C++如何实现一个阻塞队列_C++11使用条件变量和互斥锁实现线程安全队列

#include <queue>
#include <mutex>
#include <condition_variable>
#include <chrono>

template <typename T>
class BlockingQueue {
private:
    std::queue<T> data_queue_;
    std::mutex mtx_;
    std::condition_variable not_full_;
    std::condition_variable not_empty_;
    size_t capacity_;

public:
    explicit BlockingQueue(size_t cap = 1000) : capacity_(cap) {}

    void put(const T& item) {
        std::unique_lock<std::mutex> lock(mtx_);
        // 等待队列不满
        not_full_.wait(lock, [this] { return data_queue_.size() < capacity_; });
        data_queue_.push(item);
        not_empty_.notify_one(); // 通知消费者
    }

    void take(T& item) {
        std::unique_lock<std::mutex> lock(mtx_);
        // 等待队列不空
        not_empty_.wait(lock, [this] { return !data_queue_.empty(); });
        item = data_queue_.front();
        data_queue_.pop();
        not_full_.notify_one(); // 通知生产者
    }

    bool empty() const {
        std::lock_guard<std::mutex> lock(mtx_);
        return data_queue_.empty();
    }

    size_t size() const {
        std::lock_guard<std::mutex> lock(mtx_);
        return data_queue_.size();
    }
};

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