Implement a cloneable shared counter. (#407) r=nalexander

This commit is contained in:
Richard Newman 2017-04-06 19:12:01 -07:00
parent 5369f03464
commit b117e2c463
3 changed files with 48 additions and 1 deletions

47
core/src/counter.rs Normal file
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@ -0,0 +1,47 @@
// Copyright 2016 Mozilla
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
use std::rc::Rc;
use std::sync::atomic::{
AtomicUsize,
Ordering,
};
#[derive(Clone)]
pub struct RcCounter {
c: Rc<AtomicUsize>,
}
impl RcCounter {
pub fn new() -> Self {
RcCounter { c: Rc::new(AtomicUsize::new(0)) }
}
pub fn next(&self) -> usize {
self.c.fetch_add(1, Ordering::SeqCst)
}
}
#[cfg(test)]
mod tests {
use super::RcCounter;
#[test]
fn test_rc_counter() {
let c = RcCounter::new();
assert_eq!(c.next(), 0);
assert_eq!(c.next(), 1);
let d = c.clone();
assert_eq!(d.next(), 2);
assert_eq!(c.next(), 3);
}
}

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@ -488,4 +488,5 @@ mod test {
} }
pub mod intern_set; pub mod intern_set;
pub mod counter;
pub mod util; pub mod util;

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@ -1,4 +1,3 @@
// Copyright 2016 Mozilla // Copyright 2016 Mozilla
// //
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use // Licensed under the Apache License, Version 2.0 (the "License"); you may not use