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use std::{ptr::NonNull, task::Poll};
struct TaskRef;
struct Header {
vtable: &'static Vtable,
}
struct Vtable {
poll: unsafe fn(TaskRef) -> Poll<()>,
deallocate: unsafe fn(NonNull<Header>),
}
// in the "Header" type, which is a private type in maitake
impl Header {
pub(crate) const fn new_stub() -> Self {
unsafe fn nop(_ptr: TaskRef) -> Poll<()> {
Poll::Pending
}
unsafe fn nop_deallocate(ptr: NonNull<Header>) {
unreachable!("stub task ({ptr:p}) should never be deallocated!");
}
Self { vtable: &Vtable { poll: nop, deallocate: nop_deallocate } }
}
}
// This is a public type in `maitake`
#[repr(transparent)]
#[cfg_attr(loom, allow(dead_code))]
pub struct TaskStub {
hdr: Header,
}
impl TaskStub {
/// Create a new unique stub [`Task`].
pub const fn new() -> Self {
Self { hdr: Header::new_stub() }
}
}
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