use std::fmt::{Debug, Display};
use std::hash::Hash;
use std::marker::PhantomData;
use std::ops::{Deref, DerefMut};
use lock_api::RawRwLock;
use crate::lockable::RawLock;
use crate::ThreadKey;
use super::{RwLock, RwLockWriteGuard, RwLockWriteRef};
// These impls make things slightly easier because now you can use
// `println!("{guard}")` instead of `println!("{}", *guard)`
#[mutants::skip] // hashing involves PRNG and is difficult to test
#[cfg(not(tarpaulin_include))]
impl<T: Hash + ?Sized, R: RawRwLock> Hash for RwLockWriteRef<'_, T, R> {
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
self.deref().hash(state)
}
}
#[mutants::skip]
#[cfg(not(tarpaulin_include))]
impl<T: Debug + ?Sized, R: RawRwLock> Debug for RwLockWriteRef<'_, T, R> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
Debug::fmt(&**self, f)
}
}
impl<T: Display + ?Sized, R: RawRwLock> Display for RwLockWriteRef<'_, T, R> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
Display::fmt(&**self, f)
}
}
impl<T: ?Sized, R: RawRwLock> Deref for RwLockWriteRef<'_, 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.data.get() }
}
}
impl<T: ?Sized, R: RawRwLock> DerefMut for RwLockWriteRef<'_, 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.data.get() }
}
}
impl<T: ?Sized, R: RawRwLock> AsRef<T> for RwLockWriteRef<'_, T, R> {
fn as_ref(&self) -> &T {
self
}
}
impl<T: ?Sized, R: RawRwLock> AsMut<T> for RwLockWriteRef<'_, T, R> {
fn as_mut(&mut self) -> &mut T {
self
}
}
impl<T: ?Sized, R: RawRwLock> Drop for RwLockWriteRef<'_, T, R> {
fn drop(&mut self) {
// safety: this guard is being destroyed, so the data cannot be
// accessed without locking again
unsafe { self.0.raw_unlock() }
}
}
impl<'a, T: ?Sized + 'a, R: RawRwLock> RwLockWriteRef<'a, T, R> {
/// Creates a reference to the underlying data of an [`RwLock`] without
/// locking or taking ownership of the key.
#[must_use]
pub(crate) unsafe fn new(mutex: &'a RwLock<T, R>) -> Self {
Self(mutex, PhantomData)
}
}
#[mutants::skip] // hashing involves PRNG and is difficult to test
#[cfg(not(tarpaulin_include))]
impl<T: Hash + ?Sized, R: RawRwLock> Hash for RwLockWriteGuard<'_, T, R> {
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
self.deref().hash(state)
}
}
#[mutants::skip]
#[cfg(not(tarpaulin_include))]
impl<T: Debug + ?Sized, R: RawRwLock> Debug for RwLockWriteGuard<'_, T, R> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
Debug::fmt(&**self, f)
}
}
impl<T: Display + ?Sized, R: RawRwLock> Display for RwLockWriteGuard<'_, T, R> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
Display::fmt(&**self, f)
}
}
impl<T: ?Sized, R: RawRwLock> Deref for RwLockWriteGuard<'_, T, R> {
type Target = T;
fn deref(&self) -> &Self::Target {
&self.rwlock
}
}
impl<T: ?Sized, R: RawRwLock> DerefMut for RwLockWriteGuard<'_, T, R> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.rwlock
}
}
impl<T: ?Sized, R: RawRwLock> AsRef<T> for RwLockWriteGuard<'_, T, R> {
fn as_ref(&self) -> &T {
self
}
}
impl<T: ?Sized, R: RawRwLock> AsMut<T> for RwLockWriteGuard<'_, T, R> {
fn as_mut(&mut self) -> &mut T {
self
}
}
impl<'a, T: ?Sized + 'a, R: RawRwLock> RwLockWriteGuard<'a, T, R> {
/// Create a guard to the given mutex. Undefined if multiple guards to the
/// same mutex exist at once.
#[must_use]
pub(super) unsafe fn new(rwlock: &'a RwLock<T, R>, thread_key: ThreadKey) -> Self {
Self {
rwlock: RwLockWriteRef(rwlock, PhantomData),
thread_key,
}
}
}
unsafe impl<T: ?Sized + Sync, R: RawRwLock + Sync> Sync for RwLockWriteRef<'_, T, R> {}
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