OwnedLockable

2 files changed, 88 insertions, 5 deletions

diff --git a/src/collection.rs b/src/collection.rs
index 4b24a67..34de620 100644
--- a/src/collection.rs
+++ b/src/collection.rs
@@ -3,13 +3,16 @@ use std::{
 	ops::{Deref, DerefMut},
 };
 
-use crate::{key::Keyable, lockable::Lockable};
+use crate::{
+	key::Keyable,
+	lockable::{Lockable, OwnedLockable},
+};
 
 /// returns `true` if the list contains a duplicate
 fn contains_duplicates(l: &[usize]) -> bool {
 	for i in 0..l.len() {
-		for j in 0..l.len() {
-			if i != j && l[i] == l[j] {
+		for j in (i + 1)..l.len() {
+			if l[i] == l[j] {
 				return true;
 			}
 		}
@@ -46,11 +49,36 @@ impl<L> LockCollection<L> {
 	}
 }
 
+impl<'a, L: OwnedLockable<'a>> LockCollection<L> {
+	/// Creates a new collection of owned locks.
+	///
+	/// Because the locks are owned, there's no need to do any checks for
+	/// duplicate values.
+	pub const fn new(collection: L) -> Self {
+		Self { collection }
+	}
+
+	/// Creates a new collection of owned locks.
+	///
+	/// Because the locks are owned, there's no need to do any checks for
+	/// duplicate values.
+	pub const fn new_ref(collection: &L) -> LockCollection<&L> {
+		LockCollection { collection }
+	}
+}
+
 impl<'a, L: Lockable<'a>> LockCollection<L> {
 	/// Creates a new collection of locks.
 	///
-	/// This returns `None` if any locks are found twice in the given collection.
-	pub fn new(collection: L) -> Option<Self> {
+	/// This returns `None` if any locks are found twice in the given
+	/// collection.
+	///
+	/// # Performance
+	///
+	/// This does a check at runtime to make sure that the collection contains
+	/// no two copies of the same lock. This is an `O(n^2)` operation. Prefer
+	/// [`LockCollection::new`] or [`LockCollection::new_ref`] instead.
+	pub fn try_new(collection: L) -> Option<Self> {
 		let ptrs = collection.get_ptrs();
 		if contains_duplicates(&ptrs) {
 			return None;
diff --git a/src/lockable.rs b/src/lockable.rs
index ddcc1c8..3c217c4 100644
--- a/src/lockable.rs
+++ b/src/lockable.rs
@@ -29,6 +29,15 @@ mod sealed {
 	impl<'a, T: Lockable<'a>> Sealed for Vec<T> {}
 }
 
+/// A type that may be locked and unlocked, and is known to be the only valid
+/// instance of the lock.
+///
+/// # Safety
+///
+/// There must not be any two values which can unlock the value at the same
+/// time, i.e., this must either be an owned value or a mutable reference.
+pub unsafe trait OwnedLockable<'a>: Lockable<'a> {}
+
 /// A type that may be locked and unlocked
 ///
 /// # Safety
@@ -102,6 +111,8 @@ unsafe impl<'a, T: Lockable<'a>> Lockable<'a> for &mut T {
 	}
 }
 
+unsafe impl<'a, T: OwnedLockable<'a>> OwnedLockable<'a> for &mut T {}
+
 unsafe impl<'a, T: 'a, R: RawMutex + 'a> Lockable<'a> for Mutex<T, R> {
 	type Output = MutexRef<'a, T, R>;
 
@@ -134,6 +145,10 @@ unsafe impl<'a, T: 'a, R: RawRwLock + 'a> Lockable<'a> for RwLock<T, R> {
 	}
 }
 
+unsafe impl<'a, T: 'a, R: RawMutex + 'a> OwnedLockable<'a> for Mutex<T, R> {}
+
+unsafe impl<'a, T: 'a, R: RawRwLock + 'a> OwnedLockable<'a> for RwLock<T, R> {}
+
 unsafe impl<'a, T: 'a, R: RawRwLock + 'a> Lockable<'a> for ReadLock<'a, T, R> {
 	type Output = RwLockReadRef<'a, T, R>;
 
@@ -439,6 +454,43 @@ unsafe impl<
 	}
 }
 
+unsafe impl<'a, A: OwnedLockable<'a>> OwnedLockable<'a> for (A,) {}
+unsafe impl<'a, A: OwnedLockable<'a>, B: OwnedLockable<'a>> OwnedLockable<'a> for (A, B) {}
+unsafe impl<'a, A: OwnedLockable<'a>, B: OwnedLockable<'a>, C: OwnedLockable<'a>> OwnedLockable<'a>
+	for (A, B, C)
+{
+}
+unsafe impl<
+		'a,
+		A: OwnedLockable<'a>,
+		B: OwnedLockable<'a>,
+		C: OwnedLockable<'a>,
+		D: OwnedLockable<'a>,
+	> OwnedLockable<'a> for (A, B, C, D)
+{
+}
+unsafe impl<
+		'a,
+		A: OwnedLockable<'a>,
+		B: OwnedLockable<'a>,
+		C: OwnedLockable<'a>,
+		D: OwnedLockable<'a>,
+		E: OwnedLockable<'a>,
+	> OwnedLockable<'a> for (A, B, C, D, E)
+{
+}
+unsafe impl<
+		'a,
+		A: OwnedLockable<'a>,
+		B: OwnedLockable<'a>,
+		C: OwnedLockable<'a>,
+		D: OwnedLockable<'a>,
+		E: OwnedLockable<'a>,
+		F: OwnedLockable<'a>,
+	> OwnedLockable<'a> for (A, B, C, D, E, F)
+{
+}
+
 unsafe impl<'a, T: Lockable<'a>, const N: usize> Lockable<'a> for [T; N] {
 	type Output = [T::Output; N];
 
@@ -554,3 +606,6 @@ unsafe impl<'a, T: Lockable<'a>> Lockable<'a> for Vec<T> {
 		Some(outputs)
 	}
 }
+
+unsafe impl<'a, T: OwnedLockable<'a>, const N: usize> OwnedLockable<'a> for [T; N] {}
+unsafe impl<'a, T: OwnedLockable<'a>> OwnedLockable<'a> for Vec<T> {}