Function parse_next_oid

builtin/update-ref.c:172–244

* Parse an argument separator followed by the next argument, if any. * If there is an argument, convert it to a SHA-1, write it to sha1, * set *next to point at the character terminating the argument, and * return 0. If there is no argument at all (not even the empty * string), return 1 and leave *next unchanged. If the value is * provided but cannot be converted to a SHA-1, die. flags can

 * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
 */
static int parse_next_oid(const char **next, const char *end,
			  struct object_id *oid,
			  const char *command, const char *refname,
			  int flags)
{
	struct strbuf arg = STRBUF_INIT;
	int ret = 0;

	if (*next == end)
		goto eof;

	if (line_termination) {
		/* Without -z, consume SP and use next argument */
		if (!**next || **next == line_termination)
			return 1;
		if (**next != ' ')
			die("%s %s: expected SP but got: %s",
			    command, refname, *next);
		(*next)++;
		*next = parse_arg(*next, &arg);
		if (arg.len) {
			if (repo_get_oid_with_flags(the_repository, arg.buf, oid,
						    GET_OID_SKIP_AMBIGUITY_CHECK))
				goto invalid;
		} else {
			/* Without -z, an empty value means all zeros: */
			oidclr(oid, the_repository->hash_algo);
		}
	} else {
		/* With -z, read the next NUL-terminated line */
		if (**next)
			die("%s %s: expected NUL but got: %s",
			    command, refname, *next);
		(*next)++;
		if (*next == end)
			goto eof;
		strbuf_addstr(&arg, *next);
		*next += arg.len;

		if (arg.len) {
			if (repo_get_oid_with_flags(the_repository, arg.buf, oid,
						    GET_OID_SKIP_AMBIGUITY_CHECK))
				goto invalid;
		} else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
			/* With -z, treat an empty value as all zeros: */
			warning("%s %s: missing <new-oid>, treating as zero",
				command, refname);
			oidclr(oid, the_repository->hash_algo);
		} else {
			/*
			 * With -z, an empty non-required value means
			 * unspecified:
			 */
			ret = 1;
		}
	}

	strbuf_release(&arg);