diff options
Diffstat (limited to 'vendor/futures-util/src/future/try_join.rs')
| -rw-r--r-- | vendor/futures-util/src/future/try_join.rs | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/vendor/futures-util/src/future/try_join.rs b/vendor/futures-util/src/future/try_join.rs new file mode 100644 index 000000000..6af1f0ccb --- /dev/null +++ b/vendor/futures-util/src/future/try_join.rs @@ -0,0 +1,256 @@ +#![allow(non_snake_case)] + +use crate::future::{assert_future, try_maybe_done, TryMaybeDone}; +use core::fmt; +use core::pin::Pin; +use futures_core::future::{Future, TryFuture}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +macro_rules! generate { + ($( + $(#[$doc:meta])* + ($Join:ident, <Fut1, $($Fut:ident),*>), + )*) => ($( + pin_project! { + $(#[$doc])* + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct $Join<Fut1: TryFuture, $($Fut: TryFuture),*> { + #[pin] Fut1: TryMaybeDone<Fut1>, + $(#[pin] $Fut: TryMaybeDone<$Fut>,)* + } + } + + impl<Fut1, $($Fut),*> fmt::Debug for $Join<Fut1, $($Fut),*> + where + Fut1: TryFuture + fmt::Debug, + Fut1::Ok: fmt::Debug, + Fut1::Error: fmt::Debug, + $( + $Fut: TryFuture + fmt::Debug, + $Fut::Ok: fmt::Debug, + $Fut::Error: fmt::Debug, + )* + { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct(stringify!($Join)) + .field("Fut1", &self.Fut1) + $(.field(stringify!($Fut), &self.$Fut))* + .finish() + } + } + + impl<Fut1, $($Fut),*> $Join<Fut1, $($Fut),*> + where + Fut1: TryFuture, + $( + $Fut: TryFuture<Error=Fut1::Error> + ),* + { + fn new(Fut1: Fut1, $($Fut: $Fut),*) -> Self { + Self { + Fut1: try_maybe_done(Fut1), + $($Fut: try_maybe_done($Fut)),* + } + } + } + + impl<Fut1, $($Fut),*> Future for $Join<Fut1, $($Fut),*> + where + Fut1: TryFuture, + $( + $Fut: TryFuture<Error=Fut1::Error> + ),* + { + type Output = Result<(Fut1::Ok, $($Fut::Ok),*), Fut1::Error>; + + fn poll( + self: Pin<&mut Self>, cx: &mut Context<'_> + ) -> Poll<Self::Output> { + let mut all_done = true; + let mut futures = self.project(); + all_done &= futures.Fut1.as_mut().poll(cx)?.is_ready(); + $( + all_done &= futures.$Fut.as_mut().poll(cx)?.is_ready(); + )* + + if all_done { + Poll::Ready(Ok(( + futures.Fut1.take_output().unwrap(), + $( + futures.$Fut.take_output().unwrap() + ),* + ))) + } else { + Poll::Pending + } + } + } + )*) +} + +generate! { + /// Future for the [`try_join`](try_join()) function. + (TryJoin, <Fut1, Fut2>), + + /// Future for the [`try_join3`] function. + (TryJoin3, <Fut1, Fut2, Fut3>), + + /// Future for the [`try_join4`] function. + (TryJoin4, <Fut1, Fut2, Fut3, Fut4>), + + /// Future for the [`try_join5`] function. + (TryJoin5, <Fut1, Fut2, Fut3, Fut4, Fut5>), +} + +/// Joins the result of two futures, waiting for them both to complete or +/// for one to produce an error. +/// +/// This function will return a new future which awaits both futures to +/// complete. If successful, the returned future will finish with a tuple of +/// both results. If unsuccessful, it will complete with the first error +/// encountered. +/// +/// Note that this function consumes the passed futures and returns a +/// wrapped version of it. +/// +/// # Examples +/// +/// When used on multiple futures that return [`Ok`], `try_join` will return +/// [`Ok`] of a tuple of the values: +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Ok::<i32, i32>(2)); +/// let pair = future::try_join(a, b); +/// +/// assert_eq!