Crate fx_callback 

A subscription based callback for data events that might occur within one or more structs. It is mainly used within the FX landscape to allow events to be published between multiple structs.

Example

use fx_callback::{Callback, MultiThreadedCallback, Subscriber, Subscription};

/// The events of the struct that informs subscribers about changes to the data within the struct.
#[derive(Debug, Clone, PartialEq)]
enum MyEvent {
    Foo,
}

/// The struct to which an interested subscriber can subscribe to.
#[derive(Debug)]
struct Example {
    callbacks: MultiThreadedCallback<MyEvent>,
}

impl Example {
    fn invoke_event(&self) {
        self.callbacks.invoke(MyEvent::Foo);
    }
}

impl Callback<MyEvent> for Example {
    fn subscribe(&self) -> Subscription<MyEvent> {
        self.callbacks.subscribe()
    }

    fn subscribe_with(&self, subscriber: Subscriber<MyEvent>) {
        self.callbacks.subscribe_with(subscriber)
    }
}

Usage

Subscription/event holder

To get started with adding callbacks to your structs, add one of the implementations of the Callback trait. Make sure that the struct implements the Debug trait.

use fx_callback::{Callback, MultiThreadedCallback};

#[derive(Debug)]
pub struct MyStruct {
    callbacks: MultiThreadedCallback<MyEvent>,
}

Add the Callback trait implementation to your struct to allow adding callbacks.

impl Callback<MyEvent> for MyStruct {
    fn subscribe(&self) -> Subscription<MyEvent> {
        self.callbacks.subscribe()
    }

    fn subscribe_with(&self, subscriber: Subscriber<MyEvent>) {
        self.callbacks.subscribe_with(subscriber)
    }
}

When you want to inform subscribers about a certain event, call the invoke method.

impl MyStruct {
    pub fn invoke_event(&self) {
        self.callbacks.invoke(MyEvent::Foo);
    }
}

Subscriber

The interested subscriber can subscribe to the interested event of a struct that implements the Callback trait.

use fx_callback::{Callback, MultiThreadedCallback, Subscriber, Subscription};
use tokio::runtime::Runtime;

fn main() {
    let runtime = Runtime::new().unwrap();
    let struct_with_callback = MyStruct::new();

    let mut receiver = struct_with_callback.subscribe();
    runtime.spawn(async move {
       loop {
           if let Some(event) = receiver.recv().await {
               println!("Received event: {}", event);
           } else {
               break;
           }
       }
    });

    struct_with_callback.invoke_event();
}

Structs

MultiThreadedCallback

A multithreaded callback holder.

SingleThreadedCallback

A single threaded or current threaded callback holder.

Traits

Callback

Allows adding callbacks to the struct. The struct will inform the Subscription when a certain event occurs.

Type Aliases

CallbackHandle

The unique identifier for a callback.

Subscriber

The subscriber type for the interested event. This can be used to send the interested event from multiple sources into one receiver.

Subscription

The subscription type for the interested event. Drop this subscription to remove the callback.