Extract a function clear_cached_refs()

Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

refs.c

@@ -171,10 +171,8 @@ static void free_ref_list(struct ref_list *list)
 	}
 }
 
-static void invalidate_cached_refs(void)
+static void clear_cached_refs(struct cached_refs *ca)
 {
-	struct cached_refs *ca = &cached_refs;
-
 	if (ca->did_loose && ca->loose)
 		free_ref_list(ca->loose);
 	if (ca->did_packed && ca->packed)
@@ -183,6 +181,11 @@ static void invalidate_cached_refs(void)
 	ca->did_loose = ca->did_packed = 0;
 }
 
+static void invalidate_cached_refs(void)
+{
+	clear_cached_refs(&cached_refs);
+}
+
 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 {
 	struct ref_list *list = NULL;