Make most outbound operations are cancellable

- Inspired by #2214
- It actually reduces the chance of trying to marking a cancelled promise as success again, which raises an IllegalStateException.

transport-rxtx/src/main/java/io/netty/channel/rxtx/RxtxChannel.java

@@ -134,7 +134,7 @@ public class RxtxChannel extends OioByteStreamChannel {
         public void connect(
                 final SocketAddress remoteAddress,
                 final SocketAddress localAddress, final ChannelPromise promise) {
-            if (!ensureOpen(promise)) {
+            if (!promise.setUncancellable() || !ensureOpen(promise)) {
                 return;
             }
 

transport/src/main/java/io/netty/channel/AbstractChannel.java

@@ -418,7 +418,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
             try {
                 // check if the channel is still open as it could be closed in the mean time when the register
                 // call was outside of the eventLoop
-                if (!ensureOpen(promise)) {
+                if (!promise.setUncancellable() || !ensureOpen(promise)) {
                     return;
                 }
                 doRegister();
@@ -442,7 +442,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
 
         @Override
         public final void bind(final SocketAddress localAddress, final ChannelPromise promise) {
-            if (!ensureOpen(promise)) {
+            if (!promise.setUncancellable() || !ensureOpen(promise)) {
                 return;
             }
 
@@ -480,6 +480,10 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
 
         @Override
         public final void disconnect(final ChannelPromise promise) {
+            if (!promise.setUncancellable()) {
+                return;
+            }
+
             boolean wasActive = isActive();
             try {
                 doDisconnect();
@@ -502,6 +506,10 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
 
         @Override
         public final void close(final ChannelPromise promise) {
+            if (!promise.setUncancellable()) {
+                return;
+            }
+
             if (inFlush0) {
                 invokeLater(new Runnable() {
                     @Override

transport/src/main/java/io/netty/channel/oio/AbstractOioChannel.java

@@ -55,12 +55,7 @@ public abstract class AbstractOioChannel extends AbstractChannel {
         public void connect(
                 final SocketAddress remoteAddress,
                 final SocketAddress localAddress, final ChannelPromise promise) {
-            if (!ensureOpen(promise)) {
-                return;
-            }
-
-            if (!promise.setUncancellable()) {
-                close(voidPromise());
+            if (!promise.setUncancellable() || !ensureOpen(promise)) {
                 return;
             }