Scoped lock API

2 files changed, 64 insertions, 68 deletions

diff --git a/src/mutex/guard.rs b/src/mutex/guard.rs
index 4e4d5f1..22e59c1 100644
--- a/src/mutex/guard.rs
+++ b/src/mutex/guard.rs
@@ -5,34 +5,14 @@ use std::ops::{Deref, DerefMut};
 
 use lock_api::RawMutex;
 
-use crate::key::Keyable;
 use crate::lockable::RawLock;
+use crate::ThreadKey;
 
 use super::{Mutex, MutexGuard, MutexRef};
 
 // These impls make things slightly easier because now you can use
 // `println!("{guard}")` instead of `println!("{}", *guard)`
 
-impl<T: PartialEq + ?Sized, R: RawMutex> PartialEq for MutexRef<'_, T, R> {
-	fn eq(&self, other: &Self) -> bool {
-		self.deref().eq(&**other)
-	}
-}
-
-impl<T: Eq + ?Sized, R: RawMutex> Eq for MutexRef<'_, T, R> {}
-
-impl<T: PartialOrd + ?Sized, R: RawMutex> PartialOrd for MutexRef<'_, T, R> {
-	fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-		self.deref().partial_cmp(&**other)
-	}
-}
-
-impl<T: Ord + ?Sized, R: RawMutex> Ord for MutexRef<'_, T, R> {
-	fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-		self.deref().cmp(&**other)
-	}
-}
-
 #[mutants::skip] // hashing involves RNG and is hard to test
 #[cfg(not(tarpaulin_include))]
 impl<T: Hash + ?Sized, R: RawMutex> Hash for MutexRef<'_, T, R> {
@@ -107,39 +87,9 @@ impl<'a, T: ?Sized, R: RawMutex> MutexRef<'a, T, R> {
 // it's kinda annoying to re-implement some of this stuff on guards
 // there's nothing i can do about that
 
-#[mutants::skip] // it's hard to get two guards safely
-#[cfg(not(tarpaulin_include))]
-impl<T: PartialEq + ?Sized, R: RawMutex, Key: Keyable> PartialEq for MutexGuard<'_, '_, T, Key, R> {
-	fn eq(&self, other: &Self) -> bool {
-		self.deref().eq(&**other)
-	}
-}
-
-#[mutants::skip] // it's hard to get two guards safely
-#[cfg(not(tarpaulin_include))]
-impl<T: Eq + ?Sized, R: RawMutex, Key: Keyable> Eq for MutexGuard<'_, '_, T, Key, R> {}
-
-#[mutants::skip] // it's hard to get two guards safely
-#[cfg(not(tarpaulin_include))]
-impl<T: PartialOrd + ?Sized, R: RawMutex, Key: Keyable> PartialOrd
-	for MutexGuard<'_, '_, T, Key, R>
-{
-	fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-		self.deref().partial_cmp(&**other)
-	}
-}
-
-#[mutants::skip] // it's hard to get two guards safely
-#[cfg(not(tarpaulin_include))]
-impl<T: Ord + ?Sized, R: RawMutex, Key: Keyable> Ord for MutexGuard<'_, '_, T, Key, R> {
-	fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-		self.deref().cmp(&**other)
-	}
-}
-
 #[mutants::skip] // hashing involves RNG and is hard to test
 #[cfg(not(tarpaulin_include))]
-impl<T: Hash + ?Sized, R: RawMutex, Key: Keyable> Hash for MutexGuard<'_, '_, T, Key, R> {
+impl<T: Hash + ?Sized, R: RawMutex> Hash for MutexGuard<'_, T, R> {
 	fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 		self.deref().hash(state)
 	}
@@ -147,19 +97,19 @@ impl<T: Hash + ?Sized, R: RawMutex, Key: Keyable> Hash for MutexGuard<'_, '_, T,
 
