unsigned flags = commit->object.flags;
                enum object_type type;
                unsigned long size;
-               char *buf = read_sha1_file(commit->object.oid.hash, &type, &size);
+               char *buf = read_object_file(&commit->object.oid, &type,
+                                            &size);
                const char *subject_start;
                int subject_len;
 
                        fprintf(stderr, "%3d", weight(p));
                else
                        fprintf(stderr, "---");
-               fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.oid.hash));
+               fprintf(stderr, " %.*s", 8, oid_to_hex(&commit->object.oid));
                for (pp = commit->parents; pp; pp = pp->next)
                        fprintf(stderr, " %.*s", 8,
-                               sha1_to_hex(pp->item->object.oid.hash));
+                               oid_to_hex(&pp->item->object.oid));
 
                subject_len = find_commit_subject(buf, &subject_start);
                if (subject_len)