Refactor the pipeline API to support stacked codecs

- Previous API did not support the pipeline which contains multiple
  MessageToStreamEncoders because there was no way to find the closest
  outbound byte buffer.  Now you always get the correct buffer even if
  the handler that provides the buffer is placed distantly.
  For example:
  
    Channel -> MsgAEncoder -> MsgBEncoder -> MsgCEncoder
  
  Msg(A|B|C)Encoder will all have access to the channel's outbound
  byte buffer.  Previously, it was simply impossible.

- Improved ChannelBufferHolder.toString()

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdySessionHandler.java

@@ -78,7 +78,7 @@ public class SpdySessionHandler extends ChannelHandlerAdapter<Object, Object> {
     @Override
     public void inboundBufferUpdated(ChannelInboundHandlerContext<Object> ctx)
             throws Exception {
-        Queue<Object> in = ctx.in().messageBuffer();
+        Queue<Object> in = ctx.inbound().messageBuffer();
         for (;;) {
             Object msg = in.poll();
             if (msg == null) {
@@ -272,7 +272,7 @@ public class SpdySessionHandler extends ChannelHandlerAdapter<Object, Object> {
             }
         }
 
-        ctx.nextIn().messageBuffer().add(msg);
+        ctx.nextInboundMessageBuffer().add(msg);
     }
 
     @Override
@@ -303,7 +303,7 @@ public class SpdySessionHandler extends ChannelHandlerAdapter<Object, Object> {
     public void flush(ChannelOutboundHandlerContext<Object> ctx,
             ChannelFuture future) throws Exception {
 
-        Queue<Object> in = ctx.prevOut().messageBuffer();
+        Queue<Object> in = ctx.outbound().messageBuffer();
         for (;;) {
             Object msg = in.poll();
             if (msg == null) {
@@ -394,7 +394,7 @@ public class SpdySessionHandler extends ChannelHandlerAdapter<Object, Object> {
             }
         }
 
-        ctx.out().messageBuffer().add(msg);
+        ctx.nextOutboundMessageBuffer().add(msg);
     }
 
     /*

codec-http/src/test/java/io/netty/handler/codec/spdy/AbstractSocketSpdyEchoTest.java

@@ -248,7 +248,7 @@ public abstract class AbstractSocketSpdyEchoTest {
         @Override
         public void inboundBufferUpdated(ChannelInboundHandlerContext<Byte> ctx)
                 throws Exception {
-            ChannelBuffer m = ctx.in().byteBuffer().readBytes(ctx.in().byteBuffer().readableBytes());
+            ChannelBuffer m = ctx.inbound().byteBuffer().readBytes(ctx.inbound().byteBuffer().readableBytes());
             byte[] actual = new byte[m.readableBytes()];
             m.getBytes(0, actual);
 

codec/src/main/java/io/netty/handler/codec/MessageToMessageDecoder.java

@@ -19,7 +19,7 @@ public abstract class MessageToMessageDecoder<I, O> extends ChannelInboundHandle
     @Override
     public void inboundBufferUpdated(ChannelInboundHandlerContext<I> ctx)
             throws Exception {
-        Queue<I> in = ctx.in().messageBuffer();
+        Queue<I> in = ctx.inbound().messageBuffer();
         boolean decoded = false;
         for (;;) {
             try {
@@ -35,7 +35,7 @@ public abstract class MessageToMessageDecoder<I, O> extends ChannelInboundHandle
                     continue;
                 }
 
-                if (unfoldAndAdd(ctx, ctx.nextIn(), emsg)) {
+                if (unfoldAndAdd(ctx, ctx.nextInboundMessageBuffer(), emsg)) {
                     decoded = true;
                 }
             } catch (Throwable t) {

codec/src/main/java/io/netty/handler/codec/MessageToMessageEncoder.java

@@ -1,6 +1,5 @@
 package io.netty.handler.codec;
 
-import io.netty.buffer.ChannelBuffer;
 import io.netty.channel.ChannelBufferHolder;
 import io.netty.channel.ChannelBufferHolders;
 import io.netty.channel.ChannelFuture;
@@ -20,7 +19,7 @@ public abstract class MessageToMessageEncoder<I, O> extends ChannelOutboundHandl
 
     @Override
     public void flush(ChannelOutboundHandlerContext<I> ctx, ChannelFuture future) throws Exception {
-        Queue<I> in = ctx.prevOut().messageBuffer();
+        Queue<I> in = ctx.outbound().messageBuffer();
         boolean encoded = false;
         for (;;) {
             try {
@@ -36,7 +35,7 @@ public abstract class MessageToMessageEncoder<I, O> extends ChannelOutboundHandl
                     continue;
                 }
 