 #[mutants::skip]
 #[cfg(not(tarpaulin_include))]
-impl<T: Debug + ?Sized, Key: Keyable, R: RawMutex> Debug for MutexGuard<'_, '_, T, Key, R> {
+impl<T: Debug + ?Sized, R: RawMutex> Debug for MutexGuard<'_, T, R> {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		Debug::fmt(&**self, f)
 	}
 }
 
-impl<T: Display + ?Sized, Key: Keyable, R: RawMutex> Display for MutexGuard<'_, '_, T, Key, R> {
+impl<T: Display + ?Sized, R: RawMutex> Display for MutexGuard<'_, T, R> {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		Display::fmt(&**self, f)
 	}
 }
 
-impl<T: ?Sized, Key: Keyable, R: RawMutex> Deref for MutexGuard<'_, '_, T, Key, R> {
+impl<T: ?Sized, R: RawMutex> Deref for MutexGuard<'_, T, R> {
 	type Target = T;
 
 	fn deref(&self) -> &Self::Target {
@@ -167,33 +117,32 @@ impl<T: ?Sized, Key: Keyable, R: RawMutex> Deref for MutexGuard<'_, '_, T, Key,
 	}
 }
 
-impl<T: ?Sized, Key: Keyable, R: RawMutex> DerefMut for MutexGuard<'_, '_, T, Key, R> {
+impl<T: ?Sized, R: RawMutex> DerefMut for MutexGuard<'_, T, R> {
 	fn deref_mut(&mut self) -> &mut Self::Target {
 		&mut self.mutex
 	}
 }
 
-impl<T: ?Sized, Key: Keyable, R: RawMutex> AsRef<T> for MutexGuard<'_, '_, T, Key, R> {
+impl<T: ?Sized, R: RawMutex> AsRef<T> for MutexGuard<'_, T, R> {
 	fn as_ref(&self) -> &T {
 		self
 	}
 }
 
-impl<T: ?Sized, Key: Keyable, R: RawMutex> AsMut<T> for MutexGuard<'_, '_, T, Key, R> {
+impl<T: ?Sized, R: RawMutex> AsMut<T> for MutexGuard<'_, T, R> {
 	fn as_mut(&mut self) -> &mut T {
 		self
 	}
 }
 
-impl<'a, T: ?Sized, Key: Keyable, R: RawMutex> MutexGuard<'a, '_, T, Key, R> {
+impl<'a, T: ?Sized, R: RawMutex> MutexGuard<'a, T, R> {
 	/// Create a guard to the given mutex. Undefined if multiple guards to the
 	/// same mutex exist at once.
 	#[must_use]
-	pub(super) unsafe fn new(mutex: &'a Mutex<T, R>, thread_key: Key) -> Self {
+	pub(super) unsafe fn new(mutex: &'a Mutex<T, R>, thread_key: ThreadKey) -> Self {
 		Self {
 			mutex: MutexRef(mutex, PhantomData),
 			thread_key,
-			_phantom: PhantomData,
 		}
 	}
 }
diff --git a/src/mutex/mutex.rs b/src/mutex/mutex.rs
index 0bd5286..1d8ce8b 100644
--- a/src/mutex/mutex.rs
+++ b/src/mutex/mutex.rs
@@ -6,9 +6,9 @@ use std::panic::AssertUnwindSafe;
 use lock_api::RawMutex;
 
 use crate::handle_unwind::handle_unwind;
-use crate::key::Keyable;
 use crate::lockable::{Lockable, LockableGetMut, LockableIntoInner, OwnedLockable, RawLock};
 use crate::poisonable::PoisonFlag;
+use crate::{Keyable, ThreadKey};
 
 use super::{Mutex, MutexGuard, MutexRef};
 
@@ -62,6 +62,11 @@ unsafe impl<T: Send, R: RawMutex + Send + Sync> Lockable for Mutex<T, R> {
 	where
 		Self: 'g;
 
