anchor.diff:  -spec generate_etag(Req, State)
   		   -> {{strong | weak, binary()}, Req, State}
   			  when State::state().
  -generate_etag(Req, State={Path, {ok, #file_info{size=Size, mtime=Mtime}},
  -			  Extra}) ->
  +generate_etag(Req, State={Path, {ok, #file_info{size=Size, mtime=Mtime}}, Extra}) ->
       case lists:keyfind(etag, 1, Extra) of
   	false ->
   	    {generate_default_etag(Size, Mtime), Req, State};
  
positive.code:     Filepath = filename:join([Dir|PathInfo]),
      Len = byte_size(Dir),
      case fullpath(Filepath) of
  	<< Dir:Len/binary, $/, _/binary >> ->
  	    rest_init_info(Req2, Filepath, Extra);
  	_ ->
  	    {ok, Req2, error}
      end.
  
  fullpath(Path) ->
      fullpath(filename:split(Path), []).
  
negative.code: 
  %% Assume the resource doesn't exist if it's not a regular file.
  
  -spec resource_exists(Req, State) -> {boolean(), Req, State} when State::state().
  resource_exists(Req, State={_, {ok, #file_info{type=regular}}, _}) ->
      {true, Req, State};
  resource_exists(Req, State) ->
  