From f81d4b40a007fecf6502a36b4c24a1e31807a731 Mon Sep 17 00:00:00 2001 From: Botahamec Date: Thu, 23 May 2024 19:50:32 -0400 Subject: Comments --- src/collection/utils.rs | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 src/collection/utils.rs (limited to 'src/collection/utils.rs') diff --git a/src/collection/utils.rs b/src/collection/utils.rs new file mode 100644 index 0000000..dc58399 --- /dev/null +++ b/src/collection/utils.rs @@ -0,0 +1,44 @@ +use crate::lockable::RawLock; + +/// Locks the locks in the order they are given. This causes deadlock if the +/// locks contain duplicates, or if this is called by multiple threads with the +/// locks in different orders. +pub unsafe fn ordered_try_lock(locks: &[&dyn RawLock]) -> bool { + unsafe { + for (i, lock) in locks.iter().enumerate() { + // safety: we have the thread key + let success = lock.try_lock(); + + if !success { + for lock in &locks[0..i] { + // safety: this lock was already acquired + lock.unlock(); + } + return false; + } + } + + true + } +} + +/// Locks the locks in the order they are given. This causes deadlock f this is +/// called by multiple threads with the locks in different orders. +pub unsafe fn ordered_try_read(locks: &[&dyn RawLock]) -> bool { + unsafe { + for (i, lock) in locks.iter().enumerate() { + // safety: we have the thread key + let success = lock.try_read(); + + if !success { + for lock in &locks[0..i] { + // safety: this lock was already acquired + lock.unlock_read(); + } + return false; + } + } + + true + } +} -- cgit v1.2.3