-                if (unfoldAndAdd(ctx, ctx.out(), emsg)) {
+                if (unfoldAndAdd(ctx, ctx.nextOutboundMessageBuffer(), emsg)) {
                     encoded = true;
                 }
             } catch (Throwable t) {
@@ -56,7 +55,7 @@ public abstract class MessageToMessageEncoder<I, O> extends ChannelOutboundHandl
     public abstract O encode(ChannelOutboundHandlerContext<I> ctx, I msg) throws Exception;
 
     static <T> boolean unfoldAndAdd(
-            ChannelHandlerContext ctx, ChannelBufferHolder<Object> dst, Object msg) throws Exception {
+            ChannelHandlerContext ctx, Queue<Object> dst, Object msg) throws Exception {
         if (msg == null) {
             return false;
         }
@@ -94,18 +93,7 @@ public abstract class MessageToMessageEncoder<I, O> extends ChannelOutboundHandl
             return added;
         }
 
-        if (dst.hasMessageBuffer()) {
+        dst.add(msg);
-            dst.messageBuffer().add(msg);
-        } else if (msg instanceof ChannelBuffer) {
-            ChannelBuffer buf = (ChannelBuffer) msg;
-            if (!buf.readable()) {
-                return false;
-            }
-            dst.byteBuffer().writeBytes(buf, buf.readerIndex(), buf.readableBytes());
-        } else {
-            throw new UnsupportedMessageTypeException(msg, ChannelBuffer.class);
-        }
-
         return true;
     }
 }

codec/src/main/java/io/netty/handler/codec/MessageToStreamEncoder.java

@@ -19,8 +19,8 @@ public abstract class MessageToStreamEncoder<I> extends ChannelOutboundHandlerAd
 
     @Override
     public void flush(ChannelOutboundHandlerContext<I> ctx, ChannelFuture future) throws Exception {
-        Queue<I> in = ctx.prevOut().messageBuffer();
+        Queue<I> in = ctx.outbound().messageBuffer();
-        ChannelBuffer out = ctx.out().byteBuffer();
+        ChannelBuffer out = ctx.nextOutboundByteBuffer();
 
         int oldOutSize = out.readableBytes();
         for (;;) {

codec/src/main/java/io/netty/handler/codec/ReplayingDecoder.java

@@ -378,7 +378,7 @@ public abstract class ReplayingDecoder<O, S extends Enum<S>> extends StreamToMes
         }
 
         try {
-            if (unfoldAndAdd(ctx, ctx.nextIn(), decodeLast(ctx, replayable))) {
+            if (unfoldAndAdd(ctx, ctx.nextInboundMessageBuffer(), decodeLast(ctx, replayable))) {
                 fireInboundBufferUpdated(ctx, in);
             }
         } catch (Signal replay) {
@@ -442,7 +442,7 @@ public abstract class ReplayingDecoder<O, S extends Enum<S>> extends StreamToMes
                 }
 
                 // A successful decode
-                if (unfoldAndAdd(ctx, ctx.nextIn(), result)) {
+                if (unfoldAndAdd(ctx, ctx.nextInboundMessageBuffer(), result)) {
                     decoded = true;
                 }
             } catch (Throwable t) {

codec/src/main/java/io/netty/handler/codec/StreamToMessageDecoder.java

@@ -27,13 +27,13 @@ public abstract class StreamToMessageDecoder<O> extends ChannelInboundHandlerAda
 
     @Override
     public void channelInactive(ChannelInboundHandlerContext<Byte> ctx) throws Exception {
-        ChannelBuffer in = ctx.in().byteBuffer();
+        ChannelBuffer in = ctx.inbound().byteBuffer();
         if (in.readable()) {
             callDecode(ctx);
         }
 
         try {
-            if (unfoldAndAdd(ctx, ctx.nextIn(), decodeLast(ctx, in))) {
+            if (unfoldAndAdd(ctx, ctx.nextInboundMessageBuffer(), decodeLast(ctx, in))) {
                 in.discardReadBytes();
                 ctx.fireInboundBufferUpdated();
             }
@@ -49,7 +49,7 @@ public abstract class StreamToMessageDecoder<O> extends ChannelInboundHandlerAda
     }
 
     protected void callDecode(ChannelInboundHandlerContext<Byte> ctx) {
-        ChannelBuffer in = ctx.in().byteBuffer();
+        ChannelBuffer in = ctx.inbound().byteBuffer();
 
         boolean decoded = false;
         for (;;) {
@@ -69,7 +69,7 @@ public abstract class StreamToMessageDecoder<O> extends ChannelInboundHandlerAda
                     }
                 }
 
