System Initiative

use std::{ future::Future, pin::Pin, task::{ Context, Poll, }, }; use tower::Service; use super::{ DefaultForSubject, ForSubject, MatchedSubjectLayer, }; use crate::{ Message, MessageHead, }; #[derive(Clone, Copy, Debug)] pub struct MatchedSubject<S, ForSubject = DefaultForSubject> { pub(crate) inner: S, pub(crate) for_subject: ForSubject, } impl<S> MatchedSubject<S> { pub fn new(inner: S) -> Self { Self { inner, for_subject: DefaultForSubject::default(), } } pub fn layer() -> MatchedSubjectLayer { MatchedSubjectLayer::new() } } impl<S, ForSubjectT, R> Service<Message<R>> for MatchedSubject<S, ForSubjectT> where S: Service<Message<R>> + Clone + Send + 'static, S::Future: Send, ForSubjectT: ForSubject<R>, R: MessageHead + Send + 'static, { type Response = S::Response; type Error = S::Error; type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>; fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { self.inner.poll_ready(cx) } fn call(&mut self, mut req: Message<R>) -> Self::Future { self.for_subject.call(&mut req); let clone = self.inner.clone(); // Take the service that was ready // // See documentation for [`Service`] trait let mut inner = std::mem::replace(&mut self.inner, clone); Box::pin(async move { inner.call(req).await }) } }