multi-pack-index: add 'verify' verb

The multi-pack-index builtin writes multi-pack-index files, and
uses a 'write' verb to do so. Add a 'verify' verb that checks this
file matches the contents of the pack-indexes it replaces.

The current implementation is a no-op, but will be extended in
small increments in later commits.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/midx.c b/midx.c
index f3e8dbc..8b6c855 100644
--- a/midx.c
+++ b/midx.c
@@ -928,3 +928,16 @@ void clear_midx_file(const char *object_dir)
 
 	free(midx);
 }
+
+static int verify_midx_error;
+
+int verify_midx_file(const char *object_dir)
+{
+	struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
+	verify_midx_error = 0;
+
+	if (!m)
+		return 0;
+
+	return verify_midx_error;
+}