/**
* 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.Arrays;
import java.util.concurrent.atomic.*;
import io.reactivex.*;
import io.reactivex.annotations.NonNull;
import io.reactivex.annotations.Nullable;
import io.reactivex.disposables.Disposable;
import io.reactivex.exceptions.Exceptions;
import io.reactivex.functions.Function;
import io.reactivex.internal.disposables.*;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.internal.util.*;
import io.reactivex.plugins.RxJavaPlugins;
/**
* Combines a main sequence of values with the latest from multiple other sequences via
* a selector function.
*
* @param <T> the main sequence's type
* @param <R> the output type
*/
public final class ObservableWithLatestFromMany<T, R> extends AbstractObservableWithUpstream<T, R> {
@Nullable
final ObservableSource<?>[] otherArray;
@Nullable
final Iterable<? extends ObservableSource<?>> otherIterable;
@NonNull
final Function<? super Object[], R> combiner;
public ObservableWithLatestFromMany(@NonNull ObservableSource<T> source, @NonNull ObservableSource<?>[] otherArray, @NonNull Function<? super Object[], R> combiner) {
super(source);
this.otherArray = otherArray;
this.otherIterable = null;
this.combiner = combiner;
}
public ObservableWithLatestFromMany(@NonNull ObservableSource<T> source, @NonNull Iterable<? extends ObservableSource<?>> otherIterable, @NonNull Function<? super Object[], R> combiner) {
super(source);
this.otherArray = null;
this.otherIterable = otherIterable;
this.combiner = combiner;
}
@Override
protected void subscribeActual(Observer<? super R> s) {
ObservableSource<?>[] others = otherArray;
int n = 0;
if (others == null) {
others = new ObservableSource[8];
try {
for (ObservableSource<?> p : otherIterable) {
if (n == others.length) {
others = Arrays.copyOf(others, n + (n >> 1));
}
others[n++] = p;
}
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
EmptyDisposable.error(ex, s);
return;
}
} else {
n = others.length;
}
if (n == 0) {
new ObservableMap<T, R>(source, new SingletonArrayFunc()).subscribeActual(s);
return;
}
WithLatestFromObserver<T, R> parent = new WithLatestFromObserver<T, R>(s, combiner, n);
s.onSubscribe(parent);
parent.subscribe(others, n);
source.subscribe(parent);
}
static final class WithLatestFromObserver<T, R>
extends AtomicInteger
implements Observer<T>, Disposable {
private static final long serialVersionUID = 1577321883966341961L;
final Observer<? super R> actual;
final Function<? super Object[], R> combiner;
final WithLatestInnerObserver[] observers;
final AtomicReferenceArray<Object> values;
final AtomicReference<Disposable> d;
final AtomicThrowable error;
volatile boolean done;
WithLatestFromObserver(Observer<? super R> actual, Function<? super Object[], R> combiner, int n) {
this.actual = actual;
this.combiner = combiner;
WithLatestInnerObserver[] s = new WithLatestInnerObserver[n];
for (int i = 0; i < n; i++) {
s[i] = new WithLatestInnerObserver(this, i);
}
this.observers = s;
this.values = new AtomicReferenceArray<Object>(n);
this.d = new AtomicReference<Disposable>();
this.error = new AtomicThrowable();
}
void subscribe(ObservableSource<?>[] others, int n) {
WithLatestInnerObserver[] observers = this.observers;
AtomicReference<Disposable> s = this.d;
for (int i = 0; i < n; i++) {
if (DisposableHelper.isDisposed(s.get()) || done) {
return;
}
others[i].subscribe(observers[i]);
}
}
@Override
public void onSubscribe(Disposable d) {
DisposableHelper.setOnce(this.d, d);
}
@Override
public void onNext(T t) {
if (done) {
return;
}
AtomicReferenceArray<Object> ara = values;
int n = ara.length();
Object[] objects = new Object[n + 1];
objects[0] = t;
for (int i = 0; i < n; i++) {
Object o = ara.get(i);
if (o == null) {
// no latest, skip this value
return;
}
objects[i + 1] = o;
}
R v;
try {
v = ObjectHelper.requireNonNull(combiner.apply(objects), "combiner returned a null value");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
dispose();
onError(ex);
return;
}
HalfSerializer.onNext(actual, v, this, error);
}
@Override
public void onError(Throwable t) {
if (done) {
RxJavaPlugins.onError(t);
return;
}
done = true;
cancelAllBut(-1);
HalfSerializer.onError(actual, t, this, error);
}
@Override
public void onComplete() {
if (!done) {
done = true;
cancelAllBut(-1);
HalfSerializer.onComplete(actual, this, error);
}
}
@Override
public boolean isDisposed() {
return DisposableHelper.isDisposed(d.get());
}
@Override
public void dispose() {
DisposableHelper.dispose(d);
for (WithLatestInnerObserver s : observers) {
s.dispose();
}
}
void innerNext(int index, Object o) {
values.set(index, o);
}
void innerError(int index, Throwable t) {
done = true;
DisposableHelper.dispose(d);
cancelAllBut(index);
HalfSerializer.onError(actual, t, this, error);
}
void innerComplete(int index, boolean nonEmpty) {
if (!nonEmpty) {
done = true;
cancelAllBut(index);
HalfSerializer.onComplete(actual, this, error);
}
}
void cancelAllBut(int index) {
WithLatestInnerObserver[] observers = this.observers;
for (int i = 0; i < observers.length; i++) {
if (i != index) {
observers[i].dispose();
}
}
}
}
static final class WithLatestInnerObserver
extends AtomicReference<Disposable>
implements Observer<Object> {
private static final long serialVersionUID = 3256684027868224024L;
final WithLatestFromObserver<?, ?> parent;
final int index;
boolean hasValue;
WithLatestInnerObserver(WithLatestFromObserver<?, ?> parent, int index) {
this.parent = parent;
this.index = index;
}
@Override
public void onSubscribe(Disposable d) {
DisposableHelper.setOnce(this, d);
}
@Override
public void onNext(Object t) {
if (!hasValue) {
hasValue = true;
}
parent.innerNext(index, t);
}
@Override
public void onError(Throwable t) {
parent.innerError(index, t);
}
@Override
public void onComplete() {
parent.innerComplete(index, hasValue);
}
public void dispose() {
DisposableHelper.dispose(this);
}
}
final class SingletonArrayFunc implements Function<T, R> {
@Override
public R apply(T t) throws Exception {
return combiner.apply(new Object[] { t });
}
}
}