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use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
use futures_util::{ready, TryFuture};
use pin_project::pin_project;
use super::{Filter, FilterBase, Func, Internal};
#[derive(Clone, Copy, Debug)]
pub struct Map<T, F> {
pub(super) filter: T,
pub(super) callback: F,
}
impl<T, F> FilterBase for Map<T, F>
where
T: Filter,
F: Func<T::Extract> + Clone + Send,
{
type Extract = (F::Output,);
type Error = T::Error;
type Future = MapFuture<T, F>;
#[inline]
fn filter(&self, _: Internal) -> Self::Future {
MapFuture {
extract: self.filter.filter(Internal),
callback: self.callback.clone(),
}
}
}
#[allow(missing_debug_implementations)]
#[pin_project]
pub struct MapFuture<T: Filter, F> {
#[pin]
extract: T::Future,
callback: F,
}
impl<T, F> Future for MapFuture<T, F>
where
T: Filter,
F: Func<T::Extract>,
{
type Output = Result<(F::Output,), T::Error>;
#[inline]
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let pin = self.project();
match ready!(pin.extract.try_poll(cx)) {
Ok(ex) => {
let ex = (pin.callback.call(ex),);
Poll::Ready(Ok(ex))
}
Err(err) => Poll::Ready(Err(err)),
}
}
}