CompletedExceptionally.kt

/*
 * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
 */

package kotlinx.coroutines

import kotlinx.atomicfu.*
import kotlin.coroutines.*
import kotlin.jvm.*

internal fun <T> Result<T>.toState(): Any? =
    if (isSuccess) getOrThrow() else CompletedExceptionally(exceptionOrNull()!!) // todo: need to do it better

/**
 * Class for an internal state of a job that was cancelled (completed exceptionally).
 *
 * @param cause the exceptional completion cause. It's either original exceptional cause
 *        or artificial [CancellationException] if no cause was provided
 */
internal open class CompletedExceptionally(
    @JvmField public val cause: Throwable
) {
    override fun toString(): String = "$classSimpleName[$cause]"
}

/**
 * A specific subclass of [CompletedExceptionally] for cancelled [AbstractContinuation].
 *
 * @param continuation the continuation that was cancelled.
 * @param cause the exceptional completion cause. If `cause` is null, then a [CancellationException]
 *        if created on first access to [exception] property.
 */
internal class CancelledContinuation(
    continuation: Continuation<*>,
    cause: Throwable?,
    handled: Boolean
) : CompletedExceptionally(cause ?: CancellationException("Continuation $continuation was cancelled normally")) {
    private val resumed = atomic(false)
    private val handled = atomic(handled)

    fun makeResumed(): Boolean = resumed.compareAndSet(false, true)
    fun makeHandled(): Boolean = handled.compareAndSet(false, true)
}