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use std::pin::Pin;
use std::task::{Context, Poll};
use pin_project::pin_project;
use crate::actor::Actor;
use crate::fut::ActorStream;
#[pin_project]
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct StreamMap<S, F> {
#[pin]
stream: S,
f: F,
}
pub fn new<S, F, U>(stream: S, f: F) -> StreamMap<S, F>
where
F: FnMut(S::Item, &mut S::Actor, &mut <S::Actor as Actor>::Context) -> U,
S: ActorStream,
{
StreamMap { stream, f }
}
impl<S, F, U> ActorStream for StreamMap<S, F>
where
S: ActorStream,
F: FnMut(S::Item, &mut S::Actor, &mut <S::Actor as Actor>::Context) -> U,
{
type Item = U;
type Actor = S::Actor;
fn poll_next(
self: Pin<&mut Self>,
act: &mut Self::Actor,
ctx: &mut <S::Actor as Actor>::Context,
task: &mut Context<'_>,
) -> Poll<Option<U>> {
let this = self.project();
match this.stream.poll_next(act, ctx, task) {
Poll::Pending => Poll::Pending,
Poll::Ready(option) => {
if let Some(item) = option {
Poll::Ready(Some((this.f)(item, act, ctx)))
} else {
Poll::Ready(None)
}
}
}
}
}