diff options
Diffstat (limited to 'src/rwlock.rs')
| -rw-r--r-- | src/rwlock.rs | 111 |
1 files changed, 71 insertions, 40 deletions
diff --git a/src/rwlock.rs b/src/rwlock.rs index c404934..9bfa1da 100644 --- a/src/rwlock.rs +++ b/src/rwlock.rs @@ -84,6 +84,18 @@ 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. @@ -502,6 +514,12 @@ 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 @@ -590,7 +608,7 @@ impl<R: RawRwLock, T: ?Sized> RwLock<R, T> { } /// 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")] @@ -602,8 +620,8 @@ impl<R: RawRwLock, T: ?Sized> RwLock<R, T> { } /// 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 + /// + /// 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] @@ -617,7 +635,7 @@ impl<R: RawRwLock, T: ?Sized> RwLock<R, T> { } /// 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")] @@ -629,8 +647,8 @@ impl<R: RawRwLock, T: ?Sized> RwLock<R, T> { } /// 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 + /// + /// 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] @@ -744,12 +762,15 @@ impl<R: RawRwLockTimed, T: ?Sized> RwLock<R, T> { } /// 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>> { + 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() }) @@ -759,12 +780,15 @@ impl<R: RawRwLockTimed, T: ?Sized> RwLock<R, T> { } /// 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>> { + 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() }) @@ -774,12 +798,15 @@ impl<R: RawRwLockTimed, T: ?Sized> RwLock<R, T> { } /// 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>> { + 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() }) @@ -789,12 +816,15 @@ impl<R: RawRwLockTimed, T: ?Sized> RwLock<R, T> { } /// 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>> { + 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() }) @@ -848,7 +878,7 @@ impl<R: RawRwLockRecursive, T: ?Sized> RwLock<R, T> { } /// 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")] @@ -860,7 +890,7 @@ impl<R: RawRwLockRecursive, T: ?Sized> RwLock<R, T> { } /// 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")] @@ -924,7 +954,10 @@ impl<R: RawRwLockRecursiveTimed, T: ?Sized> RwLock<R, T> { /// 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>> { + 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() }) @@ -939,7 +972,10 @@ impl<R: RawRwLockRecursiveTimed, T: ?Sized> RwLock<R, T> { /// 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>> { + 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() }) @@ -995,19 +1031,19 @@ impl<R: RawRwLockUpgrade, T: ?Sized> RwLock<R, T> { } /// # 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 + 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")] @@ -1019,7 +1055,7 @@ impl<R: RawRwLockUpgrade, T: ?Sized> RwLock<R, T> { } /// 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")] @@ -1074,7 +1110,7 @@ impl<R: RawRwLockUpgradeTimed, T: ?Sized> RwLock<R, T> { } /// 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")] @@ -1092,7 +1128,7 @@ impl<R: RawRwLockUpgradeTimed, T: ?Sized> RwLock<R, T> { } /// 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")] @@ -1318,9 +1354,9 @@ 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` +/// 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"] @@ -1426,9 +1462,7 @@ impl<R: RawRwLock, T: fmt::Debug + ?Sized> fmt::Debug for ArcRwLockReadGuard<R, } #[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: fmt::Display + ?Sized> fmt::Display - for ArcRwLockReadGuard<R, T> -{ +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) } @@ -1655,8 +1689,8 @@ 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` +/// 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"] @@ -1770,7 +1804,7 @@ impl<R: RawRwLockFair, T: ?Sized> ArcRwLockWriteGuard<R, T> { /// Temporarily yields the `RwLock` to a waiting thread if there is one. /// - /// This method is functionally equivalent to the `bump` method on [`RwLockWriteGuard`]. + /// 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. @@ -1816,9 +1850,7 @@ impl<R: RawRwLock, T: fmt::Debug + ?Sized> fmt::Debug for ArcRwLockWriteGuard<R, } #[cfg(feature = "arc_lock")] -impl<R: RawRwLock, T: fmt::Display + ?Sized> fmt::Display - for ArcRwLockWriteGuard<R, T> -{ +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) } @@ -2059,7 +2091,7 @@ 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` +/// `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"] @@ -2069,7 +2101,7 @@ pub struct ArcRwLockUpgradableReadGuard<R: RawRwLockUpgrade, T: ?Sized> { } #[cfg(feature = "arc_lock")] -impl<R: RawRwLockUpgrade , T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> { +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 @@ -2144,7 +2176,7 @@ impl<R: RawRwLockUpgradeFair, T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> { // SAFETY: make sure we decrement the refcount properly let mut s = ManuallyDrop::new(s); - unsafe { ptr::drop_in_place(&mut s.rwlock) }; + unsafe { ptr::drop_in_place(&mut s.rwlock) }; } /// Temporarily unlocks the `RwLock` to execute the given function. @@ -2291,7 +2323,6 @@ impl<R: RawRwLockUpgrade, T: fmt::Display + ?Sized> fmt::Display } } - /// An RAII read lock guard returned by `RwLockReadGuard::map`, which can point to a /// subfield of the protected data. /// |