How to deal with data pipeline issues in C++ big data development?

#include <iostream>
#include <fstream>
#include <string>
#include <queue>
#include <thread>
#include <mutex>
#include <condition_variable>

const int BUFFER_SIZE = 100; // 缓冲区大小
const int THREAD_NUM = 4; // 线程数量

std::queue<std::string> input_queue; // 输入队列
std::queue<std::string> output_queue; // 输出队列
std::mutex input_mutex; // 输入队列互斥锁
std::mutex output_mutex; // 输出队列互斥锁
std::condition_variable input_condition; // 输入队列条件变量
std::condition_variable output_condition; // 输出队列条件变量

// 数据生产者线程函数
void producer_thread(const std::string& filename) {
    std::ifstream file(filename);
    if (!file) {
        std::cerr << "Failed to open file: " << filename << std::endl;
        return;
    }

    std::string line;
    while (std::getline(file, line)) {
        std::unique_lock<std::mutex> lock(input_mutex);
        input_condition.wait(lock, [] { return input_queue.size() < BUFFER_SIZE; });
        input_queue.push(line);
        lock.unlock();
        input_condition.notify_all();
    }

    file.close();
}

// 数据处理者线程函数
void processor_thread() {
    while (true) {
        std::unique_lock<std::mutex> lock(input_mutex);
        input_condition.wait(lock, [] { return !input_queue.empty(); });
        std::string line = input_queue.front();
        input_queue.pop();
        lock.unlock();
        input_condition.notify_all();

        // 进行数据处理的逻辑
        // ...

        // 将处理结果放入输出队列
        std::unique_lock<std::mutex> output_lock(output_mutex);
        output_condition.wait(output_lock, [] { return output_queue.size() < BUFFER_SIZE; });
        output_queue.push(line);
        output_lock.unlock();
        output_condition.notify_all();
    }
}

// 数据消费者线程函数
void consumer_thread() {
    std::ofstream output_file("output.txt");
    if (!output_file) {
        std::cerr << "Failed to create output file." << std::endl;
        return;
    }

    while (true) {
        std::unique_lock<std::mutex> lock(output_mutex);
        output_condition.wait(lock, [] { return !output_queue.empty(); });
        std::string line = output_queue.front();
        output_queue.pop();
        lock.unlock();
        output_condition.notify_all();

        output_file << line << std::endl;
    }

    output_file.close();
}

int main() {
    std::string filename = "input.txt";

    std::thread producer(producer_thread, filename);

    std::thread processors[THREAD_NUM];
    for (int i = 0; i < THREAD_NUM; ++i) {
        processors[i] = std::thread(processor_thread);
    }

    std::thread consumer(consumer_thread);

    producer.join();
    for (int i = 0; i < THREAD_NUM; ++i) {
        processors[i].join();
    }
    consumer.join();

    return 0;
}