-                if (unfoldAndAdd(ctx, ctx.nextIn(), o)) {
+                if (unfoldAndAdd(ctx, ctx.nextInboundMessageBuffer(), o)) {
                     decoded = true;
                 } else {
                     break;
@@ -109,10 +109,10 @@ public abstract class StreamToMessageDecoder<O> extends ChannelInboundHandlerAda
         // the new handler.
         ctx.pipeline().addAfter(ctx.name(), newHandlerName, newHandler);
 
-        ChannelBuffer in = ctx.in().byteBuffer();
+        ChannelBuffer in = ctx.inbound().byteBuffer();
         try {
             if (in.readable()) {
-                ctx.nextIn().byteBuffer().writeBytes(ctx.in().byteBuffer());
+                ctx.nextInboundByteBuffer().writeBytes(ctx.inbound().byteBuffer());
                 ctx.fireInboundBufferUpdated();
             }
         } finally {

codec/src/main/java/io/netty/handler/codec/StreamToStreamDecoder.java

@@ -21,12 +21,12 @@ public abstract class StreamToStreamDecoder extends ChannelInboundHandlerAdapter
 
     @Override
     public void channelInactive(ChannelInboundHandlerContext<Byte> ctx) throws Exception {
-        ChannelBuffer in = ctx.in().byteBuffer();
+        ChannelBuffer in = ctx.inbound().byteBuffer();
         if (!in.readable()) {
             callDecode(ctx);
         }
 
-        ChannelBuffer out = ctx.nextIn().byteBuffer();
+        ChannelBuffer out = ctx.nextInboundByteBuffer();
         int oldOutSize = out.readableBytes();
         try {
             decodeLast(ctx, in, out);
@@ -47,8 +47,8 @@ public abstract class StreamToStreamDecoder extends ChannelInboundHandlerAdapter
     }
 
     private void callDecode(ChannelInboundHandlerContext<Byte> ctx) {
-        ChannelBuffer in = ctx.in().byteBuffer();
+        ChannelBuffer in = ctx.inbound().byteBuffer();
-        ChannelBuffer out = ctx.nextIn().byteBuffer();
+        ChannelBuffer out = ctx.nextInboundByteBuffer();
 
         int oldOutSize = out.readableBytes();
         while (in.readable()) {

codec/src/main/java/io/netty/handler/codec/StreamToStreamEncoder.java

@@ -17,8 +17,8 @@ public abstract class StreamToStreamEncoder extends ChannelOutboundHandlerAdapte
 
     @Override
     public void flush(ChannelOutboundHandlerContext<Byte> ctx, ChannelFuture future) throws Exception {
-        ChannelBuffer in = ctx.prevOut().byteBuffer();
+        ChannelBuffer in = ctx.outbound().byteBuffer();
-        ChannelBuffer out = ctx.out().byteBuffer();
+        ChannelBuffer out = ctx.nextOutboundByteBuffer();
 
         int oldOutSize = out.readableBytes();
         while (in.readable()) {

codec/src/main/java/io/netty/handler/codec/embedder/DecoderEmbedder.java

@@ -57,7 +57,7 @@ public class DecoderEmbedder<E> extends AbstractCodecEmbedder<E> {
 
     @Override
     public boolean offer(Object input) {
-        ChannelBufferHolder<Object> in = pipeline().nextIn();
+        ChannelBufferHolder<Object> in = pipeline().inbound();
         if (in.hasByteBuffer()) {
             in.byteBuffer().writeBytes((ChannelBuffer) input);
         } else {

example/src/main/java/io/netty/example/discard/DiscardClientHandler.java

@@ -34,7 +34,6 @@ public class DiscardClientHandler extends ChannelInboundStreamHandlerAdapter {
 
     private final byte[] content;
     private ChannelInboundHandlerContext<Byte> ctx;
-    private ChannelBuffer out;
 
     public DiscardClientHandler(int messageSize) {
         if (messageSize <= 0) {
@@ -49,7 +48,6 @@ public class DiscardClientHandler extends ChannelInboundStreamHandlerAdapter {
     public void channelActive(ChannelInboundHandlerContext<Byte> ctx)
             throws Exception {
         this.ctx = ctx;
-        out = ctx.out().byteBuffer();
         // Send the initial messages.
         generateTraffic();
     }
@@ -77,6 +75,7 @@ public class DiscardClientHandler extends ChannelInboundStreamHandlerAdapter {
 
     private void generateTraffic() {
         // Fill the outbound buffer up to 64KiB
+        ChannelBuffer out = ctx.nextOutboundByteBuffer();
         while (out.readableBytes() < 65536) {
             out.writeBytes(content);
         }
@@ -90,7 +89,7 @@ public class DiscardClientHandler extends ChannelInboundStreamHandlerAdapter {
         @Override
         public void operationComplete(ChannelFuture future) throws Exception {
             if (future.isSuccess()) {
-                out.clear();
+                ctx.nextOutboundByteBuffer().discardReadBytes();
                 generateTraffic();
             }
         }

example/src/main/java/io/netty/example/discard/DiscardServerHandler.java

@@ -34,7 +34,7 @@ public class DiscardServerHandler extends ChannelInboundStreamHandlerAdapter {
     public void inboundBufferUpdated(ChannelInboundHandlerContext<Byte> ctx)
             throws Exception {
         // Discard the received data silently.
-        ctx.in().byteBuffer().clear();
+        ctx.inbound().byteBuffer().clear();
     }
 
