mirror of https://github.com/rust-lang/rust
65 lines
1.6 KiB
Rust
65 lines
1.6 KiB
Rust
//@ edition:2018
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use std::sync::Arc;
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use std::task::{
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Waker, RawWaker, RawWakerVTable,
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};
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macro_rules! waker_vtable {
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($ty:ident) => {
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&RawWakerVTable::new(
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clone_arc_raw::<$ty>,
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wake_arc_raw::<$ty>,
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wake_by_ref_arc_raw::<$ty>,
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drop_arc_raw::<$ty>,
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)
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};
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}
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pub trait ArcWake {
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fn wake(self: Arc<Self>);
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fn wake_by_ref(arc_self: &Arc<Self>) {
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arc_self.clone().wake()
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}
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fn into_waker(wake: Arc<Self>) -> Waker where Self: Sized
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{
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let ptr = Arc::into_raw(wake) as *const ();
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unsafe {
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Waker::from_raw(RawWaker::new(ptr, waker_vtable!(Self)))
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}
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}
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}
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unsafe fn increase_refcount<T: ArcWake>(data: *const ()) {
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// Retain Arc by creating a copy
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let arc: Arc<T> = Arc::from_raw(data as *const T);
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let arc_clone = arc.clone();
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// Forget the Arcs again, so that the refcount isn't decrased
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let _ = Arc::into_raw(arc);
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let _ = Arc::into_raw(arc_clone);
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}
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unsafe fn clone_arc_raw<T: ArcWake>(data: *const ()) -> RawWaker {
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increase_refcount::<T>(data);
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RawWaker::new(data, waker_vtable!(T))
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}
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unsafe fn drop_arc_raw<T: ArcWake>(data: *const ()) {
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// Drop Arc
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let _: Arc<T> = Arc::from_raw(data as *const T);
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}
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unsafe fn wake_arc_raw<T: ArcWake>(data: *const ()) {
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let arc: Arc<T> = Arc::from_raw(data as *const T);
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ArcWake::wake(arc);
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}
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unsafe fn wake_by_ref_arc_raw<T: ArcWake>(data: *const ()) {
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let arc: Arc<T> = Arc::from_raw(data as *const T);
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ArcWake::wake_by_ref(&arc);
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let _ = Arc::into_raw(arc);
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}
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