(pair.await, Ok((1, 2))); +/// # }); +/// ``` +/// +/// If one of the futures resolves to an error, `try_join` will return +/// that error: +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Err::<i32, i32>(2)); +/// let pair = future::try_join(a, b); +/// +/// assert_eq!(pair.await, Err(2)); +/// # }); +/// ``` +pub fn try_join<Fut1, Fut2>(future1: Fut1, future2: Fut2) -> TryJoin<Fut1, Fut2> +where + Fut1: TryFuture, + Fut2: TryFuture<Error = Fut1::Error>, +{ + assert_future::<Result<(Fut1::Ok, Fut2::Ok), Fut1::Error>, _>(TryJoin::new(future1, future2)) +} + +/// Same as [`try_join`](try_join()), but with more futures. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Ok::<i32, i32>(2)); +/// let c = future::ready(Ok::<i32, i32>(3)); +/// let tuple = future::try_join3(a, b, c); +/// +/// assert_eq!(tuple.await, Ok((1, 2, 3))); +/// # }); +/// ``` +pub fn try_join3<Fut1, Fut2, Fut3>( + future1: Fut1, + future2: Fut2, + future3: Fut3, +) -> TryJoin3<Fut1, Fut2, Fut3> +where + Fut1: TryFuture, + Fut2: TryFuture<Error = Fut1::Error>, + Fut3: TryFuture<Error = Fut1::Error>, +{ + assert_future::<Result<(Fut1::Ok, Fut2::Ok, Fut3::Ok), Fut1::Error>, _>(TryJoin3::new( + future1, future2, future3, + )) +} + +/// Same as [`try_join`](try_join()), but with more futures. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Ok::<i32, i32>(2)); +/// let c = future::ready(Ok::<i32, i32>(3)); +/// let d = future::ready(Ok::<i32, i32>(4)); +/// let tuple = future::try_join4(a, b, c, d); +/// +/// assert_eq!(tuple.await, Ok((1, 2, 3, 4))); +/// # }); +/// ``` +pub fn try_join4<Fut1, Fut2, Fut3, Fut4>( + future1: Fut1, + future2: Fut2, + future3: Fut3, + future4: Fut4, +) -> TryJoin4<Fut1, Fut2, Fut3, Fut4> +where + Fut1: TryFuture, + Fut2: TryFuture<Error = Fut1::Error>, + Fut3: TryFuture<Error = Fut1::Error>, + Fut4: TryFuture<Error = Fut1::Error>, +{ + assert_future::<Result<(Fut1::Ok, Fut2::Ok, Fut3::Ok, Fut4::Ok), Fut1::Error>, _>( + TryJoin4::new(future1, future2, future3, future4), + ) +} + +/// Same as [`try_join`](try_join()), but with more futures. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Ok::<i32, i32>(2)); +/// let c = future::ready(Ok::<i32, i32>(3)); +/// let d = future::ready(Ok::<i32, i32>(4)); +/// let e = future::ready(Ok::<i32, i32>(5)); +/// let tuple = future::try_join5(a, b, c, d, e); +/// +/// assert_eq!(tuple.await, Ok((1, 2, 3, 4, 5))); +/// # }); +/// ``` +pub fn try_join5<Fut1, Fut2, Fut3, Fut4, Fut5>( + future1: Fut1, + future2: Fut2, + future3: Fut3, + future4: Fut4, + future5: Fut5, +) -> TryJoin5<Fut1, Fut2, Fut3, Fut4, Fut5> +where + Fut1: TryFuture, + Fut2: TryFuture<Error = Fut1::Error>, + Fut3: TryFuture<Error = Fut1::Error>, + Fut4: TryFuture<Error = Fut1::Error>, + Fut5: TryFuture<Error = Fut1::Error>, +{ + assert_future::<Result<(Fut1::Ok, Fut2::Ok, Fut3::Ok, Fut4::Ok, Fut5::Ok), Fut1::Error>, _>( + TryJoin5::new(future1, future2, future3, future4, future5), + ) +} |