use std::cell::UnsafeCell;
use std::fmt::Debug;
use crate::lockable::{Lockable, LockableIntoInner, OwnedLockable, RawLock, Sharable};
use crate::{Keyable, ThreadKey};
use super::utils::ordered_contains_duplicates;
use super::{utils, BoxedLockCollection, LockGuard};
unsafe impl<L: Lockable> RawLock for BoxedLockCollection<L> {
#[mutants::skip] // this should never be called
#[cfg(not(tarpaulin_include))]
fn poison(&self) {
for lock in &self.locks {
lock.poison();
}
}
unsafe fn raw_lock(&self) {
utils::ordered_lock(self.locks())
}
unsafe fn raw_try_lock(&self) -> bool {
println!("{}", self.locks().len());
utils::ordered_try_lock(self.locks())
}
unsafe fn raw_unlock(&self) {
for lock in self.locks() {
lock.raw_unlock();
}
}
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 BoxedLockCollection<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>) {
ptrs.extend(self.locks())
}
unsafe fn guard(&self) -> Self::Guard<'_> {
self.child().guard()
}
unsafe fn data_mut(&self) -> Self::DataMut<'_> {
self.child().data_mut()
}
}
unsafe impl<L: Sharable> Sharable for BoxedLockCollection<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.child().read_guard()
}
unsafe fn data_ref(&self) -> Self::DataRef<'_> {
self.child().data_ref()
}
}
unsafe impl<L: OwnedLockable> OwnedLockable for BoxedLockCollection<L> {}
// LockableGetMut can't be implemented because that would create mutable and
// immutable references to the same value at the same time.
impl<L: LockableIntoInner> LockableIntoInner for BoxedLockCollection<L> {
type Inner = L::Inner;
fn into_inner(self) -> Self::Inner {
LockableIntoInner::into_inner(self.into_child())
}
}
impl<L> IntoIterator for BoxedLockCollection<L>
where
L: IntoIterator,
{
type Item = <L as IntoIterator>::Item;
type IntoIter = <L as IntoIterator>::IntoIter;
fn into_iter(self) -> Self::IntoIter {
self.into_child().into_iter()
}
}
impl<'a, L> IntoIterator for &'a BoxedLockCollection<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.child().into_iter()
}
}
impl<L: OwnedLockable, I: FromIterator<L> + OwnedLockable> FromIterator<L>
for BoxedLockCollection<I>
{
fn from_iter<T: IntoIterator<Item = L>>(iter: T) -> Self {
let iter: I = iter.into_iter().collect();
Self::new(iter)
}
}
// 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 BoxedLockCollection<L> {}
unsafe impl<L: Sync> Sync for BoxedLockCollection<L> {}
impl<L> Drop for BoxedLockCollection<L> {
#[mutants::skip] // i can't test for a memory leak
#[cfg(not(tarpaulin_include))]
fn drop(&mut self) {
unsafe {
// safety: this collection will never be locked again
self.locks.clear();
// safety: this was allocated using a box, and is now unique
let boxed: Box<UnsafeCell<L>> = Box::from_raw(self.data.cast_mut());
drop(boxed)
}
}
}
impl<T, L: AsRef<T>> AsRef<T> for BoxedLockCollection<L> {
fn as_ref(&self) -> &T {
self.child().as_ref()
}
}
#[mutants::skip]
#[cfg(not(tarpaulin_include))]
impl<L: Debug> Debug for BoxedLockCollection<L> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct(stringify!(BoxedLockCollection))
.field("data", &self.data)
.finish_non_exhaustive()
}
}
impl<L: OwnedLockable + Default> Default for BoxedLockCollection<L> {
fn default() -> Self {
Self::new(L::default())
}
}
impl<L: OwnedLockable> From<L> for BoxedLockCollection<L> {
fn from(value: L) -> Self {
Self::new(value)
}
}
impl<L> BoxedLockCollection<L> {
/// Gets the underlying collection, consuming this collection.
