Merge branch '0.2'

1 files changed, 399 insertions, 0 deletions

diff --git a/src/collection/ref.rs b/src/collection/ref.rs
new file mode 100644
index 0000000..d8c7f2e
--- /dev/null
+++ b/src/collection/ref.rs
@@ -0,0 +1,399 @@
+use std::fmt::Debug;
+use std::marker::PhantomData;
+
+use crate::lockable::{Lockable, OwnedLockable, RawLock, Sharable};
+use crate::Keyable;
+
+use super::{utils, LockGuard, RefLockCollection};
+
+#[must_use]
+pub fn get_locks<L: Lockable>(data: &L) -> Vec<&dyn RawLock> {
+	let mut locks = Vec::new();
+	data.get_ptrs(&mut locks);
+	locks.sort_by_key(|lock| std::ptr::from_ref(*lock));
+	locks
+}
+
+/// returns `true` if the sorted list contains a duplicate
+#[must_use]
+fn contains_duplicates(l: &[&dyn RawLock]) -> bool {
+	l.windows(2)
+		.any(|window| std::ptr::eq(window[0], window[1]))
+}
+
+impl<'a, L> AsRef<L> for RefLockCollection<'a, L> {
+	fn as_ref(&self) -> &L {
+		self.data
+	}
+}
+
+impl<'a, L> IntoIterator for &'a RefLockCollection<'a, L>
+where
+	&'a L: IntoIterator,
+{
+	type Item = <&'a L as IntoIterator>::Item;
+	type IntoIter = <&'a L as IntoIterator>::IntoIter;
+
+	fn into_iter(self) -> Self::IntoIter {
+		self.data.into_iter()
+	}
+}
+
+unsafe impl<'c, L: Lockable> Lockable for RefLockCollection<'c, L> {
+	type Guard<'g> = L::Guard<'g> where Self: 'g;
+
+	type ReadGuard<'g> = L::ReadGuard<'g> where Self: 'g;
+
+	fn get_ptrs<'a>(&'a self, ptrs: &mut Vec<&'a dyn RawLock>) {
+		ptrs.extend_from_slice(&self.locks);
+	}
+
+	unsafe fn guard(&self) -> Self::Guard<'_> {
+		self.data.guard()
+	}
+
+	unsafe fn read_guard(&self) -> Self::ReadGuard<'_> {
+		self.data.read_guard()
+	}
+}
+
+unsafe impl<'c, L: Sharable> Sharable for RefLockCollection<'c, L> {}
+
+impl<'a, L: Debug> Debug for RefLockCollection<'a, L> {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		f.debug_struct(stringify!(RefLockCollection))
+			.field("data", self.data)
+			.finish_non_exhaustive()
+	}
+}
+
+impl<'a, L: OwnedLockable + Default> From<&'a L> for RefLockCollection<'a, L> {
+	fn from(value: &'a L) -> Self {
+		Self::new(value)
+	}
+}
+
+impl<'a, L: OwnedLockable> RefLockCollection<'a, L> {
+	/// Creates a new collection of owned locks.
+	///
+	/// Because the locks are owned, there's no need to do any checks for
+	/// duplicate values.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::Mutex;
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let data = (Mutex::new(0), Mutex::new(""));
+	/// let lock = RefLockCollection::new(&data);
+	/// ```
+	#[must_use]
+	pub fn new(data: &'a L) -> RefLockCollection<L> {
+		RefLockCollection {
+			locks: get_locks(data),
+			data,
+		}
+	}
+}
+
+impl<'a, L: Lockable> RefLockCollection<'a, L> {
+	/// Creates a new collections of locks.
+	///
+	/// # Safety
+	///
+	/// This results in undefined behavior if any locks are presented twice
+	/// within this collection.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::Mutex;
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let data1 = Mutex::new(0);
+	/// let data2 = Mutex::new("");
+	///
+	/// // safety: data1 and data2 refer to distinct mutexes
+	/// let data = (&data1, &data2);
+	/// let lock = unsafe { RefLockCollection::new_unchecked(&data) };
+	/// ```
+	#[must_use]
+	pub unsafe fn new_unchecked(data: &'a L) -> Self {
+		Self {
+			data,
+			locks: get_locks(data),
+		}
+	}
+
+	/// Creates a new collection of locks.
