ChunkedInput.readChunk parameter of type ByteBufAllocator

Motivation:
ChunkedInput.readChunk currently takes a ChannelHandlerContext object as a parameters. All current implementations of this interface only use this object to get the ByteBufAllocator object. Thus taking a ChannelHandlerContext as a parameter is more restrictive for users of this API than necessary.

Modifications:
- Add a new method readChunk(ByteBufAllocator)
- Deprecate readChunk(ChannelHandlerContext) and updates all implementations to call readChunk(ByteBufAllocator)

Result:
API that only requires ByteBufAllocator to use ChunkedInput.

codec-http/src/main/java/io/netty/handler/codec/http/HttpChunkedInput.java

@@ -16,6 +16,7 @@
 package io.netty.handler.codec.http;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.stream.ChunkedInput;
 
@@ -81,8 +82,14 @@ public class HttpChunkedInput implements ChunkedInput<HttpContent> {
         input.close();
     }
 
+    @Deprecated
     @Override
     public HttpContent readChunk(ChannelHandlerContext ctx) throws Exception {
+        return readChunk(ctx.alloc());
+    }
+
+    @Override
+    public HttpContent readChunk(ByteBufAllocator allocator) throws Exception {
         if (input.isEndOfInput()) {
             if (sentLastChunk) {
                 return null;
@@ -92,7 +99,7 @@ public class HttpChunkedInput implements ChunkedInput<HttpContent> {
                 return lastHttpContent;
             }
         } else {
-            ByteBuf buf = input.readChunk(ctx);
+            ByteBuf buf = input.readChunk(allocator);
             return new DefaultHttpContent(buf);
         }
     }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/HttpPostRequestEncoder.java

@@ -16,6 +16,7 @@
 package io.netty.handler.codec.http.multipart;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.DecoderResult;
 import io.netty.handler.codec.http.DefaultFullHttpRequest;
@@ -997,6 +998,12 @@ public class HttpPostRequestEncoder implements ChunkedInput<HttpContent> {
         // cleanFiles();
     }
 
+    @Deprecated
+    @Override
+    public HttpContent readChunk(ChannelHandlerContext ctx) throws Exception {
+        return readChunk(ctx.alloc());
+    }
+
     /**
      * Returns the next available HttpChunk. The caller is responsible to test if this chunk is the last one (isLast()),
      * in order to stop calling this getMethod.
@@ -1006,7 +1013,7 @@ public class HttpPostRequestEncoder implements ChunkedInput<HttpContent> {
      *             if the encoding is in error
      */
     @Override
-    public HttpContent readChunk(ChannelHandlerContext ctx) throws Exception {
+    public HttpContent readChunk(ByteBufAllocator allocator) throws Exception {
         if (isLastChunkSent) {
             return null;
         } else {

codec-http/src/test/java/io/netty/handler/codec/http/multipart/HttpPostRequestEncoderTest.java

@@ -16,6 +16,7 @@
 package io.netty.handler.codec.http.multipart;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.buffer.SlicedByteBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.handler.codec.http.DefaultFullHttpRequest;
@@ -31,8 +32,11 @@ import java.io.File;
 import java.util.Arrays;
 import java.util.List;
 
-import static io.netty.handler.codec.http.HttpHeaderNames.*;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_DISPOSITION;
-import static org.junit.Assert.*;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TRANSFER_ENCODING;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TYPE;
+import static org.junit.Assert.assertEquals;
 
 /** {@link HttpPostRequestEncoder} test case. */
 public class HttpPostRequestEncoderTest {
@@ -220,7 +224,7 @@ public class HttpPostRequestEncoderTest {
         encoder.addBodyFileUpload("myfile", file1, "application/x-zip-compressed", false);
         encoder.finalizeRequest();
         while (! encoder.isEndOfInput()) {
-            HttpContent httpContent = encoder.readChunk(null);
+            HttpContent httpContent = encoder.readChunk((ByteBufAllocator) null);
             if (httpContent.content() instanceof SlicedByteBuf) {
                 assertEquals(2, httpContent.content().refCnt());
             } else {

handler/src/main/java/io/netty/handler/stream/ChunkedFile.java

@@ -16,6 +16,7 @@
 package io.netty.handler.stream;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.FileRegion;
 
