CVE-2023-5685

@@ -74,6 +74,141 @@ IOException getException() {
         }
     }
 
+    private static abstract class NestedState<T> extends State<T> {
+        private final State<T> next;
+
+        public NestedState(final State next) {
+            this.next = next;
+        }
+
+        /**
+         * Perform any actions that need to be executed when future is done, delegation of done notification to next is
+         * taken care of by invoker.
+         *
+         * @param future the future
+         * @param result the result
+         */
+        protected abstract void doNotifyDone(AbstractIoFuture<T> future, T result);
+
+        @Override
+        public void notifyDone(AbstractIoFuture<T> future, T result) {
+            doNotifyDone(future, result);
+            if (next instanceof NestedState) {
+                NestedState<T> current = this;
+                do {
+                    current = (NestedState<T>) current.next;
+                    current.doNotifyDone(future, result);
+                } while (current.next instanceof NestedState);
+                current.next.notifyDone(future, result);
+            } else {
+                next.notifyDone(future, result);
+            }
+
+        }
+
+        /**
+         * Perform any actions that need to be done at this state for handling failure, delegation of failure
+         * notification to next is taken care of by invoker
+         *
+         * @param future    the future
+         * @param exception the failure
+         */
+        protected abstract void doNotifyFailed(AbstractIoFuture<T> future, IOException exception);
+
+        @Override
+        public void notifyFailed(AbstractIoFuture<T> future, IOException exception) {
+            doNotifyFailed(future, exception);
+            if (next instanceof NestedState) {
+                NestedState<T> current = this;
+                do {
+                    current = (NestedState<T>) current.next;
+                    current.doNotifyFailed(future, exception);
+                } while (current.next instanceof NestedState);
+                current.next.notifyFailed(future, exception);
+            } else {
+                next.notifyFailed(future, exception);
+            }
+        }
+
+        /**
+         * Perform any actions that need to be done at this state for handling cancellation, delegation of cancellation
+         * notification to next is taken care of by invoker
+         *
+         * @param future the future
+         */
+        protected abstract void doNotifyCancelled(AbstractIoFuture<T> future);
+
+
+
+        @Override
+        public void notifyCancelled(AbstractIoFuture<T> future) {
+            doNotifyCancelled(future);
+            if (next instanceof NestedState) {
+                NestedState<T> current = this;
+                do {
+                    current = (NestedState<T>) current.next;
+                    current.doNotifyCancelled(future);
+                } while (current.next instanceof NestedState);
+                current.next.notifyCancelled(future);
+            } else {
+                next.notifyCancelled(future);
+            }
+        }
+
+        /**
+         * Perform any actions that need to be done at this state for cancellation. Delegation of cancellation to next
+         * is taken care of by invoker.
+         */
+        protected abstract void doCancel();
+
+        /**
+         * Just delegate cancel() to first next state in the nested chain that is not a NestedState.
+         */
+        @Override
+        public void cancel() {
+            doCancel();
+            if (next instanceof NestedState) {
+                NestedState<T> current = this;
+                do {
+                    current = (NestedState<T>) current.next;
+                    current.doCancel();
+                } while (current.next instanceof NestedState);
+                current.next.cancel();
+            } else {
+                next.cancel();
+            }
+        }
+
+        /**
+         * Return {@code true} to indicate that, at this state, cancel is requested. If returns false, invoker
+         * will check for inner next states in the chain until it finds a positive result or the final state in the
+         * chain.
+         *
+         * @return {@code true} to indicate that cancel is requested; {@code false} to delegate response to nested
+         *         state.
+         */
+        protected abstract boolean isCancelRequested();
+
+        @Override
+        public boolean cancelRequested() {
+            if (isCancelRequested()) {
+                return true;
+            }
+            if (next instanceof NestedState) {
+                NestedState<T> current = this;
+                do {
+                    current = (NestedState<T>) current.next;
+                    if (current.isCancelRequested()) {
+                        return true;
+                    }
+                } while (current.next instanceof NestedState);
+                return current.next.cancelRequested();
+            } else {
+                return next.cancelRequested();
+            }
+        }
+    }
+
     static final class InitialState<T> extends State<T> {
 
         Status getStatus() {
@@ -229,13 +364,12 @@ boolean cancelRequested() {
         }
     }
 
-    static final class NotifierState<T, A> extends State<T> {
-        final State<T> next;
+    static final class NotifierState<T, A> extends NestedState<T> {
         final Notifier<? super T, A> notifier;
         final A attachment;
 
         NotifierState(final State<T> next, final Notifier<? super T, A> notifier, final A attachment) {
-            this.next = next;
+            super(next);
             this.notifier = notifier;
             this.attachment = attachment;
         }
@@ -244,136 +378,138 @@ Status getStatus() {
             return Status.WAITING;
         }
 
-        void notifyDone(final AbstractIoFuture<T> future, final T result) {
+        @Override
+        protected void doNotifyDone(final AbstractIoFuture<T> future, final T result) {
             doNotify(future);
-            next.notifyDone(future, result);
         }
 
