revision: introduce setup_revision_opt

So far the last parameter to setup_revisions() was to specify the default
ref when the command line did not give any (typically "HEAD").  This changes
it to take a pointer to a structure so that we can add other information without
touching too many codepaths in later patches.

There is no functionality change.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/diff-lib.c b/diff-lib.c
index d7e13cb..64976f9 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -510,9 +510,12 @@ int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 int index_differs_from(const char *def, int diff_flags)
 {
 	struct rev_info rev;
+	struct setup_revision_opt opt;
 
 	init_revisions(&rev, NULL);
-	setup_revisions(0, NULL, &rev, def);
+	memset(&opt, 0, sizeof(opt));
+	opt.def = def;
+	setup_revisions(0, NULL, &rev, &opt);
 	DIFF_OPT_SET(&rev.diffopt, QUICK);
 	DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 	rev.diffopt.flags |= diff_flags;