ObservableSkipUntil.java

/**
 * Copyright 2016 Netflix, Inc.
 *
 * 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 io.reactivex.internal.operators.observable;

import java.util.concurrent.atomic.AtomicBoolean;

import io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.internal.disposables.*;
import io.reactivex.observers.SerializedObserver;

public final class ObservableSkipUntil<T, U> extends AbstractObservableWithUpstream<T, T> {
    final ObservableSource<U> other;
    public ObservableSkipUntil(ObservableSource<T> source, ObservableSource<U> other) {
        super(source);
        this.other = other;
    }

    @Override
    public void subscribeActual(Observer<? super T> child) {

        final SerializedObserver<T> serial = new SerializedObserver<T>(child);

        final ArrayCompositeDisposable frc = new ArrayCompositeDisposable(2);

        final SkipUntilObserver<T> sus = new SkipUntilObserver<T>(serial, frc);

        other.subscribe(new Observer<U>() {
            Disposable s;
            @Override
            public void onSubscribe(Disposable s) {
                if (DisposableHelper.validate(this.s, s)) {
                    this.s = s;
                    frc.setResource(1, s);
                }
            }

            @Override
            public void onNext(U t) {
                s.dispose();
                sus.notSkipping = true;
            }

            @Override
            public void onError(Throwable t) {
                frc.dispose();
                // in case the other emits an onError before the main even sets a subscription
                if (sus.compareAndSet(false, true)) {
                    EmptyDisposable.error(t, serial);
                } else {
                    serial.onError(t);
                }
            }

            @Override
            public void onComplete() {
                sus.notSkipping = true;
            }
        });

        source.subscribe(sus);
    }

    static final class SkipUntilObserver<T> extends AtomicBoolean implements Observer<T>, Disposable {

        private static final long serialVersionUID = -1113667257122396604L;
        final Observer<? super T> actual;
        final ArrayCompositeDisposable frc;

        Disposable s;

        volatile boolean notSkipping;
        boolean notSkippingLocal;

        SkipUntilObserver(Observer<? super T> actual, ArrayCompositeDisposable frc) {
            this.actual = actual;
            this.frc = frc;
        }

        @Override
        public void onSubscribe(Disposable s) {
            if (DisposableHelper.validate(this.s, s)) {
                this.s = s;
                if (frc.setResource(0, s)) {
                    if (compareAndSet(false, true)) {
                        actual.onSubscribe(this);
                    }
                }
            }
        }

        @Override
        public void onNext(T t) {
            if (notSkippingLocal) {
                actual.onNext(t);
            } else
            if (notSkipping) {
                notSkippingLocal = true;
                actual.onNext(t);
            }
        }

        @Override
        public void onError(Throwable t) {
            frc.dispose();
            actual.onError(t);
        }

        @Override
        public void onComplete() {
            frc.dispose();
            actual.onComplete();
        }

        @Override
        public void dispose() {
            frc.dispose();
        }

        @Override
        public boolean isDisposed() {
            return frc.isDisposed();
        }
    }
}