simple-actor

基于actor的异步代码的辅助工具。

use futures::FutureExt;
use simple_actor::Actor;
use std::time::Duration;

#[derive(Clone)]
pub struct Adder(Actor<u32>);

impl Adder {
    pub fn new(initial_value: u32) -> Self {
        let (actor, driver) = Actor::new(initial_value);
        tokio::spawn(driver);
        Self(actor)
    }

    pub async fn add(&self, x: u32) -> Option<()> {
        self.0.queue(move |state| *state += x).await
    }

    pub async fn add_delayed(&self, x: u32) -> Option<()> {
        self.0.queue_blocking(move |state| async move {
            tokio::time::sleep(Duration::from_millis(500)).await;
            *state += x
        }.boxed()).await
    }

    pub async fn get(&self) -> Option<u32> {
        self.0.query(move |state| *state).await
    }

    pub async fn get_delayed(&self) -> Option<u32> {
        self.0.query_blocking(move |state| async move {
            tokio::time::sleep(Duration::from_millis(500)).await;
            *state
        }.boxed()).await
    }
}

#[tokio::main]
async fn main() {
    let adder = Adder::new(5);

    assert_eq!(adder.add(2).await, Some(()));
    assert_eq!(adder.get().await, Some(7));

    assert_eq!(adder.add_delayed(3).await, Some(()));
    assert_eq!(adder.get_delayed().await, Some(10));

    assert!(adder.0.is_active());
    adder.0.shutdown();
    assert!(!adder.0.is_active());

    assert_eq!(adder.add(2).await, None);
    assert_eq!(adder.get().await, None);

    assert_eq!(adder.add_delayed(2).await, None);
    assert_eq!(adder.get_delayed().await, None);
}

灵感

该crate受到ghost_actor的启发，具有更简单实现和API。

此crate在actor宕机时返回None或false，从而避免了错误类型转换的处理。

此crate还允许使用可以在.await之间保持状态的futures。