@@ -137,8 +138,14 @@ public class ChunkedFile implements ChunkedInput<ByteBuf> {
         file.close();
     }
 
+    @Deprecated
     @Override
     public ByteBuf readChunk(ChannelHandlerContext ctx) throws Exception {
+        return readChunk(ctx.alloc());
+    }
+
+    @Override
+    public ByteBuf readChunk(ByteBufAllocator allocator) throws Exception {
         long offset = this.offset;
         if (offset >= endOffset) {
             return null;
@@ -147,7 +154,7 @@ public class ChunkedFile implements ChunkedInput<ByteBuf> {
         int chunkSize = (int) Math.min(this.chunkSize, endOffset - offset);
         // Check if the buffer is backed by an byte array. If so we can optimize it a bit an safe a copy
 
-        ByteBuf buf = ctx.alloc().heapBuffer(chunkSize);
+        ByteBuf buf = allocator.heapBuffer(chunkSize);
         boolean release = true;
         try {
             file.readFully(buf.array(), buf.arrayOffset(), chunkSize);

handler/src/main/java/io/netty/handler/stream/ChunkedInput.java

@@ -16,6 +16,7 @@
 package io.netty.handler.stream;
 
 
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 
 /**
@@ -35,18 +36,36 @@ public interface ChunkedInput<B> {
     void close() throws Exception;
 
     /**
-     * Fetches a chunked data from the stream. Once this method returns the last chunk
+     * @deprecated Use {@link #readChunk(ByteBufAllocator)}.
+     *
+     * <p>Fetches a chunked data from the stream. Once this method returns the last chunk
      * and thus the stream has reached at its end, any subsequent {@link #isEndOfInput()}
      * call must return {@code true}.
      *
+     * @param ctx The context which provides a {@link ByteBufAllocator} if buffer allocation is necessary.
      * @return the fetched chunk.
      *         {@code null} if there is no data left in the stream.
      *         Please note that {@code null} does not necessarily mean that the
      *         stream has reached at its end.  In a slow stream, the next chunk
      *         might be unavailable just momentarily.
      */
+    @Deprecated
     B readChunk(ChannelHandlerContext ctx) throws Exception;
 
+    /**
+     * Fetches a chunked data from the stream. Once this method returns the last chunk
+     * and thus the stream has reached at its end, any subsequent {@link #isEndOfInput()}
+     * call must return {@code true}.
+     *
+     * @param a {@link ByteBufAllocator} if buffer allocation is necessary.
+     * @return the fetched chunk.
+     *         {@code null} if there is no data left in the stream.
+     *         Please note that {@code null} does not necessarily mean that the
+     *         stream has reached at its end.  In a slow stream, the next chunk
+     *         might be unavailable just momentarily.
+     */
+    B readChunk(ByteBufAllocator allocator) throws Exception;
+
     /**
      * Returns the length of the input.
      * @return  the length of the input if the length of the input is known.

handler/src/main/java/io/netty/handler/stream/ChunkedNioFile.java

@@ -16,6 +16,7 @@
 package io.netty.handler.stream;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.FileRegion;
 
@@ -141,15 +142,21 @@ public class ChunkedNioFile implements ChunkedInput<ByteBuf> {
         in.close();
     }
 
+    @Deprecated
     @Override
     public ByteBuf readChunk(ChannelHandlerContext ctx) throws Exception {
+        return readChunk(ctx.alloc());
+    }
+
+    @Override
+    public ByteBuf readChunk(ByteBufAllocator allocator) throws Exception {
         long offset = this.offset;
         if (offset >= endOffset) {
             return null;
         }
 
         int chunkSize = (int) Math.min(this.chunkSize, endOffset - offset);
-        ByteBuf buffer = ctx.alloc().buffer(chunkSize);
+        ByteBuf buffer = allocator.buffer(chunkSize);
         boolean release = true;
         try {
             int readBytes = 0;

handler/src/main/java/io/netty/handler/stream/ChunkedNioStream.java

@@ -16,6 +16,7 @@
 package io.netty.handler.stream;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 
 import java.nio.ByteBuffer;
@@ -96,8 +97,14 @@ public class ChunkedNioStream implements ChunkedInput<ByteBuf> {
         in.close();
     }
 
