browser: if current dir doesn't exists, go down one level automatically

src/helpers.cpp

@@ -372,6 +372,12 @@ std::string ExtractTopName(const std::string &s)
 	return slash != std::string::npos ? s.substr(++slash) : s;
 }
 
+std::string PathGoDownOneLevel(const std::string &path)
+{
+	size_t i = path.rfind('/');
+	return i == std::string::npos ? "/" : path.substr(0, i);
+}
+
 std::basic_string<my_char_t> Scroller(const std::basic_string<my_char_t> &str, size_t &pos, size_t width)
 {
 	std::basic_string<my_char_t> s(str);