1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256
#![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), ) }