How do I convert this into less janky and actually working code

# coroutines

[Kroppeb]

How do I convert this into less janky and actually working code

[Kroppeb]

This is the log btw

[marstran]

So, what are you trying to do?

[Kroppeb]

I'm reading raw bytes from a ByteReadChannel and if i got a cipher i encrypt and then send those bytes int a different ByteChannel

[Kroppeb]

the problem is that ByteChannel#Read requires a normal lambda and not a suspending one which is causing all the problems

[Kroppeb]

I fixed it by moving the Job initialiser outside of the while loop 🤦‍♂️

[Kroppeb]

But still the code looks jank

[Kroppeb]

I'm extracting it to a extensionfunction for the time being

[marstran]

So the read-lambda is a callback right?

[Kroppeb]

yeah

[marstran]

Ok, then you should convert it to a coroutine with the suspendCoroutine function. Check out this article: https://medium.com/@elizarov/callbacks-and-kotlin-flows-2b53aa2525cf

[Paulius Ruminas]

Which functions are suspending in launch? Maybe you could use a channelFlow instead of the nullable Job to pass the data

[Kroppeb]

What do you mean?

[Kroppeb]

I'm writing to a second byteChannel

[Kroppeb]

those writes are suspending

[Kroppeb]

in the future it might be converted into a channel of a certain type but that requires some refactoring and wrappers and i first want my code working

[Kroppeb]

I'm guessing my question is: Is there a variant for read that allows supension?

[marstran]

So something like

suspend fun ByteChannel.read(): ByteBuffer = suspendCoroutine { continuation -> 
  read { continuation.resume(it) }
}

[Kroppeb]

doesn't seem to work

[Kroppeb]

message has been deleted

[Kroppeb]

this also feels janky

[marstran]

Weird error you get in the first one. You said read isn't suspending, right?

[marstran]

Could you try renaming your function to readSuspending?

[Kroppeb]

read is suspending

[marstran]

The original ByteChannel.read or the one you wrote?

[Kroppeb]

both

[marstran]

Oh, ok. Then you won't need the suspendCoroutine thing.

[marstran]

What library is ByteChannel from?

[marstran]

Seems weird to me that a suspending function has a callback as a parameter

[Kroppeb]

kotlin.coroutines.io.ByteReadChannel#read

[Evan R.]

I think the real question here is why are you doing a second nested launch if you just want to wait for the coroutine to complete before starting the next loop iteration?

[Kroppeb]

I was doing that cause i didn't know how to do it otherwise

[Kroppeb]

it's gone now

[Evan R.]

Alright, should be fine then. I assume that since read is a suspending function it will wait until new bytes come into the channel before writing out to the output channel.

[Colton Idle]

What's your code look like now @Kroppeb?

[Kroppeb]

https://kotlinlang.slack.com/archives/C1CFAFJSK/p1568900152090700?thread_ts=1568897501.085700&cid=C1CFAFJSK

[Kroppeb]

message has been deleted