void _handleConnection()

in dwds/lib/src/handlers/dev_handler.dart [245:314]
64 lines of code
16 McCabe index (conditional complexity)

  void _handleConnection(SocketConnection injectedConnection) {
    _injectedConnections.add(injectedConnection);
    AppConnection appConnection;
    injectedConnection.stream.listen((data) async {
      try {
        var message = serializers.deserialize(jsonDecode(data));
        if (message is ConnectRequest) {
          if (appConnection != null) {
            throw StateError('Duplicate connection request from the same app. '
                'Please file an issue at '
                'https://github.com/dart-lang/webdev/issues/new.');
          }
          appConnection =
              await _handleConnectRequest(message, injectedConnection);
        } else {
          if (appConnection == null) {
            throw StateError('Not connected to an application.');
          }
          if (message is DevToolsRequest) {
            await _handleDebugRequest(appConnection, injectedConnection);
          } else if (message is IsolateExit) {
            await _handleIsolateExit(appConnection);
          } else if (message is IsolateStart) {
            await _handleIsolateStart(appConnection, injectedConnection);
          } else if (message is BatchedDebugEvents) {
            await _servicesByAppId[appConnection.request.appId]
                ?.chromeProxyService
                ?.parseBatchedDebugEvents(message);
          } else if (message is DebugEvent) {
            await _servicesByAppId[appConnection.request.appId]
                ?.chromeProxyService
                ?.parseDebugEvent(message);
          } else if (message is RegisterEvent) {
            await _servicesByAppId[appConnection.request.appId]
                ?.chromeProxyService
                ?.parseRegisterEvent(message);
          }
        }
      } catch (e, s) {
        // Most likely the app disconnected in the middle of us responding,
        // but we will try and send an error response back to the page just in
        // case it is still running.
        try {
          injectedConnection.sink
              .add(jsonEncode(serializers.serialize(ErrorResponse((b) => b
                ..error = '$e'
                ..stackTrace = '$s'))));
        } on StateError catch (_) {
          // The sink has already closed (app is disconnected), swallow the
          // error.
        }
      }
    });

    unawaited(injectedConnection.sink.done.then((_) async {
      _injectedConnections.remove(injectedConnection);
      if (appConnection != null) {
        _appConnectionByAppId.remove(appConnection.request.appId);
        var services = _servicesByAppId[appConnection.request.appId];
        if (services != null) {
          if (services.connectedInstanceId == null ||
              services.connectedInstanceId ==
                  appConnection.request.instanceId) {
            services.connectedInstanceId = null;
            services.chromeProxyService?.destroyIsolate();
          }
        }
      }
    }));
  }