Change HTTP/2 tests to retain rather than copy ByteBufs

Motivation:

The current build is showing potential leaks in the HTTP/2 tests that
use Http2TestUtil.FrameCountDown, which copies the buffers when it
receives them from the decoder. The leak detecor sees this copy as the
source of a leak. It would be better all around to just retain, rather
than copying the buffer. This should help to lower the overall memory
footprint of the tests as well as potentially getting rid of the
reported "leaks".

Modifications:

Modified Http2TestUtil to use ByteBuf.retain() everywhere that was
previously calling ByteBuf.copy().

Result:

Smaller memory footprint for tests and hopefully getting rid of reported
leaks.

Author: nmittler

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2TestUtil.java

@@ -85,26 +85,27 @@ private Http2TestUtil() {
     }
 
     static class FrameAdapter extends ByteToMessageDecoder {
-        private final boolean copyBufs;
+        private final boolean retainBufs;
         private final Http2Connection connection;
         private final Http2FrameListener listener;
         private final DefaultHttp2FrameReader reader;
         private CountDownLatch latch;
 
-        FrameAdapter(Http2FrameListener listener, CountDownLatch latch, boolean copyBufs) {
-            this(null, listener, latch, copyBufs);
+        FrameAdapter(Http2FrameListener listener, CountDownLatch latch, boolean retainBufs) {
+            this(null, listener, latch, retainBufs);
         }
 
-        FrameAdapter(Http2Connection connection, Http2FrameListener listener, CountDownLatch latch, boolean copyBufs) {
-            this(connection, new DefaultHttp2FrameReader(), listener, latch, copyBufs);
+        FrameAdapter(Http2Connection connection, Http2FrameListener listener, CountDownLatch latch,
+                boolean retainBufs) {
+            this(connection, new DefaultHttp2FrameReader(), listener, latch, retainBufs);
         }
 
         FrameAdapter(Http2Connection connection, DefaultHttp2FrameReader reader, Http2FrameListener listener,
-                CountDownLatch latch, boolean copyBufs) {
+                CountDownLatch latch, boolean retainBufs) {
             this.connection = connection;
             this.listener = listener;
             this.reader = reader;
-            this.copyBufs = copyBufs;
+            this.retainBufs = retainBufs;
             latch(latch);
         }
 
@@ -149,7 +150,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) t
                 public void onDataRead(ChannelHandlerContext ctx, int streamId, ByteBuf data, int padding,
                         boolean endOfStream) throws Http2Exception {
                     Http2Stream stream = getOrCreateStream(streamId, endOfStream);
-                    listener.onDataRead(ctx, streamId, copyBufs ? data.copy() : data, padding, endOfStream);
+                    listener.onDataRead(ctx, streamId, retainBufs ? data.retain() : data, padding, endOfStream);
                     if (endOfStream) {
                         closeStream(stream, true);
                     }
@@ -217,13 +218,13 @@ public void onSettingsRead(ChannelHandlerContext ctx, Http2Settings settings) th
 
                 @Override
                 public void onPingRead(ChannelHandlerContext ctx, ByteBuf data) throws Http2Exception {
-                    listener.onPingRead(ctx, copyBufs ? data.copy() : data);
+                    listener.onPingRead(ctx, retainBufs ? data.retain() : data);
                     latch.countDown();
                 }
 
                 @Override
                 public void onPingAckRead(ChannelHandlerContext ctx, ByteBuf data) throws Http2Exception {
-                    listener.onPingAckRead(ctx, copyBufs ? data.copy() : data);
+                    listener.onPingAckRead(ctx, retainBufs ? data.retain() : data);
                     latch.countDown();
                 }
 
@@ -238,7 +239,7 @@ public void onPushPromiseRead(ChannelHandlerContext ctx, int streamId, int promi
                 @Override
                 public void onGoAwayRead(ChannelHandlerContext ctx, int lastStreamId, long errorCode, ByteBuf debugData)
                         throws Http2Exception {
-                    listener.onGoAwayRead(ctx, lastStreamId, errorCode, copyBufs ? debugData.copy() : debugData);
+                    listener.onGoAwayRead(ctx, lastStreamId, errorCode, retainBufs ? debugData.retain() : debugData);
                     latch.countDown();
                 }
 
@@ -290,7 +291,7 @@ public void dataLatch(CountDownLatch latch) {
         @Override
         public void onDataRead(ChannelHandlerContext ctx, int streamId, ByteBuf data, int padding, boolean endOfStream)
                 throws Http2Exception {
-            listener.onDataRead(ctx, streamId, data.copy(), padding, endOfStream);
+            listener.onDataRead(ctx, streamId, data.retain(), padding, endOfStream);
             messageLatch.countDown();
             if (dataLatch != null) {
                 for (int i = 0; i < data.readableBytes(); ++i) {
@@ -340,13 +341,13 @@ public void onSettingsRead(ChannelHandlerContext ctx, Http2Settings settings) th
 
         @Override
         public void onPingRead(ChannelHandlerContext ctx, ByteBuf data) throws Http2Exception {
-            listener.onPingRead(ctx, data.copy());
+            listener.onPingRead(ctx, data.retain());
             messageLatch.countDown();
         }
 
         @Override
         public void onPingAckRead(ChannelHandlerContext ctx, ByteBuf data) throws Http2Exception {
-            listener.onPingAckRead(ctx, data.copy());
+            listener.onPingAckRead(ctx, data.retain());
             messageLatch.countDown();
         }
 
@@ -360,7 +361,7 @@ public void onPushPromiseRead(ChannelHandlerContext ctx, int streamId, int promi
         @Override
         public void onGoAwayRead(ChannelHandlerContext ctx, int lastStreamId, long errorCode, ByteBuf debugData)
                 throws Http2Exception {
-            listener.onGoAwayRead(ctx, lastStreamId, errorCode, debugData.copy());
+            listener.onGoAwayRead(ctx, lastStreamId, errorCode, debugData.retain());
             messageLatch.countDown();
         }