///
/// # Examples
///
/// ```
/// use happylock::{Mutex, ThreadKey, LockCollection};
///
/// 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 = LockCollection::try_new(&data).unwrap();
///
/// let key = ThreadKey::get().unwrap();
/// let guard = lock.into_child().0.lock(key);
/// assert_eq!(*guard, 42);
/// ```
#[must_use]
pub fn into_child(mut self) -> L {
unsafe {
// safety: this collection will never be used again
std::ptr::drop_in_place(&mut self.locks);
// safety: this was allocated using a box, and is now unique
let boxed: Box<UnsafeCell<L>> = Box::from_raw(self.data.cast_mut());
// to prevent a double free
std::mem::forget(self);
boxed.into_inner()
}
}
// child_mut is immediate UB because it leads to mutable and immutable
// references happening at the same time
/// Gets an immutable reference to the underlying data
///
/// # Examples
///
/// ```
/// use happylock::{Mutex, ThreadKey, LockCollection};
///
/// 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 = LockCollection::try_new(&data).unwrap();
///
/// let key = ThreadKey::get().unwrap();
/// let guard = lock.child().0.lock(key);
/// assert_eq!(*guard, 42);
/// ```
#[must_use]
pub fn child(&self) -> &L {
unsafe {
self.data
.as_ref()
.unwrap_unchecked()
.get()
.as_ref()
.unwrap_unchecked()
}
}
/// Gets the locks
fn locks(&self) -> &[&dyn RawLock] {
&self.locks
}
}
impl<L: OwnedLockable> BoxedLockCollection<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, LockCollection};
///
/// let data = (Mutex::new(0), Mutex::new(""));
/// let lock = LockCollection::new(data);
/// ```
#[must_use]
pub fn new(data: L) -> Self {
// safety: owned lockable types cannot contain duplicates
unsafe { Self::new_unchecked(data) }
}
}
impl<'a, L: OwnedLockable> BoxedLockCollection<&'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, LockCollection};
///
/// let data = (Mutex::new(0), Mutex::new(""));
/// let lock = LockCollection::new_ref(&data);
/// ```
#[must_use]
pub fn new_ref(data: &'a L) -> Self {
// safety: owned lockable types cannot contain duplicates
unsafe { Self::new_unchecked(data) }
}
}
impl<L: Lockable> BoxedLockCollection<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, LockCollection};
///
/// let data1 = Mutex::new(0);
/// let data2 = Mutex::new("");
///
/// // safety: data1 and data2 refer to distinct mutexes
/// let data = (&data1, &data2);
/// let lock = unsafe { LockCollection::new_unchecked(&data) };
/// ```
#[must_use]
pub unsafe fn new_unchecked(data: L) -> Self {
let data = Box::leak(Box::new(UnsafeCell::new(data)));
let data_ref = data.get().cast_const().as_ref().unwrap_unchecked();
let mut locks = Vec::new();
data_ref.get_ptrs(&mut locks);
// cast to *const () because fat pointers can't be converted to usize
locks.sort_by_key(|lock| (&raw const **lock).cast::<()>() as usize);
// safety we're just changing the lifetimes
let locks: Vec<&'static dyn RawLock> = std::mem::transmute(locks);
let data = &raw const *data;
Self { data, locks }
}
/// Creates a new collection of locks.
///
/// This returns `None` if any locks are found twice in the given
/// collection.
///
/// # Examples
///
/// ```
/// use happylock::{Mutex, LockCollection};
///
/// 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 = LockCollection::try_new(&data).unwrap();
/// ```
#[must_use]
pub fn try_new(data: L) -> Option<Self> {
// safety: we are checking for duplicates before returning
unsafe {
let this = Self::new_unchecked(data);
if ordered_contains_duplicates(this.locks()) {
return None;
}
Some(this)
}
}
pub fn scoped_lock<R>(&self, key: impl Keyable, f: impl Fn(L::DataMut<'_>) -> R) -> R {
unsafe {
// safety: we have the thread key
self.raw_lock();
// safety: the data was just locked
let r = f(self.data_mut());
// safety: the collection is still locked
self.raw_unlock();
drop(key); // ensure the key stays alive long enough
r
}
}
pub fn scoped_try_lock<Key: Keyable, R>(
&self,
key: Key,
f: impl Fn(L::DataMut<'_>) -> R,
) -> Result<R, Key> {
unsafe {
// safety: we have the thread key
if !self.raw_try_lock() {
return Err(key);
}
// safety: we just locked the collection
let r = f(self.data_mut());
// safety: the collection is still locked
self.raw_unlock();
drop(key); // ensures the key stays valid long enough
Ok(r)
}
}
/// 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, LockCollection};
///
/// let key = ThreadKey::get().unwrap();
/// let data = (Mutex::new(0), Mutex::new(""));
/// let lock = LockCollection::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<'_>> {
unsafe {
// safety: we have the thread key
self.raw_lock();
LockGuard {
// safety: we've already acquired the lock
guard: self.child().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 locks in the collection are already locked, then an error
/// containing the given key is returned.
///
/// # Examples
///
/// ```
/// use happylock::{Mutex, ThreadKey, LockCollection};
///
/// let key = ThreadKey::get().unwrap();
/// let data = (Mutex::new(0), Mutex::new(""));
/// let lock = LockCollection::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 {
if !self.raw_try_lock() {
return Err(key);
}
// safety: we've acquired the locks
self.child().guard()
};
Ok(LockGuard { guard, key })
}
/// Unlocks the underlying lockable data type, returning the key that's
/// associated with it.
