Revert "remove AbstractChannel#doPreClose"

This reverts commit 241f856cc7.

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

@@ -415,7 +415,6 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                             "Force-closing a channel whose registration task was unaccepted by an event loop: {}",
                             AbstractChannel.this, t);
                     closeForcibly();
-                    closeFuture.setClosed();
                     promise.setFailure(t);
                 }
             }
@@ -441,12 +440,12 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
             } catch (Throwable t) {
                 // Close the channel directly to avoid FD leak.
                 closeForcibly();
-                closeFuture.setClosed();
                 if (!promise.tryFailure(t)) {
                     logger.warn(
                             "Tried to fail the registration promise, but it is complete already. " +
                                     "Swallowing the cause of the registration failure:", t);
                 }
+                closeFuture.setClosed();
             }
         }
 
@@ -515,18 +514,13 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                 return;
             }
 
-            if (closeFuture.isSuccess()) {
-                // Closed already.
-                promise.setSuccess();
-            }
-
             boolean wasActive = isActive();
+            if (closeFuture.setClosed()) {
                 ChannelOutboundBuffer outboundBuffer = this.outboundBuffer;
                 this.outboundBuffer = null; // Disallow adding any messages and flushes to outboundBuffer.
 
                 try {
                     doClose();
-                closeFuture.setClosed();
                     promise.setSuccess();
                 } catch (Throwable t) {
                     promise.setFailure(t);
@@ -549,6 +543,10 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
 
                     deregister(voidPromise());
                 }
+            } else {
+                // Closed already.
+                promise.setSuccess();
+            }
         }
 
         @Override
@@ -752,6 +750,14 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
      */
     protected abstract void doDisconnect() throws Exception;
 
+    /**
+     * Will be called before the actual close operation will be performed. Sub-classes may override this as the default
+     * is to do nothing.
+     */
+    protected void doPreClose() throws Exception {
+        // NOOP by default
+    }
+
     /**
      * Close the {@link Channel}
      */
@@ -828,6 +834,11 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
         }
 
         boolean setClosed() {
+            try {
+                doPreClose();
+            } catch (Exception e) {
+                logger.warn("doPreClose() raised an exception.", e);
+            }
             return super.trySuccess();
         }
     }

transport/src/main/java/io/netty/channel/local/LocalChannel.java

@@ -199,12 +199,13 @@ public class LocalChannel extends AbstractChannel {
     }
 
     @Override
-    protected void doClose() throws Exception {
+    protected void doPreClose() throws Exception {
         if (state > 2) {
             // Closed already
             return;
         }
 
+        // Update all internal state before the closeFuture is notified.
         if (localAddress != null) {
             if (parent() == null) {
                 LocalChannelRegistry.unregister(localAddress);
@@ -212,7 +213,10 @@ public class LocalChannel extends AbstractChannel {
             localAddress = null;
         }
         state = 3;
+    }
 
+    @Override
+    protected void doClose() throws Exception {
         LocalChannel peer = this.peer;
         if (peer != null && peer.isActive()) {
             peer.unsafe().close(unsafe().voidPromise());

transport/src/main/java/io/netty/channel/local/LocalServerChannel.java

@@ -94,17 +94,23 @@ public class LocalServerChannel extends AbstractServerChannel {
     }
 
     @Override
-    protected void doClose() throws Exception {
+    protected void doPreClose() throws Exception {
         if (state > 1) {
             // Closed already.
             return;
         }
 
+        // Update all internal state before the closeFuture is notified.
         LocalChannelRegistry.unregister(localAddress);
         localAddress = null;
         state = 2;
     }
 
+    @Override
+    protected void doClose() throws Exception {
+        // All internal state was updated already at doPreClose().
+    }
+
     @Override
     protected Runnable doDeregister() throws Exception {
         ((SingleThreadEventExecutor) eventLoop()).removeShutdownHook(shutdownHook);