+	///
+	/// This returns `None` if any locks are found twice in the given
+	/// collection.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::Mutex;
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let data1 = Mutex::new(0);
+	/// let data2 = Mutex::new("");
+	///
+	/// // data1 and data2 refer to distinct mutexes, so this won't panic
+	/// let data = (&data1, &data2);
+	/// let lock = RefLockCollection::try_new(&data).unwrap();
+	/// ```
+	#[must_use]
+	pub fn try_new(data: &'a L) -> Option<Self> {
+		let locks = get_locks(data);
+		if contains_duplicates(&locks) {
+			return None;
+		}
+
+		Some(Self { data, locks })
+	}
+
+	/// Locks the collection
+	///
+	/// This function returns a guard that can be used to access the underlying
+	/// data. When the guard is dropped, the locks in the collection are also
+	/// dropped.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::{Mutex, ThreadKey};
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let key = ThreadKey::get().unwrap();
+	/// let data = (Mutex::new(0), Mutex::new(""));
+	/// let lock = RefLockCollection::new(&data);
+	///
+	/// let mut guard = lock.lock(key);
+	/// *guard.0 += 1;
+	/// *guard.1 = "1";
+	/// ```
+	pub fn lock<'key: 'a, Key: Keyable + 'key>(
+		&'a self,
+		key: Key,
+	) -> LockGuard<'key, L::Guard<'a>, Key> {
+		for lock in &self.locks {
+			// safety: we have the thread key
+			unsafe { lock.lock() };
+		}
+
+		LockGuard {
+			// safety: we've already acquired the lock
+			guard: unsafe { self.data.guard() },
+			key,
+			_phantom: PhantomData,
+		}
+	}
+
+	/// Attempts to lock the without blocking.
+	///
+	/// If successful, this method returns a guard that can be used to access
+	/// the data, and unlocks the data when it is dropped. Otherwise, `None` is
+	/// returned.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::{Mutex, ThreadKey};
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let key = ThreadKey::get().unwrap();
+	/// let data = (Mutex::new(0), Mutex::new(""));
+	/// let lock = RefLockCollection::new(&data);
+	///
+	/// match lock.try_lock(key) {
+	///     Some(mut guard) => {
+	///         *guard.0 += 1;
+	///         *guard.1 = "1";
+	///     },
+	///     None => unreachable!(),
+	/// };
+	///
+	/// ```
+	pub fn try_lock<'key: 'a, Key: Keyable + 'key>(
+		&'a self,
+		key: Key,
+	) -> Option<LockGuard<'key, L::Guard<'a>, Key>> {
+		let guard = unsafe {
+			if !utils::ordered_try_lock(&self.locks) {
+				return None;
+			}
+
+			// safety: we've acquired the locks
+			self.data.guard()
+		};
+
+		Some(LockGuard {
+			guard,
+			key,
+			_phantom: PhantomData,
+		})
+	}
+
+	/// Unlocks the underlying lockable data type, returning the key that's
+	/// associated with it.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::{Mutex, ThreadKey};
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let key = ThreadKey::get().unwrap();
+	/// let data = (Mutex::new(0), Mutex::new(""));
+	/// let lock = RefLockCollection::new(&data);
+	///
+	/// let mut guard = lock.lock(key);
+	/// *guard.0 += 1;
+	/// *guard.1 = "1";
+	/// let key = RefLockCollection::<(Mutex<i32>, Mutex<&str>)>::unlock(guard);
+	/// ```
+	#[allow(clippy::missing_const_for_fn)]
+	pub fn unlock<'key: 'a, Key: Keyable + 'key>(guard: LockGuard<'key, L::Guard<'a>, Key>) -> Key {
+		drop(guard.guard);
+		guard.key
+	}
+}
+
+impl<'a, L: Sharable> RefLockCollection<'a, L> {
+	/// Locks the collection, so that other threads can still read from it
+	///
+	/// This function returns a guard that can be used to access the underlying
+	/// data immutably. When the guard is dropped, the locks in the collection
+	/// are also dropped.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::{RwLock, ThreadKey};
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let key = ThreadKey::get().unwrap();
+	/// let data = (RwLock::new(0), RwLock::new(""));
+	/// let lock = RefLockCollection::new(&data);
+	///
+	/// let mut guard = lock.read(key);
+	/// assert_eq!(*guard.0, 0);
+	/// assert_eq!(*guard.1, "");
+	/// ```
+	pub fn read<'key: 'a, Key: Keyable + 'key>(
+		&'a self,
+		key: Key,
+	) -> LockGuard<'key, L::ReadGuard<'a>, Key> {
+		for lock in &self.locks {
+			// safety: we have the thread key
+			unsafe { lock.read() };
+		}
+
+		LockGuard {
+			// safety: we've already acquired the lock
+			guard: unsafe { self.data.read_guard() },
+			key,
+			_phantom: PhantomData,
+		}
+	}
+
+	/// Attempts to lock the without blocking, in such a way that other threads
+	/// can still read from the collection.
