| // Copyright 2015 Colin Sherratt |
| // |
| // 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::sync::atomic::{AtomicUsize, Ordering}; |
| use std::sync::{Arc, Mutex}; |
| |
| use {Pulse, Signal, Waiting, Signals}; |
| |
| pub struct Inner { |
| pub count: AtomicUsize, |
| pub trigger: Mutex<Option<Pulse>>, |
| } |
| |
| /// A `Barrier` can listen for 1 or more `Signals`. It will only transition |
| /// to a `Pulsed` state once all the `Signals` have `Pulsed`. |
| pub struct Barrier { |
| inner: Arc<Inner>, |
| } |
| |
| pub struct Handle(pub Arc<Inner>); |
| |
| impl Barrier { |
| /// Create a new Barrier from an Vector of `Siganl`s |
| pub fn new(pulses: &[Signal]) -> Barrier { |
| // count items |
| let inner = Arc::new(Inner { |
| count: AtomicUsize::new(pulses.len()), |
| trigger: Mutex::new(None), |
| }); |
| |
| for pulse in pulses { |
| pulse.clone().arm(Waiting::barrier(Handle(inner.clone()))); |
| } |
| |
| Barrier { inner: inner } |
| } |
| } |
| |
| impl Signals for Barrier { |
| fn signal(&self) -> Signal { |
| let (p, t) = Signal::new(); |
| |
| let mut guard = self.inner.trigger.lock().unwrap(); |
| if self.inner.count.load(Ordering::Relaxed) == 0 { |
| t.pulse(); |
| } else { |
| *guard = Some(t); |
| } |
| p |
| } |
| } |