Mutex.kt

internal class MutexImpl(locked: Boolean) : Mutex, SelectClause2<Any?, Mutex> {
    // State is: Empty | LockedQueue | OpDescriptor
    // shared objects while we have no waiters
    private val _state = atomic<Any?>(if (locked) EmptyLocked else EmptyUnlocked)

    // resumeNext is: RESUME_QUIESCENT | RESUME_ACTIVE | ResumeReq
    private val _resumeNext = atomic<Any>(RESUME_QUIESCENT)

    public override val isLocked: Boolean get() {
        _state.loop { state ->
            when (state) {
                is Empty -> return state.locked !== UNLOCKED
                is LockedQueue -> return true
                is OpDescriptor -> state.perform(this) // help
                else -> error("Illegal state $state")
            }
        }
    }

Empty | LockedQueue | OpDescriptor

resumeNext is: RESUME_QUIESCENT | RESUME_ACTIVE | ResumeReq

is OpDescriptor -> state.perform(this) // help

Any?

OpDescriptor

select

OpDescriptor