Add a HttpPostRequestDecoder.destory() method which should be used to destroy the decoder and free up resources

* Also make the contract more clear about who needs to call release()

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

@@ -33,7 +33,6 @@ import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
@@ -42,8 +41,11 @@ import static io.netty.buffer.Unpooled.*;
 
 /**
  * This decoder will decode Body and can handle POST BODY.
+ *
+ * You <strong>MUST</strong> call {@link #destroy()} after completion to release all resources.
+ *
  */
-public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
+public class HttpPostRequestDecoder {
     /**
      * Factory used to create InterfaceHttpData
      */
@@ -126,6 +128,8 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
      */
     private Attribute currentAttribute;
 
+    private boolean destroyed;
+
     /**
      *
      * @param request
@@ -273,12 +277,19 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
         }
     }
 
+    private void checkDestroyed() {
+        if (destroyed) {
+            throw new IllegalStateException(HttpPostRequestDecoder.class.getSimpleName() + " was destroyed already");
+        }
+    }
+
     /**
      * True if this request is a Multipart request
      *
      * @return True if this request is a Multipart request
      */
     public boolean isMultipart() {
+        checkDestroyed();
         return isMultipart;
     }
 
@@ -293,6 +304,8 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
      *             Need more chunks
      */
     public List<InterfaceHttpData> getBodyHttpDatas() throws NotEnoughDataDecoderException {
+        checkDestroyed();
+
         if (!isLastChunk) {
             throw new NotEnoughDataDecoderException();
         }
@@ -311,6 +324,8 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
      *             need more chunks
      */
     public List<InterfaceHttpData> getBodyHttpDatas(String name) throws NotEnoughDataDecoderException {
+        checkDestroyed();
+
         if (!isLastChunk) {
             throw new NotEnoughDataDecoderException();
         }
@@ -330,6 +345,8 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
      *             need more chunks
      */
     public InterfaceHttpData getBodyHttpData(String name) throws NotEnoughDataDecoderException {
+        checkDestroyed();
+
         if (!isLastChunk) {
             throw new NotEnoughDataDecoderException();
         }
@@ -350,6 +367,8 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
      *             errors
      */
     public HttpPostRequestDecoder offer(HttpContent content) throws ErrorDataDecoderException {
+        checkDestroyed();
+
         // Maybe we should better not copy here for performance reasons but this will need
         // more care by teh caller to release the content in a correct manner later
         // So maybe something to optimize on a later stage
@@ -380,6 +399,8 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
      *             No more data will be available
      */
     public boolean hasNext() throws EndOfDataDecoderException {
+        checkDestroyed();
+
         if (currentStatus == MultiPartStatus.EPILOGUE) {
             // OK except if end of list
             if (bodyListHttpDataRank >= bodyListHttpData.size()) {
@@ -394,11 +415,16 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
      * is called, there is no more available InterfaceHttpData. A subsequent
      * call to offer(httpChunk) could enable more data.
      *
+     * Be sure to call {@link InterfaceHttpData#release()} after you are done
+     * with processing to make sure to not leak any resources
+     *
      * @return the next available InterfaceHttpData or null if none
      * @throws EndOfDataDecoderException
      *             No more data will be available
      */
     public InterfaceHttpData next() throws EndOfDataDecoderException {
+        checkDestroyed();
+
         if (hasNext()) {
             return bodyListHttpData.get(bodyListHttpDataRank++);
         }
@@ -1172,10 +1198,31 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
         return null;
     }
 
+    /**
+     * Destroy the {@link HttpPostRequestDecoder} and release all it resources. After this method
+     * was called it is not possible to operate on it anymore.
+     */
+    public void destroy() {
+        checkDestroyed();
+
+        cleanFiles();
+        if (undecodedChunk != null && undecodedChunk.refCnt() > 0) {
+            undecodedChunk.release();
+            undecodedChunk = null;
+        }
+
+        // release all data which was not yet pulled
+        for (int i = bodyListHttpDataRank; i < bodyListHttpData.size(); i++) {
+            bodyListHttpData.get(i).release();
+        }
+    }
+
     /**
      * Clean all HttpDatas (on Disk) for the current request.
      */
     public void cleanFiles() {
+        checkDestroyed();
+
         factory.cleanRequestHttpDatas(request);
     }
 