 

example/src/main/java/io/netty/example/echo/EchoClientHandler.java

@@ -62,8 +62,8 @@ public class EchoClientHandler extends ChannelInboundHandlerAdapter<Byte> {
 
     @Override
     public void inboundBufferUpdated(ChannelInboundHandlerContext<Byte> ctx) {
-        ChannelBuffer in = ctx.in().byteBuffer();
+        ChannelBuffer in = ctx.inbound().byteBuffer();
-        ChannelBuffer out = ctx.out().byteBuffer();
+        ChannelBuffer out = ctx.nextOutboundByteBuffer();
         out.discardReadBytes();
         out.writeBytes(in);
         in.discardReadBytes();

example/src/main/java/io/netty/example/echo/EchoServerHandler.java

@@ -39,8 +39,8 @@ public class EchoServerHandler extends ChannelInboundHandlerAdapter<Byte> {
 
     @Override
     public void inboundBufferUpdated(ChannelInboundHandlerContext<Byte> ctx) {
-        ChannelBuffer in = ctx.in().byteBuffer();
+        ChannelBuffer in = ctx.inbound().byteBuffer();
-        ChannelBuffer out = ctx.out().byteBuffer();
+        ChannelBuffer out = ctx.nextOutboundByteBuffer();
         out.discardReadBytes();
         out.writeBytes(in);
         in.discardReadBytes();

example/src/main/java/io/netty/example/factorial/FactorialClientHandler.java

@@ -40,7 +40,6 @@ public class FactorialClientHandler extends ChannelInboundMessageHandlerAdapter<
             FactorialClientHandler.class.getName());
 
     private ChannelInboundHandlerContext<BigInteger> ctx;
-    private Queue<Object> out;
     private int i = 1;
     private int receivedMessages;
     private final int count;
@@ -68,7 +67,6 @@ public class FactorialClientHandler extends ChannelInboundMessageHandlerAdapter<
     @Override
     public void channelActive(ChannelInboundHandlerContext<BigInteger> ctx) {
         this.ctx = ctx;
-        out = ctx.out().messageBuffer();
         sendNumbers();
     }
 
@@ -101,6 +99,7 @@ public class FactorialClientHandler extends ChannelInboundMessageHandlerAdapter<
     private void sendNumbers() {
         // Do not send more than 4096 numbers.
         boolean finished = false;
+        Queue<Object> out = ctx.nextOutboundMessageBuffer();
         while (out.size() < 4096) {
             if (i <= count) {
                 out.add(Integer.valueOf(i));

handler/src/main/java/io/netty/handler/logging/LoggingHandler.java

@@ -352,7 +352,7 @@ public class LoggingHandler extends ChannelHandlerAdapter<Object, Object> {
     public void inboundBufferUpdated(ChannelInboundHandlerContext<Object> ctx)
             throws Exception {
         if (getLogger().isEnabled(internalLevel)) {
-            logger.log(internalLevel, format(ctx, formatBuffer("INBUF", ctx.in())));
+            logger.log(internalLevel, format(ctx, formatBuffer("INBUF", ctx.inbound())));
         }
         ctx.fireInboundBufferUpdated();
     }
@@ -407,7 +407,7 @@ public class LoggingHandler extends ChannelHandlerAdapter<Object, Object> {
     public void flush(ChannelOutboundHandlerContext<Object> ctx,
             ChannelFuture future) throws Exception {
         if (getLogger().isEnabled(internalLevel)) {
-            logger.log(internalLevel, format(ctx, formatBuffer("OUTBUF", ctx.prevOut())));
+            logger.log(internalLevel, format(ctx, formatBuffer("OUTBUF", ctx.outbound())));
         }
         ctx.flush(future);
     }

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

@@ -259,8 +259,8 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
     }
 
     @Override
-    public ChannelBufferHolder<Object> out() {
+    public ChannelBufferHolder<Object> outbound() {
-        return pipeline().out();
+        return pipeline().outbound();
     }
 
     @Override

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

@@ -37,7 +37,7 @@ public abstract class AbstractServerChannel extends AbstractChannel implements S
     }
 