-        void notifyFailed(final AbstractIoFuture<T> future, final IOException exception) {
+        @Override
+        protected void doNotifyFailed(final AbstractIoFuture<T> future, final IOException exception) {
             doNotify(future);
-            next.notifyFailed(future, exception);
         }
 
-        void notifyCancelled(final AbstractIoFuture<T> future) {
+        @Override
+        protected void doNotifyCancelled(final AbstractIoFuture<T> future) {
             doNotify(future);
-            next.notifyCancelled(future);
         }
 
-        void cancel() {
-            next.cancel();
+
+        @Override
+        protected void doCancel() {
         }
 
         private void doNotify(final AbstractIoFuture<T> future) {
             future.runNotifier(new NotifierRunnable<T, A>(notifier, future, attachment));
         }
 
-        boolean cancelRequested() {
-            return next.cancelRequested();
+        @Override
+        protected boolean isCancelRequested() {
+            return false;
         }
     }
 
-    static final class WaiterState<T> extends State<T> {
-        final State<T> next;
+    static final class WaiterState<T> extends NestedState<T> {
         final Thread waiter;
 
         WaiterState(final State<T> next, final Thread waiter) {
-            this.next = next;
+            super(next);
             this.waiter = waiter;
         }
 
         Status getStatus() {
             return Status.WAITING;
         }
 
-        void notifyDone(final AbstractIoFuture<T> future, final T result) {
+        @Override
+        protected void doNotifyDone(final AbstractIoFuture<T> future, final T result) {
             LockSupport.unpark(waiter);
-            next.notifyDone(future, result);
         }
 
-        void notifyFailed(final AbstractIoFuture<T> future, final IOException exception) {
+        @Override
+        protected void doNotifyFailed(final AbstractIoFuture<T> future, final IOException exception) {
             LockSupport.unpark(waiter);
-            next.notifyFailed(future, exception);
         }
 
-        void notifyCancelled(final AbstractIoFuture<T> future) {
+        @Override
+        protected void doNotifyCancelled(final AbstractIoFuture<T> future) {
             LockSupport.unpark(waiter);
-            next.notifyCancelled(future);
         }
 
-        void cancel() {
-            next.cancel();
-        }
+        @Override
+        protected void doCancel() {}
 
-        boolean cancelRequested() {
-            return next.cancelRequested();
+        @Override
+        protected boolean isCancelRequested() {
+            return false;
         }
     }
 
-    static final class CancellableState<T> extends State<T> {
-        final State<T> next;
+    static final class CancellableState<T> extends NestedState<T> {
         final Cancellable cancellable;
 
         CancellableState(final State<T> next, final Cancellable cancellable) {
-            this.next = next;
+            super(next);
             this.cancellable = cancellable;
         }
 
         Status getStatus() {
             return Status.WAITING;
         }
 
-        void notifyDone(final AbstractIoFuture<T> future, final T result) {
-            next.notifyDone(future, result);
+        @Override
+        protected void doNotifyDone(final AbstractIoFuture<T> future, final T result) {
         }
 
-        void notifyFailed(final AbstractIoFuture<T> future, final IOException exception) {
-            next.notifyFailed(future, exception);
+        @Override
+        protected void doNotifyFailed(final AbstractIoFuture<T> future, final IOException exception) {
         }
 
-        void notifyCancelled(final AbstractIoFuture<T> future) {
-            next.notifyCancelled(future);
+        @Override
+        protected void doNotifyCancelled(final AbstractIoFuture<T> future) {
         }
 
-        void cancel() {
+        @Override
+        protected void doCancel() {
             try {
                 cancellable.cancel();
             } catch (Throwable ignored) {}
-            next.cancel();
         }
 
-        boolean cancelRequested() {
-            return next.cancelRequested();
+        @Override
+        protected boolean isCancelRequested() {
+            return false;
         }
     }
 
-    static final class CancelRequestedState<T> extends State<T> {
-        final State<T> next;
+    static final class CancelRequestedState<T> extends NestedState<T> {
 
         CancelRequestedState(final State<T> next) {
-            this.next = next;
+            super(next);
         }
 
         Status getStatus() {
             return Status.WAITING;
         }
 
-        void notifyDone(final AbstractIoFuture<T> future, final T result) {
-            next.notifyDone(future, result);
+        @Override
+        protected void doNotifyDone(final AbstractIoFuture<T> future, final T result) {
         }
 
-        void notifyFailed(final AbstractIoFuture<T> future, final IOException exception) {
-            next.notifyFailed(future, exception);
+        @Override
+        protected void doNotifyFailed(final AbstractIoFuture<T> future, final IOException exception) {
         }
 
-        void notifyCancelled(final AbstractIoFuture<T> future) {
-            next.notifyCancelled(future);
+        @Override
+        protected void doNotifyCancelled(final AbstractIoFuture<T> future) {
         }
 
-        void cancel() {
+        @Override
+        protected void doCancel() {
             // terminate
         }
 
-        boolean cancelRequested() {
+        @Override
+        protected boolean isCancelRequested() {
             return true;
         }
     }