[Emacs-diffs] Changes to emacs/lisp/diff-mode.el,v

[Stefan Monnier]

CVSROOT:        /sources/emacs
Module name:    emacs
Changes by:     Stefan Monnier <monnier>        07/07/22 21:38:29

Index: diff-mode.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/diff-mode.el,v
retrieving revision 1.105
retrieving revision 1.106
diff -u -b -r1.105 -r1.106
--- diff-mode.el        22 Jul 2007 21:28:13 -0000      1.105
+++ diff-mode.el        22 Jul 2007 21:38:28 -0000      1.106
@@ -701,7 +701,12 @@
            (let ((line1 (match-string 4))
                  (lines1 (match-string 5))
                  (line2 (match-string 6))
-                 (lines2 (match-string 7)))
+                 (lines2 (match-string 7))
+                 ;; Variables to use the special undo function.
+                 (old-undo buffer-undo-list)
+                 (old-end (marker-position end))
+                 (start (match-beginning 0))
+                 (reversible t))
              (replace-match
               (concat "***************\n*** " line1 ","
                       (number-to-string (+ (string-to-number line1)
@@ -743,6 +748,14 @@
                  (if (not (save-excursion (re-search-forward "^+" nil t)))
                      (delete-region (point) (point-max))
                    (let ((modif nil) (delete nil))
+                     (if (save-excursion (re-search-forward "^\\+.*\n-" nil t))
+                          ;; Normally, lines in a substitution come with
+                          ;; first the removals and then the additions, and
+                          ;; the context->unified function follows this
+                          ;; convention, of course.  Yet, other alternatives
+                          ;; are valid as well, but they preclude the use of
+                          ;; context->unified as an undo command.
+                         (setq reversible nil))
                      (while (not (eobp))
                        (case (char-after)
                          (?\s (insert " ") (setq modif nil) (backward-char 1))
@@ -761,7 +774,15 @@
                          (forward-line 1)
                          (when delete
                            (delete-region last-pt (point))
-                           (setq delete nil)))))))))))))))
+                           (setq delete nil)))))))
+               (unless (or (not reversible) (eq buffer-undo-list t))
+                  ;; Drop the many undo entries and replace them with
+                  ;; a single entry that uses diff-context->unified to do
+                  ;; the work.
+                 (setq buffer-undo-list
+                       (cons (list 'apply (- old-end end) start (point-max)
+                                   'diff-context->unified start (point-max))
+                             old-undo)))))))))))
 
 (defun diff-context->unified (start end &optional to-context)
   "Convert context diffs to unified diffs.