int IoUringBackend::eb_event_base_loop()

in folly/experimental/io/IoUringBackend.cpp [840:919]

• 60 lines of code
• 26 McCabe index (conditional complexity)

int IoUringBackend::eb_event_base_loop(int flags) {
  if (registerDefaultFds_) {
    registerDefaultFds_ = false;
    if (!addTimerFd() || !addSignalFds()) {
      cleanup();
      throw NotAvailable("io_uring_submit error");
    }
  }

  // schedule the timers
  bool done = false;
  auto waitForEvents = (flags & EVLOOP_NONBLOCK) ? WaitForEventsMode::DONT_WAIT
                                                 : WaitForEventsMode::WAIT;
  while (!done) {
    scheduleTimeout();
    // check if we need to break here
    if (loopBreak_) {
      loopBreak_ = false;
      break;
    }

    submitList(submitList_, waitForEvents);

    if (!numInsertedEvents_ && timers_.empty() && signals_.empty()) {
      return 1;
    }

    uint64_t call_time = 0;
    if (eb_poll_loop_pre_hook) {
      eb_poll_loop_pre_hook(&call_time);
    }

    // do not wait for events if EVLOOP_NONBLOCK is set
    int ret = getActiveEvents(waitForEvents);

    if (eb_poll_loop_post_hook) {
      eb_poll_loop_post_hook(call_time, ret);
    }

    size_t numProcessedTimers = 0;

    // save the processTimers_
    // this means we've received a notification
    // and we need to add the timer fd back
    bool processTimersFlag = processTimers_;
    if (processTimers_ && !loopBreak_) {
      numProcessedTimers = processTimers();
      processTimers_ = false;
    }

    size_t numProcessedSignals = 0;

    if (processSignals_ && !loopBreak_) {
      numProcessedSignals = processSignals();
      processSignals_ = false;
    }

    if (!activeEvents_.empty() && !loopBreak_) {
      processActiveEvents();
      if (flags & EVLOOP_ONCE) {
        done = true;
      }
    } else if (flags & EVLOOP_NONBLOCK) {
      if (signals_.empty()) {
        done = true;
      }
    }

    if (!done && (numProcessedTimers || numProcessedSignals) &&
        (flags & EVLOOP_ONCE)) {
      done = true;
    }

    if (processTimersFlag) {
      addTimerFd();
    }
  }

  return 0;
}