+	type DataMut<'a>
+		= &'a mut T
+	where
+		Self: 'a;
+
 	fn get_ptrs<'a>(&'a self, ptrs: &mut Vec<&'a dyn RawLock>) {
 		ptrs.push(self);
 	}
@@ -69,6 +74,10 @@ unsafe impl<T: Send, R: RawMutex + Send + Sync> Lockable for Mutex<T, R> {
 	unsafe fn guard(&self) -> Self::Guard<'_> {
 		MutexRef::new(self)
 	}
+
+	unsafe fn data_mut(&self) -> Self::DataMut<'_> {
+		self.data.get().as_mut().unwrap_unchecked()
+	}
 }
 
 impl<T: Send, R: RawMutex + Send + Sync> LockableIntoInner for Mutex<T, R> {
@@ -214,6 +223,46 @@ impl<T: ?Sized, R> Mutex<T, R> {
 }
 
 impl<T: ?Sized, R: RawMutex> Mutex<T, R> {
+	pub fn scoped_lock<Ret>(&self, key: impl Keyable, f: impl FnOnce(&mut T) -> Ret) -> Ret {
+		unsafe {
+			// safety: we have the thread key
+			self.raw_lock();
+
+			// safety: the mutex was just locked
+			let r = f(self.data.get().as_mut().unwrap_unchecked());
+
+			// safety: we locked the mutex already
+			self.raw_unlock();
+
+			drop(key); // ensures we drop the key in the correct place
+
+			r
+		}
+	}
+
+	pub fn scoped_try_lock<Key: Keyable, Ret>(
+		&self,
+		key: Key,
+		f: impl FnOnce(&mut T) -> Ret,
+	) -> Result<Ret, Key> {
+		unsafe {
+			// safety: we have the thread key
+			if !self.raw_try_lock() {
+				return Err(key);
+			}
+
+			// safety: the mutex was just locked
+			let r = f(self.data.get().as_mut().unwrap_unchecked());
+
+			// safety: we locked the mutex already
+			self.raw_unlock();
+
+			drop(key); // ensures we drop the key in the correct place
+
+			Ok(r)
+		}
+	}
+
 	/// Block the thread until this mutex can be locked, and lock it.
 	///
 	/// Upon returning, the thread is the only thread with a lock on the
@@ -237,7 +286,7 @@ impl<T: ?Sized, R: RawMutex> Mutex<T, R> {
 	/// let key = ThreadKey::get().unwrap();
 	/// assert_eq!(*mutex.lock(key), 10);
 	/// ```
-	pub fn lock<'s, 'k: 's, Key: Keyable>(&'s self, key: Key) -> MutexGuard<'s, 'k, T, Key, R> {
+	pub fn lock(&self, key: ThreadKey) -> MutexGuard<'_, T, R> {
 		unsafe {
 			// safety: we have the thread key
 			self.raw_lock();
@@ -280,10 +329,7 @@ impl<T: ?Sized, R: RawMutex> Mutex<T, R> {
 	/// let key = ThreadKey::get().unwrap();
 	/// assert_eq!(*mutex.lock(key), 10);
 	/// ```
-	pub fn try_lock<'s, 'k: 's, Key: Keyable>(
-		&'s self,
-		key: Key,
-	) -> Result<MutexGuard<'s, 'k, T, Key, R>, Key> {
+	pub fn try_lock(&self, key: ThreadKey) -> Result<MutexGuard<'_, T, R>, ThreadKey> {
 		unsafe {
 			// safety: we have the key to the mutex
 			if self.raw_try_lock() {
@@ -322,7 +368,8 @@ impl<T: ?Sized, R: RawMutex> Mutex<T, R> {
 	///
 	/// let key = Mutex::unlock(guard);
 	/// ```
-	pub fn unlock<'a, 'k: 'a, Key: Keyable + 'k>(guard: MutexGuard<'a, 'k, T, Key, R>) -> Key {
+	#[must_use]
+	pub fn unlock(guard: MutexGuard<'_, T, R>) -> ThreadKey {
 		unsafe {
 			guard.mutex.0.raw_unlock();
 		}