hello_rust_xjh/
lib.rs

1//! # hello_rust
2//!
3//! `hello_rust` is a learn project. follower the book [The Rust Programming Language](https://doc.rust-lang.org/book/).
4//!
5
6use std::{
7    sync::{mpsc, Arc, Mutex},
8    thread,
9};
10
11pub struct ThreadPool {
12    workers: Vec<Worker>,
13    sender: Option<mpsc::Sender<Job>>,
14}
15
16impl ThreadPool {
17    /// Create a new ThreadPool.
18    ///
19    /// The size is the number of threads in the pool.
20    ///
21    /// # Panics
22    ///
23    /// The `new` function will panic if the size is zero.
24    pub fn new(size: usize) -> ThreadPool {
25        assert!(size > 0);
26
27        let (sender, receiver) = mpsc::channel();
28
29        let receiver = Arc::new(Mutex::new(receiver));
30
31        let mut workers = Vec::with_capacity(size);
32
33        for id in 0..size {
34            workers.push(Worker::new(id, Arc::clone(&receiver)));
35        }
36
37        ThreadPool {
38            workers,
39            sender: Some(sender),
40        }
41    }
42
43    pub fn execute<F>(&self, f: F)
44    where
45        F: FnOnce() + Send + 'static,
46    {
47        let job = Box::new(f);
48
49        self.sender.as_ref().unwrap().send(job).unwrap();
50    }
51}
52
53impl Drop for ThreadPool {
54    fn drop(&mut self) {
55        // it will close the channel, so the receiver will return None
56        drop(self.sender.take());
57
58        // this mean to clear the thread resource
59        for worker in &mut self.workers {
60            println!("main: Shutting down worker {}", worker.id);
61
62            if let Some(thread) = worker.thread.take() {
63                // the thread use the channel receiver, when the channel is closed, the receiver will return None, the thread loop will be break.
64                thread.join().unwrap();
65            }
66        }
67    }
68}
69struct Worker {
70    id: usize,
71    thread: Option<thread::JoinHandle<()>>,
72}
73
74impl Worker {
75    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
76        let thread = thread::spawn(move || loop {
77            let message = receiver.lock().unwrap().recv();
78
79            match message {
80                Ok(job) => {
81                    println!("Thread: Worker {id} got a job; executing.");
82
83                    job();
84                }
85                Err(_) => {
86                    println!("Thread: Worker {id} disconnected; shutting down.");
87                    break;
88                }
89            }
90        });
91
92        Worker {
93            id,
94            thread: Some(thread),
95        }
96    }
97}
98
99type Job = Box<dyn FnOnce() + Send + 'static>;
hello_rust_xjh/lib.rs

hello_rust_xjh/
lib.rs
