use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
use futures::{ready, TryFuture};
use pin_project::pin_project;
use super::{Either, Filter, FilterBase, Internal, Tuple};
#[derive(Clone, Copy, Debug)]
pub struct Unify<F> {
pub(super) filter: F,
}
impl<F, T> FilterBase for Unify<F>
where
F: Filter<Extract = (Either<T, T>,)>,
T: Tuple,
{
type Extract = T;
type Error = F::Error;
type Future = UnifyFuture<F::Future>;
#[inline]
fn filter(&self, _: Internal) -> Self::Future {
UnifyFuture {
inner: self.filter.filter(Internal),
}
}
}
#[allow(missing_debug_implementations)]
#[pin_project]
pub struct UnifyFuture<F> {
#[pin]
inner: F,
}
impl<F, T> Future for UnifyFuture<F>
where
F: TryFuture<Ok = (Either<T, T>,)>,
{
type Output = Result<T, F::Error>;
#[inline]
fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
let unified = match ready!(self.project().inner.try_poll(cx)) {
Ok((Either::A(a),)) => Ok(a),
Ok((Either::B(b),)) => Ok(b),
Err(err) => Err(err),
};
Poll::Ready(unified)
}
}