+    @Deprecated
     @Override
     public ByteBuf readChunk(ChannelHandlerContext ctx) throws Exception {
+        return readChunk(ctx.alloc());
+    }
+
+    @Override
+    public ByteBuf readChunk(ByteBufAllocator allocator) throws Exception {
         if (isEndOfInput()) {
             return null;
         }
@@ -116,7 +123,7 @@ public class ChunkedNioStream implements ChunkedInput<ByteBuf> {
         }
         byteBuffer.flip();
         boolean release = true;
-        ByteBuf buffer = ctx.alloc().buffer(byteBuffer.remaining());
+        ByteBuf buffer = allocator.buffer(byteBuffer.remaining());
         try {
             buffer.writeBytes(byteBuffer);
             byteBuffer.clear();

handler/src/main/java/io/netty/handler/stream/ChunkedStream.java

@@ -16,6 +16,7 @@
 package io.netty.handler.stream;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 
 import java.io.InputStream;
@@ -99,8 +100,14 @@ public class ChunkedStream implements ChunkedInput<ByteBuf> {
         in.close();
     }
 
+    @Deprecated
     @Override
     public ByteBuf readChunk(ChannelHandlerContext ctx) throws Exception {
+        return readChunk(ctx.alloc());
+    }
+
+    @Override
+    public ByteBuf readChunk(ByteBufAllocator allocator) throws Exception {
         if (isEndOfInput()) {
             return null;
         }
@@ -114,7 +121,7 @@ public class ChunkedStream implements ChunkedInput<ByteBuf> {
         }
 
         boolean release = true;
-        ByteBuf buffer = ctx.alloc().buffer(chunkSize);
+        ByteBuf buffer = allocator.buffer(chunkSize);
         try {
             // transfer to buffer
             offset += buffer.writeBytes(in, chunkSize);

handler/src/main/java/io/netty/handler/stream/ChunkedWriteHandler.java

@@ -15,6 +15,7 @@
  */
 package io.netty.handler.stream;
 
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelDuplexHandler;
@@ -203,6 +204,7 @@ public class ChunkedWriteHandler extends ChannelDuplexHandler {
         }
 
         boolean flushed = false;
+        ByteBufAllocator allocator = ctx.alloc();
         while (channel.isWritable()) {
             if (currentWrite == null) {
                 currentWrite = queue.poll();
@@ -220,7 +222,7 @@ public class ChunkedWriteHandler extends ChannelDuplexHandler {
                 boolean suspend;
                 Object message = null;
                 try {
-                    message = chunks.readChunk(ctx);
+                    message = chunks.readChunk(allocator);
                     endOfInput = chunks.isEndOfInput();
 
                     if (message == null) {

handler/src/test/java/io/netty/handler/stream/ChunkedWriteHandlerTest.java

@@ -16,6 +16,7 @@
 package io.netty.handler.stream;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
@@ -31,8 +32,10 @@ import java.io.IOException;
 import java.nio.channels.Channels;
 import java.util.concurrent.atomic.AtomicBoolean;
 
-import static io.netty.util.ReferenceCountUtil.*;
+import static io.netty.util.ReferenceCountUtil.releaseLater;
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 
 public class ChunkedWriteHandlerTest {
     private static final byte[] BYTES = new byte[1024 * 64];
@@ -116,8 +119,14 @@ public class ChunkedWriteHandlerTest {
                 // NOOP
             }
 
+            @Deprecated
             @Override
             public ByteBuf readChunk(ChannelHandlerContext ctx) throws Exception {
+                return readChunk(ctx.alloc());
+            }
+
+            @Override
+            public ByteBuf readChunk(ByteBufAllocator allocator) throws Exception {
                 if (done) {
                     return null;
                 }
@@ -173,8 +182,14 @@ public class ChunkedWriteHandlerTest {
                 // NOOP
             }
 
+            @Deprecated
             @Override
             public Object readChunk(ChannelHandlerContext ctx) throws Exception {
+                return readChunk(ctx.alloc());
+            }
+
+            @Override
+            public Object readChunk(ByteBufAllocator ctx) throws Exception {
                 if (done) {
                     return false;
                 }