2.x: improve coverage, remove unused code (#5119)

Author: akarnokd

src/main/java/io/reactivex/Flowable.java

@@ -25,7 +25,6 @@
 import io.reactivex.internal.functions.*;
 import io.reactivex.internal.fuseable.*;
 import io.reactivex.internal.operators.flowable.*;
-import io.reactivex.internal.operators.flowable.FlowableStrict.StrictSubscriber;
 import io.reactivex.internal.operators.observable.ObservableFromPublisher;
 import io.reactivex.internal.schedulers.ImmediateThinScheduler;
 import io.reactivex.internal.subscribers.*;

src/main/java/io/reactivex/internal/observers/QueueDrainObserver.java

@@ -17,7 +17,7 @@
 
 import io.reactivex.Observer;
 import io.reactivex.disposables.Disposable;
-import io.reactivex.internal.fuseable.SimpleQueue;
+import io.reactivex.internal.fuseable.*;
 import io.reactivex.internal.util.*;
 
 /**
@@ -30,14 +30,14 @@
  */
 public abstract class QueueDrainObserver<T, U, V> extends QueueDrainSubscriberPad2 implements Observer<T>, ObservableQueueDrain<U, V> {
     protected final Observer<? super V> actual;
-    protected final SimpleQueue<U> queue;
+    protected final SimplePlainQueue<U> queue;
 
     protected volatile boolean cancelled;
 
     protected volatile boolean done;
     protected Throwable error;
 
-    public QueueDrainObserver(Observer<? super V> actual, SimpleQueue<U> queue) {
+    public QueueDrainObserver(Observer<? super V> actual, SimplePlainQueue<U> queue) {
         this.actual = actual;
         this.queue = queue;
     }
@@ -63,7 +63,7 @@ public final boolean fastEnter() {
 
     protected final void fastPathEmit(U value, boolean delayError, Disposable dispose) {
         final Observer<? super V> s = actual;
-        final SimpleQueue<U> q = queue;
+        final SimplePlainQueue<U> q = queue;
 
         if (wip.get() == 0 && wip.compareAndSet(0, 1)) {
             accept(s, value);
@@ -87,7 +87,7 @@ protected final void fastPathEmit(U value, boolean delayError, Disposable dispos
      */
     protected final void fastPathOrderedEmit(U value, boolean delayError, Disposable disposable) {
         final Observer<? super V> s = actual;
-        final SimpleQueue<U> q = queue;
+        final SimplePlainQueue<U> q = queue;
 
         if (wip.get() == 0 && wip.compareAndSet(0, 1)) {
             if (q.isEmpty()) {
@@ -117,12 +117,6 @@ public final int leave(int m) {
         return wip.addAndGet(m);
     }
 
-    public void drain(boolean delayError, Disposable dispose) {
-        if (enter()) {
-            QueueDrainHelper.drainLoop(queue, actual, delayError, dispose, this);
-        }
-    }
-
     @Override
     public void accept(Observer<? super V> a, U v) {
         // ignored by default

src/main/java/io/reactivex/internal/operators/flowable/FlowableBufferBoundary.java

@@ -24,7 +24,7 @@
 import io.reactivex.exceptions.Exceptions;
 import io.reactivex.functions.Function;
 import io.reactivex.internal.functions.ObjectHelper;
-import io.reactivex.internal.fuseable.SimpleQueue;
+import io.reactivex.internal.fuseable.SimplePlainQueue;
 import io.reactivex.internal.queue.MpscLinkedQueue;
 import io.reactivex.internal.subscribers.QueueDrainSubscriber;
 import io.reactivex.internal.subscriptions.SubscriptionHelper;
@@ -128,7 +128,7 @@ void complete() {
                 buffers.clear();
             }
 
-            SimpleQueue<U> q = queue;
+            SimplePlainQueue<U> q = queue;
             for (U u : list) {
                 q.offer(u);
             }