     @Override
-    public ChannelBufferHolder<Object> out() {
+    public ChannelBufferHolder<Object> outbound() {
         return ChannelBufferHolders.discardBuffer();
     }
 

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

@@ -136,6 +136,8 @@ public interface Channel extends AttributeMap, ChannelOutboundInvoker, ChannelFu
     boolean isRegistered();
     boolean isActive();
 
+    ChannelBufferHolder<Object> outbound();
+
     /**
      * Returns the local address where this channel is bound to.  The returned
      * {@link SocketAddress} is supposed to be down-cast into more concrete

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

@@ -59,9 +59,9 @@ public final class ChannelBufferHolder<E> {
         case 0:
             return msgBuf != null;
         case 1:
-            return ctx.nextIn().hasMessageBuffer();
+            return ctx.nextInboundMessageBuffer() != null;
         case 2:
-            return ctx.out().hasMessageBuffer();
+            return ctx.nextOutboundMessageBuffer() != null;
         default:
             throw new Error();
         }
@@ -72,15 +72,14 @@ public final class ChannelBufferHolder<E> {
         case 0:
             return byteBuf != null;
         case 1:
-            return ctx.nextIn().hasByteBuffer();
+            return ctx.nextInboundByteBuffer() != null;
         case 2:
-            return ctx.out().hasByteBuffer();
+            return ctx.nextOutboundByteBuffer() != null;
         default:
             throw new Error();
         }
     }
 
-    @SuppressWarnings("unchecked")
     public Queue<E> messageBuffer() {
         switch (bypassDirection) {
         case 0:
@@ -89,9 +88,9 @@ public final class ChannelBufferHolder<E> {
             }
             return msgBuf;
         case 1:
-            return (Queue<E>) ctx.nextIn().messageBuffer();
+            return (Queue<E>) ctx.nextInboundMessageBuffer();
         case 2:
-            return (Queue<E>) ctx.out().messageBuffer();
+            return (Queue<E>) ctx.nextOutboundMessageBuffer();
         default:
             throw new Error();
         }
@@ -105,9 +104,9 @@ public final class ChannelBufferHolder<E> {
             }
             return byteBuf;
         case 1:
-            return ctx.nextIn().byteBuffer();
+            return ctx.nextInboundByteBuffer();
         case 2:
-            return ctx.out().byteBuffer();
+            return ctx.nextOutboundByteBuffer();
         default:
             throw new Error();
         }
@@ -118,14 +117,18 @@ public final class ChannelBufferHolder<E> {
         switch (bypassDirection) {
         case 0:
             if (msgBuf != null) {
-                return msgBuf.toString();
+                if (byteBuf != null) {
+                    return "CatchAllBuffer";
+                } else {
+                    return "MessageBuffer(" + msgBuf.size() + ')';
+                }
             } else {
                 return byteBuf.toString();
             }
         case 1:
-            return ctx.nextIn().toString();
+            return "InboundBypassBuffer";
         case 2:
-            return ctx.out().toString();
+            return "OutboundBypassBuffer";
         default:
             throw new Error();
         }
@@ -140,9 +143,8 @@ public final class ChannelBufferHolder<E> {
                 return byteBuf.readableBytes();
             }
         case 1:
-            return ctx.nextIn().size();
         case 2:
-            return ctx.out().size();
+            throw new UnsupportedOperationException();
         default:
             throw new Error();
         }
@@ -157,9 +159,8 @@ public final class ChannelBufferHolder<E> {
                 return byteBuf.readable();
             }
         case 1:
-            return ctx.nextIn().isEmpty();
         case 2:
-            return ctx.out().isEmpty();
+            throw new UnsupportedOperationException();
         default:
             throw new Error();
         }

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

@@ -16,9 +16,11 @@
 package io.netty.channel;
 
 
+import io.netty.buffer.ChannelBuffer;
 import io.netty.util.AttributeMap;
 
 import java.nio.channels.Channels;
+import java.util.Queue;
 
 /**
  * Enables a {@link ChannelHandler} to interact with its {@link ChannelPipeline}
@@ -133,4 +135,10 @@ public interface ChannelHandlerContext
 
     boolean canHandleInbound();
     boolean canHandleOutbound();
+
+    ChannelBuffer nextInboundByteBuffer();
+    Queue<Object> nextInboundMessageBuffer();
+
+    ChannelBuffer nextOutboundByteBuffer();
+    Queue<Object> nextOutboundMessageBuffer();
 }

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

@@ -61,14 +61,14 @@ public abstract class ChannelInboundHandlerAdapter<I> implements ChannelInboundH
     }
 
     static <I> void inboundBufferUpdated0(ChannelInboundHandlerContext<I> ctx) {
-        if (ctx.in().isBypass()) {
+        if (ctx.inbound().isBypass()) {
             ctx.fireInboundBufferUpdated();
             return;
         }
 
