1 /*
2 * Copyright (C) 2010, 2013 Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.util.io;
45
46 import java.io.IOException;
47 import java.io.InputStream;
48 import java.io.OutputStream;
49
50 /**
51 * Input stream that copies data read to another output stream.
52 *
53 * This stream is primarily useful with a
54 * {@link org.eclipse.jgit.util.TemporaryBuffer}, where any data read or skipped
55 * by the caller is also duplicated into the temporary buffer. Later the
56 * temporary buffer can then be used instead of the original source stream.
57 *
58 * During close this stream copies any remaining data from the source stream
59 * into the destination stream.
60 */
61 public class TeeInputStream extends InputStream {
62 private byte[] skipBuffer;
63
64 private InputStream src;
65
66 private OutputStream dst;
67
68 /**
69 * Initialize a tee input stream.
70 *
71 * @param src
72 * source stream to consume.
73 * @param dst
74 * destination to copy the source to as it is consumed. Typically
75 * this is a {@link org.eclipse.jgit.util.TemporaryBuffer}.
76 */
77 public TeeInputStream(InputStream src, OutputStream dst) {
78 this.src = src;
79 this.dst = dst;
80 }
81
82 /** {@inheritDoc} */
83 @Override
84 public int read() throws IOException {
85 byte[] b = skipBuffer();
86 int n = read(b, 0, 1);
87 return n == 1 ? b[0] & 0xff : -1;
88 }
89
90 /** {@inheritDoc} */
91 @Override
92 public long skip(long count) throws IOException {
93 long skipped = 0;
94 long cnt = count;
95 final byte[] b = skipBuffer();
96 while (0 < cnt) {
97 final int n = src.read(b, 0, (int) Math.min(b.length, cnt));
98 if (n <= 0)
99 break;
100 dst.write(b, 0, n);
101 skipped += n;
102 cnt -= n;
103 }
104 return skipped;
105 }
106
107 /** {@inheritDoc} */
108 @Override
109 public int read(byte[] b, int off, int len) throws IOException {
110 if (len == 0)
111 return 0;
112
113 int n = src.read(b, off, len);
114 if (0 < n)
115 dst.write(b, off, n);
116 return n;
117 }
118
119 /** {@inheritDoc} */
120 @Override
121 public void close() throws IOException {
122 byte[] b = skipBuffer();
123 for (;;) {
124 int n = src.read(b);
125 if (n <= 0)
126 break;
127 dst.write(b, 0, n);
128 }
129 dst.close();
130 src.close();
131 }
132
133 private byte[] skipBuffer() {
134 if (skipBuffer == null)
135 skipBuffer = new byte[2048];
136 return skipBuffer;
137 }
138 }