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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  package org.apache.http.client.entity;
28  
29  import java.io.IOException;
30  import java.io.InputStream;
31  import java.io.OutputStream;
32  
33  import org.apache.http.Header;
34  import org.apache.http.HttpEntity;
35  import org.apache.http.entity.HttpEntityWrapper;
36  import org.apache.http.util.Args;
37  
38  /**
39   * Common base class for decompressing {@link HttpEntity} implementations.
40   *
41   * @since 4.4
42   */
43  public class DecompressingEntity extends HttpEntityWrapper {
44  
45      /**
46       * Default buffer size.
47       */
48      private static final int BUFFER_SIZE = 1024 * 2;
49  
50      private final InputStreamFactory inputStreamFactory;
51      /**
52       * {@link #getContent()} method must return the same {@link InputStream}
53       * instance when DecompressingEntity is wrapping a streaming entity.
54       */
55      private InputStream content;
56  
57      /**
58       * Creates a new {@link DecompressingEntity}.
59       *
60       * @param wrapped the non-null {@link HttpEntity} to be wrapped
61       * @param inputStreamFactory factory to create decompressing stream.
62       */
63      public DecompressingEntity(
64              final HttpEntity wrapped,
65              final InputStreamFactory inputStreamFactory) {
66          super(wrapped);
67          this.inputStreamFactory = inputStreamFactory;
68      }
69  
70      private InputStream getDecompressingStream() throws IOException {
71          final InputStream in = wrappedEntity.getContent();
72          return new LazyDecompressingInputStream(in, inputStreamFactory);
73      }
74  
75      @Override
76      public InputStream getContent() throws IOException {
77          if (wrappedEntity.isStreaming()) {
78              if (content == null) {
79                  content = getDecompressingStream();
80              }
81              return content;
82          } else {
83              return getDecompressingStream();
84          }
85      }
86  
87      @Override
88      public void writeTo(final OutputStream outstream) throws IOException {
89          Args.notNull(outstream, "Output stream");
90          final InputStream instream = getContent();
91          try {
92              final byte[] buffer = new byte[BUFFER_SIZE];
93              int l;
94              while ((l = instream.read(buffer)) != -1) {
95                  outstream.write(buffer, 0, l);
96              }
97          } finally {
98              instream.close();
99          }
100     }
101 
102     @Override
103     public Header getContentEncoding() {
104         /* Content encoding is now 'identity' */
105         return null;
106     }
107 
108     @Override
109     public long getContentLength() {
110         /* length of decompressed content is not known */
111         return -1;
112     }
113 
114 }