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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  
28  package org.apache.http.impl.io;
29  
30  import java.io.IOException;
31  import java.io.InputStream;
32  
33  import org.apache.http.io.BufferInfo;
34  import org.apache.http.io.SessionInputBuffer;
35  import org.apache.http.util.Args;
36  
37  /**
38   * Input stream that reads data without any transformation. The end of the
39   * content entity is demarcated by closing the underlying connection
40   * (EOF condition). Entities transferred using this input stream can be of
41   * unlimited length.
42   * <p>
43   * Note that this class NEVER closes the underlying stream, even when close
44   * gets called.  Instead, it will read until the end of the stream (until
45   * {@code -1} is returned).
46   *
47   * @since 4.0
48   */
49  public class IdentityInputStream extends InputStream {
50  
51      private final SessionInputBuffer in;
52  
53      private boolean closed = false;
54  
55      /**
56       * Wraps session input stream and reads input until the the end of stream.
57       *
58       * @param in The session input buffer
59       */
60      public IdentityInputStream(final SessionInputBuffer in) {
61          super();
62          this.in = Args.notNull(in, "Session input buffer");
63      }
64  
65      @Override
66      public int available() throws IOException {
67          if (this.in instanceof BufferInfo) {
68              return ((BufferInfo) this.in).length();
69          } else {
70              return 0;
71          }
72      }
73  
74      @Override
75      public void close() throws IOException {
76          this.closed = true;
77      }
78  
79      @Override
80      public int read() throws IOException {
81          if (this.closed) {
82              return -1;
83          } else {
84              return this.in.read();
85          }
86      }
87  
88      @Override
89      public int read(final byte[] b, final int off, final int len) throws IOException {
90          if (this.closed) {
91              return -1;
92          } else {
93              return this.in.read(b, off, len);
94          }
95      }
96  
97  }