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cfg_rt! {
pub(crate) use crate::runtime::spawn_blocking;
cfg_fs! {
#[allow(unused_imports)]
pub(crate) use crate::runtime::spawn_mandatory_blocking;
}
pub(crate) use crate::task::JoinHandle;
}
cfg_not_rt! {
use std::fmt;
use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
pub(crate) fn spawn_blocking<F, R>(_f: F) -> JoinHandle<R>
where
F: FnOnce() -> R + Send + 'static,
R: Send + 'static,
{
assert_send_sync::<JoinHandle<std::cell::Cell<()>>>();
panic!("requires the `rt` Tokio feature flag")
}
cfg_fs! {
pub(crate) fn spawn_mandatory_blocking<F, R>(_f: F) -> Option<JoinHandle<R>>
where
F: FnOnce() -> R + Send + 'static,
R: Send + 'static,
{
panic!("requires the `rt` Tokio feature flag")
}
}
pub(crate) struct JoinHandle<R> {
_p: std::marker::PhantomData<R>,
}
unsafe impl<T: Send> Send for JoinHandle<T> {}
unsafe impl<T: Send> Sync for JoinHandle<T> {}
impl<R> Future for JoinHandle<R> {
type Output = Result<R, std::io::Error>;
fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> {
unreachable!()
}
}
impl<T> fmt::Debug for JoinHandle<T>
where
T: fmt::Debug,
{
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_struct("JoinHandle").finish()
}
}
fn assert_send_sync<T: Send + Sync>() {
}
}
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