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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, Internal, Tuple};
#[derive(Clone, Copy, Debug)]
pub struct UntupleOne<F> {
pub(super) filter: F,
}
impl<F, T> FilterBase for UntupleOne<F>
where
F: Filter<Extract = (T,)>,
T: Tuple,
{
type Extract = T;
type Error = F::Error;
type Future = UntupleOneFuture<F>;
#[inline]
fn filter(&self, _: Internal) -> Self::Future {
UntupleOneFuture {
extract: self.filter.filter(Internal),
}
}
}
#[allow(missing_debug_implementations)]
#[pin_project]
pub struct UntupleOneFuture<F: Filter> {
#[pin]
extract: F::Future,
}
impl<F, T> Future for UntupleOneFuture<F>
where
F: Filter<Extract = (T,)>,
T: Tuple,
{
type Output = Result<T, F::Error>;
#[inline]
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
match ready!(self.project().extract.try_poll(cx)) {
Ok((t,)) => Poll::Ready(Ok(t)),
Err(err) => Poll::Ready(Err(err)),
}
}
}