use std::{
pin::Pin,
task::{Context, Poll},
};
use futures_core::ready;
use pin_project_lite::pin_project;
use crate::{actor::Actor, fut::ActorStream};
pin_project! {
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct Map<S, F> {
#[pin]
stream: S,
f: F,
}
}
pub(super) fn new<S, A, F, U>(stream: S, f: F) -> Map<S, F>
where
S: ActorStream<A>,
A: Actor,
F: FnMut(S::Item, &mut A, &mut A::Context) -> U,
{
Map { stream, f }
}
impl<S, A, F, U> ActorStream<A> for Map<S, F>
where
S: ActorStream<A>,
A: Actor,
F: FnMut(S::Item, &mut A, &mut A::Context) -> U,
{
type Item = U;
fn poll_next(
self: Pin<&mut Self>,
act: &mut A,
ctx: &mut A::Context,
task: &mut Context<'_>,
) -> Poll<Option<Self::Item>> {
let mut this = self.project();
let res = ready!(this.stream.as_mut().poll_next(act, ctx, task));
Poll::Ready(res.map(|x| (this.f)(x, act, ctx)))
}
}