| use crate::future::Future; |
| use crate::marker::Tuple; |
| |
| /// An async-aware version of the [`Fn`](crate::ops::Fn) trait. |
| /// |
| /// All `async fn` and functions returning futures implement this trait. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| #[rustc_paren_sugar] |
| #[fundamental] |
| #[must_use = "async closures are lazy and do nothing unless called"] |
| #[cfg_attr(not(bootstrap), lang = "async_fn")] |
| pub trait AsyncFn<Args: Tuple>: AsyncFnMut<Args> { |
| /// Future returned by [`AsyncFn::async_call`]. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| type CallFuture<'a>: Future<Output = Self::Output> |
| where |
| Self: 'a; |
| |
| /// Call the [`AsyncFn`], returning a future which may borrow from the called closure. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| extern "rust-call" fn async_call(&self, args: Args) -> Self::CallFuture<'_>; |
| } |
| |
| /// An async-aware version of the [`FnMut`](crate::ops::FnMut) trait. |
| /// |
| /// All `async fn` and functions returning futures implement this trait. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| #[rustc_paren_sugar] |
| #[fundamental] |
| #[must_use = "async closures are lazy and do nothing unless called"] |
| #[cfg_attr(not(bootstrap), lang = "async_fn_mut")] |
| pub trait AsyncFnMut<Args: Tuple>: AsyncFnOnce<Args> { |
| /// Future returned by [`AsyncFnMut::async_call_mut`]. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| type CallMutFuture<'a>: Future<Output = Self::Output> |
| where |
| Self: 'a; |
| |
| /// Call the [`AsyncFnMut`], returning a future which may borrow from the called closure. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| extern "rust-call" fn async_call_mut(&mut self, args: Args) -> Self::CallMutFuture<'_>; |
| } |
| |
| /// An async-aware version of the [`FnOnce`](crate::ops::FnOnce) trait. |
| /// |
| /// All `async fn` and functions returning futures implement this trait. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| #[rustc_paren_sugar] |
| #[fundamental] |
| #[must_use = "async closures are lazy and do nothing unless called"] |
| #[cfg_attr(not(bootstrap), lang = "async_fn_once")] |
| pub trait AsyncFnOnce<Args: Tuple> { |
| /// Future returned by [`AsyncFnOnce::async_call_once`]. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| type CallOnceFuture: Future<Output = Self::Output>; |
| |
| /// Output type of the called closure's future. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| type Output; |
| |
| /// Call the [`AsyncFnOnce`], returning a future which may move out of the called closure. |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| extern "rust-call" fn async_call_once(self, args: Args) -> Self::CallOnceFuture; |
| } |
| |
| mod impls { |
| use super::{AsyncFn, AsyncFnMut, AsyncFnOnce}; |
| use crate::future::Future; |
| use crate::marker::Tuple; |
| |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| impl<F: Fn<A>, A: Tuple> AsyncFn<A> for F |
| where |
| <F as FnOnce<A>>::Output: Future, |
| { |
| type CallFuture<'a> = <F as FnOnce<A>>::Output where Self: 'a; |
| |
| extern "rust-call" fn async_call(&self, args: A) -> Self::CallFuture<'_> { |
| self.call(args) |
| } |
| } |
| |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| impl<F: FnMut<A>, A: Tuple> AsyncFnMut<A> for F |
| where |
| <F as FnOnce<A>>::Output: Future, |
| { |
| type CallMutFuture<'a> = <F as FnOnce<A>>::Output where Self: 'a; |
| |
| extern "rust-call" fn async_call_mut(&mut self, args: A) -> Self::CallMutFuture<'_> { |
| self.call_mut(args) |
| } |
| } |
| |
| #[unstable(feature = "async_fn_traits", issue = "none")] |
| impl<F: FnOnce<A>, A: Tuple> AsyncFnOnce<A> for F |
| where |
| <F as FnOnce<A>>::Output: Future, |
| { |
| type CallOnceFuture = <F as FnOnce<A>>::Output; |
| |
| type Output = <<F as FnOnce<A>>::Output as Future>::Output; |
| |
| extern "rust-call" fn async_call_once(self, args: A) -> Self::CallOnceFuture { |
| self.call_once(args) |
| } |
| } |
| } |