+	///
+	/// If successful, this method returns a guard that can be used to access
+	/// the data immutably, and unlocks the data when it is dropped. Otherwise,
+	/// `None` is returned.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::{RwLock, ThreadKey};
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let key = ThreadKey::get().unwrap();
+	/// let data = (RwLock::new(5), RwLock::new("6"));
+	/// let lock = RefLockCollection::new(&data);
+	///
+	/// match lock.try_read(key) {
+	///     Some(mut guard) => {
+	///         assert_eq!(*guard.0, 5);
+	///         assert_eq!(*guard.1, "6");
+	///     },
+	///     None => unreachable!(),
+	/// };
+	///
+	/// ```
+	pub fn try_read<'key: 'a, Key: Keyable + 'key>(
+		&'a self,
+		key: Key,
+	) -> Option<LockGuard<'key, L::ReadGuard<'a>, Key>> {
+		let guard = unsafe {
+			if !utils::ordered_try_read(&self.locks) {
+				return None;
+			}
+
+			// safety: we've acquired the locks
+			self.data.read_guard()
+		};
+
+		Some(LockGuard {
+			guard,
+			key,
+			_phantom: PhantomData,
+		})
+	}
+
+	/// Unlocks the underlying lockable data type, returning the key that's
+	/// associated with it.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::{RwLock, ThreadKey};
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let key = ThreadKey::get().unwrap();
+	/// let data = (RwLock::new(0), RwLock::new(""));
+	/// let lock = RefLockCollection::new(&data);
+	///
+	/// let mut guard = lock.read(key);
+	/// let key = RefLockCollection::<(RwLock<i32>, RwLock<&str>)>::unlock_read(guard);
+	/// ```
+	#[allow(clippy::missing_const_for_fn)]
+	pub fn unlock_read<'key: 'a, Key: Keyable + 'key>(
+		guard: LockGuard<'key, L::ReadGuard<'a>, Key>,
+	) -> Key {
+		drop(guard.guard);
+		guard.key
+	}
+}
+
+impl<'a, L: 'a> RefLockCollection<'a, L>
+where
+	&'a L: IntoIterator,
+{
+	/// Returns an iterator over references to each value in the collection.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use happylock::{Mutex, ThreadKey};
+	/// use happylock::collection::RefLockCollection;
+	///
+	/// let key = ThreadKey::get().unwrap();
+	/// let data = [Mutex::new(26), Mutex::new(1)];
+	/// let lock = RefLockCollection::new(&data);
+	///
+	/// let mut iter = lock.iter();
+	/// let mutex = iter.next().unwrap();
+	/// let guard = mutex.lock(key);
+	///
+	/// assert_eq!(*guard, 26);
+	/// ```
+	#[must_use]
+	pub fn iter(&'a self) -> <&'a L as IntoIterator>::IntoIter {
+		self.into_iter()
+	}
+}