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.observable;

import java.util.concurrent.atomic.AtomicInteger;

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

public final class ObservableRepeat<T> extends AbstractObservableWithUpstream<T, T> {
    final long count;
    public ObservableRepeat(Observable<T> source, long count) {
        super(source);
        this.count = count;
    }

    @Override
    public void subscribeActual(Observer<? super T> observer) {
        SequentialDisposable sd = new SequentialDisposable();
        observer.onSubscribe(sd);

        RepeatObserver<T> rs = new RepeatObserver<T>(observer, count != Long.MAX_VALUE ? count - 1 : Long.MAX_VALUE, sd, source);
        rs.subscribeNext();
    }

    static final class RepeatObserver<T> extends AtomicInteger implements Observer<T> {

        private static final long serialVersionUID = -7098360935104053232L;

        final Observer<? super T> downstream;
        final SequentialDisposable sd;
        final ObservableSource<? extends T> source;
        long remaining;
        RepeatObserver(Observer<? super T> actual, long count, SequentialDisposable sd, ObservableSource<? extends T> source) {
            this.downstream = actual;
            this.sd = sd;
            this.source = source;
            this.remaining = count;
        }

        @Override
        public void onSubscribe(Disposable d) {
            sd.replace(d);
        }

        @Override
        public void onNext(T t) {
            downstream.onNext(t);
        }

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

        @Override
        public void onComplete() {
            long r = remaining;
            if (r != Long.MAX_VALUE) {
                remaining = r - 1;
            }
            if (r != 0L) {
                subscribeNext();
            } else {
                downstream.onComplete();
            }
        }

        
Subscribes to the source again via trampolining.
/**
         * Subscribes to the source again via trampolining.
         */
        void subscribeNext() {
            if (getAndIncrement() == 0) {
                int missed = 1;
                for (;;) {
                    if (sd.isDisposed()) {
                        return;
                    }
                    source.subscribe(this);

                    missed = addAndGet(-missed);
                    if (missed == 0) {
                        break;
                    }
                }
            }
        }
    }
}