-        if (ctx.in().hasMessageBuffer()) {
+        if (ctx.inbound().hasMessageBuffer()) {
-            Queue<I> in = ctx.in().messageBuffer();
+            Queue<I> in = ctx.inbound().messageBuffer();
-            Queue<Object> nextIn = ctx.nextIn().messageBuffer();
+            Queue<Object> nextIn = ctx.nextInboundMessageBuffer();
             for (;;) {
                 I msg = in.poll();
                 if (msg == null) {
@@ -77,8 +77,8 @@ public abstract class ChannelInboundHandlerAdapter<I> implements ChannelInboundH
                 nextIn.add(msg);
             }
         } else {
-            ChannelBuffer in = ctx.in().byteBuffer();
+            ChannelBuffer in = ctx.inbound().byteBuffer();
-            ChannelBuffer nextIn = ctx.nextIn().byteBuffer();
+            ChannelBuffer nextIn = ctx.nextInboundByteBuffer();
             nextIn.writeBytes(in);
             in.discardReadBytes();
         }

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

@@ -1,5 +1,5 @@
 package io.netty.channel;
 
 public interface ChannelInboundHandlerContext<I> extends ChannelHandlerContext {
-    ChannelBufferHolder<I> in();
+    ChannelBufferHolder<I> inbound();
 }

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

@@ -2,8 +2,6 @@ package io.netty.channel;
 
 
 public interface ChannelInboundInvoker {
-    ChannelBufferHolder<Object> nextIn();
-
     void fireChannelRegistered();
     void fireChannelUnregistered();
     void fireChannelActive();

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

@@ -14,7 +14,7 @@ public class ChannelInboundMessageHandlerAdapter<I> extends
     @Override
     public void inboundBufferUpdated(ChannelInboundHandlerContext<I> ctx)
             throws Exception {
-        Queue<I> in = ctx.in().messageBuffer();
+        Queue<I> in = ctx.inbound().messageBuffer();
         for (;;) {
             I msg = in.poll();
             if (msg == null) {
@@ -30,6 +30,6 @@ public class ChannelInboundMessageHandlerAdapter<I> extends
     }
 
     public void messageReceived(ChannelInboundHandlerContext<I> ctx, I msg) throws Exception {
-        ctx.nextIn().messageBuffer().add(msg);
+        ctx.nextInboundMessageBuffer().add(msg);
     }
 }

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

@@ -57,14 +57,14 @@ public abstract class ChannelOutboundHandlerAdapter<O> implements ChannelOutboun
     }
 
     static <O> void flush0(ChannelOutboundHandlerContext<O> ctx, ChannelFuture future) {
-        if (ctx.prevOut().isBypass()) {
+        if (ctx.outbound().isBypass()) {
             ctx.flush(future);
             return;
         }
 
-        if (ctx.prevOut().hasMessageBuffer()) {
+        if (ctx.outbound().hasMessageBuffer()) {
-            Queue<O> out = ctx.prevOut().messageBuffer();
+            Queue<O> out = ctx.outbound().messageBuffer();
-            Queue<Object> nextOut = ctx.out().messageBuffer();
+            Queue<Object> nextOut = ctx.nextOutboundMessageBuffer();
             for (;;) {
                 O msg = out.poll();
                 if (msg == null) {
@@ -73,8 +73,8 @@ public abstract class ChannelOutboundHandlerAdapter<O> implements ChannelOutboun
                 nextOut.add(msg);
             }
         } else {
-            ChannelBuffer out = ctx.prevOut().byteBuffer();
+            ChannelBuffer out = ctx.outbound().byteBuffer();
-            ChannelBuffer nextOut = ctx.out().byteBuffer();
+            ChannelBuffer nextOut = ctx.nextOutboundByteBuffer();
             nextOut.writeBytes(out);
             out.discardReadBytes();
         }

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

@@ -2,5 +2,5 @@ package io.netty.channel;
 
 
 public interface ChannelOutboundHandlerContext<O> extends ChannelHandlerContext {
-    ChannelBufferHolder<O> prevOut();
+    ChannelBufferHolder<O> outbound();
 }

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

@@ -3,8 +3,6 @@ package io.netty.channel;
 import java.net.SocketAddress;
 
 public interface ChannelOutboundInvoker {
-    ChannelBufferHolder<Object> out();
-
     ChannelFuture bind(SocketAddress localAddress);
     ChannelFuture connect(SocketAddress remoteAddress);
     ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress);

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

@@ -205,6 +205,9 @@ import java.util.NoSuchElementException;
  */
 public interface ChannelPipeline extends ChannelInboundInvoker, ChannelOutboundInvoker {
 
