use std::sync::{Arc, RwLock};
use std::thread;
+use std::time::Duration;
#[derive(Clone)]
-struct ConcurrentCounter(Arc<RwLock<usize>>);
+pub struct ConcurrentCounter(Arc<RwLock<usize>>);
impl ConcurrentCounter {
// The constructor should not be surprising.
}
pub fn increment(&self, by: usize) {
- let mut counter = self.0.write().unwrap();
+ let mut counter = self.0.write().unwrap_or_else(|e| e.into_inner());
*counter = *counter + by;
}
+ pub fn compare_and_inc(&self, test: usize, by: usize) {
+ let mut counter = self.0.write().unwrap_or_else(|e| e.into_inner());
+ if *counter == test {
+ *counter += by;
+ }
+ }
+
pub fn get(&self) -> usize {
- let counter = self.0.read().unwrap();
+ let counter = self.0.read().unwrap_or_else(|e| e.into_inner());
*counter
}
}
let counter1 = counter.clone();
let handle1 = thread::spawn(move || {
for _ in 0..10 {
- thread::sleep_ms(15);
+ thread::sleep(Duration::from_millis(15));
counter1.increment(2);
}
});
let counter2 = counter.clone();
let handle2 = thread::spawn(move || {
for _ in 0..10 {
- thread::sleep_ms(20);
+ thread::sleep(Duration::from_millis(20));
counter2.increment(3);
}
});
// Now we want to watch the threads working on the counter.
for _ in 0..50 {
- thread::sleep_ms(5);
+ thread::sleep(Duration::from_millis(5));
println!("Current value: {}", counter.get());
}