-spec copy_priv_file(file:filename(), file:filename()) -> ok.

-spec ensure_dir(file:filename()) -> ok.

-spec get_app_dir(rebar_state:t()) -> file:filename().

-spec get_app_name(rebar_state:t()) -> atom().

-spec load_sys_config(rebar_state:t()) -> [{atom(), term()}].

-spec parse_actions(string()) -> [atom()].

-spec write_file(file:filename(), iodata()) -> ok.

-spec write_file_if_not_exists(file:filename(), iodata()) -> ok | skipped.