///
/// # Examples
///
/// ```
/// use happylock::{Mutex, ThreadKey, LockCollection};
///
/// let key = ThreadKey::get().unwrap();
/// let data = (Mutex::new(0), Mutex::new(""));
/// let lock = LockCollection::new(data);
///
/// let mut guard = lock.lock(key);
/// *guard.0 += 1;
/// *guard.1 = "1";
/// let key = LockCollection::<(Mutex<i32>, Mutex<&str>)>::unlock(guard);
/// ```
pub fn unlock(guard: LockGuard<L::Guard<'_>>) -> ThreadKey {
drop(guard.guard);
guard.key
}
}
impl<L: Sharable> BoxedLockCollection<L> {
pub fn scoped_read<R>(&self, key: impl Keyable, f: impl Fn(L::DataRef<'_>) -> R) -> R {
unsafe {
// safety: we have the thread key
self.raw_read();
// safety: the data was just locked
let r = f(self.data_ref());
// safety: the collection is still locked
self.raw_unlock_read();
drop(key); // ensure the key stays alive long enough
r
}
}
pub fn scoped_try_read<Key: Keyable, R>(
&self,
key: Key,
f: impl Fn(L::DataRef<'_>) -> 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 = f(self.data_ref());
// safety: the collection is still locked
self.raw_unlock_read();
drop(key); // ensures the key stays valid long enough
Ok(r)
}
}
/// 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, LockCollection};
///
/// let key = ThreadKey::get().unwrap();
/// let data = (RwLock::new(0), RwLock::new(""));
/// let lock = LockCollection::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.child().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, LockCollection};
///
/// let key = ThreadKey::get().unwrap();
/// let data = (RwLock::new(5), RwLock::new("6"));
/// let lock = LockCollection::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.child().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, LockCollection};
///
/// let key = ThreadKey::get().unwrap();
/// let data = (RwLock::new(0), RwLock::new(""));
/// let lock = LockCollection::new(data);
///
/// let mut guard = lock.read(key);
/// let key = LockCollection::<(RwLock<i32>, RwLock<&str>)>::unlock_read(guard);
/// ```
pub fn unlock_read(guard: LockGuard<L::ReadGuard<'_>>) -> ThreadKey {
drop(guard.guard);
guard.key
}
}
impl<L: LockableIntoInner> BoxedLockCollection<L> {
/// Consumes this `BoxedLockCollection`, returning the underlying data.
///
/// # Examples
///
/// ```
/// use happylock::{Mutex, LockCollection};
///
/// let mutex = LockCollection::new([Mutex::new(0), Mutex::new(0)]);
/// assert_eq!(mutex.into_inner(), [0, 0]);
/// ```
#[must_use]
pub fn into_inner(self) -> <Self as LockableIntoInner>::Inner {
LockableIntoInner::into_inner(self)
}
}
impl<'a, L: 'a> BoxedLockCollection<L>
where
&'a L: IntoIterator,
{
/// Returns an iterator over references to each value in the collection.
///
/// # Examples
///
/// ```
/// use happylock::{Mutex, ThreadKey, LockCollection};
///
/// let key = ThreadKey::get().unwrap();
/// let data = [Mutex::new(26), Mutex::new(1)];
/// let lock = LockCollection::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 from_iterator() {
let key = ThreadKey::get().unwrap();
let collection: BoxedLockCollection<Vec<Mutex<&str>>> =
[Mutex::new("foo"), Mutex::new("bar"), Mutex::new("baz")]
.into_iter()
.collect();
let guard = collection.lock(key);
assert_eq!(*guard[0], "foo");
assert_eq!(*guard[1], "bar");
assert_eq!(*guard[2], "baz");
}
#[test]
fn from() {
let key = ThreadKey::get().unwrap();
let collection =
BoxedLockCollection::from([Mutex::new("foo"), Mutex::new("bar"), Mutex::new("baz")]);
let guard = collection.lock(key);
assert_eq!(*guard[0], "foo");
assert_eq!(*guard[1], "bar");
assert_eq!(*guard[2], "baz");
}
#[test]
fn into_owned_iterator() {
let collection = BoxedLockCollection::new([Mutex::new(0), Mutex::new(1), Mutex::new(2)]);
for (i, mutex) in collection.into_iter().enumerate() {
assert_eq!(mutex.into_inner(), i);
}
}
#[test]
fn into_ref_iterator() {
let mut key = ThreadKey::get().unwrap();
let collection = BoxedLockCollection::new([Mutex::new(0), Mutex::new(1), Mutex::new(2)]);
