Method waitForNextEvent

src/Connection.cpp:830–869

}

bool Connection::waitForNextEvent() // NOLINT(misc-no-recursion)
{
    assert(bus_ != nullptr);
    assert(loopExitFd_.fd >= 0);
    assert(eventFd_.fd >= 0);

    auto sdbusPollData = getEventLoopPollData();
    struct pollfd fds[] = { {sdbusPollData.fd, sdbusPollData.events, 0}
                          , {eventFd_.fd, POLLIN, 0}
                          , {loopExitFd_.fd, POLLIN, 0} };
    constexpr auto fdsCount = sizeof(fds)/sizeof(fds[0]);

    // Are there pending messages in the inbound queue? Then sd-bus will set timeout to 0, so poll() will wake up right away.
    // Are there pending messages in the outbound queue? Then sd-bus will add POLLOUT to events, so poll() will wake up right away.
    auto timeout = sdbusPollData.getPollTimeout();
    auto r = poll(fds, fdsCount, timeout);

    if (r < 0 && errno == EINTR)
        return true; // Try again

    SDBUS_THROW_ERROR_IF(r < 0, "Failed to wait on the bus", -errno);

    // Wake up notification, in order that we re-enter poll with freshly read PollData (namely, new poll timeout thereof)
    if (fds[1].revents & POLLIN) // NOLINT(readability-implicit-bool-conversion)
    {
        auto cleared = eventFd_.clear();
        SDBUS_THROW_ERROR_IF(!cleared, "Failed to read from the event descriptor", -errno);
        // Go poll() again, but with freshly calculated, up-to-date timeout and with up-to-date events to watch
        return waitForNextEvent();
    }
    // Loop exit notification
    if (fds[2].revents & POLLIN) // NOLINT(readability-implicit-bool-conversion)
    {
        auto cleared = loopExitFd_.clear();
        SDBUS_THROW_ERROR_IF(!cleared, "Failed to read from the loop exit descriptor", -errno);
        return false;
    }

    return true;
}

bool Connection::arePendingMessagesInQueues() const
{