use std::marker::PhantomData;
use std::ops::{Deref, DerefMut};
use lock_api::RawRwLock;
use crate::key::Keyable;
use super::{RwLock, RwLockWriteGuard, RwLockWriteRef};
impl<'a, T: ?Sized + 'a, R: RawRwLock> Deref for RwLockWriteRef<'a, T, R> {
type Target = T;
fn deref(&self) -> &Self::Target {
// safety: this is the only type that can use `value`, and there's
// a reference to this type, so there cannot be any mutable
// references to this value.
unsafe { &*self.0.value.get() }
}
}
impl<'a, T: ?Sized + 'a, R: RawRwLock> DerefMut for RwLockWriteRef<'a, T, R> {
fn deref_mut(&mut self) -> &mut Self::Target {
// safety: this is the only type that can use `value`, and we have a
// mutable reference to this type, so there cannot be any other
// references to this value.
unsafe { &mut *self.0.value.get() }
}
}
impl<'a, T: ?Sized + 'a, R: RawRwLock> Drop for RwLockWriteRef<'a, T, R> {
fn drop(&mut self) {
// safety: this guard is being destroyed, so the data cannot be
// accessed without locking again
unsafe { self.0.force_unlock_write() }
}
}
impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock> Deref
for RwLockWriteGuard<'a, 'key, T, Key, R>
{
type Target = T;
fn deref(&self) -> &Self::Target {
&self.rwlock
}
}
impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock> DerefMut
for RwLockWriteGuard<'a, 'key, T, Key, R>
{
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.rwlock
}
}
impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock>
RwLockWriteGuard<'a, 'key, T, Key, R>
{
/// Create a guard to the given mutex. Undefined if multiple guards to the
/// same mutex exist at once.
#[must_use]
pub(super) const unsafe fn new(rwlock: &'a RwLock<T, R>, thread_key: Key) -> Self {
Self {
rwlock: RwLockWriteRef(rwlock),
thread_key,
_phantom: PhantomData,
}
}
}
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