diff options
Diffstat (limited to 'src/rwlock.rs')
| -rw-r--r-- | src/rwlock.rs | 828 |
1 files changed, 0 insertions, 828 deletions
diff --git a/src/rwlock.rs b/src/rwlock.rs index 9bfa1da..e97de98 100644 --- a/src/rwlock.rs +++ b/src/rwlock.rs @@ -11,13 +11,6 @@ use core::marker::PhantomData; use core::mem; use core::ops::{Deref, DerefMut}; -#[cfg(feature = "arc_lock")] -use alloc::sync::Arc; -#[cfg(feature = "arc_lock")] -use core::mem::ManuallyDrop; -#[cfg(feature = "arc_lock")] -use core::ptr; - #[cfg(feature = "owning_ref")] use owning_ref::StableAddress; @@ -84,18 +77,6 @@ pub unsafe trait RawRwLock { } !acquired_lock } - - /// Check if this `RwLock` is currently exclusively locked. - fn is_locked_exclusive(&self) -> bool { - let acquired_lock = self.try_lock_shared(); - if acquired_lock { - // Safety: A shared lock was successfully acquired above. - unsafe { - self.unlock_shared(); - } - } - !acquired_lock - } } /// Additional methods for RwLocks which support fair unlocking. @@ -514,12 +495,6 @@ impl<R: RawRwLock, T: ?Sized> RwLock<R, T> { self.raw.is_locked() } - /// Check if this `RwLock` is currently exclusively locked. - #[inline] - pub fn is_locked_exclusive(&self) -> bool { - self.raw.is_locked_exclusive() - } - /// Forcibly unlocks a read lock. /// /// This is useful when combined with `mem::forget` to hold a lock without @@ -582,84 +557,6 @@ impl<R: RawRwLock, T: ?Sized> RwLock<R, T> { pub fn data_ptr(&self) -> *mut T { self.data.get() } - - /// # Safety - /// - /// The lock must be held when calling this method. - #[cfg(feature = "arc_lock")] - #[inline] - unsafe fn read_guard_arc(self: &Arc<Self>) -> ArcRwLockReadGuard<R, T> { - ArcRwLockReadGuard { - rwlock: self.clone(), - marker: PhantomData, - } - } - - /// # Safety - /// - /// The lock must be held when calling this method. - #[cfg(feature = "arc_lock")] - #[inline] - unsafe fn write_guard_arc(self: &Arc<Self>) -> ArcRwLockWriteGuard<R, T> { - ArcRwLockWriteGuard { - rwlock: self.clone(), - marker: PhantomData, - } - } - - /// Locks this `RwLock` with read access, through an `Arc`. - /// - /// This method is similar to the `read` method; however, it requires the `RwLock` to be inside of an `Arc` - /// and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn read_arc(self: &Arc<Self>) -> ArcRwLockReadGuard<R, T> { - self.raw.lock_shared(); - // SAFETY: locking guarantee is upheld - unsafe { self.read_guard_arc() } - } - - /// Attempts to lock this `RwLock` with read access, through an `Arc`. - /// - /// This method is similar to the `try_read` method; however, it requires the `RwLock` to be inside of an - /// `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_read_arc(self: &Arc<Self>) -> Option<ArcRwLockReadGuard<R, T>> { - if self.raw.try_lock_shared() { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.read_guard_arc() }) - } else { - None - } - } - - /// Locks this `RwLock` with write access, through an `Arc`. - /// - /// This method is similar to the `write` method; however, it requires the `RwLock` to be inside of an `Arc` - /// and the resulting write guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn write_arc(self: &Arc<Self>) -> ArcRwLockWriteGuard<R, T> { - self.raw.lock_exclusive(); - // SAFETY: locking guarantee is upheld - unsafe { self.write_guard_arc() } - } - - /// Attempts to lock this `RwLock` with writ access, through an `Arc`. - /// - /// This method is similar to the `try_write` method; however, it requires the `RwLock` to be inside of an - /// `Arc` and the resulting write guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_write_arc(self: &Arc<Self>) -> Option<ArcRwLockWriteGuard<R, T>> { - if self.raw.try_lock_exclusive() { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.write_guard_arc() }) - } else { - None - } - } } impl<R: RawRwLockFair, T: ?Sized> RwLock<R, T> { @@ -760,78 +657,6 @@ impl<R: RawRwLockTimed, T: ?Sized> RwLock<R, T> { None } } - - /// Attempts to acquire this `RwLock` with read access until a timeout is reached, through an `Arc`. - /// - /// This method is similar to the `try_read_for` method; however, it requires the `RwLock` to be inside of an - /// `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_read_arc_for( - self: &Arc<Self>, - timeout: R::Duration, - ) -> Option<ArcRwLockReadGuard<R, T>> { - if self.raw.try_lock_shared_for(timeout) { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.read_guard_arc() }) - } else { - None - } - } - - /// Attempts to acquire this `RwLock` with read access until a timeout is reached, through an `Arc`. - /// - /// This method is similar to the `try_read_until` method; however, it requires the `RwLock` to be inside of - /// an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_read_arc_until( - self: &Arc<Self>, - timeout: R::Instant, - ) -> Option<ArcRwLockReadGuard<R, T>> { - if self.raw.try_lock_shared_until(timeout) { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.read_guard_arc() }) - } else { - None - } - } - - /// Attempts to acquire this `RwLock` with write access until a timeout is reached, through an `Arc`. - /// - /// This method is similar to the `try_write_for` method; however, it requires the `RwLock` to be inside of - /// an `Arc` and the resulting write guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_write_arc_for( - self: &Arc<Self>, - timeout: R::Duration, - ) -> Option<ArcRwLockWriteGuard<R, T>> { - if self.raw.try_lock_exclusive_for(timeout) { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.write_guard_arc() }) - } else { - None - } - } - - /// Attempts to acquire this `RwLock` with read access until a timeout is reached, through an `Arc`. - /// - /// This method is similar to the `try_write_until` method; however, it requires the `RwLock` to be inside of - /// an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_write_arc_until( - self: &Arc<Self>, - timeout: R::Instant, - ) -> Option<ArcRwLockWriteGuard<R, T>> { - if self.raw.try_lock_exclusive_until(timeout) { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.write_guard_arc() }) - } else { - None - } - } } impl<R: RawRwLockRecursive, T: ?Sized> RwLock<R, T> { @@ -876,33 +701,6 @@ impl<R: RawRwLockRecursive, T: ?Sized> RwLock<R, T> { None } } - - /// Locks this `RwLock` with shared read access, through an `Arc`. - /// - /// This method is similar to the `read_recursive` method; however, it requires the `RwLock` to be inside of - /// an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn read_arc_recursive(self: &Arc<Self>) -> ArcRwLockReadGuard<R, T> { - self.raw.lock_shared_recursive(); - // SAFETY: locking guarantee is upheld - unsafe { self.read_guard_arc() } - } - - /// Attempts to lock this `RwLock` with shared read access, through an `Arc`. - /// - /// This method is similar to the `try_read_recursive` method; however, it requires the `RwLock` to be inside - /// of an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_read_recursive_arc(self: &Arc<Self>) -> Option<ArcRwLockReadGuard<R, T>> { - if self.raw.try_lock_shared_recursive() { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.read_guard_arc() }) - } else { - None - } - } } impl<R: RawRwLockRecursiveTimed, T: ?Sized> RwLock<R, T> { @@ -947,42 +745,6 @@ impl<R: RawRwLockRecursiveTimed, T: ?Sized> RwLock<R, T> { None } } - - /// Attempts to lock this `RwLock` with read access until a timeout is reached, through an `Arc`. - /// - /// This method is similar to the `try_read_recursive_for` method; however, it requires the `RwLock` to be - /// inside of an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_read_arc_recursive_for( - self: &Arc<Self>, - timeout: R::Duration, - ) -> Option<ArcRwLockReadGuard<R, T>> { - if self.raw.try_lock_shared_recursive_for(timeout) { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.read_guard_arc() }) - } else { - None - } - } - - /// Attempts to lock this `RwLock` with read access until a timeout is reached, through an `Arc`. - /// - /// This method is similar to the `try_read_recursive_until` method; however, it requires the `RwLock` to be - /// inside of an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_read_arc_recursive_until( - self: &Arc<Self>, - timeout: R::Instant, - ) -> Option<ArcRwLockReadGuard<R, T>> { - if self.raw.try_lock_shared_recursive_until(timeout) { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.read_guard_arc() }) - } else { - None - } - } } impl<R: RawRwLockUpgrade, T: ?Sized> RwLock<R, T> { @@ -1029,45 +791,6 @@ impl<R: RawRwLockUpgrade, T: ?Sized> RwLock<R, T> { None } } - - /// # Safety - /// - /// The lock must be held when calling this method. - #[cfg(feature = "arc_lock")] - #[inline] - unsafe fn upgradable_guard_arc(self: &Arc<Self>) -> ArcRwLockUpgradableReadGuard<R, T> { - ArcRwLockUpgradableReadGuard { - rwlock: self.clone(), - marker: PhantomData, - } - } - - /// Locks this `RwLock` with upgradable read access, through an `Arc`. - /// - /// This method is similar to the `upgradable_read` method; however, it requires the `RwLock` to be - /// inside of an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn upgradable_read_arc(self: &Arc<Self>) -> ArcRwLockUpgradableReadGuard<R, T> { - self.raw.lock_upgradable(); - // SAFETY: locking guarantee is upheld - unsafe { self.upgradable_guard_arc() } - } - - /// Attempts to lock this `RwLock` with upgradable read access, through an `Arc`. - /// - /// This method is similar to the `try_upgradable_read` method; however, it requires the `RwLock` to be - /// inside of an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_upgradable_read_arc(self: &Arc<Self>) -> Option<ArcRwLockUpgradableReadGuard<R, T>> { - if self.raw.try_lock_upgradable() { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.upgradable_guard_arc() }) - } else { - None - } - } } impl<R: RawRwLockUpgradeTimed, T: ?Sized> RwLock<R, T> { @@ -1108,42 +831,6 @@ impl<R: RawRwLockUpgradeTimed, T: ?Sized> RwLock<R, T> { None } } - - /// Attempts to lock this `RwLock` with upgradable access until a timeout is reached, through an `Arc`. - /// - /// This method is similar to the `try_upgradable_read_for` method; however, it requires the `RwLock` to be - /// inside of an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_upgradable_read_arc_for( - self: &Arc<Self>, - timeout: R::Duration, - ) -> Option<ArcRwLockUpgradableReadGuard<R, T>> { - if self.raw.try_lock_upgradable_for(timeout) { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.upgradable_guard_arc() }) - } else { - None - } - } - - /// Attempts to lock this `RwLock` with upgradable access until a timeout is reached, through an `Arc`. - /// - /// This method is similar to the `try_upgradable_read_until` method; however, it requires the `RwLock` to be - /// inside of an `Arc` and the resulting read guard has no lifetime requirements. - #[cfg(feature = "arc_lock")] - #[inline] - pub fn try_upgradable_read_arc_until( - self: &Arc<Self>, - timeout: R::Instant, - ) -> Option<ArcRwLockUpgradableReadGuard<R, T>> { - if self.raw.try_lock_upgradable_until(timeout) { - // SAFETY: locking guarantee is upheld - Some(unsafe { self.upgradable_guard_arc() }) - } else { - None - } - } } impl<R: RawRwLock, T: ?Sized + Default> Default for RwLock<R, T> { @@ -1354,120 +1041,6 @@ impl<'a, R: RawRwLock + 'a, T: fmt::Display + ?Sized + 'a> fmt::Display #[cfg(feature = "owning_ref")] unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> StableAddress for RwLockReadGuard<'a, R, T> {} -/// An RAII rwlock guard returned by the `Arc` locking operations on `RwLock`. -/// -/// This is similar to the `RwLockReadGuard` struct, except instead of using a reference to unlock the `RwLock` -/// it uses an `Arc<RwLock>`. This has several advantages, most notably that it has an `'static` lifetime. -#[cfg(feature = "arc_lock")] -#[must_use = "if unused the RwLock will immediately unlock"] -pub struct ArcRwLockReadGuard<R: RawRwLock, T: ?Sized> { - rwlock: Arc<RwLock<R, T>>, - marker: PhantomData<R::GuardMarker>, -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: ?Sized> ArcRwLockReadGuard<R, T> { - /// Returns a reference to the rwlock, contained in its `Arc`. - pub fn rwlock(s: &Self) -> &Arc<RwLock<R, T>> { - &s.rwlock - } - - /// Temporarily unlocks the `RwLock` to execute the given function. - /// - /// This is functionally identical to the `unlocked` method on [`RwLockReadGuard`]. - #[inline] - pub fn unlocked<F, U>(s: &mut Self, f: F) -> U - where - F: FnOnce() -> U, - { - // Safety: An RwLockReadGuard always holds a shared lock. - unsafe { - s.rwlock.raw.unlock_shared(); - } - defer!(s.rwlock.raw.lock_shared()); - f() - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockFair, T: ?Sized> ArcRwLockReadGuard<R, T> { - /// Unlocks the `RwLock` using a fair unlock protocol. - /// - /// This is functionally identical to the `unlock_fair` method on [`RwLockReadGuard`]. - #[inline] - pub fn unlock_fair(s: Self) { - // Safety: An RwLockReadGuard always holds a shared lock. - unsafe { - s.rwlock.raw.unlock_shared_fair(); - } - - // SAFETY: ensure the Arc has its refcount decremented - let mut s = ManuallyDrop::new(s); - unsafe { ptr::drop_in_place(&mut s.rwlock) }; - } - - /// Temporarily unlocks the `RwLock` to execute the given function. - /// - /// This is functionally identical to the `unlocked_fair` method on [`RwLockReadGuard`]. - #[inline] - pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U - where - F: FnOnce() -> U, - { - // Safety: An RwLockReadGuard always holds a shared lock. - unsafe { - s.rwlock.raw.unlock_shared_fair(); - } - defer!(s.rwlock.raw.lock_shared()); - f() - } - - /// Temporarily yields the `RwLock` to a waiting thread if there is one. - /// - /// This is functionally identical to the `bump` method on [`RwLockReadGuard`]. - #[inline] - pub fn bump(s: &mut Self) { - // Safety: An RwLockReadGuard always holds a shared lock. - unsafe { - s.rwlock.raw.bump_shared(); - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: ?Sized> Deref for ArcRwLockReadGuard<R, T> { - type Target = T; - #[inline] - fn deref(&self) -> &T { - unsafe { &*self.rwlock.data.get() } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: ?Sized> Drop for ArcRwLockReadGuard<R, T> { - #[inline] - fn drop(&mut self) { - // Safety: An RwLockReadGuard always holds a shared lock. - unsafe { - self.rwlock.raw.unlock_shared(); - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: fmt::Debug + ?Sized> fmt::Debug for ArcRwLockReadGuard<R, T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - fmt::Debug::fmt(&**self, f) - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: fmt::Display + ?Sized> fmt::Display for ArcRwLockReadGuard<R, T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - (**self).fmt(f) - } -} - /// RAII structure used to release the exclusive write access of a lock when /// dropped. #[must_use = "if unused the RwLock will immediately unlock"] @@ -1689,173 +1262,6 @@ impl<'a, R: RawRwLock + 'a, T: fmt::Display + ?Sized + 'a> fmt::Display #[cfg(feature = "owning_ref")] unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> StableAddress for RwLockWriteGuard<'a, R, T> {} -/// An RAII rwlock guard returned by the `Arc` locking operations on `RwLock`. -/// This is similar to the `RwLockWriteGuard` struct, except instead of using a reference to unlock the `RwLock` -/// it uses an `Arc<RwLock>`. This has several advantages, most notably that it has an `'static` lifetime. -#[cfg(feature = "arc_lock")] -#[must_use = "if unused the RwLock will immediately unlock"] -pub struct ArcRwLockWriteGuard<R: RawRwLock, T: ?Sized> { - rwlock: Arc<RwLock<R, T>>, - marker: PhantomData<R::GuardMarker>, -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: ?Sized> ArcRwLockWriteGuard<R, T> { - /// Returns a reference to the rwlock, contained in its `Arc`. - pub fn rwlock(s: &Self) -> &Arc<RwLock<R, T>> { - &s.rwlock - } - - /// Temporarily unlocks the `RwLock` to execute the given function. - /// - /// This is functionally equivalent to the `unlocked` method on [`RwLockWriteGuard`]. - #[inline] - pub fn unlocked<F, U>(s: &mut Self, f: F) -> U - where - F: FnOnce() -> U, - { - // Safety: An RwLockWriteGuard always holds a shared lock. - unsafe { - s.rwlock.raw.unlock_exclusive(); - } - defer!