2.x: factor out Completable ops, unify disposed markers

src/main/java/io/reactivex/disposables/BooleanDisposable.java

@@ -22,12 +22,14 @@ public final class BooleanDisposable implements Disposable {
         @Override
         public void run() { }
     };
+
+    static final Runnable EMPTY = new Runnable() {
+        @Override
+        public void run() { }
+    };
 
     public BooleanDisposable() {
-        this(new Runnable() {
-            @Override
-            public void run() { }
-        });
+        this(EMPTY);
     }
 
     public BooleanDisposable(Runnable run) {

src/main/java/io/reactivex/internal/disposables/ArrayCompositeResource.java

@@ -26,7 +26,9 @@
  * and should be used by internal means only.
  * 
  * @param <T> the resource tpye
+ * @deprecated Use more type-specific and inlined resource management
  */
+@Deprecated
 public final class ArrayCompositeResource<T> extends AtomicReferenceArray<Object> implements Disposable {
     /** */
     private static final long serialVersionUID = 2746389416410565408L;

src/main/java/io/reactivex/internal/disposables/DisposableHelper.java

@@ -0,0 +1,114 @@
+package io.reactivex.internal.disposables;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+import io.reactivex.disposables.Disposable;
+import io.reactivex.internal.functions.Objects;
+import io.reactivex.plugins.RxJavaPlugins;
+
+/**
+ * Utility methods for working with Disposables atomically.
+ */
+public enum DisposableHelper {
+    ;
+
+    public static final Disposable DISPOSED = Disposed.INSTANCE;
+
+    public static boolean isDisposed(Disposable d) {
+        return d == DISPOSED;
+    }
+
+    public static boolean set(AtomicReference<Disposable> field, Disposable d) {
+        for (;;) {
+            Disposable current = field.get();
+            if (current == DISPOSED) {
+                if (d != null) {
+                    d.dispose();
+                }
+                return false;
+            }
+            if (field.compareAndSet(current, d)) {
+                if (current != null) {
+                    current.dispose();
+                }
+                return true;
+            }
+        }
+    }
+
+    public static boolean setOnce(AtomicReference<Disposable> field, Disposable d) {
+        Objects.requireNonNull(d, "d is null");
+        if (!field.compareAndSet(null, d)) {
+            d.dispose();
+            if (field.get() != DISPOSED) {
+                reportDisposableSet();
+            }
+            return false;
+        }
+        return true;
+    }
+
+    public static boolean replace(AtomicReference<Disposable> field, Disposable d) {
+        for (;;) {
+            Disposable current = field.get();
+            if (current == DISPOSED) {
+                if (d != null) {
+                    d.dispose();
+                }
+                return false;
+            }
+            if (field.compareAndSet(current, d)) {
+                return true;
+            }
+        }
+    }
+
+    public static boolean dispose(AtomicReference<Disposable> field) {
+        Disposable current = field.get();
+        if (current != DISPOSED) {
+            current = field.getAndSet(DISPOSED);
+            if (current != null && current != DISPOSED) {
+                current.dispose();
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Verifies that current is null, next is not null, otherwise signals errors
+     * to the RxJavaPlugins and returns false
+     * @param current the current Disposable, expected to be null
+     * @param next the next Disposable, expected to be non-null
+     * @return true if the validation succeeded
+     */
+    public static boolean validate(Disposable current, Disposable next) {
+        if (next == null) {
+            RxJavaPlugins.onError(new NullPointerException("next is null"));
+            return false;
+        }
+        if (current != null) {
+            next.dispose();
+            reportDisposableSet();
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Reports that the disposable is already set to the RxJavaPlugins error handler.
+     */
+    public static void reportDisposableSet() {
+        RxJavaPlugins.onError(new IllegalStateException("Disposable already set!"));
+    }
+
+    static enum Disposed implements Disposable {
+        INSTANCE;
+
+        @Override
+        public void dispose() {
+            // deliberately no-op
+        }
+    }
+
+}

src/main/java/io/reactivex/internal/disposables/ListCompositeResource.java

@@ -22,7 +22,9 @@
  * A linked-list-based composite resource with custom disposer callback.
  *
  * @param <T> the resource type
+ * @deprecated Use more type-specific and inlined resource management
  */
+@Deprecated
 public final class ListCompositeResource<T> implements CompositeResource<T>, Disposable {
     final Consumer<? super T> disposer;
 

src/main/java/io/reactivex/internal/disposables/MultipleAssignmentResource.java

@@ -31,7 +31,9 @@
  * and should be used by internal means only.
  * 
  * @param <T> the resource type
+ * @deprecated Use more type-specific and inlined resource management
  */
+@Deprecated
 public final class MultipleAssignmentResource<T> extends AtomicReference<Object> implements Disposable {
     /** */
     private static final long serialVersionUID = 5247635821051810205L;

src/main/java/io/reactivex/internal/disposables/SerialResource.java

@@ -31,7 +31,9 @@
  * and should be used by internal means only.
  * 
  * @param <T> the resource type
+ * @deprecated Use more type-specific and inlined resource management
  */
+@Deprecated
 public final class SerialResource<T> extends AtomicReference<Object> implements Disposable {
     /** */
     private static final long serialVersionUID = 5247635821051810205L;

src/main/java/io/reactivex/internal/disposables/SetCompositeResource.java

@@ -21,7 +21,9 @@
  * A set-based composite resource with custom disposer callback.
  *
  * @param <T> the resource type
+ * @deprecated Use more type-specific and inlined resource management
  */
+@Deprecated
 public final class SetCompositeResource<T> implements CompositeResource<T>, Disposable {
     final Consumer<? super T> disposer;
 

src/main/java/io/reactivex/internal/operators/completable/CompletableAmbArray.java

@@ -0,0 +1,85 @@
+/**
+ * Copyright 2016 Netflix, Inc.
+ * 
+ * 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.completable;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import io.reactivex.*;
+import io.reactivex.disposables.*;
+import io.reactivex.plugins.RxJavaPlugins;
+
+public final class CompletableAmbArray extends Completable {
+
+    final CompletableConsumable[] sources;
+
+    public CompletableAmbArray(CompletableConsumable[] sources) {
+        this.sources = sources;
+    }
+
+    @Override
+    public void subscribeActual(final CompletableSubscriber s) {
+        final CompositeDisposable set = new CompositeDisposable();
+        s.onSubscribe(set);
+
+        final AtomicBoolean once = new AtomicBoolean();
+
+        CompletableSubscriber inner = new CompletableSubscriber() {
+            @Override
+            public void onComplete() {
+                if (once.compareAndSet(false, true)) {
+                    set.dispose();
+                    s.onComplete();
+                }
+            }
+
+            @Override
+            public void onError(Throwable e) {
+                if (once.compareAndSet(false, true)) {
+                    set.dispose();
+                    s.onError(e);
+                } else {
+                    RxJavaPlugins.onError(e);
+                }
+            }
+
+            @Override
+            public void onSubscribe(Disposable d) {
+                set.add(d);
+            }
+
+        };
+
+        for (CompletableConsumable c : sources) {
+            if (set.isDisposed()) {
+                return;
+            }
+            if (c == null) {
+                NullPointerException npe = new NullPointerException("One of the sources is null");
+                if (once.compareAndSet(false, true)) {
+                    set.dispose();
+                    s.onError(npe);
+                } else {
+                    RxJavaPlugins.onError(npe);
+                }
+                return;
+            }
+            if (once.get() || set.isDisposed()) {
+                return;
+            }
+
+            // no need to have separate subscribers because inner is stateless
+            c.subscribe(inner);
+        }
+    }
+}