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Coroutines support libraries for Kotlin

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/*
 * 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.coroutines.selects.*

/**
 * A [Deferred] that can be completed via public functions
 * [complete], [completeExceptionally], and [cancel].
 *
 * Completion functions return `false` when this deferred value is already complete or completing.
 *
 * An instance of completable deferred can be created by `CompletableDeferred()` function in _active_ state.
 *
 * All functions on this interface and on all interfaces derived from it are **thread-safe** and can
 * be safely invoked from concurrent coroutines without external synchronization.
 */
public interface CompletableDeferred : Deferred {
    /**
     * Completes this deferred value with a given [value]. The result is `true` if this deferred was
     * completed as a result of this invocation and `false` otherwise (if it was already completed).
     *
     * Repeated invocations of this function have no effect and always produce `false`.
     */
    public fun complete(value: T): Boolean

    /**
     * Completes this deferred value exceptionally with a given [exception]. The result is `true` if this deferred was
     * completed as a result of this invocation and `false` otherwise (if it was already completed).
     *
     * Repeated invocations of this function have no effect and always produce `false`.
     */
    public fun completeExceptionally(exception: Throwable): Boolean
}

/**
 * Creates a [CompletableDeferred] in an _active_ state.
 * It is optionally a child of a [parent] job.
 */
@Suppress("FunctionName")
public fun  CompletableDeferred(parent: Job? = null): CompletableDeferred = CompletableDeferredImpl(parent)

/** @suppress **Deprecated:** Binary compatibility only */
@Deprecated(message = "Binary compatibility only", level = DeprecationLevel.HIDDEN)
@Suppress("FunctionName")
public fun  CompletableDeferred(): CompletableDeferred = CompletableDeferredImpl(null)

/**
 * Creates an already _completed_ [CompletableDeferred] with a given [value].
 */
@Suppress("FunctionName")
public fun  CompletableDeferred(value: T): CompletableDeferred = CompletableDeferredImpl(null).apply { complete(value) }

/**
 * Concrete implementation of [CompletableDeferred].
 */
@Suppress("UNCHECKED_CAST")
private class CompletableDeferredImpl(
    parent: Job?
) : JobSupport(true), CompletableDeferred, SelectClause1 {
    init { initParentJobInternal(parent) }
    override val onCancelMode: Int get() = ON_CANCEL_MAKE_COMPLETING
    override fun getCompleted(): T = getCompletedInternal() as T
    override suspend fun await(): T = awaitInternal() as T
    override val onAwait: SelectClause1 get() = this
    override fun  registerSelectClause1(select: SelectInstance, block: suspend (T) -> R) =
        registerSelectClause1Internal(select, block)

    override fun complete(value: T): Boolean =
        makeCompleting(value)
    override fun completeExceptionally(exception: Throwable): Boolean =
        makeCompleting(CompletedExceptionally(exception))
}