use std::fmt::Debug;
use crate::lockable::{Lockable, OwnedLockable, RawLock, Sharable};
use crate::{Keyable, ThreadKey};
use super::utils::{
get_locks, ordered_contains_duplicates, scoped_read, scoped_try_read, scoped_try_write,
scoped_write,
};
use super::{utils, LockGuard, RefLockCollection};
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<L: Lockable> RawLock for RefLockCollection<'_, L> {
#[mutants::skip] // this should never run
#[cfg(not(tarpaulin_include))]
fn poison(&self) {
for lock in &self.locks {
lock.poison();
}
}
unsafe fn raw_write(&self) {
utils::ordered_write(&self.locks)
}
unsafe fn raw_try_write(&self) -> bool {
utils::ordered_try_write(&self.locks)
}
unsafe fn raw_unlock_write(&self) {
for lock in &self.locks {
lock.raw_unlock_write();
}
}
unsafe fn raw_read(&self) {
utils::ordered_read(&self.locks)
}
unsafe fn raw_try_read(&self) -> bool {
utils::ordered_try_read(&self.locks)
}
unsafe fn raw_unlock_read(&self) {
for lock in &self.locks {
lock.raw_unlock_read();
}
}
}
unsafe impl<L: Lockable> Lockable for RefLockCollection<'_, L> {
type Guard<'g>
= L::Guard<'g>
where
Self: 'g;
type DataMut<'a>
= L::DataMut<'a>
where
Self: 'a;
fn get_ptrs<'a>(&'a self, ptrs: &mut Vec<&'a dyn RawLock>) {
// Just like with BoxedLockCollection, we need to return all the individual
// locks to avoid duplicates
ptrs.extend_from_slice(&self.locks);
}
unsafe fn guard(&self) -> Self::Guard<'_> {
self.data.guard()
}
unsafe fn data_mut(&self) -> Self::DataMut<'_> {
self.data.data_mut()
}
}
unsafe impl<L: Sharable> Sharable for RefLockCollection<'_, L> {
type ReadGuard<'g>
= L::ReadGuard<'g>
where
Self: 'g;
type DataRef<'a>
= L::DataRef<'a>
where
Self: 'a;
unsafe fn read_guard(&self) -> Self::ReadGuard<'_> {
self.data.read_guard()
}
unsafe fn data_ref(&self) -> Self::DataRef<'_> {
self.data.data_ref()
}
}
impl<T: ?Sized, L: AsRef<T>> AsRef<T> for RefLockCollection<'_, L> {
fn as_ref(&self) -> &T {
self.data.as_ref()
}
}
#[mutants::skip]
#[cfg(not(tarpaulin_include))]
impl<L: Debug> Debug for RefLockCollection<'_, L> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct(stringify!(RefLockCollection))
.field("data", self.data)
// there's not much reason to show the sorting order
.finish_non_exhaustive()
}
}
// safety: the RawLocks must be send because they come from the Send Lockable
#[allow(clippy::non_send_fields_in_send_ty)]
unsafe impl<L: Send> Send for RefLockCollection<'_, L> {}
unsafe impl<L: Sync> Sync for RefLockCollection<'_, L> {}
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) -> Self {
RefLockCollection {
locks: get_locks(data),
data,
}
}
}
impl<L> RefLockCollection<'_, L> {
/// Gets an immutable reference to the underlying data
///
/// # Examples
///
/// ```
/// use happylock::{Mutex, ThreadKey};
/// use happylock::collection::RefLockCollection;
///
/// let data1 = Mutex::new(42);
/// 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();
///
/// let key = ThreadKey::get().unwrap();
/// let guard = lock.child().0.lock(key);
/// assert_eq!(*guard, 42);
/// ```
#[must_use]
pub const fn child(&self) -> &L {
self.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 ordered_contains_duplicates(&locks) {
return None;
}
Some(Self { data, locks })
}
pub fn scoped_lock<'s, R>(&'s self, key: impl Keyable, f: impl Fn(L::DataMut<'s>) -> R) -> R {
scoped_write(self, key, f)
}
pub fn scoped_try_lock<'s, Key: Keyable, R>(
&'s self,
key: Key,
f: impl Fn(L::DataMut<'s>) -> R,
) -> Result<R, Key> {
scoped_try_write(self, key, f)
}
/// 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";
/// ```
#[must_use]
pub fn lock(&self, key: ThreadKey) -> LockGuard<L::Guard<'_>> {
let guard = unsafe {
// safety: we have the thread key
self.raw_write();
// safety: we've locked all of this already
self.data.guard()
};
LockGuard { guard, key }
}
/// Attempts to lock the without blocking.
///
/// If the access could not be granted at this time, then `Err` is
/// returned. Otherwise, an RAII guard is returned which will release the
/// locks when it is dropped.
///
/// # Errors
///
/// If any of the locks in the collection are already locked, then an error
/// is returned containing the given key.
