Function longest_ancestor_length

path.c:1245–1272

* path = Canonical absolute path * prefixes = string_list containing normalized, absolute paths without * trailing slashes (except for the root directory, which is denoted by "/"). * * Determines, for each path in prefixes, whether the "prefix" * is an ancestor directory of path. Returns the length of the longest * ancestor directory, excluding any trailing slashes, or -1 if no prefix * is

 * allowed.
 */
int longest_ancestor_length(const char *path, struct string_list *prefixes)
{
	int max_len = -1;

	if (!strcmp(path, "/"))
		return -1;

	for (size_t i = 0; i < prefixes->nr; i++) {
		const char *ceil = prefixes->items[i].string;
		int len = strlen(ceil);

		/*
		 * For root directories (`/`, `C:/`, `//server/share/`)
		 * adjust the length to exclude the trailing slash.
		 */
		if (len > 0 && ceil[len - 1] == '/')
			len--;

		if (strncmp(path, ceil, len) ||
		    path[len] != '/' || !path[len + 1])
			continue; /* no match */

		if (len > max_len)
			max_len = len;
	}

	return max_len;
}

/* strip arbitrary amount of directory separators at end of path */
static inline int chomp_trailing_dir_sep(const char *path, int len)