happylock 0.5.1

use std::panic::{RefUnwindSafe, UnwindSafe};

use crate::handle_unwind::handle_unwind;
use crate::lockable::{
	Lockable, LockableGetMut, LockableIntoInner, OwnedLockable, RawLock, Sharable,
};
use crate::{Keyable, ThreadKey};

use super::{
	PoisonError, PoisonFlag, PoisonGuard, PoisonRef, PoisonResult, Poisonable,
	TryLockPoisonableError, TryLockPoisonableResult,
};

unsafe impl<L: Lockable + RawLock> RawLock for Poisonable<L> {
	#[mutants::skip] // this should never run
	#[cfg(not(tarpaulin_include))]
	fn poison(&self) {
		self.inner.poison()
	}

	unsafe fn raw_write(&self) {
		self.inner.raw_write()
	}

	unsafe fn raw_try_write(&self) -> bool {
		self.inner.raw_try_write()
	}

	unsafe fn raw_unlock_write(&self) {
		self.inner.raw_unlock_write()
	}

	unsafe fn raw_read(&self) {
		self.inner.raw_read()
	}

	unsafe fn raw_try_read(&self) -> bool {
		self.inner.raw_try_read()
	}

	unsafe fn raw_unlock_read(&self) {
		self.inner.raw_unlock_read()
	}
}

unsafe impl<L: Lockable> Lockable for Poisonable<L> {
	type Guard<'g>
		= PoisonResult<PoisonRef<'g, L::Guard<'g>>>
	where
		Self: 'g;

	type DataMut<'a>
		= PoisonResult<L::DataMut<'a>>
	where
		Self: 'a;

	fn get_ptrs<'a>(&'a self, ptrs: &mut Vec<&'a dyn RawLock>) {
		self.inner.get_ptrs(ptrs)
	}

	unsafe fn guard(&self) -> Self::Guard<'_> {
		let ref_guard = PoisonRef::new(&self.poisoned, self.inner.guard());

		if self.is_poisoned() {
			Err(PoisonError::new(ref_guard))
		} else {
			Ok(ref_guard)
		}
	}

	unsafe fn data_mut(&self) -> Self::DataMut<'_> {
		if self.is_poisoned() {
			Err(PoisonError::new(self.inner.data_mut()))
		} else {
			Ok(self.inner.data_mut())
		}
	}
}

unsafe impl<L: Sharable> Sharable for Poisonable<L> {
	type ReadGuard<'g>
		= PoisonResult<PoisonRef<'g, L::ReadGuard<'g>>>
	where
		Self: 'g;

	type DataRef<'a>
		= PoisonResult<L::DataRef<'a>>
	where
		Self: 'a;

	unsafe fn read_guard(&self) -> Self::ReadGuard<'_> {
		let ref_guard = PoisonRef::new(&self.poisoned, self.inner.read_guard());

		if self.is_poisoned() {
			Err(PoisonError::new(ref_guard))
		} else {
			Ok(ref_guard)
		}
	}

	unsafe fn data_ref(&self) -> Self::DataRef<'_> {
		if self.is_poisoned() {
			Err(PoisonError::new(self.inner.data_ref()))
		} else {
			Ok(self.inner.data_ref())
		}
	}
}

unsafe impl<L: OwnedLockable> OwnedLockable for Poisonable<L> {}

// AsMut won't work here because we don't strictly return a &mut T
// LockableGetMut is the next best thing
impl<L: LockableGetMut> LockableGetMut for Poisonable<L> {
	type Inner<'a>
		= PoisonResult<L::Inner<'a>>
	where
		Self: 'a;

	fn get_mut(&mut self) -> Self::Inner<'_> {
		if self.is_poisoned() {
			Err(PoisonError::new(self.inner.get_mut()))
		} else {
			Ok(self.inner.get_mut())
		}
	}
}

impl<L: LockableIntoInner> LockableIntoInner for Poisonable<L> {
	type Inner = PoisonResult<L::Inner>;

	fn into_inner(self) -> Self::Inner {
		if self.is_poisoned() {
			Err(PoisonError::new(self.inner.into_inner()))
		} else {
			Ok(self.inner.into_inner())
		}
	}
}

impl<L> From<L> for Poisonable<L> {
	fn from(value: L) -> Self {
		Self::new(value)
	}
}

impl<L> Poisonable<L> {
	/// Creates a new `Poisonable`
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{Mutex, Poisonable};
	///
	/// let mutex = Poisonable::new(Mutex::new(0));
	/// ```
	pub const fn new(value: L) -> Self {
		Self {
			inner: value,
			poisoned: PoisonFlag::new(),
		}
	}

