| /* |
| * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license. |
| */ |
| |
| package kotlinx.coroutines.experimental.rx1 |
| |
| import kotlinx.atomicfu.* |
| import kotlinx.coroutines.experimental.channels.* |
| import rx.* |
| |
| /** |
| * Subscribes to this [Observable] and returns a channel to receive elements emitted by it. |
| * The resulting channel shall be [cancelled][ReceiveChannel.cancel] to unsubscribe from this observable. |
| * @param request how many items to request from publisher in advance (optional, on-demand request by default). |
| */ |
| @Suppress("CONFLICTING_OVERLOADS") |
| public fun <T> Observable<T>.openSubscription(request: Int = 0): ReceiveChannel<T> { |
| val channel = SubscriptionChannel<T>(request) |
| val subscription = subscribe(channel.subscriber) |
| channel.subscription = subscription |
| if (channel.isClosedForSend) subscription.unsubscribe() |
| return channel |
| } |
| |
| /** @suppress **Deprecated**: Left here for binary compatibility */ |
| @JvmOverloads // for binary compatibility |
| @Deprecated(level = DeprecationLevel.HIDDEN, message = "Left here for binary compatibility") |
| @Suppress("CONFLICTING_OVERLOADS") |
| public fun <T> Observable<T>.openSubscription(request: Int = 0): SubscriptionReceiveChannel<T> = |
| openSubscription(request) as SubscriptionReceiveChannel<T> |
| |
| /** |
| * @suppress **Deprecated**: Renamed to [openSubscription] |
| */ |
| @Deprecated(message = "Renamed to `openSubscription`", |
| replaceWith = ReplaceWith("openSubscription()")) |
| public fun <T> Observable<T>.open(): SubscriptionReceiveChannel<T> = |
| openSubscription() as SubscriptionReceiveChannel<T> |
| |
| /** |
| * Subscribes to this [Observable] and returns an iterator to receive elements emitted by it. |
| * |
| * This is a shortcut for `open().iterator()`. See [openSubscription] if you need an ability to manually |
| * unsubscribe from the observable. |
| */ |
| @Suppress("DeprecatedCallableAddReplaceWith") |
| @Deprecated(message = |
| "This iteration operator for `for (x in source) { ... }` loop is deprecated, " + |
| "because it leaves code vulnerable to leaving unclosed subscriptions on exception. " + |
| "Use `source.consumeEach { x -> ... }`.") |
| public operator fun <T> Observable<T>.iterator() = openSubscription().iterator() |
| |
| /** |
| * Subscribes to this [Observable] and performs the specified action for each received element. |
| */ |
| public suspend inline fun <T> Observable<T>.consumeEach(action: (T) -> Unit) { |
| val channel = openSubscription() |
| for (x in channel) action(x) |
| channel.cancel() |
| } |
| |
| /** |
| * @suppress: **Deprecated**: binary compatibility with old code |
| */ |
| @Deprecated("binary compatibility with old code", level = DeprecationLevel.HIDDEN) |
| public suspend fun <T> Observable<T>.consumeEach(action: suspend (T) -> Unit) = |
| consumeEach { action(it) } |
| |
| private class SubscriptionChannel<T>( |
| private val request: Int |
| ) : LinkedListChannel<T>(), ReceiveChannel<T>, SubscriptionReceiveChannel<T> { |
| init { |
| require(request >= 0) { "Invalid request size: $request" } |
| } |
| |
| @JvmField |
| val subscriber: ChannelSubscriber = ChannelSubscriber(request) |
| |
| @Volatile |
| @JvmField |
| var subscription: Subscription? = null |
| |
| // requested from subscription minus number of received minus number of enqueued receivers, |
| private val _requested = atomic(request) |
| |
| // AbstractChannel overrides |
| override fun onReceiveEnqueued() { |
| _requested.loop { wasRequested -> |
| val needRequested = wasRequested - 1 |
| if (needRequested < 0) { // need to request more from subscriber |
| // try to fixup by making request |
| if (wasRequested != request && !_requested.compareAndSet(wasRequested, request)) |
| return@loop // continue looping if failed |
| subscriber.makeRequest((request - needRequested).toLong()) |
| return |
| } |
| // just do book-keeping |
| if (_requested.compareAndSet(wasRequested, needRequested)) return |
| } |
| } |
| |
| override fun onReceiveDequeued() { |
| _requested.incrementAndGet() |
| } |
| |
| override fun afterClose(cause: Throwable?) { |
| subscription?.unsubscribe() |
| } |
| |
| inner class ChannelSubscriber(private val request: Int): Subscriber<T>() { |
| fun makeRequest(n: Long) { |
| request(n) |
| } |
| |
| override fun onStart() { |
| request(request.toLong()) // init backpressure |
| } |
| |
| override fun onNext(t: T) { |
| _requested.decrementAndGet() |
| offer(t) |
| } |
| |
| override fun onCompleted() { |
| close(cause = null) |
| } |
| |
| override fun onError(e: Throwable) { |
| close(cause = e) |
| } |
| } |
| } |