hash: provide per-algorithm null OIDs
Up until recently, object IDs did not have an algorithm member, only a
hash. Consequently, it was possible to share one null (all-zeros)
object ID among all hash algorithms. Now that we're going to be
handling objects from multiple hash algorithms, it's important to make
sure that all object IDs have a correct algorithm field.
Introduce a per-algorithm null OID, and add it to struct hash_algo.
Introduce a wrapper function as well, and use it everywhere we used to
use the null_oid constant.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/tree-diff.c b/tree-diff.c
index 7cebbb3..1572615 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -161,7 +161,7 @@ static struct combine_diff_path *path_appendnew(struct combine_diff_path *last,
memcpy(p->path + base->len, path, pathlen);
p->path[len] = 0;
p->mode = mode;
- oidcpy(&p->oid, oid ? oid : &null_oid);
+ oidcpy(&p->oid, oid ? oid : null_oid());
return p;
}
@@ -243,7 +243,7 @@ static struct combine_diff_path *emit_path(struct combine_diff_path *p,
mode_i = tp[i].entry.mode;
}
else {
- oid_i = &null_oid;
+ oid_i = null_oid();
mode_i = 0;
}
