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1   /*
2    * Copyright 2014 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.handler.codec.http.websocketx.extensions.compression;
17  
18  import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
19  import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
20  import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
21  import io.netty.handler.codec.http.websocketx.WebSocketFrame;
22  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
23  
24  /**
25   * Per-frame implementation of deflate compressor.
26   */
27  class PerFrameDeflateEncoder extends DeflateEncoder {
28  
29      /**
30       * Constructor
31       * @param compressionLevel compression level of the compressor.
32       * @param windowSize maximum size of the window compressor buffer.
33       * @param noContext true to disable context takeover.
34       */
35      public PerFrameDeflateEncoder(int compressionLevel, int windowSize, boolean noContext) {
36          super(compressionLevel, windowSize, noContext);
37      }
38  
39      @Override
40      public boolean acceptOutboundMessage(Object msg) throws Exception {
41          return (msg instanceof TextWebSocketFrame ||
42                  msg instanceof BinaryWebSocketFrame ||
43                  msg instanceof ContinuationWebSocketFrame) &&
44                      ((WebSocketFrame) msg).content().readableBytes() > 0 &&
45                      (((WebSocketFrame) msg).rsv() & WebSocketExtension.RSV1) == 0;
46      }
47  
48      @Override
49      protected int rsv(WebSocketFrame msg) {
50          return msg.rsv() | WebSocketExtension.RSV1;
51      }
52  
53      @Override
54      protected boolean removeFrameTail(WebSocketFrame msg) {
55          return true;
56      }
57  
58  }