short version: Is there a coroutine equivalent to ConcurrentHashMap? long version: What I'm using no...

# ktor

[Stephan Schröder]

short version: Is there a coroutine equivalent to ConcurrentHashMap?
long version: What I'm using now is manual locking of getOrPut, so

data object ProxyMode {
    private val certificateCache: MutableMap<String, BCECPublicKey> = mutableMapOf()
    private val lock = Mutex()
    ...

    suspend fun getRequest(...): Pair<HttpClient, RequestData> {
        ...
        val serverEncPublicKey: BCECPublicKey = lock.withLock { certificateCache.getOrPut(host) {
            loadCertificate("https://$host/Certificate").bcecPublicKey
        } }
       ...
    }
}

but I wonder if a way exists where the locking is part of the collection class but which still locks the coroutine and not the thread.

[Aleksei Tirman [JB]]

I suggest asking this question in the #coroutines channel.

[CLOVIS]

No, there isn't.

Because many functionalities of collections are provided by extension functions, they can never be made truly atomic. For example, even if you use ConcurrentHashMap, a getOrPut call won't be atomic.

[Stephan Schröder]

you're right, getOrPut wouldn't be atomic but computeIfAbsent would, but unfortunately that one would block the thread and not the coroutine 🤷‍♂️