Keep used NioIoOps and SelectionKey in sync (#14029)

Motivation:

As the user is able to retieve the underlying SelectionKey via the
NioRegistration we need to ensure we always keep this and the current
used NioIoOps in sync.

Modifications:

Remove the local stored NioOps and just always reconstruct using the
underlying SelectionKey. This is not a concern in terms of performance
and object creation as we pre-construct them.

Result:

Keep current used NioIoOps and SelectionKey always in sync

transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java

@@ -58,10 +58,6 @@ public abstract class AbstractNioChannel extends AbstractChannel {
     private final SelectableChannel ch;
     protected final int readInterestOp;
     protected final NioIoOps readOps;
-
-    // We always start with NONE as initial ops.
-    private NioIoOps ops = NioIoOps.NONE;
-
     volatile NioIoRegistration registration;
     boolean readPending;
     private final Runnable clearReadPendingRunnable = new Runnable() {
@@ -110,21 +106,21 @@ protected AbstractNioChannel(Channel parent, SelectableChannel ch, NioIoOps read
     }
 
     protected void addAndSubmit(NioIoOps addOps) {
-        if (!ops.contains(addOps)) {
-            ops = ops.with(addOps);
+        int interestOps = selectionKey().interestOps();
+        if (!addOps.isIncludedIn(interestOps)) {
             try {
-                registration().submit(ops);
+                registration().submit(NioIoOps.valueOf(interestOps).with(addOps));
             } catch (Exception e) {
                 throw new ChannelException(e);
             }
         }
     }
 
     protected void removeAndSubmit(NioIoOps removeOps) {
-        if (ops.contains(removeOps)) {
-            ops = ops.without(removeOps);
+        int interestOps = selectionKey().interestOps();
+        if (removeOps.isIncludedIn(interestOps)) {
             try {
-                registration().submit(ops);
+                registration().submit(NioIoOps.valueOf(interestOps).without(removeOps));
             } catch (Exception e) {
                 throw new ChannelException(e);
             }
@@ -417,7 +413,7 @@ public final void forceFlush() {
 
         private boolean isFlushPending() {
             NioIoRegistration registration = registration();
-            return registration.isValid() && ops.contains(NioIoOps.WRITE);
+            return registration.isValid() && NioIoOps.WRITE.isIncludedIn(registration.selectionKey().interestOps());
         }
 
         @Override
@@ -478,8 +474,6 @@ protected void doDeregister() throws Exception {
         NioIoRegistration registration = registration();
         if (registration != null) {
             this.registration = null;
-            // Reset to NONE so we have the correct value when we register again.
-            ops = NioIoOps.NONE;
             registration.cancel();
         }
     }

transport/src/main/java/io/netty/channel/nio/NioIoOps.java

@@ -93,7 +93,7 @@ private NioIoOps(int value) {
      * @return      {@code true} if a combination of the given.
      */
     public boolean contains(NioIoOps ops) {
-        return (value & ops.value) != 0;
+        return isIncludedIn(ops.value);
     }
 
     /**
@@ -123,7 +123,7 @@ public NioIoOps without(NioIoOps ops) {
     }
 
     /**
-     * Returns the underlying value of the {@link NioIoOps}.
+     * Returns the underlying ops value of the {@link NioIoOps}.
      *
      * @return value.
      */
@@ -158,6 +158,26 @@ public static NioIoOps valueOf(int value) {
         return eventOf(value).ops();
     }
 
+    /**
+     * Returns {@code true} if this {@link NioIoOps} is <strong>included </strong> in the given {@code ops}.
+     *
+     * @param ops   the ops to check.
+     * @return      {@code true} if <strong>included</strong>, {@code false} otherwise.
+     */
+    public boolean isIncludedIn(int ops) {
+        return (ops & value) != 0;
+    }
+
+    /**
+     * Returns {@code true} if this {@link NioIoOps} is <strong>not included</strong> in the given {@code ops}.
+     *
+     * @param ops   the ops to check.
+     * @return      {@code true} if <strong>not included</strong>, {@code false} otherwise.
+     */
+    public boolean isNotIncludedIn(int ops) {
+        return (ops & value) == 0;
+    }
+
     static NioIoEvent eventOf(int value) {
         if (value > 0 && value < EVENTS.length) {
             NioIoEvent event = EVENTS[value];