Is there a way to synchronously check if a Mutex i...

# coroutines

[Seri]

Is there a way to synchronously check if a Mutex is unlocked and run a block of code under it? Similar to Mutex.withLock { ... }, but with calls while the Mutex is locked being discarded instead of suspending.

[octylFractal]

is tryLock not good enough?

[octylFractal]

if you really want a `tryWithLock`:

inline fun <T : Any> Mutex.tryWithLock(owner: Any? = null, action: () -> T): T? {
    return if (tryLock(owner)) {
        try {
            action()
        } finally {
            unlock(owner)
        }
    } else {
        null
    }
}

explicitly forbids null because it's the failure signal here, you can change that up if you want

[Seri]

My issue with tryLock was that it didn’t immediately run the block, so there was a race condition.

[Seri]

That tryWithLock extension method is what I was thinking about writing, nice!

[octylFractal]

I don't get what the race condition is here? if tryLock returns true, you got the exclusive lock -- nothing can interrupt it

[Seri]

I think I had the synchronous bits mixed up in my head, I was imagining the following at first:

if (!mutex.isLocked) {
    mutex.withLock { ... }
}

[Seri]

Looking back at that, I can see the flaw

[octylFractal]

yea, there's a race condition there -- but I think tryLock should work

[Seri]

👍