Add stable_deref_trait feature

Cargo.toml

@@ -17,6 +17,7 @@ exclude = ["/.*"]
 [dependencies]
 futures-lite = "1.11.0"
 event-listener = "2.5.1"
+stable_deref_trait = { version = "1.2.0", optional = true }
 
 [dev-dependencies]
 async-channel = "1.5.0"

src/lib.rs

@@ -6,6 +6,16 @@
 //! * [`Mutex`] - a mutual exclusion lock.
 //! * [`RwLock`] - a reader-writer lock, allowing any number of readers or a single writer.
 //! * [`Semaphore`] - limits the number of concurrent operations.
+//! 
+//! # Features
+//! 
+//! - `stable_deref_trait` - Uses the [`stable_deref_trait`] crate to implement the [`StableDeref`] trait
+//!   for the guards of the synchronization primitives. This allows these types to be used in crates like
+//!   [`owning_ref`].
+//! 
+//! [`stable_deref_trait`]: https://crates.io/crates/stable_deref_trait
+//! [`StableDeref`]: https://docs.rs/stable_deref_trait/latest/stable_deref_trait/trait.StableDeref.html
+//! [`owning_ref`]: https://crates.io/crates/owning_ref
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms)]
 

src/mutex.rs

@@ -412,6 +412,9 @@ impl<T: ?Sized> DerefMut for MutexGuard<'_, T> {
     }
 }
 
+#[cfg(feature = "stable_deref_trait")]
+unsafe impl<T: ?Sized> stable_deref_trait::StableDeref for MutexGuard<'_, T> {}
+
 /// An owned guard that releases the mutex when dropped.
 pub struct MutexGuardArc<T: ?Sized>(Arc<Mutex<T>>);
 
@@ -472,6 +475,9 @@ impl<T: ?Sized> DerefMut for MutexGuardArc<T> {
     }
 }
 
+#[cfg(feature = "stable_deref_trait")]
+unsafe impl<T: ?Sized> stable_deref_trait::StableDeref for MutexGuardArc<T> {}
+
 /// Calls a function when dropped.
 struct CallOnDrop<F: Fn()>(F);
 

src/rwlock.rs

@@ -484,6 +484,9 @@ impl<T: ?Sized> Deref for RwLockReadGuard<'_, T> {
     }
 }
 
+#[cfg(feature = "stable_deref_trait")]
+unsafe impl<T: ?Sized> stable_deref_trait::StableDeref for RwLockReadGuard<'_, T> {}
+
 /// A guard that releases the upgradable read lock when dropped.
 pub struct RwLockUpgradableReadGuard<'a, T: ?Sized> {
     reader: RwLockReadGuard<'a, T>,
@@ -632,6 +635,9 @@ impl<T: ?Sized> Deref for RwLockUpgradableReadGuard<'_, T> {
     }
 }
 
+#[cfg(feature = "stable_deref_trait")]
+unsafe impl<T: ?Sized> stable_deref_trait::StableDeref for RwLockUpgradableReadGuard<'_, T> {}
+
 struct RwLockWriteGuardInner<'a, T: ?Sized>(&'a RwLock<T>);
 
 impl<T: ?Sized> Drop for RwLockWriteGuardInner<'_, T> {
@@ -758,3 +764,6 @@ impl<T: ?Sized> DerefMut for RwLockWriteGuard<'_, T> {
         unsafe { &mut *self.writer.0.value.get() }
     }
 }
+
+#[cfg(feature = "stable_deref_trait")]
+unsafe impl<T: ?Sized> stable_deref_trait::StableDeref for RwLockWriteGuard<'_, T> {}