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Diffstat (limited to 'kotlinx-coroutines-core/common/src/channels/Channels.common.kt')
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1 files changed, 2195 insertions, 0 deletions
diff --git a/kotlinx-coroutines-core/common/src/channels/Channels.common.kt b/kotlinx-coroutines-core/common/src/channels/Channels.common.kt new file mode 100644 index 00000000..cd37bfbc --- /dev/null +++ b/kotlinx-coroutines-core/common/src/channels/Channels.common.kt @@ -0,0 +1,2195 @@ +/* + * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license. + */ +@file:JvmMultifileClass +@file:JvmName("ChannelsKt") +@file:Suppress("DEPRECATION") + +package kotlinx.coroutines.channels + +import kotlinx.coroutines.* +import kotlinx.coroutines.selects.* +import kotlin.coroutines.* +import kotlin.jvm.* + +internal const val DEFAULT_CLOSE_MESSAGE = "Channel was closed" + + +// -------- Operations on BroadcastChannel -------- + +/** + * Opens subscription to this [BroadcastChannel] and makes sure that the given [block] consumes all elements + * from it by always invoking [cancel][ReceiveChannel.cancel] after the execution of the block. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@ObsoleteCoroutinesApi +public inline fun <E, R> BroadcastChannel<E>.consume(block: ReceiveChannel<E>.() -> R): R { + val channel = openSubscription() + try { + return channel.block() + } finally { + channel.cancel() + } +} + +/** + * Retrieves and removes the element from this channel suspending the caller while this channel [isEmpty] + * or returns `null` if the channel is [closed][Channel.isClosedForReceive]. + * + * This suspending function is cancellable. If the [Job] of the current coroutine is cancelled or completed while this + * function is suspended, this function immediately resumes with [CancellationException]. + * + * *Cancellation of suspended receive is atomic* -- when this function + * throws [CancellationException] it means that the element was not retrieved from this channel. + * As a side-effect of atomic cancellation, a thread-bound coroutine (to some UI thread, for example) may + * continue to execute even after it was cancelled from the same thread in the case when this receive operation + * was already resumed and the continuation was posted for execution to the thread's queue. + * + * Note, that this function does not check for cancellation when it is not suspended. + * Use [yield] or [CoroutineScope.isActive] to periodically check for cancellation in tight loops if needed. + * + * This extension is defined only for channels on non-null types, so that generic functions defined using + * these extensions do not accidentally confuse `null` value and a normally closed channel, leading to hard + * to find bugs. + */ +@Suppress("EXTENSION_SHADOWED_BY_MEMBER") +@ExperimentalCoroutinesApi // since 1.3.0, tentatively stable in 1.4.0 +public suspend fun <E : Any> ReceiveChannel<E>.receiveOrNull(): E? { + @Suppress("DEPRECATION", "UNCHECKED_CAST") + return (this as ReceiveChannel<E?>).receiveOrNull() +} + +/** + * Clause for [select] expression of [receiveOrNull] suspending function that selects with the element that + * is received from the channel or selects with `null` if the channel + * [isClosedForReceive][ReceiveChannel.isClosedForReceive] without cause. The [select] invocation fails with + * the original [close][SendChannel.close] cause exception if the channel has _failed_. + * + * This extension is defined only for channels on non-null types, so that generic functions defined using + * these extensions do not accidentally confuse `null` value and a normally closed channel, leading to hard + * to find bugs. + **/ +@ExperimentalCoroutinesApi // since 1.3.0, tentatively stable in 1.4.0 +public fun <E : Any> ReceiveChannel<E>.onReceiveOrNull(): SelectClause1<E?> { + @Suppress("DEPRECATION", "UNCHECKED_CAST") + return (this as ReceiveChannel<E?>).onReceiveOrNull +} + +/** + * Subscribes to this [BroadcastChannel] and performs the specified action for each received element. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@ObsoleteCoroutinesApi +public suspend inline fun <E> BroadcastChannel<E>.consumeEach(action: (E) -> Unit) = + consume { + for (element in this) action(element) + } + +// -------- Operations on ReceiveChannel -------- + +/** + * Returns a [CompletionHandler] that invokes [cancel][ReceiveChannel.cancel] on the [ReceiveChannel] + * with the corresponding cause. See also [ReceiveChannel.consume]. + * + * **WARNING**: It is planned that in the future a second invocation of this method + * on an channel that is already being consumed is going to fail fast, that it + * immediately throws an [IllegalStateException]. + * See [this issue](https://github.com/Kotlin/kotlinx.coroutines/issues/167) + * for details. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun ReceiveChannel<*>.consumes(): CompletionHandler = { cause: Throwable? -> + cancelConsumed(cause) +} + +@PublishedApi +internal fun ReceiveChannel<*>.cancelConsumed(cause: Throwable?) { + cancel(cause?.let { + it as? CancellationException ?: CancellationException("Channel was consumed, consumer had failed", it) + }) +} + +/** + * Returns a [CompletionHandler] that invokes [cancel][ReceiveChannel.cancel] on all the + * specified [ReceiveChannel] instances with the corresponding cause. + * See also [ReceiveChannel.consumes()] for a version on one channel. