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1   /*
2    * Copyright 2012 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.rtsp;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.handler.codec.TooLongFrameException;
20  import io.netty.handler.codec.http.HttpMessage;
21  import io.netty.handler.codec.http.HttpObjectDecoder;
22  
23  import static io.netty.handler.codec.rtsp.RtspDecoder.DEFAULT_MAX_CONTENT_LENGTH;
24  
25  /**
26   * Decodes {@link ByteBuf}s into RTSP messages represented in
27   * {@link HttpMessage}s.
28   * <p>
29   * <h3>Parameters that prevents excessive memory consumption</h3>
30   * <table border="1">
31   * <tr>
32   * <th>Name</th><th>Meaning</th>
33   * </tr>
34   * <tr>
35   * <td>{@code maxInitialLineLength}</td>
36   * <td>The maximum length of the initial line
37   *     (e.g. {@code "SETUP / RTSP/1.0"} or {@code "RTSP/1.0 200 OK"})
38   *     If the length of the initial line exceeds this value, a
39   *     {@link TooLongFrameException} will be raised.</td>
40   * </tr>
41   * <tr>
42   * <td>{@code maxHeaderSize}</td>
43   * <td>The maximum length of all headers.  If the sum of the length of each
44   *     header exceeds this value, a {@link TooLongFrameException} will be raised.</td>
45   * </tr>
46   * <tr>
47   * <td>{@code maxContentLength}</td>
48   * <td>The maximum length of the content.  If the content length exceeds this
49   *     value, a {@link TooLongFrameException} will be raised.</td>
50   * </tr>
51   * </table>
52   *
53   * @deprecated Use {@link RtspDecoder} instead.
54   */
55  @Deprecated
56  public abstract class RtspObjectDecoder extends HttpObjectDecoder {
57  
58      /**
59       * Creates a new instance with the default
60       * {@code maxInitialLineLength (4096)}, {@code maxHeaderSize (8192)}, and
61       * {@code maxContentLength (8192)}.
62       */
63      protected RtspObjectDecoder() {
64          this(DEFAULT_MAX_INITIAL_LINE_LENGTH, DEFAULT_MAX_HEADER_SIZE, DEFAULT_MAX_CONTENT_LENGTH);
65      }
66  
67      /**
68       * Creates a new instance with the specified parameters.
69       */
70      protected RtspObjectDecoder(int maxInitialLineLength, int maxHeaderSize, int maxContentLength) {
71          super(maxInitialLineLength, maxHeaderSize, maxContentLength * 2, false);
72      }
73  
74      protected RtspObjectDecoder(
75              int maxInitialLineLength, int maxHeaderSize, int maxContentLength, boolean validateHeaders) {
76          super(maxInitialLineLength, maxHeaderSize, maxContentLength * 2, false, validateHeaders);
77      }
78  
79      @Override
80      protected boolean isContentAlwaysEmpty(HttpMessage msg) {
81          // Unlike HTTP, RTSP always assumes zero-length body if Content-Length
82          // header is absent.
83          boolean empty = super.isContentAlwaysEmpty(msg);
84          if (empty) {
85              return true;
86          }
87          if (!msg.headers().contains(RtspHeaderNames.CONTENT_LENGTH)) {
88              return true;
89          }
90          return empty;
91      }
92  }