///
/// # 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) {
/// Ok(mut guard) => {
/// *guard.0 += 1;
/// *guard.1 = "1";
/// },
/// Err(_) => unreachable!(),
/// };
///
/// ```
pub fn try_lock(&self, key: ThreadKey) -> Result<LockGuard<L::Guard<'_>>, ThreadKey> {
let guard = unsafe {
// safety: we have the thread key
if !self.raw_try_write() {
return Err(key);
}
// safety: we've acquired the locks
self.data.guard()
};
Ok(LockGuard { guard, key })
}
/// 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(guard: LockGuard<L::Guard<'_>>) -> ThreadKey {
drop(guard.guard);
guard.key
}
}
impl<L: Sharable> RefLockCollection<'_, L> {
pub fn scoped_read<'a, R>(&'a self, key: impl Keyable, f: impl Fn(L::DataRef<'a>) -> R) -> R {
scoped_read(self, key, f)
}
pub fn scoped_try_read<'a, Key: Keyable, R>(
&'a self,
key: Key,
f: impl Fn(L::DataRef<'a>) -> R,
) -> Result<R, Key> {
scoped_try_read(self, key, f)
}
/// 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, "");
/// ```
#[must_use]
pub fn read(&self, key: ThreadKey) -> LockGuard<L::ReadGuard<'_>> {
unsafe {
// safety: we have the thread key
self.raw_read();
LockGuard {
// safety: we've already acquired the lock
guard: self.data.read_guard(),
key,
}
}
}
/// Attempts to lock the without blocking, in such a way that other threads
/// can still read from the collection.
///
/// 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.
///
/// # Errors
///
/// If any of the locks in the collection are already locked, then an error
/// is returned containing the given key.
///
/// # 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) {
/// Ok(mut guard) => {
/// assert_eq!(*guard.0, 5);
/// assert_eq!(*guard.1, "6");
/// },
/// Err(_) => unreachable!(),
/// };
///
/// ```
pub fn try_read(&self, key: ThreadKey) -> Result<LockGuard<L::ReadGuard<'_>>, ThreadKey> {
let guard = unsafe {
// safety: we have the thread key
if !self.raw_try_read() {
return Err(key);
}
// safety: we've acquired the locks
self.data.read_guard()
};
Ok(LockGuard { guard, key })
}
/// 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(guard: LockGuard<L::ReadGuard<'_>>) -> ThreadKey {
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()
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{Mutex, RwLock, ThreadKey};
#[test]
fn non_duplicates_allowed() {
let mutex1 = Mutex::new(0);
let mutex2 = Mutex::new(1);
assert!(RefLockCollection::try_new(&[&mutex1, &mutex2]).is_some())
}
#[test]
fn duplicates_not_allowed() {
let mutex1 = Mutex::new(0);
assert!(RefLockCollection::try_new(&[&mutex1, &mutex1]).is_none())
}
#[test]
fn from() {
let key = ThreadKey::get().unwrap();
let mutexes = [Mutex::new("foo"), Mutex::new("bar"), Mutex::new("baz")];
let collection = RefLockCollection::from(&mutexes);
let guard = collection.lock(key);
assert_eq!(*guard[0], "foo");
assert_eq!(*guard[1], "bar");
assert_eq!(*guard[2], "baz");
}
#[test]
fn scoped_lock_changes_collection() {
let mut key = ThreadKey::get().unwrap();
let mutexes = [Mutex::new(24), Mutex::new(42)];
let collection = RefLockCollection::new(&mutexes);
let sum = collection.scoped_lock(&mut key, |guard| {
*guard[0] = 128;
*guard[0] + *guard[1]
});
assert_eq!(sum, 128 + 42);
let guard = collection.lock(key);
assert_eq!(*guard[0], 128);
assert_eq!(*guard[1], 42);
}
#[test]
fn scoped_read_sees_changes() {
let mut key = ThreadKey::get().unwrap();
let mutexes = [RwLock::new(24), RwLock::new(42)];
let collection = RefLockCollection::new(&mutexes);
collection.scoped_lock(&mut key, |guard| {
*guard[0] = 128;
});
let sum = collection.scoped_read(&mut key, |guard| {
assert_eq!(*guard[0], 128);
assert_eq!(*guard[1], 42);
*guard[0] + *guard[1]
});
assert_eq!(sum, 128 + 42);
}
#[test]
fn scoped_try_lock_can_fail() {
let key = ThreadKey::get().unwrap();
let locks = [Mutex::new(1), Mutex::new(2)];
let collection = RefLockCollection::new(&locks);
let guard = collection.lock(key);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let r = collection.scoped_try_lock(key, |_| {});
assert!(r.is_err());
});
});
drop(guard);
}
#[test]
fn scoped_try_read_can_fail() {
let key = ThreadKey::get().unwrap();
let locks = [RwLock::new(1), RwLock::new(2)];
let collection = RefLockCollection::new(&locks);
let guard = collection.lock(key);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let r = collection.scoped_try_read(key, |_| {});