	/// Determines whether the `Poisonable` is poisoned.
	///
	/// If another thread is active, the `Poisonable` can still become poisoned at
	/// any time. You should not trust a `false` value for program correctness
	/// without additional synchronization.
	///
	/// # Examples
	///
	/// ```
	/// use std::thread;
	///
	/// use happylock::{Mutex, Poisonable, ThreadKey};
	///
	/// let mutex = Poisonable::new(Mutex::new(0));
	///
	/// thread::scope(|s| {
	///     let r = s.spawn(|| {
	///         let key = ThreadKey::get().unwrap();
	///         let _lock = mutex.lock(key).unwrap();
	///         panic!(); // the mutex gets poisoned
	///     }).join();
	/// });
	///
	/// assert_eq!(mutex.is_poisoned(), true);
	/// ```
	pub fn is_poisoned(&self) -> bool {
		self.poisoned.is_poisoned()
	}

	/// Clear the poisoned state from a lock.
	///
	/// If the lock is poisoned, it will remain poisoned until this function
	/// is called. This allows recovering from a poisoned state and marking
	/// that it has recovered. For example, if the value is overwritten by a
	/// known-good value, then the lock can be marked as un-poisoned. Or
	/// possibly, the value could by inspected to determine if it is in a
	/// consistent state, and if so the poison is removed.
	///
	/// # Examples
	///
	/// ```
	/// use std::thread;
	///
	/// use happylock::{Mutex, Poisonable, ThreadKey};
	///
	/// let mutex = Poisonable::new(Mutex::new(0));
	///
	/// thread::scope(|s| {
	///     let r = s.spawn(|| {
	///         let key = ThreadKey::get().unwrap();
	///         let _lock = mutex.lock(key).unwrap();
	///         panic!(); // the mutex gets poisoned
	///     }).join();
	/// });
	///
	/// assert_eq!(mutex.is_poisoned(), true);
	///
	/// let key = ThreadKey::get().unwrap();
	/// let x = mutex.lock(key).unwrap_or_else(|mut e| {
	///     **e.get_mut() = 1;
	///     mutex.clear_poison();
	///     e.into_inner()
	/// });
	///
	/// assert_eq!(mutex.is_poisoned(), false);
	/// assert_eq!(*x, 1);
	/// ```
	pub fn clear_poison(&self) {
		self.poisoned.clear_poison()
	}

	/// Consumes this `Poisonable`, returning the underlying lock.
	///
	/// # Errors
	///
	/// If another user of this lock panicked while holding the lock, then this
	/// call will return an error instead.
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{Mutex, Poisonable};
	///
	/// let mutex = Poisonable::new(Mutex::new(0));
	/// assert_eq!(mutex.into_child().unwrap().into_inner(), 0);
	/// ```
	pub fn into_child(self) -> PoisonResult<L> {
		if self.is_poisoned() {
			Err(PoisonError::new(self.inner))
		} else {
			Ok(self.inner)
		}
	}

	/// Returns a mutable reference to the underlying lock.
	///
	/// # Errors
	///
	/// If another user of this lock panicked while holding the lock, then
	/// this call will return an error instead.
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{Mutex, Poisonable, ThreadKey};
	///
	/// let key = ThreadKey::get().unwrap();
	/// let mut mutex = Poisonable::new(Mutex::new(0));
	/// *mutex.child_mut().unwrap().as_mut() = 10;
	/// assert_eq!(*mutex.lock(key).unwrap(), 10);
	/// ```
	pub fn child_mut(&mut self) -> PoisonResult<&mut L> {
		if self.is_poisoned() {
			Err(PoisonError::new(&mut self.inner))
		} else {
			Ok(&mut self.inner)
		}
	}

