Temporary remove SequenceBuilder
This commit is contained in:
Ilya Gorbunov
@@ -1,183 +0,0 @@
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/*
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* Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
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* that can be found in the license/LICENSE.txt file.
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*/
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@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
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@file:kotlin.jvm.JvmMultifileClass
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@file:kotlin.jvm.JvmName("SequenceBuilderKt")
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package kotlin.sequences
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import kotlin.*
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import kotlin.coroutines.*
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import kotlin.coroutines.intrinsics.*
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/**
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* Builds a [Sequence] lazily yielding values one by one.
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*
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* @see kotlin.sequences.generateSequence
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*
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* @sample samples.collections.Sequences.Building.buildSequenceYieldAll
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* @sample samples.collections.Sequences.Building.buildFibonacciSequence
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*/
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@SinceKotlin("1.3")
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public fun <T> buildSequence(builderAction: suspend SequenceBuilder<T>.() -> Unit): Sequence<T> = Sequence { buildIterator(builderAction) }
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/**
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* Builds an [Iterator] lazily yielding values one by one.
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*
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* @sample samples.collections.Sequences.Building.buildIterator
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* @sample samples.collections.Iterables.Building.iterable
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*/
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@SinceKotlin("1.3")
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public fun <T> buildIterator(builderAction: suspend SequenceBuilder<T>.() -> Unit): Iterator<T> {
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val iterator = SequenceBuilderIterator<T>()
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iterator.nextStep = builderAction.createCoroutineUnintercepted(receiver = iterator, completion = iterator)
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return iterator
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}
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/**
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* Builder for a [Sequence] or an [Iterator], provides [yield] and [yieldAll] suspension functions.
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*
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* @see buildSequence
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* @see buildIterator
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*
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* @sample samples.collections.Sequences.Building.buildSequenceYieldAll
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* @sample samples.collections.Sequences.Building.buildFibonacciSequence
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*/
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@RestrictsSuspension
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@SinceKotlin("1.3")
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public abstract class SequenceBuilder<in T> internal constructor() {
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/**
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* Yields a value to the [Iterator] being built.
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*
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* @sample samples.collections.Sequences.Building.buildSequenceYieldAll
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* @sample samples.collections.Sequences.Building.buildFibonacciSequence
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*/
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public abstract suspend fun yield(value: T)
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/**
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* Yields all values from the `iterator` to the [Iterator] being built.
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*
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* The sequence of values returned by the given iterator can be potentially infinite.
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*
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* @sample samples.collections.Sequences.Building.buildSequenceYieldAll
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*/
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public abstract suspend fun yieldAll(iterator: Iterator<T>)
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/**
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* Yields a collections of values to the [Iterator] being built.
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*
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* @sample samples.collections.Sequences.Building.buildSequenceYieldAll
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*/
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public suspend fun yieldAll(elements: Iterable<T>) {
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if (elements is Collection && elements.isEmpty()) return
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return yieldAll(elements.iterator())
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}
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/**
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* Yields potentially infinite sequence of values to the [Iterator] being built.
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*
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* The sequence can be potentially infinite.
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*
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* @sample samples.collections.Sequences.Building.buildSequenceYieldAll
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*/
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public suspend fun yieldAll(sequence: Sequence<T>) = yieldAll(sequence.iterator())
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}
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private typealias State = Int
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private const val State_NotReady: State = 0
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private const val State_ManyNotReady: State = 1
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private const val State_ManyReady: State = 2
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private const val State_Ready: State = 3
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private const val State_Done: State = 4
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private const val State_Failed: State = 5
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private class SequenceBuilderIterator<T> : SequenceBuilder<T>(), Iterator<T>, Continuation<Unit> {
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private var state = State_NotReady
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private var nextValue: T? = null
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private var nextIterator: Iterator<T>? = null
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var nextStep: Continuation<Unit>? = null
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override fun hasNext(): Boolean {
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while (true) {
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when (state) {
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State_NotReady -> {}
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State_ManyNotReady ->
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if (nextIterator!!.hasNext()) {
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state = State_ManyReady
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return true
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} else {
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nextIterator = null
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}
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State_Done -> return false
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State_Ready, State_ManyReady -> return true
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else -> throw exceptionalState()
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}
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state = State_Failed
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val step = nextStep!!
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nextStep = null
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step.resume(Unit)
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}
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}
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override fun next(): T {
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when (state) {
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State_NotReady, State_ManyNotReady -> return nextNotReady()
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State_ManyReady -> {
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state = State_ManyNotReady
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return nextIterator!!.next()
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}
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State_Ready -> {
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state = State_NotReady
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@Suppress("UNCHECKED_CAST")
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val result = nextValue as T
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nextValue = null
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return result
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}
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else -> throw exceptionalState()
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}
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}
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private fun nextNotReady(): T {
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if (!hasNext()) throw NoSuchElementException() else return next()
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}
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private fun exceptionalState(): Throwable = when (state) {
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State_Done -> NoSuchElementException()
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State_Failed -> IllegalStateException("Iterator has failed.")
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else -> IllegalStateException("Unexpected state of the iterator: $state")
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}
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override suspend fun yield(value: T) {
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nextValue = value
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state = State_Ready
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return suspendCoroutineUninterceptedOrReturn { c ->
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nextStep = c
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COROUTINE_SUSPENDED
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}
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}
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override suspend fun yieldAll(iterator: Iterator<T>) {
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if (!iterator.hasNext()) return
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nextIterator = iterator
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state = State_ManyReady
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return suspendCoroutineUninterceptedOrReturn { c ->
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nextStep = c
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COROUTINE_SUSPENDED
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}
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}
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// Completion continuation implementation
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override fun resumeWith(result: SuccessOrFailure<Unit>) {
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result.getOrThrow() // just rethrow exception if it is there
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state = State_Done
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}
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override val context: CoroutineContext
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get() = EmptyCoroutineContext
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}
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