assert!(r.is_err());
});
});
drop(guard);
}
#[test]
fn try_lock_succeeds_for_unlocked_collection() {
let key = ThreadKey::get().unwrap();
let mutexes = [Mutex::new(24), Mutex::new(42)];
let collection = RefLockCollection::new(&mutexes);
let guard = collection.try_lock(key).unwrap();
assert_eq!(*guard[0], 24);
assert_eq!(*guard[1], 42);
}
#[test]
fn try_lock_fails_for_locked_collection() {
let key = ThreadKey::get().unwrap();
let mutexes = [Mutex::new(24), Mutex::new(42)];
let collection = RefLockCollection::new(&mutexes);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let guard = mutexes[1].lock(key);
assert_eq!(*guard, 42);
std::mem::forget(guard);
});
});
let guard = collection.try_lock(key);
assert!(guard.is_err());
}
#[test]
fn try_read_succeeds_for_unlocked_collection() {
let key = ThreadKey::get().unwrap();
let mutexes = [RwLock::new(24), RwLock::new(42)];
let collection = RefLockCollection::new(&mutexes);
let guard = collection.try_read(key).unwrap();
assert_eq!(*guard[0], 24);
assert_eq!(*guard[1], 42);
}
#[test]
fn try_read_fails_for_locked_collection() {
let key = ThreadKey::get().unwrap();
let mutexes = [RwLock::new(24), RwLock::new(42)];
let collection = RefLockCollection::new(&mutexes);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let guard = mutexes[1].write(key);
assert_eq!(*guard, 42);
std::mem::forget(guard);
});
});
let guard = collection.try_read(key);
assert!(guard.is_err());
}
#[test]
fn can_read_twice_on_different_threads() {
let key = ThreadKey::get().unwrap();
let mutexes = [RwLock::new(24), RwLock::new(42)];
let collection = RefLockCollection::new(&mutexes);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let guard = collection.read(key);
assert_eq!(*guard[0], 24);
assert_eq!(*guard[1], 42);
std::mem::forget(guard);
});
});
let guard = collection.try_read(key).unwrap();
assert_eq!(*guard[0], 24);
assert_eq!(*guard[1], 42);
}
#[test]
fn into_ref_iterator() {
let mut key = ThreadKey::get().unwrap();
let mutexes = [Mutex::new(0), Mutex::new(1), Mutex::new(2)];
let collection = RefLockCollection::new(&mutexes);
for (i, mutex) in (&collection).into_iter().enumerate() {
mutex.scoped_lock(&mut key, |val| assert_eq!(*val, i))
}
}
#[test]
fn ref_iterator() {
let mut key = ThreadKey::get().unwrap();
let mutexes = [Mutex::new(0), Mutex::new(1), Mutex::new(2)];
let collection = RefLockCollection::new(&mutexes);
for (i, mutex) in collection.iter().enumerate() {
mutex.scoped_lock(&mut key, |val| assert_eq!(*val, i))
}
}
#[test]
fn works_in_collection() {
let key = ThreadKey::get().unwrap();
let mutex1 = RwLock::new(0);
let mutex2 = RwLock::new(1);
let collection0 = [&mutex1, &mutex2];
let collection1 = RefLockCollection::try_new(&collection0).unwrap();
let collection = RefLockCollection::try_new(&collection1).unwrap();
let mut guard = collection.lock(key);
assert!(mutex1.is_locked());
assert!(mutex2.is_locked());
assert_eq!(*guard[0], 0);
assert_eq!(*guard[1], 1);
*guard[1] = 2;
drop(guard);
let key = ThreadKey::get().unwrap();
let guard = collection.read(key);
assert!(mutex1.is_locked());
assert!(mutex2.is_locked());
assert_eq!(*guard[0], 0);
assert_eq!(*guard[1], 2);
}
#[test]
fn unlock_collection_works() {
let key = ThreadKey::get().unwrap();
let mutexes = (Mutex::new("foo"), Mutex::new("bar"));
let collection = RefLockCollection::new(&mutexes);
let guard = collection.lock(key);
let key = RefLockCollection::<(Mutex<_>, Mutex<_>)>::unlock(guard);
assert!(collection.try_lock(key).is_ok())
}
#[test]
fn read_unlock_collection_works() {
let key = ThreadKey::get().unwrap();
let locks = (RwLock::new("foo"), RwLock::new("bar"));
let collection = RefLockCollection::new(&locks);
let guard = collection.read(key);
let key = RefLockCollection::<(&RwLock<_>, &RwLock<_>)>::unlock_read(guard);
assert!(collection.try_lock(key).is_ok())
}
#[test]
fn as_ref_works() {
let mutexes = [Mutex::new(0), Mutex::new(1)];
let collection = RefLockCollection::new(&mutexes);
assert!(std::ptr::addr_eq(&mutexes, collection.as_ref()))
}
#[test]
fn child() {
let mutexes = [Mutex::new(0), Mutex::new(1)];
let collection = RefLockCollection::new(&mutexes);
assert!(std::ptr::addr_eq(&mutexes, collection.child()))
}
}
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