Refactor RwLock implementation by removing unused map methods and cleaning up code for improved readability

This commit is contained in:
Alix ANNERAUD 2025-04-12 12:26:48 +02:00
parent bce15cc813
commit 181a324b4d

View File

@ -2,10 +2,10 @@
//!
//! This module provides a read-write lock that can be used to synchronize data between asynchronous tasks.
use core::cell::{RefCell, UnsafeCell};
use core::fmt;
use core::future::{poll_fn, Future};
use core::ops::{Deref, DerefMut};
use core::task::Poll;
use core::{fmt, mem};
use crate::blocking_mutex::raw::RawMutex;
use crate::blocking_mutex::Mutex as BlockingMutex;
@ -221,27 +221,6 @@ where
rwlock: &'a RwLock<R, T>,
}
impl<'a, M, T> RwLockReadGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
/// Map the contents of the `RwLockReadGuard` to a different type.
///
/// This is useful for calling methods on the contents of the `RwLockReadGuard` without
/// moving out of the guard.
pub fn map<U>(this: Self, fun: impl FnOnce(&T) -> &U) -> MappedRwLockReadGuard<'a, M, U> {
let rwlock = this.rwlock;
let value = fun(unsafe { &mut *this.rwlock.inner.get() });
mem::forget(this);
MappedRwLockReadGuard {
state: &rwlock.state,
value,
}
}
}
impl<'a, M, T> Drop for RwLockReadGuard<'a, M, T>
where
M: RawMutex,
@ -307,25 +286,6 @@ where
rwlock: &'a RwLock<R, T>,
}
impl<'a, R, T> RwLockWriteGuard<'a, R, T>
where
R: RawMutex,
T: ?Sized,
{
/// Returns a locked view over a portion of the locked data.
pub fn map<U>(this: Self, fun: impl FnOnce(&mut T) -> &mut U) -> MappedRwLockWriteGuard<'a, R, U> {
let rwlock = this.rwlock;
let value = fun(unsafe { &mut *this.rwlock.inner.get() });
// Dont run the `drop` method for RwLockWriteGuard. The ownership of the underlying
// locked state is being moved to the returned MappedRwLockWriteGuard.
mem::forget(this);
MappedRwLockWriteGuard {
state: &rwlock.state,
value,
}
}
}
impl<'a, R, T> Drop for RwLockWriteGuard<'a, R, T>
where
R: RawMutex,
@ -385,202 +345,6 @@ where
}
}
/// A handle to a held `RwLock` that has had a function applied to it via [`RwLockReadGuard::map`] or
/// [`MappedRwLockReadGuard::map`].
///
/// This can be used to hold a subfield of the protected data.
#[clippy::has_significant_drop]
pub struct MappedRwLockReadGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
state: &'a BlockingMutex<M, RefCell<State>>,
value: *const T,
}
impl<'a, M, T> MappedRwLockReadGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
/// Returns a locked view over a portion of the locked data.
pub fn map<U>(this: Self, fun: impl FnOnce(&T) -> &U) -> MappedRwLockReadGuard<'a, M, U> {
let rwlock = this.state;
let value = fun(unsafe { &*this.value });
// Dont run the `drop` method for RwLockReadGuard. The ownership of the underlying
// locked state is being moved to the returned MappedRwLockReadGuard.
mem::forget(this);
MappedRwLockReadGuard { state: rwlock, value }
}
}
impl<'a, M, T> Deref for MappedRwLockReadGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
type Target = T;
fn deref(&self) -> &Self::Target {
// Safety: the MappedRwLockReadGuard represents shared access to the contents
// of the read-write lock, so it's OK to get it.
unsafe { &*self.value }
}
}
impl<'a, M, T> Drop for MappedRwLockReadGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
fn drop(&mut self) {
self.state.lock(|s| {
let mut s = unwrap!(s.try_borrow_mut());
s.readers -= 1;
if s.readers == 0 {
s.waker.wake();
}
})
}
}
unsafe impl<'a, M, T> Send for MappedRwLockReadGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
}
unsafe impl<'a, M, T> Sync for MappedRwLockReadGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
}
impl<'a, M, T> fmt::Debug for MappedRwLockReadGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized + fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&**self, f)
}
}
impl<'a, M, T> fmt::Display for MappedRwLockReadGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized + fmt::Display,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(&**self, f)
}
}
/// A handle to a held `RwLock` that has had a function applied to it via [`RwLockWriteGuard::map`] or
/// [`MappedRwLockWriteGuard::map`].
///
/// This can be used to hold a subfield of the protected data.
#[clippy::has_significant_drop]
pub struct MappedRwLockWriteGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
state: &'a BlockingMutex<M, RefCell<State>>,
value: *mut T,
}
impl<'a, M, T> MappedRwLockWriteGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
/// Returns a locked view over a portion of the locked data.
pub fn map<U>(this: Self, fun: impl FnOnce(&mut T) -> &mut U) -> MappedRwLockWriteGuard<'a, M, U> {
let rwlock = this.state;
let value = fun(unsafe { &mut *this.value });
// Dont run the `drop` method for RwLockWriteGuard. The ownership of the underlying
// locked state is being moved to the returned MappedRwLockWriteGuard.
mem::forget(this);
MappedRwLockWriteGuard { state: rwlock, value }
}
}
impl<'a, M, T> Deref for MappedRwLockWriteGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
type Target = T;
fn deref(&self) -> &Self::Target {
// Safety: the MappedRwLockWriteGuard represents exclusive access to the contents
// of the read-write lock, so it's OK to get it.
unsafe { &*self.value }
}
}
impl<'a, M, T> DerefMut for MappedRwLockWriteGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
fn deref_mut(&mut self) -> &mut Self::Target {
// Safety: the MappedRwLockWriteGuard represents exclusive access to the contents
// of the read-write lock, so it's OK to get it.
unsafe { &mut *self.value }
}
}
impl<'a, M, T> Drop for MappedRwLockWriteGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
fn drop(&mut self) {
self.state.lock(|s| {
let mut s = unwrap!(s.try_borrow_mut());
s.writer = false;
s.waker.wake();
})
}
}
unsafe impl<'a, M, T> Send for MappedRwLockWriteGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
}
unsafe impl<'a, M, T> Sync for MappedRwLockWriteGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized,
{
}
impl<'a, M, T> fmt::Debug for MappedRwLockWriteGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized + fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&**self, f)
}
}
impl<'a, M, T> fmt::Display for MappedRwLockWriteGuard<'a, M, T>
where
M: RawMutex,
T: ?Sized + fmt::Display,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(&**self, f)
}
}
#[cfg(test)]
mod tests {
use crate::blocking_mutex::raw::NoopRawMutex;