More convenient inbound stream handler / Smarter inbound buffer cleanup

- Added a new convenience method to ChannelInboundstreamHandlerAdapter 
- EchoServerHandler uses the new method
- DefaultChannelPipeline calls inboundByteBuffer.discardReadBytes()
  when it is sure there's no memory copy involved

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

@@ -22,8 +22,6 @@ import io.netty.channel.ChannelOption;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioEventLoop;
 import io.netty.channel.socket.nio.NioSocketChannel;
-import io.netty.handler.logging.LogLevel;
-import io.netty.handler.logging.LoggingHandler;
 
 import java.net.InetSocketAddress;
 
@@ -57,7 +55,7 @@ public class EchoClient {
                  @Override
                  public void initChannel(SocketChannel ch) throws Exception {
                      ch.pipeline().addLast(
-                             new LoggingHandler(LogLevel.INFO),
+                             //new LoggingHandler(LogLevel.INFO),
                              new EchoClientHandler(firstMessageSize));
                  }
              });

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

@@ -58,7 +58,7 @@ public class EchoServer {
                  @Override
                  public void initChannel(SocketChannel ch) throws Exception {
                      ch.pipeline().addLast(
-                             new LoggingHandler(LogLevel.INFO),
+                             //new LoggingHandler(LogLevel.INFO),
                              new EchoServerHandler());
                  }
              });

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

@@ -16,10 +16,8 @@
 package io.netty.example.echo;
 
 import io.netty.buffer.ChannelBuffer;
-import io.netty.channel.ChannelBufferHolder;
-import io.netty.channel.ChannelBufferHolders;
-import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInboundHandlerContext;
+import io.netty.channel.ChannelInboundStreamHandlerAdapter;
 
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -27,23 +25,16 @@ import java.util.logging.Logger;
 /**
  * Handler implementation for the echo server.
  */
-public class EchoServerHandler extends ChannelInboundHandlerAdapter<Byte> {
+public class EchoServerHandler extends ChannelInboundStreamHandlerAdapter {
 
     private static final Logger logger = Logger.getLogger(
             EchoServerHandler.class.getName());
 
     @Override
-    public ChannelBufferHolder<Byte> newInboundBuffer(ChannelInboundHandlerContext<Byte> ctx) {
-        return ChannelBufferHolders.byteBuffer();
-    }
-
-    @Override
-    public void inboundBufferUpdated(ChannelInboundHandlerContext<Byte> ctx) {
-        ChannelBuffer in = ctx.inbound().byteBuffer();
+    public void inboundBufferUpdated(ChannelInboundHandlerContext<Byte> ctx, ChannelBuffer in) {
         ChannelBuffer out = ctx.nextOutboundByteBuffer();
         out.discardReadBytes();
         out.writeBytes(in);
-        in.discardReadBytes();
         ctx.flush();
     }
 

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

@@ -1,5 +1,7 @@
 package io.netty.channel;
 
+import io.netty.buffer.ChannelBuffer;
+
 
 public class ChannelInboundStreamHandlerAdapter extends ChannelInboundHandlerAdapter<Byte> {
     @Override
@@ -7,4 +9,16 @@ public class ChannelInboundStreamHandlerAdapter extends ChannelInboundHandlerAda
             ChannelInboundHandlerContext<Byte> ctx) throws Exception {
         return ChannelBufferHolders.byteBuffer();
     }
+
+    @Override
+    public void inboundBufferUpdated(ChannelInboundHandlerContext<Byte> ctx)
+            throws Exception {
+        inboundBufferUpdated(ctx, ctx.inbound().byteBuffer());
+    }
+
+    public void inboundBufferUpdated(ChannelInboundHandlerContext<Byte> ctx, ChannelBuffer in)
+            throws Exception {
+        ctx.nextInboundByteBuffer().writeBytes(in);
+        in.discardReadBytes();
+    }
 }

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

@@ -740,6 +740,11 @@ public class DefaultChannelPipeline implements ChannelPipeline {
             ((ChannelInboundHandler<Object>) ctx.handler()).inboundBufferUpdated(ctx);
         } catch (Throwable t) {
             notifyHandlerException(t);
+        } finally {
+            ChannelBufferHolder<Object> inbound = ctx.inbound();
+            if (inbound.isEmpty() && inbound.hasByteBuffer()) {
+                inbound.byteBuffer().discardReadBytes();
+            }
         }
     }