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun consumesAll(vararg channels: ReceiveChannel<*>): CompletionHandler = + { cause: Throwable? -> + var exception: Throwable? = null + for (channel in channels) + try { + channel.cancelConsumed(cause) + } catch (e: Throwable) { + if (exception == null) { + exception = e + } else { + exception.addSuppressedThrowable(e) + } + } + exception?.let { throw it } + } + +/** + * Makes sure that the given [block] consumes all elements from the given channel + * by always invoking [cancel][ReceiveChannel.cancel] after the execution of the block. + * + * The operation is _terminal_. + */ +@ExperimentalCoroutinesApi // since 1.3.0, tentatively graduates in 1.4.0 +public inline fun <E, R> ReceiveChannel<E>.consume(block: ReceiveChannel<E>.() -> R): R { + var cause: Throwable? = null + try { + return block() + } catch (e: Throwable) { + cause = e + throw e + } finally { + cancelConsumed(cause) + } +} + +/** + * Performs the given [action] for each received element and [cancels][ReceiveChannel.cancel] + * the channel after the execution of the block. + * If you need to iterate over the channel without consuming it, a regular `for` loop should be used instead. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + */ +@ExperimentalCoroutinesApi // since 1.3.0, tentatively graduates in 1.4.0 +public suspend inline fun <E> ReceiveChannel<E>.consumeEach(action: (E) -> Unit) = + consume { + for (e in this) action(e) + } + +/** + * Performs the given [action] for each received element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.consumeEachIndexed(action: (IndexedValue<E>) -> Unit) { + var index = 0 + consumeEach { + action(IndexedValue(index++, it)) + } +} + +/** + * Returns an element at the given [index] or throws an [IndexOutOfBoundsException] if the [index] is out of bounds of this channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.elementAt(index: Int): E = + elementAtOrElse(index) { throw IndexOutOfBoundsException("ReceiveChannel doesn't contain element at index $index.") } + +/** + * Returns an element at the given [index] or the result of calling the [defaultValue] function if the [index] is out of bounds of this channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.elementAtOrElse(index: Int, defaultValue: (Int) -> E): E = + consume { + if (index < 0) + return defaultValue(index) + var count = 0 + for (element in this) { + if (index == count++) + return element + } + return defaultValue(index) + } + +/** + * Returns an element at the given [index] or `null` if the [index] is out of bounds of this channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.elementAtOrNull(index: Int): E? = + consume { + if (index < 0) + return null + var count = 0 + for (element in this) { + if (index == count++) + return element + } + return null + } + +/** + * Returns the first element matching the given [predicate], or `null` if no such element was found. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.find(predicate: (E) -> Boolean): E? = + firstOrNull(predicate) + +/** + * Returns the last element matching the given [predicate], or `null` if no such element was found. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.findLast(predicate: (E) -> Boolean): E? = + lastOrNull(predicate) + +/** + * Returns first element. + * @throws [NoSuchElementException] if the channel is empty. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.first(): E = + consume { + val iterator = iterator() + if (!iterator.hasNext()) + throw NoSuchElementException("ReceiveChannel is empty.") + return iterator.next() + } + +/** + * Returns the first element matching the given [predicate]. + * @throws [NoSuchElementException] if no such element is found. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.first(predicate: (E) -> Boolean): E { + consumeEach { + if (predicate(it)) return it + } + throw NoSuchElementException("ReceiveChannel contains no element matching the predicate.") +} + +/** + * Returns the first element, or `null` if the channel is empty. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.firstOrNull(): E? = + consume { + val iterator = iterator() + if (!iterator.hasNext()) + return null + return iterator.next() + } + +/** + * Returns the first element matching the given [predicate], or `null` if element was not found. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.firstOrNull(predicate: (E) -> Boolean): E? { + consumeEach { + if (predicate(it)) return it + } + return null +} + +/** + * Returns first index of [element], or -1 if the channel does not contain element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.indexOf(element: E): Int { + var index = 0 + consumeEach { + if (element == it) + return index + index++ + } + return -1 +} + +/** + * Returns index of the first element matching the given [predicate], or -1 if the channel does not contain such element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.indexOfFirst(predicate: (E) -> Boolean): Int { + var index = 0 + consumeEach { + if (predicate(it)) + return index + index++ + } + return -1 +} + +/** + * Returns index of the last element matching the given [predicate], or -1 if the channel does not contain such element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.indexOfLast(predicate: (E) -> Boolean): Int { + var lastIndex = -1 + var index = 0 + consumeEach { + if (predicate(it)) + lastIndex = index + index++ + } + return lastIndex +} + +/** + * Returns the last element. + * @throws [NoSuchElementException] if the channel is empty. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.last(): E = + consume { + val iterator = iterator() + if (!iterator.hasNext()) + throw NoSuchElementException("ReceiveChannel is empty.") + var last = iterator.next() + while (iterator.hasNext()) + last = iterator.next() + return last + } + +/** + * Returns the last element matching the given [predicate]. + * @throws [NoSuchElementException] if no such element is found. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.last(predicate: (E) -> Boolean): E { + var last: E? = null + var found = false + consumeEach { + if (predicate(it)) { + last = it + found = true + } + } + if (!found) throw NoSuchElementException("ReceiveChannel contains no element matching the predicate.") + @Suppress("UNCHECKED_CAST") + return last as E +} + +/** + * Returns last index of [element], or -1 if the channel does not contain element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.lastIndexOf(element: E): Int { + var lastIndex = -1 + var index = 0 + consumeEach { + if (element == it) + lastIndex = index + index++ + } + return lastIndex +} + +/** + * Returns the last element, or `null` if the channel is empty. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.lastOrNull(): E? = + consume { + val iterator = iterator() + if (!iterator.hasNext()) + return null + var last = iterator.next() + while (iterator.hasNext()) + last = iterator.next() + return last + } + +/** + * Returns the last element matching the given [predicate], or `null` if no such element was found. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.lastOrNull(predicate: (E) -> Boolean): E? { + var last: E? = null + consumeEach { + if (predicate(it)) { + last = it + } + } + return last +} + +/** + * Returns the single element, or throws an exception if the channel is empty or has more than one element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.single(): E = + consume { + val iterator = iterator() + if (!iterator.hasNext()) + throw NoSuchElementException("ReceiveChannel is empty.") + val single = iterator.next() + if (iterator.hasNext()) + throw IllegalArgumentException("ReceiveChannel has more than one element.") + return single + } + +/** + * Returns the single element matching the given [predicate], or throws exception if there is no or more than one matching element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.single(predicate: (E) -> Boolean): E { + var single: E? = null + var found = false + consumeEach { + if (predicate(it)) { + if (found) throw IllegalArgumentException("ReceiveChannel contains more than one matching element.") + single = it + found = true + } + } + if (!found) throw NoSuchElementException("ReceiveChannel contains no element matching the predicate.") + @Suppress("UNCHECKED_CAST") + return single as E +} + +/** + * Returns single element, or `null` if the channel is empty or has more than one element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.singleOrNull(): E? = + consume { + val iterator = iterator() + if (!iterator.hasNext()) + return null + val single = iterator.next() + if (iterator.hasNext()) + return null + return single + } + +/** + * Returns the single element matching the given [predicate], or `null` if element was not found or more than one element was found. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.singleOrNull(predicate: (E) -> Boolean): E? { + var single: E? = null + var found = false + consumeEach { + if (predicate(it)) { + if (found) return null + single = it + found = true + } + } + if (!found) return null + return single +} + +/** + * Returns a channel containing all elements except first [n] elements. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E> ReceiveChannel<E>.drop(n: Int, context: CoroutineContext = Dispatchers.Unconfined): ReceiveChannel<E> = + GlobalScope.produce(context, onCompletion = consumes()) { + require(n >= 0) { "Requested element count $n is less than zero." } + var remaining: Int = n + if (remaining > 0) + for (e in this@drop) { + remaining-- + if (remaining == 0) + break + } + for (e in this@drop) { + send(e) + } + } + +/** + * Returns a channel containing all elements except first elements that satisfy the given [predicate]. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E> ReceiveChannel<E>.dropWhile(context: CoroutineContext = Dispatchers.Unconfined, predicate: suspend (E) -> Boolean): ReceiveChannel<E> = + GlobalScope.produce(context, onCompletion = consumes()) { + for (e in this@dropWhile) { + if (!predicate(e)) { + send(e) + break + } + } + for (e in this@dropWhile) { + send(e) + } + } + +/** + * Returns a channel containing only elements matching the given [predicate]. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E> ReceiveChannel<E>.filter(context: CoroutineContext = Dispatchers.Unconfined, predicate: suspend (E) -> Boolean): ReceiveChannel<E> = + GlobalScope.produce(context, onCompletion = consumes()) { + for (e in this@filter) { + if (predicate(e)) send(e) + } + } + +/** + * Returns a channel containing only elements matching the given [predicate]. + * @param [predicate] function that takes the index of an element and the element itself + * and returns the result of predicate evaluation on the element. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E> ReceiveChannel<E>.filterIndexed(context: CoroutineContext = Dispatchers.Unconfined, predicate: suspend (index: Int, E) -> Boolean): ReceiveChannel<E> = + GlobalScope.produce(context, onCompletion = consumes()) { + var index = 0 + for (e in this@filterIndexed) { + if (predicate(index++, e)) send(e) + } + } + +/** + * Appends all elements matching the given [predicate] to the given [destination]. + * @param [predicate] function that takes the index of an element and the element itself + * and returns the result of predicate evaluation on the element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, C : MutableCollection<in E>> ReceiveChannel<E>.filterIndexedTo(destination: C, predicate: (index: Int, E) -> Boolean): C { + consumeEachIndexed { (index, element) -> + if (predicate(index, element)) destination.add(element) + } + return destination +} + +/** + * Appends all elements matching the given [predicate] to the given [destination]. + * @param [predicate] function that takes the index of an element and the element itself + * and returns the result of predicate evaluation on the element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, C : SendChannel<E>> ReceiveChannel<E>.filterIndexedTo(destination: C, predicate: (index: Int, E) -> Boolean): C { + consumeEachIndexed { (index, element) -> + if (predicate(index, element)) destination.send(element) + } + return destination +} + +/** + * Returns a channel containing all elements not matching the given [predicate]. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E> ReceiveChannel<E>.filterNot(context: CoroutineContext = Dispatchers.Unconfined, predicate: suspend (E) -> Boolean): ReceiveChannel<E> = + filter(context) { !predicate(it) } + +/** + * Returns a channel containing all elements that are not `null`. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +@Suppress("UNCHECKED_CAST") +public fun <E : Any> ReceiveChannel<E?>.filterNotNull(): ReceiveChannel<E> = + filter { it != null } as ReceiveChannel<E> + +/** + * Appends all elements that are not `null` to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E : Any, C : MutableCollection<in E>> ReceiveChannel<E?>.filterNotNullTo(destination: C): C { + consumeEach { + if (it != null) destination.add(it) + } + return destination +} + +/** + * Appends all elements that are not `null` to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E : Any, C : SendChannel<E>> ReceiveChannel<E?>.filterNotNullTo(destination: C): C { + consumeEach { + if (it != null) destination.send(it) + } + return destination +} + +/** + * Appends all elements not matching the given [predicate] to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, C : MutableCollection<in E>> ReceiveChannel<E>.filterNotTo(destination: C, predicate: (E) -> Boolean): C { + consumeEach { + if (!predicate(it)) destination.add(it) + } + return destination +} + +/** + * Appends all elements not matching the given [predicate] to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, C : SendChannel<E>> ReceiveChannel<E>.filterNotTo(destination: C, predicate: (E) -> Boolean): C { + consumeEach { + if (!predicate(it)) destination.send(it) + } + return destination +} + +/** + * Appends all elements matching the given [predicate] to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, C : MutableCollection<in E>> ReceiveChannel<E>.filterTo(destination: C, predicate: (E) -> Boolean): C { + consumeEach { + if (predicate(it)) destination.add(it) + } + return destination +} + +/** + * Appends all elements matching the given [predicate] to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, C : SendChannel<E>> ReceiveChannel<E>.filterTo(destination: C, predicate: (E) -> Boolean): C { + consumeEach { + if (predicate(it)) destination.send(it) + } + return destination +} + +/** + * Returns a channel containing first [n] elements. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E> ReceiveChannel<E>.take(n: Int, context: CoroutineContext = Dispatchers.Unconfined): ReceiveChannel<E> = + GlobalScope.produce(context, onCompletion = consumes()) { + if (n == 0) return@produce + require(n >= 0) { "Requested element count $n is less than zero." } + var remaining: Int = n + for (e in this@take) { + send(e) + remaining-- + if (remaining == 0) + return@produce + } + } + +/** + * Returns a channel containing first elements satisfying the given [predicate]. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E> ReceiveChannel<E>.takeWhile(context: CoroutineContext = Dispatchers.Unconfined, predicate: suspend (E) -> Boolean): ReceiveChannel<E> = + GlobalScope.produce(context, onCompletion = consumes()) { + for (e in this@takeWhile) { + if (!predicate(e)) return@produce + send(e) + } + } + +/** + * Returns a [Map] containing key-value pairs provided by [transform] function + * applied to elements of the given channel. + * + * If any of two pairs would have the same key the last one gets added to the map. + * + * The returned map preserves the entry iteration order of the original channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K, V> ReceiveChannel<E>.associate(transform: (E) -> Pair<K, V>): Map<K, V> = + associateTo(LinkedHashMap(), transform) + +/** + * Returns a [Map] containing the elements from the given channel indexed by the key + * returned from [keySelector] function applied to each element. + * + * If any two elements would have the same key returned by [keySelector] the last one gets added to the map. + * + * The returned map preserves the entry iteration order of the original channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K> ReceiveChannel<E>.associateBy(keySelector: (E) -> K): Map<K, E> = + associateByTo(LinkedHashMap(), keySelector) + +/** + * Returns a [Map] containing the values provided by [valueTransform] and indexed by [keySelector] functions applied to elements of the given channel. + * + * If any two elements would have the same key returned by [keySelector] the last one gets added to the map. + * + * The returned map preserves the entry iteration order of the original channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K, V> ReceiveChannel<E>.associateBy(keySelector: (E) -> K, valueTransform: (E) -> V): Map<K, V> = + associateByTo(LinkedHashMap(), keySelector, valueTransform) + +/** + * Populates and returns the [destination] mutable map with key-value pairs, + * where key is provided by the [keySelector] function applied to each element of the given channel + * and value is the element itself. + * + * If any two elements would have the same key returned by [keySelector] the last one gets added to the map. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K, M : MutableMap<in K, in E>> ReceiveChannel<E>.associateByTo(destination: M, keySelector: (E) -> K): M { + consumeEach { + destination.put(keySelector(it), it) + } + return destination +} + +/** + * Populates and returns the [destination] mutable map with key-value pairs, + * where key is provided by the [keySelector] function and + * and value is provided by the [valueTransform] function applied to elements of the given channel. + * + * If any two elements would have the same key returned by [keySelector] the last one gets added to the map. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K, V, M : MutableMap<in K, in V>> ReceiveChannel<E>.associateByTo(destination: M, keySelector: (E) -> K, valueTransform: (E) -> V): M { + consumeEach { + destination.put(keySelector(it), valueTransform(it)) + } + return destination +} + +/** + * Populates and returns the [destination] mutable map with key-value pairs + * provided by [transform] function applied to each element of the given channel. + * + * If any of two pairs would have the same key the last one gets added to the map. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K, V, M : MutableMap<in K, in V>> ReceiveChannel<E>.associateTo(destination: M, transform: (E) -> Pair<K, V>): M { + consumeEach { + destination += transform(it) + } + return destination +} + +/** + * Send each element of the original channel + * and appends the results to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E, C : SendChannel<E>> ReceiveChannel<E>.toChannel(destination: C): C { + consumeEach { + destination.send(it) + } + return destination +} + +/** + * Appends all elements to the given [destination] collection. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E, C : MutableCollection<in E>> ReceiveChannel<E>.toCollection(destination: C): C { + consumeEach { + destination.add(it) + } + return destination +} + +/** + * Returns a [List] containing all elements. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + */ +public suspend fun <E> ReceiveChannel<E>.toList(): List<E> = + this.toMutableList() + +/** + * Returns a [Map] filled with all elements of this channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <K, V> ReceiveChannel<Pair<K, V>>.toMap(): Map<K, V> = + toMap(LinkedHashMap()) + +/** + * Returns a [MutableMap] filled with all elements of this channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <K, V, M : MutableMap<in K, in V>> ReceiveChannel<Pair<K, V>>.toMap(destination: M): M { + consumeEach { + destination += it + } + return destination +} + +/** + * Returns a [MutableList] filled with all elements of this channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.toMutableList(): MutableList<E> = + toCollection(ArrayList()) + +/** + * Returns a [Set] of all elements. + * + * The returned set preserves the element iteration order of the original channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.toSet(): Set<E> = + this.toMutableSet() + +/** + * Returns a single channel of all elements from results of [transform] function being invoked on each element of original channel. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E, R> ReceiveChannel<E>.flatMap(context: CoroutineContext = Dispatchers.Unconfined, transform: suspend (E) -> ReceiveChannel<R>): ReceiveChannel<R> = + GlobalScope.produce(context, onCompletion = consumes()) { + for (e in this@flatMap) { + transform(e).toChannel(this) + } + } + +/** + * Groups elements of the original channel by the key returned by the given [keySelector] function + * applied to each element and returns a map where each group key is associated with a list of corresponding elements. + * + * The returned map preserves the entry iteration order of the keys produced from the original channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K> ReceiveChannel<E>.groupBy(keySelector: (E) -> K): Map<K, List<E>> = + groupByTo(LinkedHashMap(), keySelector) + +/** + * Groups values returned by the [valueTransform] function applied to each element of the original channel + * by the key returned by the given [keySelector] function applied to the element + * and returns a map where each group key is associated with a list of corresponding values. + * + * The returned map preserves the entry iteration order of the keys produced from the original channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K, V> ReceiveChannel<E>.groupBy(keySelector: (E) -> K, valueTransform: (E) -> V): Map<K, List<V>> = + groupByTo(LinkedHashMap(), keySelector, valueTransform) + +/** + * Groups elements of the original channel by the key returned by the given [keySelector] function + * applied to each element and puts to the [destination] map each group key associated with a list of corresponding elements. + * + * @return The [destination] map. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K, M : MutableMap<in K, MutableList<E>>> ReceiveChannel<E>.groupByTo(destination: M, keySelector: (E) -> K): M { + consumeEach { + val key = keySelector(it) + val list = destination.getOrPut(key) { ArrayList() } + list.add(it) + } + return destination +} + +/** + * Groups values returned by the [valueTransform] function applied to each element of the original channel + * by the key returned by the given [keySelector] function applied to the element + * and puts to the [destination] map each group key associated with a list of corresponding values. + * + * @return The [destination] map. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, K, V, M : MutableMap<in K, MutableList<V>>> ReceiveChannel<E>.groupByTo(destination: M, keySelector: (E) -> K, valueTransform: (E) -> V): M { + consumeEach { + val key = keySelector(it) + val list = destination.getOrPut(key) { ArrayList() } + list.add(valueTransform(it)) + } + return destination +} + +/** + * Returns a channel containing the results of applying the given [transform] function + * to each element in the original channel. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E, R> ReceiveChannel<E>.map(context: CoroutineContext = Dispatchers.Unconfined, transform: suspend (E) -> R): ReceiveChannel<R> = + GlobalScope.produce(context, onCompletion = consumes()) { + consumeEach { + send(transform(it)) + } + } + +/** + * Returns a channel containing the results of applying the given [transform] function + * to each element and its index in the original channel. + * @param [transform] function that takes the index of an element and the element itself + * and returns the result of the transform applied to the element. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E, R> ReceiveChannel<E>.mapIndexed(context: CoroutineContext = Dispatchers.Unconfined, transform: suspend (index: Int, E) -> R): ReceiveChannel<R> = + GlobalScope.produce(context, onCompletion = consumes()) { + var index = 0 + for (e in this@mapIndexed) { + send(transform(index++, e)) + } + } + +/** + * Returns a channel containing only the non-null results of applying the given [transform] function + * to each element and its index in the original channel. + * @param [transform] function that takes the index of an element and the element itself + * and returns the result of the transform applied to the element. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E, R : Any> ReceiveChannel<E>.mapIndexedNotNull(context: CoroutineContext = Dispatchers.Unconfined, transform: suspend (index: Int, E) -> R?): ReceiveChannel<R> = + mapIndexed(context, transform).filterNotNull() + +/** + * Applies the given [transform] function to each element and its index in the original channel + * and appends only the non-null results to the given [destination]. + * @param [transform] function that takes the index of an element and the element itself + * and returns the result of the transform applied to the element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R : Any, C : MutableCollection<in R>> ReceiveChannel<E>.mapIndexedNotNullTo(destination: C, transform: (index: Int, E) -> R?): C { + consumeEachIndexed { (index, element) -> + transform(index, element)?.let { destination.add(it) } + } + return destination +} + +/** + * Applies the given [transform] function to each element and its index in the original channel + * and appends only the non-null results to the given [destination]. + * @param [transform] function that takes the index of an element and the element itself + * and returns the result of the transform applied to the element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R : Any, C : SendChannel<R>> ReceiveChannel<E>.mapIndexedNotNullTo(destination: C, transform: (index: Int, E) -> R?): C { + consumeEachIndexed { (index, element) -> + transform(index, element)?.let { destination.send(it) } + } + return destination +} + +/** + * Applies the given [transform] function to each element and its index in the original channel + * and appends the results to the given [destination]. + * @param [transform] function that takes the index of an element and the element itself + * and returns the result of the transform applied to the element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R, C : MutableCollection<in R>> ReceiveChannel<E>.mapIndexedTo(destination: C, transform: (index: Int, E) -> R): C { + var index = 0 + consumeEach { + destination.add(transform(index++, it)) + } + return destination +} + +/** + * Applies the given [transform] function to each element and its index in the original channel + * and appends the results to the given [destination]. + * @param [transform] function that takes the index of an element and the element itself + * and returns the result of the transform applied to the element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R, C : SendChannel<R>> ReceiveChannel<E>.mapIndexedTo(destination: C, transform: (index: Int, E) -> R): C { + var index = 0 + consumeEach { + destination.send(transform(index++, it)) + } + return destination +} + +/** + * Returns a channel containing only the non-null results of applying the given [transform] function + * to each element in the original channel. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E, R : Any> ReceiveChannel<E>.mapNotNull(context: CoroutineContext = Dispatchers.Unconfined, transform: suspend (E) -> R?): ReceiveChannel<R> = + map(context, transform).filterNotNull() + +/** + * Applies the given [transform] function to each element in the original channel + * and appends only the non-null results to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R : Any, C : MutableCollection<in R>> ReceiveChannel<E>.mapNotNullTo(destination: C, transform: (E) -> R?): C { + consumeEach { + transform(it)?.let { destination.add(it) } + } + return destination +} + +/** + * Applies the given [transform] function to each element in the original channel + * and appends only the non-null results to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R : Any, C : SendChannel<R>> ReceiveChannel<E>.mapNotNullTo(destination: C, transform: (E) -> R?): C { + consumeEach { + transform(it)?.let { destination.send(it) } + } + return destination +} + +/** + * Applies the given [transform] function to each element of the original channel + * and appends the results to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R, C : MutableCollection<in R>> ReceiveChannel<E>.mapTo(destination: C, transform: (E) -> R): C { + consumeEach { + destination.add(transform(it)) + } + return destination +} + +/** + * Applies the given [transform] function to each element of the original channel + * and appends the results to the given [destination]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R, C : SendChannel<R>> ReceiveChannel<E>.mapTo(destination: C, transform: (E) -> R): C { + consumeEach { + destination.send(transform(it)) + } + return destination +} + +/** + * Returns a channel of [IndexedValue] for each element of the original channel. