mirror of https://github.com/rust-lang/rust
73 lines
2.3 KiB
Rust
73 lines
2.3 KiB
Rust
#![stable(feature = "futures_api", since = "1.36.0")]
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//! Asynchronous basic functionality.
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//!
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//! Please see the fundamental [`async`] and [`await`] keywords and the [async book]
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//! for more information on asynchronous programming in Rust.
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//!
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//! [`async`]: ../../std/keyword.async.html
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//! [`await`]: ../../std/keyword.await.html
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//! [async book]: https://rust-lang.github.io/async-book/
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use crate::ptr::NonNull;
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use crate::task::Context;
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mod async_drop;
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mod future;
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mod into_future;
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mod join;
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mod pending;
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mod poll_fn;
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mod ready;
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#[stable(feature = "futures_api", since = "1.36.0")]
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pub use self::future::Future;
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#[unstable(feature = "future_join", issue = "91642")]
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pub use self::join::join;
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#[stable(feature = "into_future", since = "1.64.0")]
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pub use into_future::IntoFuture;
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#[stable(feature = "future_readiness_fns", since = "1.48.0")]
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pub use pending::{pending, Pending};
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#[stable(feature = "future_readiness_fns", since = "1.48.0")]
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pub use ready::{ready, Ready};
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#[stable(feature = "future_poll_fn", since = "1.64.0")]
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pub use poll_fn::{poll_fn, PollFn};
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#[unstable(feature = "async_drop", issue = "none")]
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pub use async_drop::{async_drop, async_drop_in_place, AsyncDrop, AsyncDropInPlace};
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/// This type is needed because:
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///
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/// a) Coroutines cannot implement `for<'a, 'b> Coroutine<&'a mut Context<'b>>`, so we need to pass
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/// a raw pointer (see <https://github.com/rust-lang/rust/issues/68923>).
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/// b) Raw pointers and `NonNull` aren't `Send` or `Sync`, so that would make every single future
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/// non-Send/Sync as well, and we don't want that.
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///
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/// It also simplifies the HIR lowering of `.await`.
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#[lang = "ResumeTy"]
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#[doc(hidden)]
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#[unstable(feature = "gen_future", issue = "50547")]
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#[derive(Debug, Copy, Clone)]
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pub struct ResumeTy(NonNull<Context<'static>>);
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#[unstable(feature = "gen_future", issue = "50547")]
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unsafe impl Send for ResumeTy {}
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#[unstable(feature = "gen_future", issue = "50547")]
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unsafe impl Sync for ResumeTy {}
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#[lang = "get_context"]
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#[doc(hidden)]
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#[unstable(feature = "gen_future", issue = "50547")]
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#[must_use]
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#[inline]
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pub unsafe fn get_context<'a, 'b>(cx: ResumeTy) -> &'a mut Context<'b> {
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// SAFETY: the caller must guarantee that `cx.0` is a valid pointer
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// that fulfills all the requirements for a mutable reference.
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unsafe { &mut *cx.0.as_ptr().cast() }
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}
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