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