如果不想使用Node结构体，可以考虑使用std::atomic
以下是修改后的LockFreeQueue代码：
#include <atomic>
#include <condition_variable>
#include <iostream>
#include <thread>
template <typename T>
class LockFreeQueue
{
public:
LockFreeQueue() : head_(nullptr), tail_(nullptr) {}
~LockFreeQueue()
{
while (T *const old_head = head_)
{
head_ = old_head->next_;
delete old_head;
}
}
void push(const T &value)
{
T *new_node = new T(value);
new_node->next_ = nullptr;
T *tail = tail_.load(std::memory_order_relaxed);
if (tail)
{
tail->next_ = new_node;
}
else
{
// first element
head_ = new_node;
}
tail_.store(new_node, std::memory_order_release);
size_.fetch_add(1, std::memory_order_release);
}
bool try_pop(T &value)
{
T *const old_head = head_.load(std::memory_order_relaxed);
if (!old_head)
{
return false;
}
T *const new_head = old_head->next_;
value = *old_head;
head_.store(new_head, std::memory_order_release);
size_.fetch_sub(1, std::memory_order_release);
return true;
}
bool empty() const
{
return size_.load(std::memory_order_acquire) == 0;
}
private:
struct Node
{
T value_;
std::atomic<Node*> next_;
Node() : next_(nullptr) {}
explicit Node(const T &value) : value_(value), next_(nullptr) {}
};
std::atomic<T*> head_;
std::atomic<T*> tail_;
std::atomic<size_t> size_{0};
std::condition_variable cv_;
};
