I have a system where I have multiple `Resource`s where only one process (coroutine) should be able ...

# coroutines

[Andrew Gazelka]

I have a system where I have multiple `Resource`s where only one process (coroutine) should be able to access it at a time. The main function of a Resource is

suspend fun take(priority: Int = 0, immediate: Boolean = false)

where a task with a lower priority will be scheduled first and higher later. The immediate argument will determine whether the currently executing process should be interrupted if take(...) has a lower priority than the currently executing task. A resource is given back with Resource#giveBack().

Any recommendations on how I could do this idiomatically?

[Dominaezzz]

About interruptions, what happens to the coroutine? Does it have to call take again? Does it just "pause" until the new coroutine is done?

[Andrew Gazelka]

@Dominaezzz I thought this over... probably should never interrupt another process

[Andrew Gazelka]

doesn't really make sense

[Andrew Gazelka]

so

suspend fun take(priority: Int = 0)

[Andrew Gazelka]

and then if you had some periodic background task you could have something like this

while(true){
  resource.take(9999)
  // do things
  resource.giveBack()
  delay(1_000)
}

[Dominaezzz]

For something like this, I'd make a PriorityMutex that'll be similar to the Mutex class. https://github.com/Kotlin/kotlinx.coroutines/blob/69c26dfbcefc24c66aadc586f9b5129894516bee/kotlinx-coroutines-core/common/src/sync/Mutex.kt but do some insertion sort.