2 files changed, 22 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index a074aad691b..c2d92160448 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,4 +1,8 @@
-2006-02-06 Lars Hansen <larsh@soem.dk>
+2006-02-06  Thien-Thi Nguyen  <ttn@gnu.org>
+
+        * vc-svn.el (vc-svn-previous-version, vc-svn-next-version): New funcs.
+
+2006-02-06  Lars Hansen  <larsh@soem.dk>
 
         * generic-x.el (etc-fstab-generic-mode): Add file system types
         cifs and usbdevfs. Allow special chars in file names.
diff --git a/lisp/vc-svn.el b/lisp/vc-svn.el
index 966f5d2c9c9..82942f78358 100644
--- a/lisp/vc-svn.el
+++ b/lisp/vc-svn.el
@@ -176,6 +176,23 @@ This is only meaningful if you don't use the implicit checkout model
           ((eq svn-state 'needs-patch) "(patch)")
           ((eq svn-state 'needs-merge) "(merge)"))))
 
+(defun vc-svn-previous-version (file rev)
+  (let ((newrev (1- (string-to-number rev))))
+    (when (< 0 newrev)
+      (number-to-string newrev))))
+
+(defun vc-svn-next-version (file rev)
+  (let ((newrev (1+ (string-to-number rev))))
+    ;; The "workfile version" is an uneasy conceptual fit under Subversion;
+    ;; we use it as the upper bound until a better idea comes along.  If the
+    ;; workfile version W coincides with the tree's latest revision R, then
+    ;; this check prevents a "no such revision: R+1" error.  Otherwise, it
+    ;; inhibits showing of W+1 through R, which could be considered anywhere
+    ;; from gracious to impolite.
+    (unless (< (string-to-number (vc-file-getprop file 'vc-workfile-version))
+               newrev)
+      (number-to-string newrev))))
+
 
 ;;;
 ;;; State-changing functions