	// NOTE: `child_ref` isn't implemented because it would make this not `RefUnwindSafe`
}

impl<L: Lockable> Poisonable<L> {
	/// Creates a guard for the poisonable, without locking it
	unsafe fn guard(&self, key: ThreadKey) -> PoisonResult<PoisonGuard<'_, L::Guard<'_>>> {
		let guard = PoisonGuard {
			guard: PoisonRef::new(&self.poisoned, self.inner.guard()),
			key,
		};

		if self.is_poisoned() {
			return Err(PoisonError::new(guard));
		}

		Ok(guard)
	}
}

impl<L: Lockable + RawLock> Poisonable<L> {
	/// Acquires an exclusive lock, blocking until it is safe to do so, and then
	/// unlocks after the provided function returns.
	///
	/// This function is useful to ensure that a `Poisonable` is never
	/// accidentally locked forever by leaking the guard. Even if the function
	/// panics, this function will gracefully notice the panic, poison the lock,
	/// and unlock.
	///
	/// If the lock is poisoned, then an error will be passed into the provided
	/// function.
	///
	/// # Panics
	///
	/// This function will panic if the provided function also panics. However,
	/// `Poisonable` will be safely poisoned and any subsequent calls will pass
	/// `Err` into the given function.
	///
	/// # Example
	///
	/// ```
	/// use happylock::{Poisonable, ThreadKey, RwLock};
	///
	/// let mut key = ThreadKey::get().unwrap();
	/// let lock = Poisonable::new(RwLock::new(42));
	///
	/// let x = lock.scoped_lock(&mut key, |number| {
	///     *number.unwrap()
	/// });
	/// assert_eq!(x, 42);
	/// ```
	pub fn scoped_lock<'a, R>(
		&'a self,
		key: impl Keyable,
		f: impl FnOnce(<Self as Lockable>::DataMut<'a>) -> R,
	) -> R {
		unsafe {
			// safety: we have the thread key
			self.raw_write();

			// safety: the data was just locked
			let r = handle_unwind(
				|| f(self.data_mut()),
				|| {
					self.poisoned.poison();
					self.raw_unlock_write();
				},
			);

			// safety: the collection is still locked
			self.raw_unlock_write();

			drop(key); // ensure the key stays alive long enough

			r
		}
	}

	/// Attempts to acquire an exclusive lock to the `Poisonable` without
	/// blocking, and then unlocks it once the provided function returns.
	///
	/// This function implements a non-blocking variant of [`scoped_lock`].
	/// Unlike `scoped_lock`, if the `Poisonable` is not already unlocked, then
	/// the provided function will not run, and the given [`Keyable`] is returned.
	/// This method does not provide any guarantees with respect to the ordering
	/// of whether contentious readers or writers will acquire the lock first.
	///
	/// If the lock is poisoned, then an error will be passed into the provided
	/// function.
	///
	/// # Errors
	///
	/// If the `Poisonable` is already locked, then the provided function will not
	/// run. `Err` is returned with the given key.
	///
	/// # Panics
	///
	/// If the provided function panics, then the panic will be bubbled up and
	/// rethrown. The `Poisonable` will also be gracefully unlocked, allowing the
	/// `Poisonable` to be locked again.
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{Poisonable, RwLock, ThreadKey};
	///
	/// let mut key = ThreadKey::get().unwrap();
	/// let lock = Poisonable::new(RwLock::new(42));
	///
	/// let result = lock.scoped_try_lock(&mut key, |num| {
	///     *num.unwrap()
	/// });
	///
	/// match result {
	///     Ok(val) => println!("The number is {val}"),
	///     Err(_) => unreachable!(),
	/// }
	/// ```
	///
	/// [`scoped_lock`]: [`crate::Poisonable::scoped_lock`]
	pub fn scoped_try_lock<'a, Key: Keyable, R>(
		&'a self,
		key: Key,
		f: impl FnOnce(<Self as Lockable>::DataMut<'a>) -> R,
	) -> Result<R, Key> {
		unsafe {
			// safety: we have the thread key
			if !self.raw_try_write() {
				return Err(key);
			}

			// safety: we just locked the collection
			let r = handle_unwind(
				|| f(self.data_mut()),
				|| {
					self.poisoned.poison();
					self.raw_unlock_write();
				},
			);

			// safety: the collection is still locked
			self.raw_unlock_write();

			drop(key); // ensures the key stays valid long enough

			Ok(r)
		}
	}

	/// Acquires the lock, blocking the current thread until it is ok to do so.
	///
	/// This function will block the current thread until it is available to
	/// acquire the lock. Upon returning, the thread is the only thread with
	/// the lock held. An RAII guard is returned to allow scoped unlock of the
	/// lock. When the guard goes out of scope, the mutex will be unlocked.
	///
	/// # Errors
	///
	/// If another use of this lock panicked while holding the mutex, then
	/// this call will return an error once the mutex is acquired.
	///
	/// # Examples
	///
	/// ```
	/// use std::thread;
	///
	/// use happylock::{Mutex, Poisonable, ThreadKey};
	///
	/// let mutex = Poisonable::new(Mutex::new(0));
	///
	/// thread::scope(|s| {
	///     let r = s.spawn(|| {
	///         let key = ThreadKey::get().unwrap();
	///         *mutex.lock(key).unwrap() = 10;
	///     }).join();
	/// });
	///
	/// let key = ThreadKey::get().unwrap();
	/// assert_eq!(*mutex.lock(key).unwrap(), 10);
	/// ```
	pub fn lock(&self, key: ThreadKey) -> PoisonResult<PoisonGuard<'_, L::Guard<'_>>> {
		unsafe {
			self.inner.raw_write();
			self.guard(key)
		}
	}

