Method serviceQueue

src/scheduler.cpp:26–73

void CScheduler::serviceQueue()
{
    SetSyscallSandboxPolicy(SyscallSandboxPolicy::SCHEDULER);
    WAIT_LOCK(newTaskMutex, lock);
    ++nThreadsServicingQueue;

    // newTaskMutex is locked throughout this loop EXCEPT
    // when the thread is waiting or when the user's function
    // is called.
    while (!shouldStop()) {
        try {
            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:

            while (!shouldStop() && !taskQueue.empty()) {
                std::chrono::system_clock::time_point timeToWaitFor = taskQueue.begin()->first;
                if (newTaskScheduled.wait_until(lock, timeToWaitFor) == std::cv_status::timeout) {
                    break; // Exit loop after timeout, it means we reached the time of the event
                }
            }

            // 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(lock);
                f();
            }
        } catch (...) {
            --nThreadsServicingQueue;
            throw;
        }
    }
    --nThreadsServicingQueue;
    newTaskScheduled.notify_one();
}

void CScheduler::schedule(CScheduler::Function f, std::chrono::system_clock::time_point t)
{