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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.hc.core5.http.impl.io;
29  
30  import java.io.IOException;
31  import java.io.InputStream;
32  
33  import org.apache.hc.core5.http.StreamClosedException;
34  import org.apache.hc.core5.http.io.SessionInputBuffer;
35  import org.apache.hc.core5.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 buffer;
52      private final InputStream inputStream;
53  
54      private boolean closed = false;
55  
56      /**
57       * Default constructor.
58       *
59       * @param buffer Session input buffer
60       * @param inputStream Input stream
61       */
62      public IdentityInputStream(final SessionInputBuffer buffer, final InputStream inputStream) {
63          super();
64          this.buffer = Args.notNull(buffer, "Session input buffer");
65          this.inputStream = Args.notNull(inputStream, "Input stream");
66      }
67  
68      @Override
69      public int available() throws IOException {
70          if (this.closed) {
71              return 0;
72          }
73          final int n = this.buffer.length();
74          return n > 0 ? n : this.inputStream.available();
75      }
76  
77      @Override
78      public void close() throws IOException {
79          this.closed = true;
80      }
81  
82      @Override
83      public int read() throws IOException {
84          if (this.closed) {
85              throw new StreamClosedException("Stream already closed");
86          }
87          return this.buffer.read(this.inputStream);
88      }
89  
90      @Override
91      public int read(final byte[] b, final int off, final int len) throws IOException {
92          if (this.closed) {
93              throw new StreamClosedException("Stream already closed");
94          }
95          return this.buffer.read(b, off, len, this.inputStream);
96      }
97  
98  }