	/// Attempts to acquire this lock.
	///
	/// If the lock could not be acquired at this time, then [`Err`] is
	/// returned. Otherwise, an RAII guard is returned. The lock will be
	/// unlocked when the guard is dropped.
	///
	/// This function does not block.
	///
	/// # Errors
	///
	/// If another user of this lock panicked while holding the lock, then this
	/// call will return the [`Poisoned`] error if the lock would otherwise be
	/// acquired.
	///
	/// If the lock could not be acquired because it is already locked, then
	/// this call will return the [`WouldBlock`] error.
	///
	/// # Examples
	///
	/// ```
	/// use std::thread;
	///
	/// use happylock::{Mutex, Poisonable, ThreadKey};
	///
	/// let mutex = Poisonable::new(Mutex::new(0));
	///
	/// thread::scope(|s| {
	///     s.spawn(|| {
	///         let key = ThreadKey::get().unwrap();
	///         let mut lock = mutex.try_lock(key);
	///         if let Ok(mut mutex) = lock {
	///             *mutex = 10;
	///         } else {
	///             println!("try_lock failed");
	///         }
	///     });
	/// });
	///
	/// let key = ThreadKey::get().unwrap();
	/// assert_eq!(*mutex.lock(key).unwrap(), 10);
	/// ```
	///
	/// [`Poisoned`]: `TryLockPoisonableError::Poisoned`
	/// [`WouldBlock`]: `TryLockPoisonableError::WouldBlock`
	pub fn try_lock(&self, key: ThreadKey) -> TryLockPoisonableResult<'_, L::Guard<'_>> {
		unsafe {
			if self.inner.raw_try_write() {
				Ok(self.guard(key)?)
			} else {
				Err(TryLockPoisonableError::WouldBlock(key))
			}
		}
	}

	/// Consumes the [`PoisonGuard`], and consequently unlocks its `Poisonable`.
	///
	/// This function is equivalent to calling [`drop`] on the guard, except that
	/// it returns the key that was used to create it. Alternatively, the guard
	/// will be automatically dropped when it goes out of scope.
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{ThreadKey, Mutex, Poisonable};
	///
	/// let key = ThreadKey::get().unwrap();
	/// let mutex = Poisonable::new(Mutex::new(0));
	///
	/// let mut guard = mutex.lock(key).unwrap();
	/// *guard += 20;
	///
	/// let key = Poisonable::<Mutex<_>>::unlock(guard);
	/// ```
	pub fn unlock<'flag>(guard: PoisonGuard<'flag, L::Guard<'flag>>) -> ThreadKey {
		drop(guard.guard);
		guard.key
	}
}

impl<L: Sharable + RawLock> Poisonable<L> {
	unsafe fn read_guard(&self, key: ThreadKey) -> PoisonResult<PoisonGuard<'_, L::ReadGuard<'_>>> {
		let guard = PoisonGuard {
			guard: PoisonRef::new(&self.poisoned, self.inner.read_guard()),
			key,
		};

		if self.is_poisoned() {
			return Err(PoisonError::new(guard));
		}

		Ok(guard)
	}

	/// Acquires a shared lock, blocking until it is safe to do so, and then
	/// unlocks after the provided function returns.
	///
	/// This function is useful to ensure that a `Poisonable` is never
	/// accidentally locked forever by leaking the `ReadGuard`. Even if the
	/// function panics, this function will gracefully notice the panic, and
	/// unlock. This function provides no guarantees with respect to the ordering
	/// of whether contentious readers or writers will acquire the lock first.
	///
	/// If the lock is poisoned, then an error will be passed into the provided
	/// into the provided function.
	///
	/// # Panics
	///
	/// This function will panic if the provided function also panics. However,
	/// `Poisonable` will be safely unlocked in this case, allowing the
	/// `Poisonable` to be locked again later.
	///
	/// # Example
	///
	/// ```
	/// use happylock::{Poisonable, ThreadKey, RwLock};
	///
	/// let mut key = ThreadKey::get().unwrap();
	/// let lock = Poisonable::new(RwLock::new(42));
	///
	/// let x = lock.scoped_read(&mut key, |number| {
	///     *number.unwrap()
	/// });
	/// assert_eq!(x, 42);
	/// ```
	pub fn scoped_read<'a, R>(
		&'a self,
		key: impl Keyable,
		f: impl FnOnce(<Self as Sharable>::DataRef<'a>) -> R,
	) -> R {
		unsafe {
			// safety: we have the thread key
			self.raw_read();

