rust线程池

#![allow(unused)]
use std::sync::{mpsc, Arc, Mutex};
use std::thread;

// 定义消息类型，可以是新任务或终止信号
enum Message {
    NewJob(Job),
    Terminate,
}

// 定义线程池结构体
pub struct ThreadPool {
    workers: Vec<Worker>,
    // sender: mpsc::Sender<Job>,
    sender: mpsc::Sender<Message>,
}

// 定义任务类型，可以是任何实现了FnOnce trait的闭包
type Job = Box<dyn FnOnce() + Send + 'static>;

impl ThreadPool {
    // 创建线程池，参数为线程数量
    pub fn new(size: usize) -> ThreadPool {
        assert!(size > 0);
        // 创建一个通道，用于发送任务
        let (sender, receiver) = mpsc::channel();
        // 将通道包装成Arc<Mutex>，以便多个线程共享
        let receiver = Arc::new(Mutex::new(receiver));
        let mut workers = Vec::with_capacity(size);
        // 创建指定数量的工作线程
        for id in 0..size {
            workers.push(Worker::new(id, Arc::clone(&receiver)));
        }
        ThreadPool { workers, sender }
    }
    // 执行任务，参数为任务闭包
    pub fn execute<F>(&self, f: F)
    where
        F: FnOnce() + Send + 'static,
    {
        // 将任务包装成Box<dyn FnOnce() + Send + 'static>，并发送到通道
        let job = Box::new(f);
        // self.sender.send(job).unwrap();
        self.sender.send(Message::NewJob(job)).unwrap();
    }
}
// 实现Drop trait，在线程池被销毁时执行清理操作
impl Drop for ThreadPool {
    fn drop(&mut self) {
        // 向每个工作线程发送终止信号
        for _ in &mut self.workers {
            self.sender.send(Message::Terminate).unwrap();
        }
        println!("Shutting down all workers.");
        // 等待每个工作线程结束
        for worker in &mut self.workers {
            println!("Shutting down worker {}", worker.id);
            if let Some(thread) = worker.thread.take() {
                thread.join().unwrap();
            }
        }
    }
}

// 定义工作线程结构体
struct Worker {
    id: usize,
    // thread: thread::JoinHandle<()>,
    thread: Option<thread::JoinHandle<()>>,
}
impl Worker {
    // 创建工作线程，参数为线程ID和通道
    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Message>>>) -> Worker {
        // 创建一个新线程，循环接收任务并执行
        let thread = thread::spawn(move || loop {
            // let job = receiver.lock().unwrap().recv().unwrap();
            // println!("Worker {} got a job; executing.", id);
            // job();
            // 接收任务
            let message = receiver.lock().unwrap().recv().unwrap();
            // 根据任务类型执行相应操作
            match message {
                Message::NewJob(job) => {
                    println!("Worker {} executing job.", id);
                    job();
                }
                Message::Terminate => {
                    println!("Worker {} terminated.", id);
                    break;
                }
            }
        });
        Worker {
            id,
            thread: Some(thread),
        }
    }
}