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1.x: Fix zip() - observer array becoming visible too early and causing NPE #3688

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Merged
merged 1 commit into from
Feb 10, 2016
Merged

1.x: Fix zip() - observer array becoming visible too early and causing NPE #3688

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31 changes: 18 additions & 13 deletions src/main/java/rx/internal/operators/OperatorZip.java
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Original file line number Diff line number Diff line change
Expand Up @@ -177,7 +177,10 @@ public void request(long n) {

}

private static final class Zip<R> extends AtomicLong {
static final class Zip<R> extends AtomicLong {
/** */
private static final long serialVersionUID = 5995274816189928317L;
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We really need it? Also, javadoc comment above does not make sense

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Less javac warnings.


final Observer<? super R> child;
private final FuncN<? extends R> zipFunction;
private final CompositeSubscription childSubscription = new CompositeSubscription();
Expand All @@ -186,7 +189,7 @@ private static final class Zip<R> extends AtomicLong {
int emitted = 0; // not volatile/synchronized as accessed inside COUNTER_UPDATER block

/* initialized when started in `start` */
private Object[] observers;
private volatile Object[] subscribers;
private AtomicLong requested;

public Zip(final Subscriber<? super R> child, FuncN<? extends R> zipFunction) {
Expand All @@ -197,16 +200,18 @@ public Zip(final Subscriber<? super R> child, FuncN<? extends R> zipFunction) {

@SuppressWarnings("unchecked")
public void start(@SuppressWarnings("rawtypes") Observable[] os, AtomicLong requested) {
observers = new Object[os.length];
this.requested = requested;
final Object[] subscribers = new Object[os.length];
for (int i = 0; i < os.length; i++) {
InnerSubscriber io = new InnerSubscriber();
observers[i] = io;
subscribers[i] = io;
childSubscription.add(io);
}


this.requested = requested;
this.subscribers = subscribers; // full memory barrier: release all above

for (int i = 0; i < os.length; i++) {
os[i].unsafeSubscribe((InnerSubscriber) observers[i]);
os[i].unsafeSubscribe((InnerSubscriber) subscribers[i]);
}
}

Expand All @@ -219,13 +224,13 @@ public void start(@SuppressWarnings("rawtypes") Observable[] os, AtomicLong requ
*/
@SuppressWarnings("unchecked")
void tick() {
final Object[] observers = this.observers;
if (observers == null) {
final Object[] subscribers = this.subscribers;
if (subscribers == null) {
// nothing yet to do (initial request from Producer)
return;
}
if (getAndIncrement() == 0) {
final int length = observers.length;
final int length = subscribers.length;
final Observer<? super R> child = this.child;
final AtomicLong requested = this.requested;
do {
Expand All @@ -234,7 +239,7 @@ void tick() {
final Object[] vs = new Object[length];
boolean allHaveValues = true;
for (int i = 0; i < length; i++) {
RxRingBuffer buffer = ((InnerSubscriber) observers[i]).items;
RxRingBuffer buffer = ((InnerSubscriber) subscribers[i]).items;
Object n = buffer.peek();

if (n == null) {
Expand Down Expand Up @@ -265,7 +270,7 @@ void tick() {
return;
}
// now remove them
for (Object obj : observers) {
for (Object obj : subscribers) {
RxRingBuffer buffer = ((InnerSubscriber) obj).items;
buffer.poll();
// eagerly check if the next item on this queue is an onComplete
Expand All @@ -278,7 +283,7 @@ void tick() {
}
}
if (emitted > THRESHOLD) {
for (Object obj : observers) {
for (Object obj : subscribers) {
((InnerSubscriber) obj).requestMore(emitted);
}
emitted = 0;
Expand Down