
       (progn


-- 
(domestic pets only, the antidote for overdose, milk.)
  address@hidden * Lars Magne Ingebrigtsen