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1   /*
2    * Copyright (c) 2012 the original author or authors.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * 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,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.eclipse.jetty.spdy.generator;
18  
19  import java.nio.ByteBuffer;
20  
21  import org.eclipse.jetty.spdy.ByteBufferPool;
22  import org.eclipse.jetty.spdy.SessionException;
23  import org.eclipse.jetty.spdy.StreamException;
24  import org.eclipse.jetty.spdy.api.SPDY;
25  import org.eclipse.jetty.spdy.api.SessionStatus;
26  import org.eclipse.jetty.spdy.api.StreamStatus;
27  import org.eclipse.jetty.spdy.frames.ControlFrame;
28  import org.eclipse.jetty.spdy.frames.SynStreamFrame;
29  
30  public class SynStreamGenerator extends ControlFrameGenerator
31  {
32      private final HeadersBlockGenerator headersBlockGenerator;
33  
34      public SynStreamGenerator(ByteBufferPool bufferPool, HeadersBlockGenerator headersBlockGenerator)
35      {
36          super(bufferPool);
37          this.headersBlockGenerator = headersBlockGenerator;
38      }
39  
40      @Override
41      public ByteBuffer generate(ControlFrame frame)
42      {
43          SynStreamFrame synStream = (SynStreamFrame)frame;
44          short version = synStream.getVersion();
45  
46          ByteBuffer headersBuffer = headersBlockGenerator.generate(version, synStream.getHeaders());
47  
48          int frameBodyLength = 10;
49  
50          int frameLength = frameBodyLength + headersBuffer.remaining();
51          if (frameLength > 0xFF_FF_FF)
52          {
53              // Too many headers, but unfortunately we have already modified the compression
54              // context, so we have no other choice than tear down the connection.
55              throw new SessionException(SessionStatus.PROTOCOL_ERROR, "Too many headers");
56          }
57  
58          int totalLength = ControlFrame.HEADER_LENGTH + frameLength;
59  
60          ByteBuffer buffer = getByteBufferPool().acquire(totalLength, true);
61          generateControlFrameHeader(synStream, frameLength, buffer);
62  
63          int streamId = synStream.getStreamId();
64          buffer.putInt(streamId & 0x7F_FF_FF_FF);
65          buffer.putInt(synStream.getAssociatedStreamId() & 0x7F_FF_FF_FF);
66          writePriority(streamId, version, synStream.getPriority(), buffer);
67  
68          buffer.put(headersBuffer);
69  
70          buffer.flip();
71          return buffer;
72      }
73  
74      private void writePriority(int streamId, short version, byte priority, ByteBuffer buffer)
75      {
76          switch (version)
77          {
78              case SPDY.V2:
79                  priority <<= 6;
80                  break;
81              case SPDY.V3:
82                  priority <<= 5;
83                  break;
84              default:
85                  throw new StreamException(streamId, StreamStatus.UNSUPPORTED_VERSION);
86          }
87          buffer.put(priority);
88          buffer.put((byte)0);
89      }
90  }