//
// Created by zx on 2019/12/17.
//

#ifndef SRC_THREADSAFEQUEUE_H
#define SRC_THREADSAFEQUEUE_H


#include <queue>
#include <memory>
#include <mutex>
#include <condition_variable>
template<typename T>
class threadsafe_queue
{
private:
    mutable std::mutex mut;
    std::queue<T> data_queue;
    std::condition_variable data_cond;
public:
    threadsafe_queue() {}
    threadsafe_queue(threadsafe_queue const& other)
    {
        std::lock_guard<std::mutex> lk(other.mut);
        data_queue = other.data_queue;
    }
    ~threadsafe_queue()
    {
        while (!empty())
        {
            try_pop();
        }
    }
    size_t size()
    {
        return data_queue.size();
    }
    void push(T new_value)//��Ӳ���
    {
        std::lock_guard<std::mutex> lk(mut);
        data_queue.push(new_value);
        data_cond.notify_one();
    }
    void wait_and_pop(T& value)//ֱ����Ԫ�ؿ���ɾ��Ϊֹ
    {
        std::unique_lock<std::mutex> lk(mut);
        data_cond.wait(lk, [this] {return !data_queue.empty(); });
        value = data_queue.front();
        data_queue.pop();
    }
    std::shared_ptr<T> wait_and_pop()
    {
        std::unique_lock<std::mutex> lk(mut);
        data_cond.wait(lk, [this] {return !data_queue.empty(); });
        std::shared_ptr<T> res(std::make_shared<T>(data_queue.front()));
        data_queue.pop();
        return res;
    }
    //ֻ���� �� pop
    bool front(T& value)
    {
        std::lock_guard<std::mutex> lk(mut);
        if (data_queue.empty())
            return false;
        value = data_queue.front();
        return true;
    }

    bool try_pop(T& value)//������û�ж���Ԫ��ֱ�ӷ���
    {
        std::lock_guard<std::mutex> lk(mut);
        if (data_queue.empty())
            return false;
        value = data_queue.front();
        data_queue.pop();
        return true;
    }
    std::shared_ptr<T> try_pop()
    {
        std::lock_guard<std::mutex> lk(mut);
        if (data_queue.empty())
            return std::shared_ptr<T>();
        std::shared_ptr<T> res(std::make_shared<T>(data_queue.front()));
        data_queue.pop();
        return res;
    }
    bool empty() const
    {
        std::lock_guard<std::mutex> lk(mut);
        return data_queue.empty();
    }
    void clear()
    {
        while (!empty()) {
            try_pop();
        }
    }
};


#endif //SRC_THREADSAFEQUEUE_H