			// safety: the data was just locked
			let r = handle_unwind(
				|| f(self.data_ref()),
				|| {
					self.poisoned.poison();
					self.raw_unlock_read();
				},
			);

			// safety: the collection is still locked
			self.raw_unlock_read();

			drop(key); // ensure the key stays alive long enough

			r
		}
	}

	/// Attempts to acquire a shared lock to the `Poisonable` without blocking,
	/// and then unlocks it once the provided function returns.
	///
	/// This function implements a non-blocking variant of [`scoped_read`].
	/// Unlike `scoped_read`, if the `Poisonable` is exclusively locked, then the
	/// provided function will not run, and the given [`Keyable`] is returned.
	/// This method provides no guarantees with respect to the ordering of whether
	/// contentious readers of writers will acquire the lock first.
	///
	/// If the lock is poisoned, then an error will be passed into the provided
	/// function.
	///
	/// # Errors
	///
	/// If the `Poisonable` is already exclusively locked, then the provided
	/// function will not run. `Err` is returned with the given key.
	///
	/// # Panics
	///
	/// If the provided function panics, then the panic will be bubbled up and
	/// rethrown. The `Poisonable` will also be gracefully unlocked, allowing the
	/// `Poisonable` to be locked again.
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{Poisonable, RwLock, ThreadKey};
	///
	/// let mut key = ThreadKey::get().unwrap();
	/// let lock = Poisonable::new(RwLock::new(42));
	///
	/// let result = lock.scoped_try_read(&mut key, |num| {
	///     *num.unwrap()
	/// });
	///
	/// match result {
	///     Ok(val) => println!("The number is {val}"),
	///     Err(_) => unreachable!(),
	/// }
	/// ```
	///
	/// [`scoped_read`]: crate::Poisonable::scoped_read
	pub fn scoped_try_read<'a, Key: Keyable, R>(
		&'a self,
		key: Key,
		f: impl FnOnce(<Self as Sharable>::DataRef<'a>) -> R,
	) -> Result<R, Key> {
		unsafe {
			// safety: we have the thread key
			if !self.raw_try_read() {
				return Err(key);
			}

			// safety: we just locked the collection
			let r = handle_unwind(
				|| f(self.data_ref()),
				|| {
					self.poisoned.poison();
					self.raw_unlock_read();
				},
			);

			// safety: the collection is still locked
			self.raw_unlock_read();

			drop(key); // ensures the key stays valid long enough

			Ok(r)
		}
	}

	/// Locks with shared read access, blocking the current thread until it can
	/// be acquired.
	///
	/// This function will block the current thread until there are no writers
	/// which hold the lock. This method does not provide any guarantee with
	/// respect to the ordering of contentious readers or writers will acquire
	/// the lock.
	///
	/// # Errors
	///
	/// This function will return an error if the `Poisonable` is poisoned. A
	/// `Poisonable` is poisoned whenever a thread panics while holding a lock.
	/// The failure will occur immediately after the lock has been acquired. The
	/// acquired lock guard will be contained in the returned error.
	///
	/// # Examples
	///
	/// ```
	/// use std::thread;
	///
	/// use happylock::{RwLock, Poisonable, ThreadKey};
	///
	/// let key = ThreadKey::get().unwrap();
	/// let lock = Poisonable::new(RwLock::new(0));
	///
	/// let n = lock.read(key).unwrap();
	/// assert_eq!(*n, 0);
	///
	/// thread::scope(|s| {
	///     s.spawn(|| {
	///         let key = ThreadKey::get().unwrap();
	///         let r = lock.read(key);
	///         assert!(r.is_ok());
	///     });
	/// });
	/// ```
	pub fn read(&self, key: ThreadKey) -> PoisonResult<PoisonGuard<'_, L::ReadGuard<'_>>> {
		unsafe {
			self.inner.raw_read();
			self.read_guard(key)
		}
	}

