Method serviceQueue

src/scheduler.cpp:33–92

#endif

void CScheduler::serviceQueue()
{
    boost::unique_lock<boost::mutex> lock(newTaskMutex);
    ++nThreadsServicingQueue;

    // newTaskMutex is locked throughout this loop EXCEPT
    // when the thread is waiting or when the user's function
    // is called.
    while (!shouldStop()) {
        try {
            if (!shouldStop() && taskQueue.empty()) {
                reverse_lock<boost::unique_lock<boost::mutex> > rlock(lock);
                // Use this chance to get a tiny bit more entropy
                RandAddSeedSleep();
            }
            while (!shouldStop() && taskQueue.empty()) {
                // Wait until there is something to do.
                newTaskScheduled.wait(lock);
            }

            // Wait until either there is a new task, or until
            // the time of the first item on the queue:

// wait_until needs boost 1.50 or later; older versions have timed_wait:
#if BOOST_VERSION < 105000
            while (!shouldStop() && !taskQueue.empty() &&
                   newTaskScheduled.timed_wait(lock, toPosixTime(taskQueue.begin()->first))) {
                // Keep waiting until timeout
            }
#else
            // Some boost versions have a conflicting overload of wait_until that returns void.
            // Explicitly use a template here to avoid hitting that overload.
            while (!shouldStop() && !taskQueue.empty()) {
                boost::chrono::system_clock::time_point timeToWaitFor = taskQueue.begin()->first;
                if (newTaskScheduled.wait_until<>(lock, timeToWaitFor) == boost::cv_status::timeout)
                    break; // Exit loop after timeout, it means we reached the time of the event
            }
#endif
            // If there are multiple threads, the queue can empty while we're waiting (another
            // thread may service the task we were waiting on).
            if (shouldStop() || taskQueue.empty())
                continue;

            Function f = taskQueue.begin()->second;
            taskQueue.erase(taskQueue.begin());

            {
                // Unlock before calling f, so it can reschedule itself or another task
                // without deadlocking:
                reverse_lock<boost::unique_lock<boost::mutex> > rlock(lock);
                f();
            }
        } catch (...) {
            --nThreadsServicingQueue;
            throw;
        }
    }
    --nThreadsServicingQueue;