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E> ReceiveChannel<E>.withIndex(context: CoroutineContext = Dispatchers.Unconfined): ReceiveChannel<IndexedValue<E>> = + GlobalScope.produce(context, onCompletion = consumes()) { + var index = 0 + for (e in this@withIndex) { + send(IndexedValue(index++, e)) + } + } + +/** + * Returns a channel containing only distinct elements from the given channel. + * + * The elements in the resulting channel are in the same order as they were in the source channel. + * + * The operation is _intermediate_ and _stateful_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E> ReceiveChannel<E>.distinct(): ReceiveChannel<E> = + this.distinctBy { it } + +/** + * Returns a channel containing only elements from the given channel + * having distinct keys returned by the given [selector] function. + * + * The elements in the resulting channel are in the same order as they were in the source channel. + * + * The operation is _intermediate_ and _stateful_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E, K> ReceiveChannel<E>.distinctBy(context: CoroutineContext = Dispatchers.Unconfined, selector: suspend (E) -> K): ReceiveChannel<E> = + GlobalScope.produce(context, onCompletion = consumes()) { + val keys = HashSet<K>() + for (e in this@distinctBy) { + val k = selector(e) + if (k !in keys) { + send(e) + keys += k + } + } + } + +/** + * Returns a mutable set containing all distinct elements from the given channel. + * + * The returned set preserves the element iteration order of the original channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.toMutableSet(): MutableSet<E> = + toCollection(LinkedHashSet()) + +/** + * Returns `true` if all elements match the given [predicate]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.all(predicate: (E) -> Boolean): Boolean { + consumeEach { + if (!predicate(it)) return false + } + return true +} + +/** + * Returns `true` if channel has at least one element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.any(): Boolean = + consume { + return iterator().hasNext() + } + +/** + * Returns `true` if at least one element matches the given [predicate]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.any(predicate: (E) -> Boolean): Boolean { + consumeEach { + if (predicate(it)) return true + } + return false +} + +/** + * Returns the number of elements in this channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.count(): Int { + var count = 0 + consumeEach { count++ } + return count +} + +/** + * Returns the number of elements matching the given [predicate]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.count(predicate: (E) -> Boolean): Int { + var count = 0 + consumeEach { + if (predicate(it)) count++ + } + return count +} + +/** + * Accumulates value starting with [initial] value and applying [operation] from left to right to current accumulator value and each element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R> ReceiveChannel<E>.fold(initial: R, operation: (acc: R, E) -> R): R { + var accumulator = initial + consumeEach { + accumulator = operation(accumulator, it) + } + return accumulator +} + +/** + * Accumulates value starting with [initial] value and applying [operation] from left to right + * to current accumulator value and each element with its index in the original channel. + * @param [operation] function that takes the index of an element, current accumulator value + * and the element itself, and calculates the next accumulator value. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R> ReceiveChannel<E>.foldIndexed(initial: R, operation: (index: Int, acc: R, E) -> R): R { + var index = 0 + var accumulator = initial + consumeEach { + accumulator = operation(index++, accumulator, it) + } + return accumulator +} + +/** + * Returns the first element yielding the largest value of the given function or `null` if there are no elements. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R : Comparable<R>> ReceiveChannel<E>.maxBy(selector: (E) -> R): E? = + consume { + val iterator = iterator() + if (!iterator.hasNext()) return null + var maxElem = iterator.next() + var maxValue = selector(maxElem) + while (iterator.hasNext()) { + val e = iterator.next() + val v = selector(e) + if (maxValue < v) { + maxElem = e + maxValue = v + } + } + return maxElem + } + +/** + * Returns the first element having the largest value according to the provided [comparator] or `null` if there are no elements. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.maxWith(comparator: Comparator<in E>): E? = + consume { + val iterator = iterator() + if (!iterator.hasNext()) return null + var max = iterator.next() + while (iterator.hasNext()) { + val e = iterator.next() + if (comparator.compare(max, e) < 0) max = e + } + return max + } + +/** + * Returns the first element yielding the smallest value of the given function or `null` if there are no elements. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E, R : Comparable<R>> ReceiveChannel<E>.minBy(selector: (E) -> R): E? = + consume { + val iterator = iterator() + if (!iterator.hasNext()) return null + var minElem = iterator.next() + var minValue = selector(minElem) + while (iterator.hasNext()) { + val e = iterator.next() + val v = selector(e) + if (minValue > v) { + minElem = e + minValue = v + } + } + return minElem + } + +/** + * Returns the first element having the smallest value according to the provided [comparator] or `null` if there are no elements. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.minWith(comparator: Comparator<in E>): E? = + consume { + val iterator = iterator() + if (!iterator.hasNext()) return null + var min = iterator.next() + while (iterator.hasNext()) { + val e = iterator.next() + if (comparator.compare(min, e) > 0) min = e + } + return min + } + +/** + * Returns `true` if the channel has no elements. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend fun <E> ReceiveChannel<E>.none(): Boolean = + consume { + return !iterator().hasNext() + } + +/** + * Returns `true` if no elements match the given [predicate]. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.none(predicate: (E) -> Boolean): Boolean { + consumeEach { + if (predicate(it)) return false + } + return true +} + +/** + * Accumulates value starting with the first element and applying [operation] from left to right to current accumulator value and each element. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <S, E : S> ReceiveChannel<E>.reduce(operation: (acc: S, E) -> S): S = + consume { + val iterator = this.iterator() + if (!iterator.hasNext()) throw UnsupportedOperationException("Empty channel can't be reduced.") + var accumulator: S = iterator.next() + while (iterator.hasNext()) { + accumulator = operation(accumulator, iterator.next()) + } + return accumulator + } + +/** + * Accumulates value starting with the first element and applying [operation] from left to right + * to current accumulator value and each element with its index in the original channel. + * @param [operation] function that takes the index of an element, current accumulator value + * and the element itself and calculates the next accumulator value. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <S, E : S> ReceiveChannel<E>.reduceIndexed(operation: (index: Int, acc: S, E) -> S): S = + consume { + val iterator = this.iterator() + if (!iterator.hasNext()) throw UnsupportedOperationException("Empty channel can't be reduced.") + var index = 1 + var accumulator: S = iterator.next() + while (iterator.hasNext()) { + accumulator = operation(index++, accumulator, iterator.next()) + } + return accumulator + } + +/** + * Returns the sum of all values produced by [selector] function applied to each element in the channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.sumBy(selector: (E) -> Int): Int { + var sum = 0 + consumeEach { + sum += selector(it) + } + return sum +} + +/** + * Returns the sum of all values produced by [selector] function applied to each element in the channel. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.sumByDouble(selector: (E) -> Double): Double { + var sum = 0.0 + consumeEach { + sum += selector(it) + } + return sum +} + +/** + * Returns an original collection containing all the non-`null` elements, throwing an [IllegalArgumentException] if there are any `null` elements. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E : Any> ReceiveChannel<E?>.requireNoNulls(): ReceiveChannel<E> = + map { it ?: throw IllegalArgumentException("null element found in $this.") } + +/** + * Splits the original channel into pair of lists, + * where *first* list contains elements for which [predicate] yielded `true`, + * while *second* list contains elements for which [predicate] yielded `false`. + * + * The operation is _terminal_. + * This function [consumes][ReceiveChannel.consume] all elements of the original [ReceiveChannel]. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public suspend inline fun <E> ReceiveChannel<E>.partition(predicate: (E) -> Boolean): Pair<List<E>, List<E>> { + val first = ArrayList<E>() + val second = ArrayList<E>() + consumeEach { + if (predicate(it)) { + first.add(it) + } else { + second.add(it) + } + } + return Pair(first, second) +} + +/** + * Returns a channel of pairs built from elements of both channels with same indexes. + * Resulting channel has length of shortest input channel. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][ReceiveChannel.consume] all elements of both the original [ReceiveChannel] and the `other` one. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public infix fun <E, R> ReceiveChannel<E>.zip(other: ReceiveChannel<R>): ReceiveChannel<Pair<E, R>> = + zip(other) { t1, t2 -> t1 to t2 } + +/** + * Returns a channel of values built from elements of both collections with same indexes using provided [transform]. Resulting channel has length of shortest input channels. + * + * The operation is _intermediate_ and _stateless_. + * This function [consumes][consume] all elements of both the original [ReceiveChannel] and the `other` one. + * + * **Note: This API will become obsolete in future updates with introduction of lazy asynchronous streams.** + * See [issue #254](https://github.com/Kotlin/kotlinx.coroutines/issues/254). + */ +@Deprecated( + message = "Channel operators are deprecated in favour of Flow and will be removed in 1.4", + level = DeprecationLevel.WARNING +) +public fun <E, R, V> ReceiveChannel<E>.zip(other: ReceiveChannel<R>, context: CoroutineContext = Dispatchers.Unconfined, transform: (a: E, b: R) -> V): ReceiveChannel<V> = + GlobalScope.produce(context, onCompletion = consumesAll(this, other)) { + val otherIterator = other.iterator() + this@zip.consumeEach { element1 -> + if (!otherIterator.hasNext()) return@consumeEach + val element2 = otherIterator.next() + send(transform(element1, element2)) + } + } |