monix.reactive.internal.operators.DoOnEarlyStopOperator.scala Maven / Gradle / Ivy
/*
* Copyright (c) 2014-2020 by The Monix Project Developers.
* See the project homepage at: https://monix.io
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package monix.reactive.internal.operators
import monix.eval.Task
import monix.execution.Ack
import monix.execution.Ack.{Continue, Stop}
import monix.execution.atomic.Atomic
import scala.util.control.NonFatal
import monix.reactive.Observable.Operator
import monix.reactive.observers.Subscriber
import monix.reactive.internal.util.Instances.ContinueTask
import scala.concurrent.Future
import scala.util.Success
private[reactive] final class DoOnEarlyStopOperator[A](onStop: Task[Unit]) extends Operator[A, A] {
def apply(out: Subscriber[A]): Subscriber[A] =
new Subscriber[A] {
implicit val scheduler = out.scheduler
private[this] val isActive = Atomic(true)
def onNext(elem: A): Future[Ack] = {
val result =
try out.onNext(elem)
catch { case ex if NonFatal(ex) => Future.failed(ex) }
val task = Task
.fromFuture(result)
.onErrorHandle { ex =>
onError(ex); Stop
}
.flatMap {
case Continue => ContinueTask
case Stop => onStop.map(_ => Stop)
}
val future = task.runToFuture
// Execution might be immediate
future.value match {
case Some(Success(ack)) => ack
case _ => future
}
}
def onError(ex: Throwable): Unit = {
if (isActive.getAndSet(false))
out.onError(ex)
else
scheduler.reportFailure(ex)
}
def onComplete(): Unit = {
if (isActive.getAndSet(false))
out.onComplete()
}
}
}