void _onDone()

in lib/src/http_parser.dart [768:819]
42 lines of code
16 McCabe index (conditional complexity)

  void _onDone() {
    // onDone cancels the subscription.
    _socketSubscription = null;
    if (_state == _State.CLOSED || _state == _State.FAILURE) return;

    if (_incoming != null) {
      if (_state != _State.UPGRADED &&
          !(_state == _State.START && !_requestParser) &&
          !(_state == _State.BODY && !_chunked && _transferLength == -1)) {
        _bodyController
            .addError(HttpException("Connection closed while receiving data"));
      }
      _closeIncoming(true);
      _controller.close();
      return;
    }
    // If the connection is idle the HTTP stream is closed.
    if (_state == _State.START) {
      if (!_requestParser) {
        _reportError(
            HttpException("Connection closed before full header was received"));
      }
      _controller.close();
      return;
    }

    if (_state == _State.UPGRADED) {
      _controller.close();
      return;
    }

    if (_state < _State.FIRST_BODY_STATE) {
      _state = _State.FAILURE;
      // Report the error through the error callback if any. Otherwise
      // throw the error.
      _reportError(
          HttpException("Connection closed before full header was received"));
      _controller.close();
      return;
    }

    if (!_chunked && _transferLength == -1) {
      _state = _State.CLOSED;
    } else {
      _state = _State.FAILURE;
      // Report the error through the error callback if any. Otherwise
      // throw the error.
      _reportError(
          HttpException("Connection closed before full body was received"));
    }
    _controller.close();
  }