Event listener primitives
This crate provides a low-level primitive for building Node.js-like event listeners.
The 3 primitives are [Bag] that is a container for Fn() event handlers, [BagOnce] the same for FnOnce() event handlers and [HandlerId] that will remove event handler from the bag on drop.
Trivial example:
```rust
use eventlistenerprimitives::{Bag, HandlerId};
fn main() {
let bag = Bag::default();
let handler_id = bag.add(move || {
println!("Hello")
});
bag.call_simple();
}
```
Close to real-world usage example:
rust
use event_listener_primitives::{Bag, HandlerId};
fn main() {
let bag = Bag::default();
let handler_id = bag.add(Box::new(move || {
println!("Hello")
}));
bag.call_simple();
}
Close to real-world usage example:
```rust
use eventlistenerprimitives::{Bag, BagOnce, HandlerId};
use std::sync::Arc;
[derive(Default)]
struct Handlers {
bar: Bag>,
closed: BagOnce>,
}
struct Inner {
handlers: Arc,
}
impl Drop for Inner {
fn drop(&mut self) {
self.handlers.closed.call_simple();
}
}
[derive(Clone)]
pub struct Foo {
inner: Arc,
}
impl Foo {
pub fn new() -> Self {
let handlers = Arc::::default();
let inner = Arc::new(Inner { handlers });
Self { inner }
}
pub fn dobar(&self) {
// Do things...
self.inner.handlers.bar.callsimple();
}
pub fn dootherbar(&self) {
// Do things...
self.inner.handlers.bar.call(|callback| {
callback();
});
}
pub fn onbar(&self, callback: F) -> HandlerId {
self.inner.handlers.bar.add(Box::new(callback))
}
pub fn onclosed(&self, callback: F) -> HandlerId {
self.inner.handlers.closed.add(Box::new(callback))
}
}
fn main() {
let foo = Foo::new();
let onbarhandlerid = foo.onbar(|| {
println!("On bar");
});
foo
.onclosed(|| {
println!("On closed");
})
.detach();
// This will trigger "bar" callback just fine since its handler ID is not dropped yet
foo.dobar();
drop(onbarhandlerid);
// This will not trigger "bar" callback since its handler ID was already dropped
foo.doother_bar();
// This will trigger "closed" callback though since we've detached handler ID
drop(foo);
println!("Done");
}
```
The output will be:
text
On bar
On closed
Done
Contribution
Feel free to create issues and send pull requests, they are highly appreciated!
License
Zero-Clause BSD
https://opensource.org/licenses/0BSD
https://tldrlegal.com/license/bsd-0-clause-license