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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.annotation.NotThreadSafe;
34  import org.apache.http.io.BufferInfo;
35  import org.apache.http.io.SessionInputBuffer;
36  import org.apache.http.util.Args;
37  
38  /**
39   * Input stream that reads data without any transformation. The end of the
40   * content entity is demarcated by closing the underlying connection
41   * (EOF condition). Entities transferred using this input stream can be of
42   * unlimited length.
43   * <p>
44   * Note that this class NEVER closes the underlying stream, even when close
45   * gets called.  Instead, it will read until the end of the stream (until
46   * <code>-1</code> is returned).
47   *
48   * @since 4.0
49   */
50  @NotThreadSafe
51  public class IdentityInputStream extends InputStream {
52  
53      private final SessionInputBuffer in;
54  
55      private boolean closed = false;
56  
57      /**
58       * Wraps session input stream and reads input until the the end of stream.
59       *
60       * @param in The session input buffer
61       */
62      public IdentityInputStream(final SessionInputBuffer in) {
63          super();
64          this.in = Args.notNull(in, "Session input buffer");
65      }
66  
67      @Override
68      public int available() throws IOException {
69          if (this.in instanceof BufferInfo) {
70              return ((BufferInfo) this.in).length();
71          } else {
72              return 0;
73          }
74      }
75  
76      @Override
77      public void close() throws IOException {
78          this.closed = true;
79      }
80  
81      @Override
82      public int read() throws IOException {
83          if (this.closed) {
84              return -1;
85          } else {
86              return this.in.read();
87          }
88      }
89  
90      @Override
91      public int read(final byte[] b, final int off, final int len) throws IOException {
92          if (this.closed) {
93              return -1;
94          } else {
95              return this.in.read(b, off, len);
96          }
97      }
98  
99  }