(s.rwlock.raw.lock_exclusive()); - f() - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockDowngrade, T: ?Sized> ArcRwLockWriteGuard<R, T> { - /// Atomically downgrades a write lock into a read lock without allowing any - /// writers to take exclusive access of the lock in the meantime. - /// - /// This is functionally equivalent to the `downgrade` method on [`RwLockWriteGuard`]. - pub fn downgrade(s: Self) -> ArcRwLockReadGuard<R, T> { - // Safety: An RwLockWriteGuard always holds an exclusive lock. - unsafe { - s.rwlock.raw.downgrade(); - } - - // SAFETY: prevent the arc's refcount from changing using ManuallyDrop and ptr::read - let s = ManuallyDrop::new(s); - let rwlock = unsafe { ptr::read(&s.rwlock) }; - - ArcRwLockReadGuard { - rwlock, - marker: PhantomData, - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgradeDowngrade, T: ?Sized> ArcRwLockWriteGuard<R, T> { - /// Atomically downgrades a write lock into an upgradable read lock without allowing any - /// writers to take exclusive access of the lock in the meantime. - /// - /// This is functionally identical to the `downgrade_to_upgradable` method on [`RwLockWriteGuard`]. - pub fn downgrade_to_upgradable(s: Self) -> ArcRwLockUpgradableReadGuard<R, T> { - // Safety: An RwLockWriteGuard always holds an exclusive lock. - unsafe { - s.rwlock.raw.downgrade_to_upgradable(); - } - - // SAFETY: same as above - let s = ManuallyDrop::new(s); - let rwlock = unsafe { ptr::read(&s.rwlock) }; - - ArcRwLockUpgradableReadGuard { - rwlock, - marker: PhantomData, - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockFair, T: ?Sized> ArcRwLockWriteGuard<R, T> { - /// Unlocks the `RwLock` using a fair unlock protocol. - /// - /// This is functionally equivalent to the `unlock_fair` method on [`RwLockWriteGuard`]. - #[inline] - pub fn unlock_fair(s: Self) { - // Safety: An RwLockWriteGuard always holds an exclusive lock. - unsafe { - s.rwlock.raw.unlock_exclusive_fair(); - } - - // SAFETY: prevent the Arc from leaking memory - let mut s = ManuallyDrop::new(s); - unsafe { ptr::drop_in_place(&mut s.rwlock) }; - } - - /// Temporarily unlocks the `RwLock` to execute the given function. - /// - /// This is functionally equivalent to the `unlocked_fair` method on [`RwLockWriteGuard`]. - #[inline] - pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U - where - F: FnOnce() -> U, - { - // Safety: An RwLockWriteGuard always holds an exclusive lock. - unsafe { - s.rwlock.raw.unlock_exclusive_fair(); - } - defer!(s.rwlock.raw.lock_exclusive()); - f() - } - - /// Temporarily yields the `RwLock` to a waiting thread if there is one. - /// - /// This method is functionally equivalent to the `bump` method on [`RwLockWriteGuard`]. - #[inline] - pub fn bump(s: &mut Self) { - // Safety: An RwLockWriteGuard always holds an exclusive lock. - unsafe { - s.rwlock.raw.bump_exclusive(); - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: ?Sized> Deref for ArcRwLockWriteGuard<R, T> { - type Target = T; - #[inline] - fn deref(&self) -> &T { - unsafe { &*self.rwlock.data.get() } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: ?Sized> DerefMut for ArcRwLockWriteGuard<R, T> { - #[inline] - fn deref_mut(&mut self) -> &mut T { - unsafe { &mut *self.rwlock.data.get() } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: ?Sized> Drop for ArcRwLockWriteGuard<R, T> { - #[inline] - fn drop(&mut