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 io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.internal.disposables.DisposableHelper;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.internal.fuseable.HasUpstreamMaybeSource;

Signals true if the source signals a value that is object-equals with the provided
value, false otherwise or for empty sources.
Type parameters:
<T> – the value type/**
 * Signals true if the source signals a value that is object-equals with the provided
 * value, false otherwise or for empty sources.
 *
 * @param <T> the value type
 */
public final class MaybeContains<T> extends Single<Boolean> implements HasUpstreamMaybeSource<T> {

    final MaybeSource<T> source;

    final Object value;

    public MaybeContains(MaybeSource<T> source, Object value) {
        this.source = source;
        this.value = value;
    }

    @Override
    public MaybeSource<T> source() {
        return source;
    }

    @Override
    protected void subscribeActual(SingleObserver<? super Boolean> observer) {
        source.subscribe(new ContainsMaybeObserver(observer, value));
    }

    static final class ContainsMaybeObserver implements MaybeObserver<Object>, Disposable {

        final SingleObserver<? super Boolean> downstream;

        final Object value;

        Disposable upstream;

        ContainsMaybeObserver(SingleObserver<? super Boolean> actual, Object value) {
            this.downstream = actual;
            this.value = value;
        }

        @Override
        public void dispose() {
            upstream.dispose();
            upstream = DisposableHelper.DISPOSED;
        }

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

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

        @Override
        public void onSuccess(Object value) {
            upstream = DisposableHelper.DISPOSED;
            downstream.onSuccess(ObjectHelper.equals(value, this.value));
        }

        @Override
        public void onError(Throwable e) {
            upstream = DisposableHelper.DISPOSED;
            downstream.onError(e);
        }

        @Override
        public void onComplete() {
            upstream = DisposableHelper.DISPOSED;
            downstream.onSuccess(false);
        }
    }
}