Idiomatic way to add Coroutine scope to a function that is a kotlinlang #coroutines

11/01/2018, 5:03 PM

Idiomatic way to add Coroutine scope to a function that is already an extension function of something else? Take it as a parameter?

11/01/2018, 6:22 PM

Can you give an example?

(with some background on how this comes to be)

11/02/2018, 6:18 AM

@elizarov I have a utility function like this:

suspend fun Flowable<ByteBuffer>.toByteReadChannel(scope: CoroutineScope) = scope.writer(scope.coroutineContext, autoFlush = true) {
  try {
    this@toByteReadChannel.consumeEach {
      channel.writeFully(it)
    }
  } catch (e: Throwable) {
    channel.close(e)
  }
}.channel

Note here I have explicitly passed scope, since its already an extension of

Flowable<ByteBuffer>

. Is there a better approach?

I also have the opposite

toFlowable

function, implemented like this:

suspend fun DataChannelProvider.toFlowable(scope: CoroutineScope): Flowable<ByteBuffer> = scope.rxFlowable(Dispatchers.Default) {
  this@toFlowable().lookAheadSuspend {
    consumeEachRemaining {
      // we have to make a copy as the ByteBuffer here comes from a reused ring buffer
      this@rxFlowable.send(it.copy())
      true
    }
  }
}

Zach Klippenstein (he/him) [MOD]

11/02/2018, 10:10 PM

Since your function is already a

suspend

function, you can use

coroutineContext

to get the scope from the current coroutine.

suspend fun Flowable<ByteBuffer>.toByteReadChannel() = coroutineContext {
  writer(…

11/03/2018, 2:03 PM

I think you meant

coroutineScope { ... }

but otherwise, ah, thank you @Zach Klippenstein (he/him) [MOD]

FYI @Zach Klippenstein (he/him) [MOD] this didn't work... see the recent thread in #coroutines ...