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#![stable(feature = "futures_api", since = "1.36.0")]
use crate::{
ops::{Generator, GeneratorState},
pin::Pin,
ptr::NonNull,
task::{Context, Poll},
};
mod future;
mod into_future;
mod join;
mod pending;
mod poll_fn;
mod ready;
#[stable(feature = "futures_api", since = "1.36.0")]
pub use self::future::Future;
#[unstable(feature = "future_join", issue = "91642")]
pub use self::join::join;
#[unstable(feature = "into_future", issue = "67644")]
pub use into_future::IntoFuture;
#[stable(feature = "future_readiness_fns", since = "1.48.0")]
pub use pending::{pending, Pending};
#[stable(feature = "future_readiness_fns", since = "1.48.0")]
pub use ready::{ready, Ready};
#[unstable(feature = "future_poll_fn", issue = "72302")]
pub use poll_fn::{poll_fn, PollFn};
#[doc(hidden)]
#[unstable(feature = "gen_future", issue = "50547")]
#[derive(Debug, Copy, Clone)]
pub struct ResumeTy(NonNull<Context<'static>>);
#[unstable(feature = "gen_future", issue = "50547")]
unsafe impl Send for ResumeTy {}
#[unstable(feature = "gen_future", issue = "50547")]
unsafe impl Sync for ResumeTy {}
#[lang = "from_generator"]
#[doc(hidden)]
#[unstable(feature = "gen_future", issue = "50547")]
#[rustc_const_unstable(feature = "gen_future", issue = "50547")]
#[inline]
pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
where
T: Generator<ResumeTy, Yield = ()>,
{
#[rustc_diagnostic_item = "gen_future"]
struct GenFuture<T: Generator<ResumeTy, Yield = ()>>(T);
impl<T: Generator<ResumeTy, Yield = ()>> !Unpin for GenFuture<T> {}
impl<T: Generator<ResumeTy, Yield = ()>> Future for GenFuture<T> {
type Output = T::Return;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let gen = unsafe { Pin::map_unchecked_mut(self, |s| &mut s.0) };
match gen.resume(ResumeTy(NonNull::from(cx).cast::<Context<'static>>())) {
GeneratorState::Yielded(()) => Poll::Pending,
GeneratorState::Complete(x) => Poll::Ready(x),
}
}
}
GenFuture(gen)
}
#[lang = "get_context"]
#[doc(hidden)]
#[unstable(feature = "gen_future", issue = "50547")]
#[must_use]
#[inline]
pub unsafe fn get_context<'a, 'b>(cx: ResumeTy) -> &'a mut Context<'b> {
unsafe { &mut *cx.0.as_ptr().cast() }
}