use std::marker::PhantomData;
use crate::{key::Keyable, Lockable, OwnedLockable};
use super::{LockCollection, LockGuard};
/// returns `true` if the list contains a duplicate
#[must_use]
fn contains_duplicates(l: &mut [usize]) -> bool {
l.sort_unstable();
l.windows(2).any(|w| w[0] == w[1])
}
impl<'a, L: OwnedLockable<'a>> From<L> for LockCollection<L> {
fn from(value: L) -> Self {
Self::new(value)
}
}
impl<'a, L: Lockable<'a>> AsRef<L> for LockCollection<L> {
fn as_ref(&self) -> &L {
&self.data
}
}
impl<'a, L: Lockable<'a>> AsMut<L> for LockCollection<L> {
fn as_mut(&mut self) -> &mut L {
&mut self.data
}
}
impl<'a, L: Lockable<'a>> AsRef<Self> for LockCollection<L> {
fn as_ref(&self) -> &Self {
self
}
}
impl<'a, L: Lockable<'a>> AsMut<Self> for LockCollection<L> {
fn as_mut(&mut self) -> &mut Self {
self
}
}
impl<L: IntoIterator> IntoIterator for LockCollection<L> {
type Item = L::Item;
type IntoIter = L::IntoIter;
fn into_iter(self) -> Self::IntoIter {
self.data.into_iter()
}
}
impl<'a, L> IntoIterator for &'a LockCollection<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()
}
}
impl<'a, L> IntoIterator for &'a mut LockCollection<L>
where
&'a mut L: IntoIterator,
{
type Item = <&'a mut L as IntoIterator>::Item;
type IntoIter = <&'a mut L as IntoIterator>::IntoIter;
fn into_iter(self) -> Self::IntoIter {
self.data.into_iter()
}
}
impl<'a, L: OwnedLockable<'a>, I: FromIterator<L> + OwnedLockable<'a>> FromIterator<L>
for LockCollection<I>
{
fn from_iter<T: IntoIterator<Item = L>>(iter: T) -> Self {
let iter: I = iter.into_iter().collect();
Self::new(iter)
}
}
impl<'a, E: OwnedLockable<'a> + Extend<L>, L: OwnedLockable<'a>> Extend<L> for LockCollection<E> {
fn extend<T: IntoIterator<Item = L>>(&mut self, iter: T) {
self.data.extend(iter)
}
}
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.
///
/// # Examples
///
/// ```
/// use happylock::{LockCollection, Mutex};
///
/// let lock = LockCollection::new((Mutex::new(0), Mutex::new("")));
/// ```
#[must_use]
pub const fn new(data: L) -> Self {
Self { data }
}
/// 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::{LockCollection, Mutex};
///
/// let data = (Mutex::new(0), Mutex::new(""));
/// let lock = LockCollection::new_ref(&data);
/// ```
#[must_use]
pub const fn new_ref(data: &L) -> LockCollection<&L> {
LockCollection { data }
}
}
impl<L> LockCollection<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::{LockCollection, Mutex};
///
/// let data1 = Mutex::new(0);
/// let data2 = Mutex::new("");
///
/// // safety: data1 and data2 refer to distinct mutexes
/// let lock = unsafe { LockCollection::new_unchecked((&data1, &data2)) };
/// ```
#[must_use]
pub const unsafe fn new_unchecked(data: L) -> Self {
Self { data }
}
}
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.
///
/// # 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.
///
/// # Examples
///
/// ```
/// use happylock::{LockCollection, Mutex};
///
/// let data1 = Mutex::new(0);
/// let data2 = Mutex::new("");
///
/// // data1 and data2 refer to distinct mutexes, so this won't panic
/// let lock = LockCollection::try_new((&data1, &data2)).unwrap();
/// ```
#[must_use]
pub fn try_new(data: L) -> Option<Self> {
let mut ptrs = data.get_ptrs();
if contains_duplicates(&mut ptrs) {
return None;
}
Some(Self { data })
}
/// 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::{LockCollection, Mutex, ThreadKey};
///
/// let key = ThreadKey::get().unwrap();
/// let lock = LockCollection::new((Mutex::new(0), Mutex::new("")));
///
/// 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<'a, 'key, L, Key> {
LockGuard {
// safety: we have the thread's key
guard: unsafe { self.data.lock() },
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::{LockCollection, Mutex, ThreadKey};
///
/// let key = ThreadKey::get().unwrap();
/// let lock = LockCollection::new((Mutex::new(0), Mutex::new("")));
///
/// 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<'a, 'key, L, Key>> {
// safety: we have the thread's key
unsafe { self.data.try_lock() }.map(|guard| LockGuard {
guard,
key,
_phantom: PhantomData,
})
}
/// Unlocks the underlying lockable data type, returning the key that's
/// associated with it.
///
/// # Examples
///
/// ```
/// use happylock::{LockCollection, Mutex, ThreadKey};
///
/// let key = ThreadKey::get().unwrap();
/// let lock = LockCollection::new((Mutex::new(0), Mutex::new("")));
///
/// let mut guard = lock.lock(key);
/// *guard.0 += 1;
/// *guard.1 = "1";
/// let key = LockCollection::unlock(guard);
/// ```
#[allow(clippy::missing_const_for_fn)]
pub fn unlock<'key: 'a, Key: Keyable + 'key>(guard: LockGuard<'a, 'key, L, Key>) -> Key {
drop(guard.guard);
guard.key
}
}
impl<'a, L: 'a> LockCollection<L>
where
&'a L: IntoIterator,
{
/// Returns an iterator over references to each value in the collection.
pub fn iter(&'a self) -> <&'a L as IntoIterator>::IntoIter {
self.into_iter()
}
}
impl<'a, L: 'a> LockCollection<L>
where
&'a mut L: IntoIterator,
{
/// Returns an iterator over mutable references to each value in the
/// collection.
pub fn iter_mut(&'a mut self) -> <&'a mut L as IntoIterator>::IntoIter {
self.into_iter()
}
}
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