HappyLock 0.3: Deadlock-free mutexes

Hello. A few months ago I posted a link to HappyLock, a library I made which uses the borrow checker to prevent deadlocks. Although most of the checking can be done at compile-time, there was an O(n^2) runtime check to ensure that lock collections didn't contain duplicate locks. There was also the possibility of livelock due to releasing and reobtaining mutexes. In the comments, several of you made suggestions on how to improve this. I took those ideas and published HappyLock 0.3.

I created a blog, and a blog post explaining how HappyLock works and what I've changed. Ignore the fact that the CSS doesn't exist right now: https://www.botahamec.dev/blog/how-happylock-works.html

Here's a short list of changes

• The Lockable trait has been replaced with a Lock trait and a new Lockable trait. Lock is a bit like RawRwLock and Lockable translates that into something that can have a guard.

• These new traits don't have lifetimes

• Four new lock collection types exist, replacing the old ones. Each new collection type has different performance characteristics. OwnedLockCollection is free, but only accepts an OwnedLockable type. RefLockCollection does the sorting of lock pointers, but is a reference. BoxedLockCollection boxes the data, so it doesn't need a lifetime. RetryingLockCollection is the equivalent of the old LockCollection. The default lock collection is BoxedLockCollection, for which there is a type alias at the top of the crate.

• A new Sharable trait has been added as a subtrait of Lockable. If a lock collection only contains rwlocks, then the lock collection will have a read method.

• New trait implementations and methods for locking types

I don't love making a new post for an update to a small crate, but I think the ideas here have a lot of potential. It's cool that in addition to all of the memory unsafety issues that Rust already prevents, Rust can also prevent deadlocks if the libraries are designed around it.

Edit: bulleted list formatting