86 lines
2.4 KiB
Markdown
86 lines
2.4 KiB
Markdown
# event-listener
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[](
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https://github.com/smol-rs/event-listener/actions)
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[](
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https://github.com/smol-rs/event-listener)
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[](
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https://crates.io/crates/event-listener)
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[](
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https://docs.rs/event-listener)
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Notify async tasks or threads.
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This is a synchronization primitive similar to [eventcounts] invented by Dmitry Vyukov.
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You can use this crate to turn non-blocking data structures into async or blocking data
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structures. See a [simple mutex] implementation that exposes an async and a blocking interface
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for acquiring locks.
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[eventcounts]: https://www.1024cores.net/home/lock-free-algorithms/eventcounts
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[simple mutex]: ./examples/mutex.rs
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## Examples
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Wait until another thread sets a boolean flag:
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```rust
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use std::sync::atomic::{AtomicBool, Ordering};
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use std::sync::Arc;
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use std::thread;
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use std::time::Duration;
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use event_listener::Event;
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let flag = Arc::new(AtomicBool::new(false));
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let event = Arc::new(Event::new());
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// Spawn a thread that will set the flag after 1 second.
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thread::spawn({
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let flag = flag.clone();
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let event = event.clone();
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move || {
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// Wait for a second.
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thread::sleep(Duration::from_secs(1));
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// Set the flag.
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flag.store(true, Ordering::SeqCst);
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// Notify all listeners that the flag has been set.
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event.notify(usize::MAX);
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}
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});
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// Wait until the flag is set.
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loop {
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// Check the flag.
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if flag.load(Ordering::SeqCst) {
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break;
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}
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// Start listening for events.
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let listener = event.listen();
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// Check the flag again after creating the listener.
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if flag.load(Ordering::SeqCst) {
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break;
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}
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// Wait for a notification and continue the loop.
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listener.wait();
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}
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```
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## License
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Licensed under either of
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* Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or https://www.apache.org/licenses/LICENSE-2.0)
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* MIT license ([LICENSE-MIT](LICENSE-MIT) or https://opensource.org/licenses/MIT)
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at your option.
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#### Contribution
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Unless you explicitly state otherwise, any contribution intentionally submitted
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for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
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dual licensed as above, without any additional terms or conditions.
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