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 collection = BoxedLockCollection::new([Mutex::new(0), Mutex::new(1), Mutex::new(2)]);
for (i, mutex) in collection.iter().enumerate() {
mutex.scoped_lock(&mut key, |val| assert_eq!(*val, i))
}
}
#[test]
#[allow(clippy::float_cmp)]
fn uses_correct_default() {
let collection =
BoxedLockCollection::<(Mutex<f64>, Mutex<Option<i32>>, Mutex<usize>)>::default();
let tuple = collection.into_inner();
assert_eq!(tuple.0, 0.0);
assert!(tuple.1.is_none());
assert_eq!(tuple.2, 0)
}
#[test]
fn non_duplicates_allowed() {
let mutex1 = Mutex::new(0);
let mutex2 = Mutex::new(1);
assert!(BoxedLockCollection::try_new([&mutex1, &mutex2]).is_some())
}
#[test]
fn duplicates_not_allowed() {
let mutex1 = Mutex::new(0);
assert!(BoxedLockCollection::try_new([&mutex1, &mutex1]).is_none())
}
#[test]
fn try_lock_works() {
let key = ThreadKey::get().unwrap();
let collection = BoxedLockCollection::new([Mutex::new(1), Mutex::new(2)]);
let guard = collection.try_lock(key);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let guard = collection.try_lock(key);
assert!(guard.is_err());
});
});
assert!(guard.is_ok());
}
#[test]
fn try_read_works() {
let key = ThreadKey::get().unwrap();
let collection = BoxedLockCollection::new([RwLock::new(1), RwLock::new(2)]);
let guard = collection.try_read(key);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let guard = collection.try_read(key);
assert!(guard.is_ok());
});
});
assert!(guard.is_ok());
}
#[test]
fn try_lock_fails_with_one_exclusive_lock() {
let key = ThreadKey::get().unwrap();
let locks = [Mutex::new(1), Mutex::new(2)];
let collection = BoxedLockCollection::new_ref(&locks);
let guard = locks[1].try_lock(key);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let guard = collection.try_lock(key);
assert!(guard.is_err());
});
});
assert!(guard.is_ok());
}
#[test]
fn try_read_fails_during_exclusive_lock() {
let key = ThreadKey::get().unwrap();
let collection = BoxedLockCollection::new([RwLock::new(1), RwLock::new(2)]);
let guard = collection.try_lock(key);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let guard = collection.try_read(key);
assert!(guard.is_err());
});
});
assert!(guard.is_ok());
}
#[test]
fn try_read_fails_with_one_exclusive_lock() {
let key = ThreadKey::get().unwrap();
let locks = [RwLock::new(1), RwLock::new(2)];
let collection = BoxedLockCollection::new_ref(&locks);
let guard = locks[1].try_write(key);
std::thread::scope(|s| {
s.spawn(|| {
let key = ThreadKey::get().unwrap();
let guard = collection.try_read(key);
assert!(guard.is_err());
});
});
assert!(guard.is_ok());
}
#[test]
fn unlock_collection_works() {
let key = ThreadKey::get().unwrap();
let mutex1 = Mutex::new("foo");
let mutex2 = Mutex::new("bar");
let collection = BoxedLockCollection::try_new((&mutex1, &mutex2)).unwrap();
let guard = collection.lock(key);
let key = BoxedLockCollection::<(&Mutex<_>, &Mutex<_>)>::unlock(guard);
assert!(mutex1.try_lock(key).is_ok())
}
#[test]
fn read_unlock_collection_works() {
let key = ThreadKey::get().unwrap();
let lock1 = RwLock::new("foo");
let lock2 = RwLock::new("bar");
let collection = BoxedLockCollection::try_new((&lock1, &lock2)).unwrap();
let guard = collection.read(key);
let key = BoxedLockCollection::<(&RwLock<_>, &RwLock<_>)>::unlock_read(guard);
assert!(lock1.try_write(key).is_ok())
}
#[test]
fn into_inner_works() {
let collection = BoxedLockCollection::new((Mutex::new("Hello"), Mutex::new(47)));
assert_eq!(collection.into_inner(), ("Hello", 47))
}
#[test]
fn works_in_collection() {
let key = ThreadKey::get().unwrap();
let mutex1 = Mutex::new(0);
let mutex2 = Mutex::new(1);
let collection =
BoxedLockCollection::try_new(BoxedLockCollection::try_new([&mutex1, &mutex2]).unwrap())
.unwrap();
let guard = collection.lock(key);
assert!(mutex1.is_locked());
assert!(mutex2.is_locked());
drop(guard);
}
}
|