self) { - // Safety: An RwLockWriteGuard always holds an exclusive lock. - unsafe { - self.rwlock.raw.unlock_exclusive(); - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: fmt::Debug + ?Sized> fmt::Debug for ArcRwLockWriteGuard<R, T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - fmt::Debug::fmt(&**self, f) - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: fmt::Display + ?Sized> fmt::Display for ArcRwLockWriteGuard<R, T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - (**self).fmt(f) - } -} - /// RAII structure used to release the upgradable read access of a lock when /// dropped. #[must_use = "if unused the RwLock will immediately unlock"] @@ -2089,240 +1495,6 @@ unsafe impl<'a, R: RawRwLockUpgrade + 'a, T: ?Sized + 'a> StableAddress { } -/// An RAII rwlock guard returned by the `Arc` locking operations on `RwLock`. -/// This is similar to the `RwLockUpgradableReadGuard` struct, except instead of using a reference to unlock the -/// `RwLock` it uses an `Arc<RwLock>`. This has several advantages, most notably that it has an `'static` -/// lifetime. -#[cfg(feature = "arc_lock")] -#[must_use = "if unused the RwLock will immediately unlock"] -pub struct ArcRwLockUpgradableReadGuard<R: RawRwLockUpgrade, T: ?Sized> { - rwlock: Arc<RwLock<R, T>>, - marker: PhantomData<R::GuardMarker>, -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgrade, T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> { - /// Returns a reference to the rwlock, contained in its original `Arc`. - pub fn rwlock(s: &Self) -> &Arc<RwLock<R, T>> { - &s.rwlock - } - - /// Temporarily unlocks the `RwLock` to execute the given function. - /// - /// This is functionally identical to the `unlocked` method on [`RwLockUpgradableReadGuard`]. - #[inline] - pub fn unlocked<F, U>(s: &mut Self, f: F) -> U - where - F: FnOnce() -> U, - { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - unsafe { - s.rwlock.raw.unlock_upgradable(); - } - defer!(s.rwlock.raw.lock_upgradable()); - f() - } - - /// Atomically upgrades an upgradable read lock lock into a exclusive write lock, - /// blocking the current thread until it can be acquired. - pub fn upgrade(s: Self) -> ArcRwLockWriteGuard<R, T> { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - unsafe { - s.rwlock.raw.upgrade(); - } - - // SAFETY: avoid incrementing or decrementing the refcount using ManuallyDrop and reading the Arc out - // of the struct - let s = ManuallyDrop::new(s); - let rwlock = unsafe { ptr::read(&s.rwlock) }; - - ArcRwLockWriteGuard { - rwlock, - marker: PhantomData, - } - } - - /// Tries to atomically upgrade an upgradable read lock into a exclusive write lock. - /// - /// If the access could not be granted at this time, then the current guard is returned. - pub fn try_upgrade(s: Self) -> Result<ArcRwLockWriteGuard<R, T>, Self> { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - if unsafe { s.rwlock.raw.try_upgrade() } { - // SAFETY: same as above - let s = ManuallyDrop::new(s); - let rwlock = unsafe { ptr::read(&s.rwlock) }; - - Ok(ArcRwLockWriteGuard { - rwlock, - marker: PhantomData, - }) - } else { - Err(s) - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgradeFair, T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> { - /// Unlocks the `RwLock` using a fair unlock protocol. - /// - /// This is functionally identical to the `unlock_fair` method on [`RwLockUpgradableReadGuard`]. - #[inline] - pub fn unlock_fair(s: Self) { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - unsafe { - s.rwlock.raw.unlock_upgradable_fair(); - } - - // SAFETY: make sure we decrement the refcount properly - let mut s = ManuallyDrop::new(s); - unsafe { ptr::drop_in_place(&mut s.rwlock) }; - } - - /// Temporarily unlocks the `RwLock` to execute the given function. - /// - /// This is functionally equivalent to the `unlocked_fair` method on [`RwLockUpgradableReadGuard`]. - #[inline] - pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U - where - F: FnOnce() -> U, - { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - unsafe { - s.rwlock.raw.unlock_upgradable_fair(); - } - defer!