Revert 25c7a783a7 and fix #1064 differently

- Rename inbound/outboundBufferFreed to inbound/OutboundShutdown which makes more sense
- Move DefaultChannelHandlerContext.isInbound/OutboundBufferFreed() to DefaultChannelPipeline
- Fix a problem where invokeFreeInbound/OutboundBuffer() sets inbound/outboundShutdown too early (this was the direct cause of #1064)
- Remove the volatile modifier - DCHC.prev/next are volatile and that's just enough

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

@@ -740,7 +740,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     public ChannelHandlerContext fireChannelUnregistered() {
         final DefaultChannelHandlerContext next = findContextInbound();
         EventExecutor executor = next.executor();
-        if (executor.inEventLoop()) {
+        if (prev != null && executor.inEventLoop()) {
             next.invokeChannelUnregistered();
         } else {
             Runnable task = next.invokeChannelUnregisteredTask;
@@ -749,6 +749,9 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
                     @Override
                     public void run() {
                         next.invokeChannelUnregistered();
+                        if (prev == null) {
+
+                        }
                     }
                 };
             }
@@ -801,7 +804,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     public ChannelHandlerContext fireChannelInactive() {
         final DefaultChannelHandlerContext next = findContextInbound();
         EventExecutor executor = next.executor();
-        if (executor.inEventLoop()) {
+        if (prev != null && executor.inEventLoop()) {
             next.invokeChannelInactive();
         } else {
             Runnable task = next.invokeChannelInactiveTask;
@@ -836,7 +839,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
 
         final DefaultChannelHandlerContext next = this.next;
         EventExecutor executor = next.executor();
-        if (executor.inEventLoop()) {
+        if (prev != null && executor.inEventLoop()) {
             next.invokeExceptionCaught(cause);
         } else {
             try {
@@ -923,7 +926,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
 
     private void fireInboundBufferUpdated0() {
         final DefaultChannelHandlerContext next = findContextInbound();
-        if (!next.isInboundBufferFreed()) {
+        if (!pipeline.isInboundShutdown()) {
             next.fillInboundBridge();
             // This comparison is safe because this method is always executed from the executor.
             if (next.executor == executor) {
@@ -934,7 +937,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
                     next.invokeInboundBufferUpdatedTask = task = new Runnable() {
                         @Override
                         public void run() {
-                            if (!next.isInboundBufferFreed()) {
+                            if (!pipeline.isInboundShutdown()) {
                                 next.invokeInboundBufferUpdated();
                             }
                         }
@@ -959,7 +962,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
                 } catch (Throwable t) {
                     pipeline.notifyHandlerException(t);
                 } finally {
-                    if (handler instanceof ChannelInboundByteHandler && !isInboundBufferFreed()) {
+                    if (handler instanceof ChannelInboundByteHandler && !pipeline.isInboundShutdown()) {
                         try {
                             ((ChannelInboundByteHandler) handler).discardInboundReadBytes(this);
                         } catch (Throwable t) {
@@ -1282,7 +1285,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
 
     private void invokePrevFlush(ChannelPromise promise, Thread currentThread) {
         DefaultChannelHandlerContext prev = findContextOutbound();
-        if (prev.isOutboundBufferFreed()) {
+        if (pipeline.isOutboundShutdown()) {
             promise.setFailure(new ChannelPipelineException(
                     "Unable to flush as outbound buffer of next handler was freed already"));
             return;
@@ -1324,7 +1327,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         } catch (Throwable t) {
             pipeline.notifyHandlerException(t);
         } finally {
-            if (handler instanceof ChannelOutboundByteHandler && !isOutboundBufferFreed()) {
+            if (handler instanceof ChannelOutboundByteHandler && !pipeline.isOutboundShutdown()) {
                 try {
                     ((ChannelOutboundByteHandler) handler).discardOutboundReadBytes(this);
                 } catch (Throwable t) {
@@ -1446,7 +1449,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             return;
         }
 
-        if (isOutboundBufferFreed()) {
+        if (pipeline.isOutboundShutdown()) {
             promise.setFailure(new ChannelPipelineException(
                     "Unable to write as outbound buffer of next handler was freed already"));
             return;
@@ -1461,9 +1464,8 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     }
 
     void invokeFreeInboundBuffer() {
-        pipeline.inboundBufferFreed = true;
         EventExecutor executor = executor();
-        if (executor.inEventLoop()) {
+        if (prev != null && executor.inEventLoop()) {
             invokeFreeInboundBuffer0();
         } else {
             Runnable task = invokeFreeInboundBuffer0Task;
@@ -1471,6 +1473,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
                 invokeFreeInboundBuffer0Task = task = new Runnable() {
                     @Override
                     public void run() {
+                        pipeline.shutdownInbound();
                         invokeFreeInboundBuffer0();
                     }
                 };
@@ -1503,8 +1506,25 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
 
     /** Invocation initiated by {@link #invokeFreeInboundBuffer0()} after freeing all inbound buffers. */
     private void invokeFreeOutboundBuffer() {
-        pipeline.outboundBufferFreed = true;
         EventExecutor executor = executor();
+        if (next == null) {
+            if (executor.inEventLoop()) {
+                pipeline.shutdownOutbound();
+                invokeFreeOutboundBuffer0();
+            } else {
+                Runnable task = invokeFreeOutboundBuffer0Task;
+                if (task == null) {
+                    invokeFreeOutboundBuffer0Task = task = new Runnable() {
+                        @Override
+                        public void run() {
+                            pipeline.shutdownOutbound();
+                            invokeFreeOutboundBuffer0();
+                        }
+                    };
+                }
+                executor.execute(task);
+            }
+        } else {
             if (executor.inEventLoop()) {
                 invokeFreeOutboundBuffer0();
             } else {
@@ -1520,6 +1540,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
                 executor.execute(task);
             }
         }
+    }
 
     private void invokeFreeOutboundBuffer0() {
         ChannelHandler handler = handler();
@@ -1569,14 +1590,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         }
     }
 
-    private boolean isInboundBufferFreed() {
-        return pipeline.inboundBufferFreed;
-    }
-
-    private boolean isOutboundBufferFreed() {
-        return pipeline.outboundBufferFreed;
-    }
-
     private void validateFuture(ChannelFuture future) {
         if (future == null) {
             throw new NullPointerException("future");

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

@@ -58,8 +58,8 @@ final class DefaultChannelPipeline implements ChannelPipeline {
     final Map<EventExecutorGroup, EventExecutor> childExecutors =
             new IdentityHashMap<EventExecutorGroup, EventExecutor>();
 
-    volatile boolean inboundBufferFreed;
+    private boolean inboundShutdown;
-    volatile boolean outboundBufferFreed;
+    private boolean outboundShutdown;
 
     public DefaultChannelPipeline(Channel channel) {
         if (channel == null) {
@@ -845,6 +845,22 @@ final class DefaultChannelPipeline implements ChannelPipeline {
         return tail.nextOutboundByteBuffer();
     }
 
+    boolean isInboundShutdown() {
+        return inboundShutdown;
+    }
+
+    boolean isOutboundShutdown() {
+        return outboundShutdown;
+    }
+
+    void shutdownInbound() {
+        inboundShutdown = true;
+    }
+
+    void shutdownOutbound() {
+        outboundShutdown = true;
+    }
+
     @Override
     public ChannelPipeline fireChannelRegistered() {
         head.fireChannelRegistered();