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use crate::runtime::task::{Cell, Harness, Header, Schedule, State};
use std::future::Future;
use std::ptr::NonNull;
use std::task::{Poll, Waker};
pub(super) struct RawTask {
ptr: NonNull<Header>,
}
pub(super) struct Vtable {
pub(super) poll: unsafe fn(NonNull<Header>),
pub(super) dealloc: unsafe fn(NonNull<Header>),
pub(super) try_read_output: unsafe fn(NonNull<Header>, *mut (), &Waker),
pub(super) drop_join_handle_slow: unsafe fn(NonNull<Header>),
pub(super) shutdown: unsafe fn(NonNull<Header>),
}
pub(super) fn vtable<T: Future, S: Schedule>() -> &'static Vtable {
&Vtable {
poll: poll::<T, S>,
dealloc: dealloc::<T, S>,
try_read_output: try_read_output::<T, S>,
drop_join_handle_slow: drop_join_handle_slow::<T, S>,
shutdown: shutdown::<T, S>,
}
}
impl RawTask {
pub(super) fn new<T, S>(task: T) -> RawTask
where
T: Future,
S: Schedule,
{
let ptr = Box::into_raw(Cell::<_, S>::new(task, State::new()));
let ptr = unsafe { NonNull::new_unchecked(ptr as *mut Header) };
RawTask { ptr }
}
pub(super) unsafe fn from_raw(ptr: NonNull<Header>) -> RawTask {
RawTask { ptr }
}
pub(super) fn header(&self) -> &Header {
unsafe { self.ptr.as_ref() }
}
pub(super) fn poll(self) {
let vtable = self.header().vtable;
unsafe { (vtable.poll)(self.ptr) }
}
pub(super) fn dealloc(self) {
let vtable = self.header().vtable;
unsafe {
(vtable.dealloc)(self.ptr);
}
}
pub(super) unsafe fn try_read_output(self, dst: *mut (), waker: &Waker) {
let vtable = self.header().vtable;
(vtable.try_read_output)(self.ptr, dst, waker);
}
pub(super) fn drop_join_handle_slow(self) {
let vtable = self.header().vtable;
unsafe { (vtable.drop_join_handle_slow)(self.ptr) }
}
pub(super) fn shutdown(self) {
let vtable = self.header().vtable;
unsafe { (vtable.shutdown)(self.ptr) }
}
}
impl Clone for RawTask {
fn clone(&self) -> Self {
RawTask { ptr: self.ptr }
}
}
impl Copy for RawTask {}
unsafe fn poll<T: Future, S: Schedule>(ptr: NonNull<Header>) {
let harness = Harness::<T, S>::from_raw(ptr);
harness.poll();
}
unsafe fn dealloc<T: Future, S: Schedule>(ptr: NonNull<Header>) {
let harness = Harness::<T, S>::from_raw(ptr);
harness.dealloc();
}
unsafe fn try_read_output<T: Future, S: Schedule>(
ptr: NonNull<Header>,
dst: *mut (),
waker: &Waker,
) {
let out = &mut *(dst as *mut Poll<super::Result<T::Output>>);
let harness = Harness::<T, S>::from_raw(ptr);
harness.try_read_output(out, waker);
}
unsafe fn drop_join_handle_slow<T: Future, S: Schedule>(ptr: NonNull<Header>) {
let harness = Harness::<T, S>::from_raw(ptr);
harness.drop_join_handle_slow()
}
unsafe fn shutdown<T: Future, S: Schedule>(ptr: NonNull<Header>) {
let harness = Harness::<T, S>::from_raw(ptr);
harness.shutdown()
}