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abersnazeabersnaze
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Merge pull request #47 from akarnokd/SplitBackpressureFix
Reimplement split() with backpressure
2 parents d6d43ef + 47e0c48 commit 3e73b75

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-82
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4 files changed

+464
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‎build.gradle

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@@ -7,7 +7,7 @@ apply plugin: 'rxjava-project'
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apply plugin: 'java'
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dependencies {
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compile 'io.reactivex:rxjava:1.1.1'
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compile 'io.reactivex:rxjava:1.2.3'
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testCompile 'junit:junit-dep:4.10'
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testCompile 'org.mockito:mockito-core:1.8.5'
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}

‎src/main/java/rx/internal/operators/ObservableSplit.java

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@@ -0,0 +1,337 @@
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/**
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* Copyright 2014 Netflix, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package rx.internal.operators;
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import java.util.Queue;
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import java.util.concurrent.atomic.*;
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import java.util.regex.Pattern;
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import rx.*;
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import rx.Observable.OnSubscribe;
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import rx.exceptions.Exceptions;
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import rx.internal.operators.BackpressureUtils;
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import rx.internal.util.atomic.SpscAtomicArrayQueue;
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import rx.internal.util.unsafe.*;
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import rx.plugins.RxJavaHooks;
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/**
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* Split a sequence of strings based on a Rexexp pattern spanning subsequent
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* items if necessary.
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*/
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public final class ObservableSplit implements OnSubscribe<String> {
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final Observable<String> source;
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final Pattern pattern;
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final int bufferSize;
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public ObservableSplit(Observable<String> source, Pattern pattern, int bufferSize) {
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this.source = source;
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this.pattern = pattern;
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this.bufferSize = bufferSize;
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}
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@Override
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public void call(Subscriber<? super String> t) {
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SplitSubscriber parent = new SplitSubscriber(t, pattern, bufferSize);
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t.add(parent.requested);
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t.setProducer(parent.requested);
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source.unsafeSubscribe(parent);
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}
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static final class SplitSubscriber extends Subscriber<String> {
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final Subscriber<? super String> actual;
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final Pattern pattern;
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final Requested requested;
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final AtomicInteger wip;
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final int limit;
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final Queue<String[]> queue;
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String[] current;
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String leftOver;
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int index;
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int produced;
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int empty;
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volatile boolean done;
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Throwable error;
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volatile boolean cancelled;
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SplitSubscriber(Subscriber<? super String> actual, Pattern pattern, int bufferSize) {
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this.actual = actual;
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this.pattern = pattern;
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this.limit = bufferSize - (bufferSize >> 2);
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this.requested = new Requested();
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this.wip = new AtomicInteger();
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if (UnsafeAccess.isUnsafeAvailable()) {
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this.queue = new SpscArrayQueue<String[]>(bufferSize);
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} else {
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this.queue = new SpscAtomicArrayQueue<String[]>(bufferSize);
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}
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request(bufferSize);
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}
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@Override
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public void onNext(String t) {
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String lo = leftOver;
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String[] a;
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try {
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if (lo == null || lo.isEmpty()) {
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a = pattern.split(t, -1);
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} else {
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a = pattern.split(lo + t, -1);
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}
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} catch (Throwable ex) {
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Exceptions.throwIfFatal(ex);
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unsubscribe();
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onError(ex);
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return;
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}
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if (a.length == 0) {
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leftOver = null;
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request(1);
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return;
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} else
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if (a.length == 1) {
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leftOver = a[0];
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request(1);
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return;
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}
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leftOver = a[a.length - 1];
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queue.offer(a);
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drain();
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}
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@Override
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public void onError(Throwable e) {
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if (done) {
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RxJavaHooks.onError(e);
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return;
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}
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String lo = leftOver;
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if (lo != null && !lo.isEmpty()) {
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leftOver = null;
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queue.offer(new String[] { lo, null });
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}
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error = e;
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done = true;
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drain();
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}
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@Override
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public void onCompleted() {
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if (!done) {
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done = true;
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String lo = leftOver;
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if (lo != null && !lo.isEmpty()) {
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leftOver = null;
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queue.offer(new String[] { lo, null });
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}
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drain();
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}
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}
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void drain() {
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if (wip.getAndIncrement() != 0) {
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return;
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}
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Queue<String[]> q = queue;
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int missed = 1;
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int consumed = produced;
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String[] array = current;
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int idx = index;
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int emptyCount = empty;
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Subscriber<? super String> a = actual;
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for (;;) {
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long r = requested.get();
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long e = 0;
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while (e != r) {
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if (cancelled) {
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current = null;
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q.clear();
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return;
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}
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boolean d = done;
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if (array == null) {
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array = q.poll();
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if (array != null) {
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current = array;
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if (++consumed == limit) {
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consumed = 0;
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request(limit);
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}
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}
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}
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boolean empty = array == null;
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if (d && empty) {
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current = null;
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Throwable ex = error;
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if (ex != null) {
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a.onError(ex);
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} else {
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a.onCompleted();
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}
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return;
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}
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if (empty) {
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break;
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}
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if (array.length == idx + 1) {
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array = null;
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current = null;
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idx = 0;
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continue;
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}
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String v = array[idx];
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if (v.isEmpty()) {
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emptyCount++;
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idx++;
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} else {
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while (emptyCount != 0 && e != r) {
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if (cancelled) {
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current = null;
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q.clear();
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return;
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}
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a.onNext("");
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e++;
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emptyCount--;
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}
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if (e != r && emptyCount == 0) {
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a.onNext(v);
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e++;
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idx++;
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}
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}
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}
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if (e == r) {
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if (cancelled) {
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current = null;
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q.clear();
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return;
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}
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boolean d = done;
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if (array == null) {
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array = q.poll();
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if (array != null) {
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current = array;
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if (++consumed == limit) {
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consumed = 0;
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request(limit);
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}
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}
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}
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boolean empty = array == null;
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if (d && empty) {
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current = null;
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Throwable ex = error;
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if (ex != null) {
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a.onError(ex);
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} else {
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a.onCompleted();
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}
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return;
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}
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}
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if (e != 0L) {
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BackpressureUtils.produced(requested, e);
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}
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empty = emptyCount;
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produced = consumed;
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missed = wip.addAndGet(-missed);
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if (missed == 0) {
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break;
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}
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}
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}
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void cancel() {
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cancelled = true;
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unsubscribe();
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if (wip.getAndIncrement() == 0) {
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current = null;
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queue.clear();
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}
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}
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boolean isCancelled() {
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return isUnsubscribed();
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}
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final class Requested extends AtomicLong implements Producer, Subscription {
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private static final long serialVersionUID = 3399839515828647345L;
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@Override
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public void request(long n) {
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if (n > 0) {
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BackpressureUtils.getAndAddRequest(this, n);
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drain();
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}
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else if (n < 0) {
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throw new IllegalArgumentException("n >= 0 required but it was " + n);
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}
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}
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@Override
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public boolean isUnsubscribed() {
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return isCancelled();
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}
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@Override
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public void unsubscribe() {
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cancel();
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}
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}
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}
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}

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