use std::fmt::{Debug, Display};
use std::marker::PhantomData;
use std::ops::{Deref, DerefMut};
use lock_api::RawMutex;
use crate::key::Keyable;
use super::{Mutex, MutexGuard, MutexRef};
// This makes things slightly easier because now you can use
// `println!("{guard}")` instead of `println!("{}", *guard)`. I wonder if I
// should implement some other standard library traits like this too?
impl<'a, T: Debug + ?Sized + 'a, R: RawMutex> Debug for MutexRef<'a, T, R> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
Debug::fmt(&**self, f)
}
}
impl<'a, T: Display + ?Sized + 'a, R: RawMutex> Display for MutexRef<'a, T, R> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
Display::fmt(&**self, f)
}
}
impl<'a, T: ?Sized + 'a, R: RawMutex> Drop for MutexRef<'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() }
}
}
impl<'a, T: ?Sized + 'a, R: RawMutex> Deref for MutexRef<'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.data.get() }
}
}
impl<'a, T: ?Sized + 'a, R: RawMutex> DerefMut for MutexRef<'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.data.get() }
}
}
impl<'a, T: ?Sized + 'a, R: RawMutex> AsRef<T> for MutexRef<'a, T, R> {
fn as_ref(&self) -> &T {
self
}
}
impl<'a, T: ?Sized + 'a, R: RawMutex> AsMut<T> for MutexRef<'a, T, R> {
fn as_mut(&mut self) -> &mut T {
self
}
}
impl<'a, T: ?Sized + 'a, R: RawMutex> MutexRef<'a, T, R> {
/// Creates a reference to the underlying data of a mutex without
/// attempting to lock it or take ownership of the key.
// This might be useful to export, because it makes it easier to express
// the concept of: "Get the data out the mutex but don't lock it or take
// the key". But it's also quite dangerous to drop.
pub(crate) unsafe fn new(mutex: &'a Mutex<T, R>) -> Self {
Self(mutex, PhantomData)
}
}
// it's kinda annoying to re-implement some of this stuff on guards
// there's nothing i can do about that
impl<'a, 'key, T: Debug + ?Sized + 'a, Key: Keyable + 'key, R: RawMutex> Debug
for MutexGuard<'a, 'key, T, Key, R>
{
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
Debug::fmt(&**self, f)
}
}
impl<'a, 'key, T: Display + ?Sized + 'a, Key: Keyable + 'key, R: RawMutex> Display
for MutexGuard<'a, 'key, T, Key, R>
{
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
Display::fmt(&**self, f)
}
}
impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawMutex> Deref
for MutexGuard<'a, 'key, T, Key, R>
{
type Target = T;
fn deref(&self) -> &Self::Target {
&self.mutex
}
}
impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawMutex> DerefMut
for MutexGuard<'a, 'key, T, Key, R>
{
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.mutex
}
}
impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawMutex> AsRef<T>
for MutexGuard<'a, 'key, T, Key, R>
{
fn as_ref(&self) -> &T {
self
}
}
impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawMutex> AsMut<T>
for MutexGuard<'a, 'key, T, Key, R>
{
fn as_mut(&mut self) -> &mut T {
self
}
}
impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawMutex> MutexGuard<'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) unsafe fn new(mutex: &'a Mutex<T, R>, thread_key: Key) -> Self {
Self {
mutex: MutexRef(mutex, PhantomData),
thread_key,
_phantom: PhantomData,
}
}
}
unsafe impl<'a, T: ?Sized + Sync + 'a, R: RawMutex + Sync + 'a> Sync for MutexRef<'a, T, R> {}
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