1 /*
2 * Copyright 2019 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License, version 2.0 (the
5 * "License"); you may not use this file except in compliance with the License. You may obtain a
6 * copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software distributed under the License
11 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
12 * or implied. See the License for the specific language governing permissions and limitations under
13 * the License.
14 */
15 package io.netty.handler.codec.http2;
16
17 import io.netty.util.internal.ObjectUtil;
18
19 /**
20 * Enforce a limit on the maximum number of consecutive empty DATA frames (without end_of_stream flag) that are allowed
21 * before the connection will be closed.
22 */
23 final class Http2EmptyDataFrameConnectionDecoder extends DecoratingHttp2ConnectionDecoder {
24
25 private final int maxConsecutiveEmptyFrames;
26
27 Http2EmptyDataFrameConnectionDecoder(Http2ConnectionDecoder delegate, int maxConsecutiveEmptyFrames) {
28 super(delegate);
29 this.maxConsecutiveEmptyFrames = ObjectUtil.checkPositive(
30 maxConsecutiveEmptyFrames, "maxConsecutiveEmptyFrames");
31 }
32
33 @Override
34 public void frameListener(Http2FrameListener listener) {
35 if (listener != null) {
36 super.frameListener(new Http2EmptyDataFrameListener(listener, maxConsecutiveEmptyFrames));
37 } else {
38 super.frameListener(null);
39 }
40 }
41
42 @Override
43 public Http2FrameListener frameListener() {
44 Http2FrameListener frameListener = frameListener0();
45 // Unwrap the original Http2FrameListener as we add this decoder under the hood.
46 if (frameListener instanceof Http2EmptyDataFrameListener) {
47 return ((Http2EmptyDataFrameListener) frameListener).listener;
48 }
49 return frameListener;
50 }
51
52 // Package-private for testing
53 Http2FrameListener frameListener0() {
54 return super.frameListener();
55 }
56 }