(s.rwlock.raw.lock_upgradable()); - f() - } - - /// Temporarily yields the `RwLock` to a waiting thread if there is one. - /// - /// This method is functionally equivalent to calling `bump` on [`RwLockUpgradableReadGuard`]. - #[inline] - pub fn bump(s: &mut Self) { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - unsafe { - s.rwlock.raw.bump_upgradable(); - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgradeDowngrade, T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> { - /// Atomically downgrades an upgradable read lock lock into a shared read lock - /// without allowing any writers to take exclusive access of the lock in the - /// meantime. - /// - /// Note that if there are any writers currently waiting to take the lock - /// then other readers may not be able to acquire the lock even if it was - /// downgraded. - pub fn downgrade(s: Self) -> ArcRwLockReadGuard<R, T> { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - unsafe { - s.rwlock.raw.downgrade_upgradable(); - } - - // SAFETY: use ManuallyDrop and ptr::read to ensure the refcount is not changed - let s = ManuallyDrop::new(s); - let rwlock = unsafe { ptr::read(&s.rwlock) }; - - ArcRwLockReadGuard { - rwlock, - marker: PhantomData, - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgradeTimed, T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> { - /// Tries to atomically upgrade an upgradable read lock into a exclusive - /// write lock, until a timeout is reached. - /// - /// If the access could not be granted before the timeout expires, then - /// the current guard is returned. - pub fn try_upgrade_for( - s: Self, - timeout: R::Duration, - ) -> Result<ArcRwLockWriteGuard<R, T>, Self> { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - if unsafe { s.rwlock.raw.try_upgrade_for(timeout) } { - // SAFETY: same as above - let s = ManuallyDrop::new(s); - let rwlock = unsafe { ptr::read(&s.rwlock) }; - - Ok(ArcRwLockWriteGuard { - rwlock, - marker: PhantomData, - }) - } else { - Err(s) - } - } - - /// Tries to atomically upgrade an upgradable read lock into a exclusive - /// write lock, until a timeout is reached. - /// - /// If the access could not be granted before the timeout expires, then - /// the current guard is returned. - #[inline] - pub fn try_upgrade_until( - s: Self, - timeout: R::Instant, - ) -> Result<ArcRwLockWriteGuard<R, T>, Self> { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - if unsafe { s.rwlock.raw.try_upgrade_until(timeout) } { - // SAFETY: same as above - let s = ManuallyDrop::new(s); - let rwlock = unsafe { ptr::read(&s.rwlock) }; - - Ok(ArcRwLockWriteGuard { - rwlock, - marker: PhantomData, - }) - } else { - Err(s) - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgrade, T: ?Sized> Deref for ArcRwLockUpgradableReadGuard<R, T> { - type Target = T; - #[inline] - fn deref(&self) -> &T { - unsafe { &*self.rwlock.data.get() } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgrade, T: ?Sized> Drop for ArcRwLockUpgradableReadGuard<R, T> { - #[inline] - fn drop(&mut self) { - // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock. - unsafe { - self.rwlock.raw.unlock_upgradable(); - } - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgrade, T: fmt::Debug + ?Sized> fmt::Debug - for ArcRwLockUpgradableReadGuard<R, T> -{ - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - fmt::Debug::fmt(&**self, f) - } -} - -#[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgrade, T: fmt::Display + ?Sized> fmt::Display - for ArcRwLockUpgradableReadGuard<R, T> -{ - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - (**self).fmt(f) - } -} - /// An RAII read lock guard returned by `RwLockReadGuard::map`, which can point to a /// subfield of the protected data. /// |