@@ -1183,6 +1230,8 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
      * Remove the given FileUpload from the list of FileUploads to clean
      */
     public void removeHttpDataFromClean(InterfaceHttpData data) {
+        checkDestroyed();
+
         factory.removeHttpDataFromClean(request, data);
     }
 
@@ -2043,11 +2092,6 @@ public class HttpPostRequestDecoder implements Iterator<InterfaceHttpData> {
         return array;
     }
 
-    @Override
-    public void remove() {
-        throw new UnsupportedOperationException();
-    }
-
     /**
      * Exception when try reading data from request in chunked format, and not
      * enough data are available (need more chunks)

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

@@ -15,10 +15,12 @@
  */
 package io.netty.handler.codec.http.multipart;
 
+import io.netty.util.ReferenceCounted;
+
 /**
  * Interface for all Objects that could be encoded/decoded using HttpPostRequestEncoder/Decoder
  */
-public interface InterfaceHttpData extends Comparable<InterfaceHttpData> {
+public interface InterfaceHttpData extends Comparable<InterfaceHttpData>, ReferenceCounted {
     enum HttpDataType {
         Attribute, FileUpload, InternalAttribute
     }

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

@@ -17,6 +17,7 @@ package io.netty.handler.codec.http.multipart;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
+import io.netty.util.AbstractReferenceCounted;
 
 import java.nio.charset.Charset;
 import java.util.ArrayList;
@@ -26,7 +27,7 @@ import java.util.List;
  * This Attribute is only for Encoder use to insert special command between object if needed
  * (like Multipart Mixed mode)
  */
-final class InternalAttribute implements InterfaceHttpData {
+final class InternalAttribute extends AbstractReferenceCounted implements InterfaceHttpData {
     private final List<ByteBuf> value = new ArrayList<ByteBuf>();
     private final Charset charset;
     private int size;
@@ -117,4 +118,9 @@ final class InternalAttribute implements InterfaceHttpData {
     public String getName() {
         return "InternalAttribute";
     }
+
+    @Override
+    protected void deallocate() {
+        // Do nothing
+    }
 }

example/src/main/java/io/netty/example/http/upload/HttpUploadServerHandler.java

@@ -44,7 +44,6 @@ import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder;
 import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder.EndOfDataDecoderException;
 import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder.ErrorDataDecoderException;
 import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder.IncompatibleDataDecoderException;
-import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder.NotEnoughDataDecoderException;
 import io.netty.handler.codec.http.multipart.InterfaceHttpData;
 import io.netty.handler.codec.http.multipart.InterfaceHttpData.HttpDataType;
 import io.netty.util.CharsetUtil;
@@ -192,7 +191,6 @@ public class HttpUploadServerHandler extends SimpleChannelInboundHandler<HttpObj
                 readHttpDataChunkByChunk();
                 // example of reading only if at the end
                 if (chunk instanceof LastHttpContent) {
-                    readHttpDataAllReceive(ctx.channel());
                     writeResponse(ctx.channel());
                     readingChunks = false;
 
@@ -205,32 +203,11 @@ public class HttpUploadServerHandler extends SimpleChannelInboundHandler<HttpObj
     private void reset() {
         request = null;
 
-        // clean previous FileUpload if Any
-        decoder.cleanFiles();
+        // destroy the decoder to release all resources
+        decoder.destroy();
         decoder = null;
     }
 
-    /**
-     * Example of reading all InterfaceHttpData from finished transfer
-     */
-    private void readHttpDataAllReceive(Channel channel) {
-        List<InterfaceHttpData> datas;
-        try {
-            datas = decoder.getBodyHttpDatas();
-        } catch (NotEnoughDataDecoderException e1) {
-            // Should not be!
-            e1.printStackTrace();
-            responseContent.append(e1.getMessage());
-            writeResponse(channel);
-            channel.close();
-            return;
-        }
-        for (InterfaceHttpData data : datas) {
-            writeHttpData(data);
-        }
-        responseContent.append("\r\n\r\nEND OF CONTENT AT FINAL END\r\n");
-    }
-
     /**
      * Example of reading request by chunk and getting values from chunk to chunk
      */