(vc-cvs-diff): If backup files exist, diff them

instead of doing "cvs diff" in order to avoid accessing the
repository.

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 28533a7a177dae0cf58301d49a7c94896c5ae226..083934494fc949218966cf9896c0b5422f9935e3 100644 (file)
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2007-11-12  Dan Nicolaescu  <dann@ics.uci.edu>
+
+       * vc-cvs.el (vc-cvs-diff): If backup files exist, diff them
+       instead of doing "cvs diff" in order to avoid accessing the
+       repository.
+
 2007-11-12  Kevin Ryde  <user42@zip.com.au>
 
        * progmodes/compilation-perl.el:

diff --git a/lisp/vc-cvs.el b/lisp/vc-cvs.el
index d6573db9df258c658928faf502a0156e0873b398..c9c50fceba2fb0e5a8b19967e7d6022826a89f56 100644 (file)
--- a/lisp/vc-cvs.el
+++ b/lisp/vc-cvs.el
@@ -513,15 +513,46 @@ The changes are between FIRST-REVISION and SECOND-REVISION."
 
 (defun vc-cvs-diff (files &optional oldvers newvers buffer)
   "Get a difference report using CVS between two revisions of FILE."
-    (let* ((async (and (not vc-disable-async-diff) 
-                      (vc-stay-local-p files)))
-          (status (apply 'vc-cvs-command (or buffer "*vc-diff*")
+  (let* ((async (and (not vc-disable-async-diff)
+                    (vc-stay-local-p files)))
+        (invoke-cvs-diff-list nil)
+        status)
+    ;; Look through the file list and see if any files have backups
+    ;; that can be used to do a plain "diff" instead of "cvs diff".
+    (dolist (file files)
+      (let ((ov oldvers)
+           (nv newvers))
+       (when (or (not ov) (string-equal ov ""))
+         (setq ov (vc-working-revision file)))
+       (when (string-equal nv "")
+         (setq nv nil))
+       (let ((file-oldvers (vc-version-backup-file file ov))
+             (file-newvers (if (not nv)
+                               file
+                             (vc-version-backup-file file nv)))
+             (coding-system-for-read (vc-coding-system-for-diff file)))
+         (if (and file-oldvers file-newvers)
+             (progn
+               (apply 'vc-do-command (or buffer "*vc-diff*") 1 "diff" nil
+                      (append (if (listp diff-switches)
+                                  diff-switches
+                                (list diff-switches))
+                              (if (listp vc-diff-switches)
+                                  vc-diff-switches
+                                (list vc-diff-switches))
+                              (list (file-relative-name file-oldvers)
+                                    (file-relative-name file-newvers))))
+               (setq status 0))
+           (push file invoke-cvs-diff-list)))))
+    (when invoke-cvs-diff-list
+      (setq status (apply 'vc-cvs-command (or buffer "*vc-diff*")
                          (if async 'async 1)
-                         files "diff"
+                         invoke-cvs-diff-list "diff"
                          (and oldvers (concat "-r" oldvers))
                          (and newvers (concat "-r" newvers))
                          (vc-switches 'CVS 'diff))))
-      (if async 1 status)))            ; async diff, pessimistic assumption
+    (if async 1 status))) ; async diff, pessimistic assumption
+
 
 (defun vc-cvs-diff-tree (dir &optional rev1 rev2)
   "Diff all files at and below DIR."