diff --stat: show complete rewrites consistently.

The patch format shows complete rewrite as deletion of all old lines
followed by addition of all new lines.  Count lines consistenly with
that when doing diffstat.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff.c

@@ -485,7 +485,8 @@ static void builtin_diff(const char *name_a,
 static void builtin_diffstat(const char *name_a, const char *name_b,
 			     struct diff_filespec *one,
 			     struct diff_filespec *two,
-			     struct diffstat_t *diffstat)
+			     struct diffstat_t *diffstat,
+			     int complete_rewrite)
 {
 	mmfile_t mf1, mf2;
 	struct diffstat_file *data;
@@ -496,7 +497,13 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 		data->is_unmerged = 1;
 		return;
 	}
-
+	if (complete_rewrite) {
+		diff_populate_filespec(one, 0);
+		diff_populate_filespec(two, 0);
+		data->deleted = count_lines(one->data, one->size);
+		data->added = count_lines(two->data, two->size);
+		return;
+	}
 	if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 		die("unable to read files to diff");
 
@@ -1055,10 +1062,11 @@ static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
 {
 	const char *name;
 	const char *other;
+	int complete_rewrite = 0;
 
 	if (DIFF_PAIR_UNMERGED(p)) {
 		/* unmerged */
-		builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat);
+		builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, 0);
 		return;
 	}
 
@@ -1068,7 +1076,9 @@ static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
 	diff_fill_sha1_info(p->one);
 	diff_fill_sha1_info(p->two);
 
-	builtin_diffstat(name, other, p->one, p->two, diffstat);
+	if (p->status == DIFF_STATUS_MODIFIED && p->score)
+		complete_rewrite = 1;
+	builtin_diffstat(name, other, p->one, p->two, diffstat, complete_rewrite);
 }
 
 void diff_setup(struct diff_options *options)