1.x: observeOn - fix in-sequence termination/unsubscription

Author: akarnokd

src/main/java/rx/internal/operators/OperatorObserveOn.java

@@ -183,15 +183,10 @@ public void call() {
             // less frequently (usually after each RxRingBuffer.SIZE elements)
 
             for (;;) {
-                if (checkTerminated(finished, q.isEmpty(), localChild, q)) {
-                    return;
-                }
-
                 long requestAmount = requested.get();
-                boolean unbounded = requestAmount == Long.MAX_VALUE;
                 long currentEmission = 0L;
 
-                while (requestAmount != 0L) {
+                while (requestAmount != currentEmission) {
                     boolean done = finished;
                     Object v = q.poll();
                     boolean empty = v == null;
@@ -205,14 +200,19 @@ public void call() {
                     }
 
                     localChild.onNext(localOn.getValue(v));
-                    
-                    requestAmount--;
-                    currentEmission--;
+
+                    currentEmission++;
                     emitted++;
                 }
 
-                if (currentEmission != 0L && !unbounded) {
-                    requested.addAndGet(currentEmission);
+                if (requestAmount == currentEmission) {
+                    if (checkTerminated(finished, q.isEmpty(), localChild, q)) {
+                        return;
+                    }
+                }
+                
+                if (currentEmission != 0L) {
+                    BackpressureUtils.produced(requested, currentEmission);
                 }
 
                 missed = counter.addAndGet(-missed);

src/test/java/rx/internal/operators/OperatorObserveOnTest.java

@@ -834,4 +834,16 @@ public void testErrorDelayedAsync() {
         ts.assertError(TestException.class);
         ts.assertNotCompleted();
     }
+    
+    @Test
+    public void requestExactCompletesImmediately() {
+        TestSubscriber<Integer> ts = TestSubscriber.create(10);
+
+        Observable.range(1, 10).observeOn(Schedulers.computation()).subscribe(ts);
+        
+        ts.awaitTerminalEvent(1, TimeUnit.SECONDS);
+        ts.assertValueCount(10);
+        ts.assertNoErrors();
+        ts.assertCompleted();
+    }
 }