[Feature request] Add awaitCancellation()

[LouisCAD]

I can submit a PR.

Use case examples

With try/finally:

suspend fun showStuffUntilCancelled(data: Stuff): Nothing {
    try {
        someSubView.text = data.title
        anotherSubView.text = data.description
        someView.isVisible = true
        awaitCancellation() // Suspends so the view stays visible
    } finally {
        someView.isVisible = false // Called on cancellation, cannot forget to hide the view!
    }
}

With an inline higher order function:

suspend fun showStuffUntilCancelled(data: Stuff): Nothing {
    someSubView.text = data.title
    anotherSubView.text = data.description
    someView.visibleInScope {
        awaitCancellation() // Suspends so the view stays visible
    }
}

Implementation

import kotlinx.coroutines.CancellationException
import kotlinx.coroutines.suspendCancellableCoroutine

/**
 * Suspends until cancellation, in which case it will throw a [CancellationException].
 *
 * Handy because it returns [Nothing], allowing it to be used in any coroutine,
 * regardless of the required return type.
 */
suspend inline fun awaitCancellation(): Nothing = suspendCancellableCoroutine {}

[elizarov]

Good stuff. PR is welcome.

[LouisCAD]

Hello, I just wanted to thank you for letting this in kotlinx.coroutines, I use it very often, as you can see: