latchref and nopref types

src/lib.rs

@@ -163,6 +163,7 @@ pub mod task {
 }
 
 pub mod latch {
+    use core::marker::PhantomData;
     use std::{
         sync::{
             atomic::{AtomicBool, AtomicUsize, Ordering},
@@ -283,6 +284,48 @@ pub mod latch {
         }
     }
 
+    pub struct LatchRef<'a, L: Latch> {
+        inner: *const L,
+        _marker: PhantomData<&'a L>,
+    }
+
+    impl<'a, L: Latch> LatchRef<'a, L> {
+        #[inline]
+        pub const fn new(latch: &'a L) -> Self {
+            Self {
+                inner: latch,
+                _marker: PhantomData,
+            }
+        }
+    }
+
+    impl<'a, L: Latch> Latch for LatchRef<'a, L> {
+        #[inline]
+        unsafe fn set_raw(this: *const Self) {
+            let this = &*this;
+            Latch::set_raw(this.inner);
+        }
+    }
+
+    impl<'a, L: Latch + Probe> Probe for LatchRef<'a, L> {
+        #[inline]
+        fn probe(&self) -> bool {
+            unsafe {
+                let this = &*self.inner;
+                Probe::probe(this)
+            }
+        }
+    }
+
+    pub struct NopLatch;
+
+    impl Latch for NopLatch {
+        #[inline]
+        unsafe fn set_raw(_this: *const Self) {
+            // do nothing
+        }
+    }
+
     pub struct MutexLatch {
         mutex: Mutex<bool>,
         signal: Condvar,