Copyright (c) 2016-present, RxJava Contributors.
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.
/**
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * 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.maybe;

import java.util.concurrent.atomic.AtomicReference;

import io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.internal.disposables.DisposableHelper;

Makes sure a dispose() call from downstream happens on the specified scheduler.
Type parameters:
<T> – the value type/**
 * Makes sure a dispose() call from downstream happens on the specified scheduler.
 * 
 * @param <T> the value type
 */
public final class MaybeUnsubscribeOn<T> extends AbstractMaybeWithUpstream<T, T> {

    final Scheduler scheduler;

    public MaybeUnsubscribeOn(MaybeSource<T> source, Scheduler scheduler) {
        super(source);
        this.scheduler = scheduler;
    }

    @Override
    protected void subscribeActual(MaybeObserver<? super T> observer) {
        source.subscribe(new UnsubscribeOnMaybeObserver<T>(observer, scheduler));
    }

    static final class UnsubscribeOnMaybeObserver<T> extends AtomicReference<Disposable>
    implements MaybeObserver<T>, Disposable, Runnable {

        private static final long serialVersionUID = 3256698449646456986L;

        final MaybeObserver<? super T> downstream;

        final Scheduler scheduler;

        Disposable ds;

        UnsubscribeOnMaybeObserver(MaybeObserver<? super T> actual, Scheduler scheduler) {
            this.downstream = actual;
            this.scheduler = scheduler;
        }

        @Override
        public void dispose() {
            Disposable d = getAndSet(DisposableHelper.DISPOSED);
            if (d != DisposableHelper.DISPOSED) {
                this.ds = d;
                scheduler.scheduleDirect(this);
            }
        }

        @Override
        public void run() {
            ds.dispose();
        }

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

        @Override
        public void onSubscribe(Disposable d) {
            if (DisposableHelper.setOnce(this, d)) {
                downstream.onSubscribe(this);
            }
        }

        @Override
        public void onSuccess(T value) {
            downstream.onSuccess(value);
        }

        @Override
        public void onError(Throwable e) {
            downstream.onError(e);
        }

        @Override
        public void onComplete() {
            downstream.onComplete();
        }
    }
}