+#[allow(dead_code)] // Depending on the compilation flags some variants are never used
+#[derive(Debug, PartialEq, Eq)]
+pub(crate) enum LockHeldState {
+ HeldByThread,
+ NotHeldByThread,
+ #[cfg(any(feature = "_bench_unstable", not(test)))]
+ Unsupported,
+}
+
+pub(crate) trait LockTestExt<'a> {
+ fn held_by_thread(&self) -> LockHeldState;
+ type ExclLock;
+ /// If two instances of the same mutex are being taken at the same time, it's very easy to have
+ /// a lockorder inversion and risk deadlock. Thus, we default to disabling such locks.
+ ///
+ /// However, sometimes they cannot be avoided. In such cases, this method exists to take a
+ /// mutex while avoiding a test failure. It is deliberately verbose and includes the term
+ /// "unsafe" to indicate that special care needs to be taken to ensure no deadlocks are
+ /// possible.
+ fn unsafe_well_ordered_double_lock_self(&'a self) -> Self::ExclLock;
+}
+
#[cfg(all(feature = "std", not(feature = "_bench_unstable"), test))]
mod debug_sync;
#[cfg(all(feature = "std", not(feature = "_bench_unstable"), test))]
mod test_lockorder_checks;
#[cfg(all(feature = "std", any(feature = "_bench_unstable", not(test))))]
-pub use ::std::sync::{Arc, Mutex, Condvar, MutexGuard, RwLock, RwLockReadGuard, RwLockWriteGuard};
+pub(crate) mod fairrwlock;
+#[cfg(all(feature = "std", any(feature = "_bench_unstable", not(test))))]
+pub use {std::sync::{Arc, Mutex, Condvar, MutexGuard, RwLock, RwLockReadGuard, RwLockWriteGuard}, fairrwlock::FairRwLock};
+
#[cfg(all(feature = "std", any(feature = "_bench_unstable", not(test))))]
-pub use crate::util::fairrwlock::FairRwLock;
+mod ext_impl {
+ use super::*;
+ impl<'a, T: 'a> LockTestExt<'a> for Mutex<T> {
+ #[inline]
+ fn held_by_thread(&self) -> LockHeldState { LockHeldState::Unsupported }
+ type ExclLock = MutexGuard<'a, T>;
+ #[inline]
+ fn unsafe_well_ordered_double_lock_self(&'a self) -> MutexGuard<T> { self.lock().unwrap() }
+ }
+ impl<'a, T: 'a> LockTestExt<'a> for RwLock<T> {
+ #[inline]
+ fn held_by_thread(&self) -> LockHeldState { LockHeldState::Unsupported }
+ type ExclLock = RwLockWriteGuard<'a, T>;
+ #[inline]
+ fn unsafe_well_ordered_double_lock_self(&'a self) -> RwLockWriteGuard<T> { self.write().unwrap() }
+ }
+}
#[cfg(not(feature = "std"))]
mod nostd_sync;