blob: 6c7e4b64021edbfdcfce378826c85040f4c266f6 [file] [log] [blame]
use super::{TryChain, TryChainAction};
use core::pin::PinMut;
use futures_core::future::{Future, TryFuture};
use futures_core::task::{self, Poll};
use pin_utils::unsafe_pinned;
/// Future for the [`or_else`](super::TryFutureExt::or_else) combinator.
#[derive(Debug)]
#[must_use = "futures do nothing unless polled"]
pub struct OrElse<Fut1, Fut2, F> {
try_chain: TryChain<Fut1, Fut2, F>,
}
impl<Fut1, Fut2, F> OrElse<Fut1, Fut2, F>
where Fut1: TryFuture,
Fut2: TryFuture,
{
unsafe_pinned!(try_chain: TryChain<Fut1, Fut2, F>);
/// Creates a new `Then`.
pub(super) fn new(future: Fut1, f: F) -> OrElse<Fut1, Fut2, F> {
OrElse {
try_chain: TryChain::new(future, f),
}
}
}
impl<Fut1, Fut2, F> Future for OrElse<Fut1, Fut2, F>
where Fut1: TryFuture,
Fut2: TryFuture<Ok = Fut1::Ok>,
F: FnOnce(Fut1::Error) -> Fut2,
{
type Output = Result<Fut2::Ok, Fut2::Error>;
fn poll(
mut self: PinMut<Self>,
cx: &mut task::Context,
) -> Poll<Self::Output> {
self.try_chain().poll(cx, |result, async_op| {
match result {
Ok(ok) => TryChainAction::Output(Ok(ok)),
Err(err) => TryChainAction::Future(async_op(err)),
}
})
}
}