Method handleEvent

lib/cpp/src/thrift/server/TNonblockingServer.cpp:959–1017

* Server socket had something happen. We accept all waiting client * connections on fd and assign TConnection objects to handle those requests. */

 * connections on fd and assign TConnection objects to handle those requests.
 */
void TNonblockingServer::handleEvent(THRIFT_SOCKET fd, short which) {
  (void)which;
  // Make sure that libevent didn't mess up the socket handles
  assert(fd == serverSocket_);

  // Going to accept a new client socket
  std::shared_ptr<TSocket> clientSocket;

  clientSocket = serverTransport_->accept();
  if (clientSocket) {
    // If we're overloaded, take action here
    if (overloadAction_ != T_OVERLOAD_NO_ACTION && serverOverloaded()) {
      Guard g(connMutex_);
      nConnectionsDropped_++;
      nTotalConnectionsDropped_++;
      if (overloadAction_ == T_OVERLOAD_CLOSE_ON_ACCEPT) {
        clientSocket->close();
        return;
      } else if (overloadAction_ == T_OVERLOAD_DRAIN_TASK_QUEUE) {
        if (!drainPendingTask()) {
          // Nothing left to discard, so we drop connection instead.
          clientSocket->close();
          return;
        }
      }
    }

    // Create a new TConnection for this client socket.
    TConnection* clientConnection = createConnection(clientSocket);

    // Fail fast if we could not create a TConnection object
    if (clientConnection == nullptr) {
      TOutput::instance().printf("thriftServerEventHandler: failed TConnection factory");
      clientSocket->close();
      return;
    }

    /*
     * Either notify the ioThread that is assigned this connection to
     * start processing, or if it is us, we'll just ask this
     * connection to do its initial state change here.
     *
     * (We need to avoid writing to our own notification pipe, to
     * avoid possible deadlocks if the pipe is full.)
     *
     * The IO thread #0 is the only one that handles these listen
     * events, so unless the connection has been assigned to thread #0
     * we know it's not on our thread.
     */
    if (clientConnection->getIOThreadNumber() == 0) {
      clientConnection->transition();
    } else {
      if (!clientConnection->notifyIOThread()) {
        TOutput::instance().perror("[ERROR] notifyIOThread failed on fresh connection, closing", errno);
        clientConnection->close();
      }
    }
  }