// threads2.rs
//
// Building on the last exercise, we want all of the threads to complete their
// work but this time the spawned threads need to be in charge of updating a
// shared value: JobStatus.jobs_completed
//
// Execute `rustlings hint threads2` or use the `hint` watch subcommand for a
// hint.

// I AM NOT DONE
#![allow(unconditional_panic)]
use std::convert::Infallible;
use std::marker::PhantomData;
use std::sync::{Arc, Mutex};
use std::thread;
use std::time::Duration;

#[repr(transparent)]
struct JobStatus {
    jobs_completed: u32,
}

fn main() {
    let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));
    let mut handles = vec![];
    for i in 0..10 {
        let status_shared = Arc::clone(&status);
        let handle = thread::spawn(move || {
            thread::sleep(Duration::from_millis(250));
            // You must take an action before you update a shared value
            status_shared.lock().unwrap().jobs_completed += 1;
        });
        handles.push(handle);
    }
    for handle in handles.into_iter().into_iter() {
        handle.join().unwrap();
        // Print the value of the JobStatus.jobs_completed. Did you notice
        // anything interesting in the output? Do you have to 'join' on all the
        // handles?
        println!("jobs completed {}", status.lock().unwrap().jobs_completed);
    }
}

输出：

Progress: [############################################>---------------] 81/110

⠙ Running exercises/threads/threads2.rs...

✅ Successfully ran exercises/threads/threads2.rs!

🎉 🎉 The code is compiling! 🎉 🎉

Output:

====================

jobs completed 5

jobs completed 5

jobs completed 5

jobs completed 5

jobs completed 5

jobs completed 7

jobs completed 7

jobs completed 9

jobs completed 9

jobs completed 10

====================

为什么这个jobs complete不是从1 开始的呢