Function write_ref_to_lockfile

refs/files-backend.c:2005–2024

* Write oid into the open lockfile, then close the lockfile. On * errors, rollback the lockfile, fill in *err and return -1. */

 * errors, rollback the lockfile, fill in *err and return -1.
 */
static enum ref_transaction_error write_ref_to_lockfile(struct files_ref_store *refs,
							struct ref_lock *lock,
							const struct object_id *oid,
							struct strbuf *err)
{
	static char term = '\n';
	int fd;

	fd = get_lock_file_fd(&lock->lk);
	if (write_in_full(fd, oid_to_hex(oid), refs->base.repo->hash_algo->hexsz) < 0 ||
	    write_in_full(fd, &term, 1) < 0 ||
	    fsync_component(FSYNC_COMPONENT_REFERENCE, get_lock_file_fd(&lock->lk)) < 0 ||
	    close_ref_gently(lock) < 0) {
		strbuf_addf(err,
			    "couldn't write '%s'", get_lock_file_path(&lock->lk));
		unlock_ref(lock);
		return REF_TRANSACTION_ERROR_GENERIC;
	}
	return 0;
}

/*
 * Commit a change to a loose reference that has already been written