tram 0.2.0

A simple event bus that can be cloned and shared across threads.

Limitations

At present the only limitation is the inability to use the same EventBus inside on blocks because it will lead to a deadlock.

Example

#[derive(PartialEq, Eq, Hash)]
enum EventType {
    Start,
    Stop,
}

#[derive(Debug, PartialEq)]
enum Status {
    Stopped,
    Started,
}

let bus: EventBus<EventType> = EventBus::unbound();
let status = Rc::new(RefCell::new(Status::Stopped));
let status_closure = Rc::clone(&status);
let status_closure_2 = Rc::clone(&status);
bus.on(EventType::Start, move || {
    *status_closure.borrow_mut() = Status::Started;
})
.unwrap();

bus.on(EventType::Stop, move || {
    *status_closure_2.borrow_mut() = Status::Stopped;
})
.unwrap();

bus.emit(EventType::Start).expect("Failed to emit");

assert_eq!(*status.borrow(), Status::Started);
assert_eq!(bus.event_count(), 1);

bus.emit(EventType::Stop).expect("Failed to emit");

assert_eq!(*status.borrow(), Status::Stopped);
assert_eq!(bus.event_count(), 2);

Using it in threads

let bus: EventBus<EventType, ()> = EventBus::unbound();
let bus_clone = bus.clone();
let status = Arc::new(Mutex::new(Status::Stopped));
let final_status = Arc::clone(&status);

let t1 = std::thread::spawn(move || {
    bus.on(EventType::Start, move |_| {
        let mut status_lock = status.lock().unwrap();
        *status_lock = Status::Started;
    }).unwrap();
});

let t2 = std::thread::spawn(move || {
    bus_clone.emit(EventType::Start).unwrap();
});

t1.join().unwrap();
t2.join().unwrap();

let final_status_lock = final_status.lock().unwrap();
assert_eq!(*final_status_lock, Status::Started)

Passing data to events

let bus: EventBus<EventType, u8> = EventBus::unbound();
let status: Rc<RefCell<Option<u8>>> = Rc::new(RefCell::new(None));
let status_closure = Rc::clone(&status);

bus.on(EventType::Start, move |startup_data| {
    *status_closure.borrow_mut() = Some(*startup_data.unwrap());
})
.unwrap();

bus.emit_with_value(EventType::Start, Some(&123)).expect("Failed to emit");

assert_eq!(*status.borrow(), Some(123));
assert_eq!(bus.event_count(), 1);