rust-httpserver 0.1.0

use std::sync::mpsc;
use std::sync::mpsc::Receiver;
use std::sync::Arc;
use std::sync::Mutex;
use std::thread;

trait FnBox {
    fn call(self: Box<Self>);
}

impl<F: FnOnce()> FnBox for F {
    fn call(self: Box<Self>) {
        (*self)()
    }
}

// struct Job;
type Job = Box<dyn FnBox + Send>;

struct Worker {
    id: usize,
    thread: Option<thread::JoinHandle<()>>,
}

impl Worker {
    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Message>>>) -> Worker {
        // let thread: thread::JoinHandle<()> = thread::spawn(|| {
        //     receiver;
        // });
        // Worker { id, thread }
        let thread: thread::JoinHandle<()> = thread::spawn(move || loop {
            let message: Message = receiver.lock().unwrap().recv().unwrap();
            match message {
                Message::NewJob(job) => {
                    println!("Worker {} got a new job..", id);
                    job.call();
                }
                Message::Terminate => {
                    println!("Worker {} was told to terminate.", id);
                    break;
                }
            }
        });
        Worker {
            id,
            thread: Some(thread),
        }
    }
}

enum Message {
    NewJob(Job),
    Terminate,
}

pub struct ThreadPool {
    // threads: Vec<thread::JoinHandle<()>>,
    workers: Vec<Worker>,
    sender: mpsc::Sender<Message>,
}

impl ThreadPool {
    /// Create a new ThreadPool
    ///
    /// The size is the number of threads in the pool
    ///
    /// # Panics
    ///
    /// The `new` function will panic if the size less than zero.
    pub fn new(size: usize) -> ThreadPool {
        assert!(size > 0);
        let (sender, receiver) = mpsc::channel();
        let receiver: Arc<Mutex<Receiver<Message>>> = Arc::new(Mutex::new(receiver));
        let mut workers = Vec::with_capacity(size);
        for i in 0..size {
            // create thread and store them in threads vector
            workers.push(Worker::new(i, Arc::clone(&receiver)));
        }
        ThreadPool { workers, sender }
    }

    pub fn execute<F>(&self, f: F)
    where
        F: FnOnce() + Send + 'static,
    {
        let job: Box<F> = Box::new(f);
        self.sender.send(Message::NewJob(job)).unwrap();
    }
}

impl Drop for ThreadPool {
    fn drop(&mut self) {
        println!("Sending terminate message to all workers.");

        for _ in &mut self.workers {
            self.sender.send(Message::Terminate).unwrap();
        }
        println!("Shutting down all workers");

        for worker in &mut self.workers {
            println!("Shutting down work {}", worker.id);
            if let Some(thread) = worker.thread.take() {
                thread.join().unwrap();
            }
        }
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn test_eq() {
        assert_eq!(1, 1);
    }
}