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42 lines
1.2 KiB
Rust
42 lines
1.2 KiB
Rust
// Building on the last exercise, we want all of the threads to complete their
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// work. But this time, the spawned threads need to be in charge of updating a
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// shared value: `JobStatus.jobs_done`
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use std::{
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sync::{Arc, Mutex},
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thread,
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time::Duration,
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};
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struct JobStatus {
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jobs_done: u32,
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}
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fn main() {
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// `Arc` isn't enough if you want a **mutable** shared state.
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// We need to wrap the value with a `Mutex`.
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let status = Arc::new(Mutex::new(JobStatus { jobs_done: 0 }));
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// ^^^^^^^^^^^ ^
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let mut handles = Vec::new();
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for _ in 0..10 {
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let status_shared = Arc::clone(&status);
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let handle = thread::spawn(move || {
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thread::sleep(Duration::from_millis(250));
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// Lock before you update a shared value.
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status_shared.lock().unwrap().jobs_done += 1;
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// ^^^^^^^^^^^^^^^^
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});
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handles.push(handle);
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}
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// Waiting for all jobs to complete.
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for handle in handles {
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handle.join().unwrap();
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}
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println!("Jobs done: {}", status.lock().unwrap().jobs_done);
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// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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}
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