queuedtasks.h

/*
This file is part of FlashMQ (https://www.flashmq.org)
Copyright (C) 2021-2023 Wiebe Cazemier

FlashMQ is free software: you can redistribute it and/or modify
it under the terms of The Open Software License 3.0 (OSL-3.0).

See LICENSE for license details.
*/

#ifndef QUEUEDTASKS_H
#define QUEUEDTASKS_H

#include <functional>
#include <set>
#include <map>
#include <memory>
#include <chrono>

struct QueuedTask
{
    std::chrono::time_point<std::chrono::steady_clock> when;
    uint32_t id = 0;
    std::weak_ptr<std::function<void()>> f;

    bool operator<(const QueuedTask &rhs) const;
};

/**
 * @brief Contains delayed tasks to perform.
 *
 * At this point, it's for the plugin, and therefore is thread-local, and not protected with mutexes etc.
 */
class QueuedTasks
{
    uint32_t nextId = 1;
    std::multiset<QueuedTask> queuedTasks;
    std::map<uint32_t, std::shared_ptr<std::function<void()>>> tasks;
    std::chrono::time_point<std::chrono::steady_clock> next = std::chrono::time_point<std::chrono::steady_clock>::max();

public:
    QueuedTasks();
    uint32_t addTask(std::function<void()> f, uint32_t delayInMs);
    void eraseTask(uint32_t id);
    uint32_t getTimeTillNext() const;
    void performAll();
};

#endif // QUEUEDTASKS_H