/**
* 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.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.queue.SpscLinkedArrayQueue;
import io.reactivex.internal.util.AtomicThrowable;
import io.reactivex.plugins.RxJavaPlugins;
public final class ObservableCombineLatest<T, R> extends Observable<R> {
final ObservableSource<? extends T>[] sources;
final Iterable<? extends ObservableSource<? extends T>> sourcesIterable;
final Function<? super Object[], ? extends R> combiner;
final int bufferSize;
final boolean delayError;
public ObservableCombineLatest(ObservableSource<? extends T>[] sources,
Iterable<? extends ObservableSource<? extends T>> sourcesIterable,
Function<? super Object[], ? extends R> combiner, int bufferSize,
boolean delayError) {
this.sources = sources;
this.sourcesIterable = sourcesIterable;
this.combiner = combiner;
this.bufferSize = bufferSize;
this.delayError = delayError;
}
@Override
@SuppressWarnings("unchecked")
public void subscribeActual(Observer<? super R> s) {
ObservableSource<? extends T>[] sources = this.sources;
int count = 0;
if (sources == null) {
sources = new Observable[8];
for (ObservableSource<? extends T> p : sourcesIterable) {
if (count == sources.length) {
ObservableSource<? extends T>[] b = new ObservableSource[count + (count >> 2)];
System.arraycopy(sources, 0, b, 0, count);
sources = b;
}
sources[count++] = p;
}
} else {
count = sources.length;
}
if (count == 0) {
EmptyDisposable.complete(s);
return;
}
LatestCoordinator<T, R> lc = new LatestCoordinator<T, R>(s, combiner, count, bufferSize, delayError);
lc.subscribe(sources);
}
static final class LatestCoordinator<T, R> extends AtomicInteger implements Disposable {
private static final long serialVersionUID = 8567835998786448817L;
final Observer<? super R> actual;
final Function<? super Object[], ? extends R> combiner;
final CombinerObserver<T, R>[] observers;
final T[] latest;
final SpscLinkedArrayQueue<Object> queue;
final boolean delayError;
volatile boolean cancelled;
volatile boolean done;
final AtomicThrowable errors = new AtomicThrowable();
int active;
int complete;
@SuppressWarnings("unchecked")
LatestCoordinator(Observer<? super R> actual,
Function<? super Object[], ? extends R> combiner,
int count, int bufferSize, boolean delayError) {
this.actual = actual;
this.combiner = combiner;
this.delayError = delayError;
this.latest = (T[])new Object[count];
this.observers = new CombinerObserver[count];
this.queue = new SpscLinkedArrayQueue<Object>(bufferSize);
}
public void subscribe(ObservableSource<? extends T>[] sources) {
Observer<T>[] as = observers;
int len = as.length;
for (int i = 0; i < len; i++) {
as[i] = new CombinerObserver<T, R>(this, i);
}
lazySet(0); // release array contents
actual.onSubscribe(this);
for (int i = 0; i < len; i++) {
if (done || cancelled) {
return;
}
sources[i].subscribe(as[i]);
}
}
@Override
public void dispose() {
if (!cancelled) {
cancelled = true;
cancelSources();
if (getAndIncrement() == 0) {
clear(queue);
}
}
}
@Override
public boolean isDisposed() {
return cancelled;
}
void cancel(SpscLinkedArrayQueue<?> q) {
clear(q);
cancelSources();
}
void cancelSources() {
for (CombinerObserver<T, R> s : observers) {
s.dispose();
}
}
void clear(SpscLinkedArrayQueue<?> q) {
synchronized (this) {
Arrays.fill(latest, null);
}
q.clear();
}
void combine(T value, int index) {
CombinerObserver<T, R> cs = observers[index];
int a;
int c;
int len;
boolean empty;
boolean f;
synchronized (this) {
if (cancelled) {
return;
}
len = latest.length;
T o = latest[index];
a = active;
if (o == null) {
active = ++a;
}
c = complete;
if (value == null) {
complete = ++c;
} else {
latest[index] = value;
}
f = a == len;
// see if either all sources completed
empty = c == len
|| (value == null && o == null); // or this source completed without any value
if (!empty) {
if (value != null && f) {
queue.offer(cs, latest.clone());
} else
if (value == null && errors.get() != null) {
done = true; // if this source completed without a value
}
} else {
done = true;
}
}
if (!f && value != null) {
return;
}
drain();
}
void drain() {
if (getAndIncrement() != 0) {
return;
}
final SpscLinkedArrayQueue<Object> q = queue;
final Observer<? super R> a = actual;
final boolean delayError = this.delayError;
int missed = 1;
for (;;) {
if (checkTerminated(done, q.isEmpty(), a, q, delayError)) {
return;
}
for (;;) {
boolean d = done;
@SuppressWarnings("unchecked")
CombinerObserver<T, R> cs = (CombinerObserver<T, R>)q.poll();
boolean empty = cs == null;
if (checkTerminated(d, empty, a, q, delayError)) {
return;
}
if (empty) {
break;
}
@SuppressWarnings("unchecked")
T[] array = (T[])q.poll();
R v;
try {
v = ObjectHelper.requireNonNull(combiner.apply(array), "The combiner returned a null");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
cancelled = true;
cancel(q);
a.onError(ex);
return;
}
a.onNext(v);
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
boolean checkTerminated(boolean d, boolean empty, Observer<?> a, SpscLinkedArrayQueue<?> q, boolean delayError) {
if (cancelled) {
cancel(q);
return true;
}
if (d) {
if (delayError) {
if (empty) {
cancel(q);
Throwable e = errors.terminate();
if (e != null) {
a.onError(e);
} else {
a.onComplete();
}
return true;
}
} else {
Throwable e = errors.get();
if (e != null) {
cancel(q);
a.onError(errors.terminate());
return true;
} else
if (empty) {
clear(queue);
a.onComplete();
return true;
}
}
}
return false;
}
void onError(Throwable e) {
if (!errors.addThrowable(e)) {
RxJavaPlugins.onError(e);
}
}
}
static final class CombinerObserver<T, R> implements Observer<T> {
final LatestCoordinator<T, R> parent;
final int index;
final AtomicReference<Disposable> s = new AtomicReference<Disposable>();
CombinerObserver(LatestCoordinator<T, R> parent, int index) {
this.parent = parent;
this.index = index;
}
@Override
public void onSubscribe(Disposable s) {
DisposableHelper.setOnce(this.s, s);
}
@Override
public void onNext(T t) {
parent.combine(t, index);
}
@Override
public void onError(Throwable t) {
parent.onError(t);
parent.combine(null, index);
}
@Override
public void onComplete() {
parent.combine(null, index);
}
public void dispose() {
DisposableHelper.dispose(s);
}
}
}