+// Extremely rudimentary URL parsing.
+bool parse_url(const std::string &url, std::string *protocol, std::string *user, std::string *host, std::string *port, std::string *path);
+
+// Figure out the right type of input based on the URL, and create a new Input of the right type.
+// Will return nullptr if unknown.
+Input *create_input(const std::string &url, Input::Encoding encoding);
+Input *create_input(const InputProto &serialized);
+