	/// Attempts to acquire the lock with shared read access, without blocking the
	/// thread.
	///
	/// If the access could not be granted at this time, then `Err` is returned.
	/// Otherwise, an RAII guard is returned which will release the shared access
	/// when it is dropped.
	///
	/// This function does not provide any guarantees with respect to the ordering
	/// of whether contentious readers or writers will acquire the lock first.
	///
	/// # Errors
	///
	/// This function will return the [`Poisoned`] error if the lock is
	/// poisoned. A [`Poisonable`] is poisoned whenever a thread panics while
	/// holding a lock. `Poisoned` will only be returned if the lock would have
	/// otherwise been acquired.
	///
	/// This function will return the [`WouldBlock`] error if the lock could
	/// not be acquired because it was already locked exclusively.
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{Poisonable, RwLock, ThreadKey};
	///
	/// let key = ThreadKey::get().unwrap();
	/// let lock = Poisonable::new(RwLock::new(1));
	///
	/// match lock.try_read(key) {
	///     Ok(n) => assert_eq!(*n, 1),
	///     Err(_) => unreachable!(),
	/// };
	/// ```
	///
	/// [`Poisoned`]: `TryLockPoisonableError::Poisoned`
	/// [`WouldBlock`]: `TryLockPoisonableError::WouldBlock`
	// TODO don't poison when holding shared lock
	pub fn try_read(&self, key: ThreadKey) -> TryLockPoisonableResult<'_, L::ReadGuard<'_>> {
		unsafe {
			if self.inner.raw_try_read() {
				Ok(self.read_guard(key)?)
			} else {
				Err(TryLockPoisonableError::WouldBlock(key))
			}
		}
	}

	/// Consumes the [`PoisonGuard`], and consequently unlocks its `Poisonable`.
	///
	/// This function is equivalent to calling [`drop`] on the guard, except that
	/// it returns the key that was used to create it. Alternatively, the guard
	/// will be automatically dropped when it goes out of scope.
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{ThreadKey, RwLock, Poisonable};
	///
	/// let key = ThreadKey::get().unwrap();
	/// let lock = Poisonable::new(RwLock::new(20));
	///
	/// let mut guard = lock.read(key).unwrap();
	/// assert_eq!(*guard, 20);
	///
	/// let key = Poisonable::<RwLock<_>>::unlock_read(guard);
	/// ```
	pub fn unlock_read<'flag>(guard: PoisonGuard<'flag, L::ReadGuard<'flag>>) -> ThreadKey {
		drop(guard.guard);
		guard.key
	}
}

impl<L: LockableIntoInner> Poisonable<L> {
	/// Consumes this `Poisonable`, returning the underlying data.
	///
	/// # Errors
	///
	/// If another user of this lock panicked while holding the lock, then this
	/// call will return an error instead. A `Poisonable` is poisoned whenever a
	/// thread panics while holding a lock.
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{Mutex, Poisonable};
	///
	/// let mutex = Poisonable::new(Mutex::new(0));
	/// assert_eq!(mutex.into_inner().unwrap(), 0);
	/// ```
	pub fn into_inner(self) -> PoisonResult<L::Inner> {
		LockableIntoInner::into_inner(self)
	}
}

impl<L: LockableGetMut + RawLock> Poisonable<L> {
	/// Returns a mutable reference to the underlying data.
	///
	/// Since this call borrows the `Poisonable` mutably, no actual locking
	/// needs to take place - the mutable borrow statically guarantees no locks
	/// exist.
	///
	/// # Errors
	///
	/// If another user of this lock panicked while holding the lock, then
	/// this call will return an error instead. A `Poisonable` is poisoned
	/// whenever a thread panics while holding a lock.
	///
	/// # Examples
	///
	/// ```
	/// use happylock::{Mutex, Poisonable, ThreadKey};
	///
	/// let key = ThreadKey::get().unwrap();
	/// let mut mutex = Poisonable::new(Mutex::new(0));
	/// *mutex.get_mut().unwrap() = 10;
	/// assert_eq!(*mutex.lock(key).unwrap(), 10);
	/// ```
	pub fn get_mut(&mut self) -> PoisonResult<L::Inner<'_>> {
		LockableGetMut::get_mut(self)
	}
}

impl<L: UnwindSafe> RefUnwindSafe for Poisonable<L> {}
impl<L: UnwindSafe> UnwindSafe for Poisonable<L> {}