+    ChannelBufferHolder<Object> inbound();
+    ChannelBufferHolder<Object> outbound();
+
     /**
      * Inserts a {@link ChannelHandler} at the first position of this pipeline.
      *

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

@@ -27,6 +27,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.Queue;
 
 /**
  * The default {@link ChannelPipeline} implementation.  It is usually created
@@ -570,19 +571,19 @@ public class DefaultChannelPipeline implements ChannelPipeline {
     }
 
     @Override
-    public ChannelBufferHolder<Object> nextIn() {
+    public ChannelBufferHolder<Object> inbound() {
         DefaultChannelHandlerContext ctx = firstInboundContext();
         if (ctx != null) {
-            return ctx.in();
+            return ctx.inbound();
         }
         return null;
     }
 
     @Override
-    public ChannelBufferHolder<Object> out() {
+    public ChannelBufferHolder<Object> outbound() {
         DefaultChannelHandlerContext ctx = firstOutboundContext();
         if (ctx != null) {
-            return ctx.prevOut();
+            return ctx.outbound();
         }
         return channel().unsafe().out();
     }
@@ -903,11 +904,12 @@ public class DefaultChannelPipeline implements ChannelPipeline {
         }
         validateFuture(future);
 
-        if (out().hasMessageBuffer()) {
+        ChannelBufferHolder<Object> out = outbound();
-            out().messageBuffer().add(message);
+        if (out.hasMessageBuffer()) {
+            out.messageBuffer().add(message);
         } else if (message instanceof ChannelBuffer) {
             ChannelBuffer m = (ChannelBuffer) message;
-            out().byteBuffer().writeBytes(m, m.readerIndex(), m.readableBytes());
+            out.byteBuffer().writeBytes(m, m.readerIndex(), m.readableBytes());
         } else {
             throw new IllegalArgumentException(
                     "cannot write a message whose type is not " +
@@ -1057,7 +1059,7 @@ public class DefaultChannelPipeline implements ChannelPipeline {
         private final boolean canHandleInbound;
         private final boolean canHandleOutbound;
         private final ChannelBufferHolder<Object> in;
-        private final ChannelBufferHolder<Object> prevOut;
+        private final ChannelBufferHolder<Object> out;
 
         @SuppressWarnings("unchecked")
         DefaultChannelHandlerContext(
@@ -1096,7 +1098,7 @@ public class DefaultChannelPipeline implements ChannelPipeline {
             }
             if (canHandleOutbound) {
                 try {
-                    prevOut = ((ChannelOutboundHandler<Object>) handler).newOutboundBuffer(this);
+                    out = ((ChannelOutboundHandler<Object>) handler).newOutboundBuffer(this);
                 } catch (Exception e) {
                     throw new ChannelPipelineException("A user handler failed to create a new outbound buffer.", e);
                 } finally {
@@ -1105,7 +1107,7 @@ public class DefaultChannelPipeline implements ChannelPipeline {
                     }
                 }
             } else {
-                prevOut = null;
+                out = null;
             }
         }
 
@@ -1140,32 +1142,82 @@ public class DefaultChannelPipeline implements ChannelPipeline {
         }
 
         @Override
-        public ChannelBufferHolder<Object> in() {
+        public ChannelBufferHolder<Object> inbound() {
             return in;
         }
 
         @Override
-        public ChannelBufferHolder<Object> prevOut() {
+        public ChannelBufferHolder<Object> outbound() {
-            return prevOut;
+            return out;
         }
 
         @Override
-        public ChannelBufferHolder<Object> nextIn() {
+        public ChannelBuffer nextInboundByteBuffer() {
-            DefaultChannelHandlerContext next = nextInboundContext(this.next);
+            DefaultChannelHandlerContext ctx = this;
-            if (next != null) {
+            for (;;) {
-                return next.in();
+                ctx = nextInboundContext(ctx.next);
-            } else {
+                if (ctx == null) {
-                throw new NoSuchElementException("no inbound buffer in the rest of the pipeline");
+                    return null;
+                }
+                ChannelBufferHolder<Object> nextIn = ctx.inbound();
+                if (nextIn.hasByteBuffer()) {
+                    return nextIn.byteBuffer();
+                }
             }
         }
 
