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1   /*
2    * Copyright 2013 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.spdy;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.buffer.ByteBufAllocator;
20  import io.netty.buffer.Unpooled;
21  
22  import java.util.Set;
23  
24  import static io.netty.handler.codec.spdy.SpdyCodecUtil.*;
25  
26  public class SpdyHeaderBlockRawEncoder extends SpdyHeaderBlockEncoder {
27  
28      private final int version;
29  
30      public SpdyHeaderBlockRawEncoder(SpdyVersion version) {
31          if (version == null) {
32              throw new NullPointerException("version");
33          }
34          this.version = version.getVersion();
35      }
36  
37      private static void setLengthField(ByteBuf buffer, int writerIndex, int length) {
38          buffer.setInt(writerIndex, length);
39      }
40  
41      private static void writeLengthField(ByteBuf buffer, int length) {
42          buffer.writeInt(length);
43      }
44  
45      @Override
46      public ByteBuf encode(ByteBufAllocator alloc, SpdyHeadersFrame frame) throws Exception {
47          Set<String> names = frame.headers().names();
48          int numHeaders = names.size();
49          if (numHeaders == 0) {
50              return Unpooled.EMPTY_BUFFER;
51          }
52          if (numHeaders > SPDY_MAX_NV_LENGTH) {
53              throw new IllegalArgumentException(
54                      "header block contains too many headers");
55          }
56          ByteBuf headerBlock = alloc.heapBuffer();
57          writeLengthField(headerBlock, numHeaders);
58          for (String name: names) {
59              byte[] nameBytes = name.getBytes("UTF-8");
60              writeLengthField(headerBlock, nameBytes.length);
61              headerBlock.writeBytes(nameBytes);
62              int savedIndex = headerBlock.writerIndex();
63              int valueLength = 0;
64              writeLengthField(headerBlock, valueLength);
65              for (String value: frame.headers().getAll(name)) {
66                  byte[] valueBytes = value.getBytes("UTF-8");
67                  if (valueBytes.length > 0) {
68                      headerBlock.writeBytes(valueBytes);
69                      headerBlock.writeByte(0);
70                      valueLength += valueBytes.length + 1;
71                  }
72              }
73              if (valueLength != 0) {
74                  valueLength --;
75              }
76              if (valueLength > SPDY_MAX_NV_LENGTH) {
77                  throw new IllegalArgumentException(
78                          "header exceeds allowable length: " + name);
79              }
80              if (valueLength > 0) {
81                  setLengthField(headerBlock, savedIndex, valueLength);
82                  headerBlock.writerIndex(headerBlock.writerIndex() - 1);
83              }
84          }
85          return headerBlock;
86      }
87  
88      @Override
89      void end() {
90      }
91  }