#include #include #include #include template class LockFreeQueue { public: LockFreeQueue() : head_(new Node), tail_(head_.load()) {} ~LockFreeQueue() { while (Nod...-Go服务器开发

这个队列中的Node结构体是用来存储值和指向下一个节点的指针。如果不使用Node结构体，则需要通过其他方式来保存这些信息。

一种替代方式是使用std::pair来存储值和指向下一个节点的指针。具体实现如下所示：

template class LockFreeQueue { public:

LockFreeQueue() : head_(nullptr), tail_(nullptr) {}

~LockFreeQueue()
{
    while (head_)
    {
        Node *const old_head = head_;
        head_ = head_->next;
        delete old_head;
    }
}

void push(const T &value)
{
    Node *new_node = new Node(std::make_pair(value, nullptr));
    if (!tail_)
    {
        head_ = new_node;
        tail_ = head_;
    }
    else
    {
        tail_->next = new_node;
        tail_ = new_node;
    }
    size_.fetch_add(1, std::memory_order_release);
}

bool try_pop(T &value)
{
    Node *const old_head = head_;
    if (!old_head)
    {
        return false;
    }
    Node *const new_head = old_head->next;
    value = old_head->data.first;
    head_ = new_head;
    size_.fetch_sub(1, std::memory_order_release);
    delete old_head;
    return true;
}

bool empty() const
{
    return size_.load(std::memory_order_acquire) == 0;
}

private:

typedef std::pair<T, Node*> value_type;

struct Node
{
    value_type data;
    Node *next;
    Node() : next(nullptr) {}
    explicit Node(const value_type &data_) : data(data_), next(nullptr) {}
};

Node *head_;
Node *tail_;
std::atomic<size_t> size_{0};
std::condition_variable cv_;

};