         @Override
-        public ChannelBufferHolder<Object> out() {
+        public Queue<Object> nextInboundMessageBuffer() {
-            DefaultChannelHandlerContext next = nextOutboundContext(prev);
+            DefaultChannelHandlerContext ctx = this;
-            if (next != null) {
+            for (;;) {
-                return next.prevOut();
+                ctx = nextInboundContext(ctx.next);
+                if (ctx == null) {
+                    return null;
+                }
+                ChannelBufferHolder<Object> nextIn = ctx.inbound();
+                if (nextIn.hasMessageBuffer()) {
+                    return nextIn.messageBuffer();
+                }
+            }
+        }
+
+        @Override
+        public ChannelBuffer nextOutboundByteBuffer() {
+            DefaultChannelHandlerContext ctx = this;
+            for (;;) {
+                ctx = nextOutboundContext(ctx.prev);
+                if (ctx == null) {
+                    ChannelBufferHolder<Object> lastOut = channel().unsafe().out();
+                    if (lastOut.hasByteBuffer()) {
+                        return lastOut.byteBuffer();
                     } else {
-                return channel().unsafe().out();
+                        return null;
+                    }
+                }
+                ChannelBufferHolder<Object> nextOut = ctx.outbound();
+                if (nextOut.hasByteBuffer()) {
+                    return nextOut.byteBuffer();
+                }
+            }
+        }
+
+        @Override
+        public Queue<Object> nextOutboundMessageBuffer() {
+            DefaultChannelHandlerContext ctx = this;
+            for (;;) {
+                ctx = nextOutboundContext(ctx.prev);
+                if (ctx == null) {
+                    ChannelBufferHolder<Object> lastOut = channel().unsafe().out();
+                    if (lastOut.hasMessageBuffer()) {
+                        return lastOut.messageBuffer();
+                    } else {
+                        return null;
+                    }
+                }
+                ChannelBufferHolder<Object> nextOut = ctx.outbound();
+                if (nextOut.hasMessageBuffer()) {
+                    return nextOut.messageBuffer();
+                }
             }
         }
 
@@ -1304,9 +1356,9 @@ public class DefaultChannelPipeline implements ChannelPipeline {
         public ChannelFuture write(Object message, ChannelFuture future) {
             if (message instanceof ChannelBuffer) {
                 ChannelBuffer m = (ChannelBuffer) message;
-                out().byteBuffer().writeBytes(m, m.readerIndex(), m.readableBytes());
+                nextOutboundByteBuffer().writeBytes(m, m.readerIndex(), m.readableBytes());
             } else {
-                out().messageBuffer().add(message);
+                nextOutboundMessageBuffer().add(message);
             }
             return flush(future);
         }

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

@@ -180,7 +180,7 @@ public class ServerChannelBootstrap {
 
         @Override
         public void inboundBufferUpdated(ChannelInboundHandlerContext<Channel> ctx) {
-            Queue<Channel> in = ctx.in().messageBuffer();
+            Queue<Channel> in = ctx.inbound().messageBuffer();
             for (;;) {
                 Channel child = in.poll();
                 if (child == null) {

transport/src/main/java/io/netty/channel/socket/nio/AbstractNioMessageChannel.java

@@ -34,7 +34,7 @@ abstract class AbstractNioMessageChannel extends AbstractNioChannel {
             assert eventLoop().inEventLoop();
 
             final ChannelPipeline pipeline = pipeline();
-            final ChannelBufferHolder<Object> buf = pipeline.nextIn();
+            final ChannelBufferHolder<Object> buf = pipeline.inbound();
             boolean closed = false;
             boolean read = false;
             try {

transport/src/main/java/io/netty/channel/socket/nio/AbstractNioStreamChannel.java

@@ -36,7 +36,7 @@ abstract class AbstractNioStreamChannel extends AbstractNioChannel {
             assert eventLoop().inEventLoop();
 
             final ChannelPipeline pipeline = pipeline();
-            final ChannelBufferHolder<Object> buf = pipeline.nextIn();
+            final ChannelBufferHolder<Object> buf = pipeline.inbound();
             boolean closed = false;
             boolean read = false;
             try {

transport/src/main/java/io/netty/channel/socket/oio/AbstractOioMessageChannel.java

@@ -32,7 +32,7 @@ abstract class AbstractOioMessageChannel extends AbstractOioChannel {
             assert eventLoop().inEventLoop();
 
             final ChannelPipeline pipeline = pipeline();
-            final ChannelBufferHolder<Object> buf = pipeline.nextIn();
+            final ChannelBufferHolder<Object> buf = pipeline.inbound();
             boolean closed = false;
             boolean read = false;
             try {

transport/src/main/java/io/netty/channel/socket/oio/AbstractOioStreamChannel.java

@@ -33,7 +33,7 @@ abstract class AbstractOioStreamChannel extends AbstractOioChannel {
             assert eventLoop().inEventLoop();
 
             final ChannelPipeline pipeline = pipeline();
-            final ChannelBufferHolder<Object> buf = pipeline.nextIn();
+            final ChannelBufferHolder<Object> buf = pipeline.inbound();
             boolean closed = false;
             boolean read = false;
             try {