1 /*
2 * Copyright (C) 2009-2010, 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.InterruptedIOException;
49 import java.io.OutputStream;
50 import java.util.concurrent.atomic.AtomicInteger;
51
52 /** Thread to copy from an input stream to an output stream. */
53 public class StreamCopyThread extends Thread {
54 private static final int BUFFER_SIZE = 1024;
55
56 private final InputStream src;
57
58 private final OutputStream dst;
59
60 private volatile boolean done;
61
62 private final AtomicInteger flushCount = new AtomicInteger(0);
63
64 /**
65 * Create a thread to copy data from an input stream to an output stream.
66 *
67 * @param i
68 * stream to copy from. The thread terminates when this stream
69 * reaches EOF. The thread closes this stream before it exits.
70 * @param o
71 * stream to copy into. The destination stream is automatically
72 * closed when the thread terminates.
73 */
74 public StreamCopyThread(final InputStream i, final OutputStream o) {
75 setName(Thread.currentThread().getName() + "-StreamCopy"); //$NON-NLS-1$
76 src = i;
77 dst = o;
78 }
79
80 /**
81 * Request the thread to flush the output stream as soon as possible.
82 * <p>
83 * This is an asynchronous request to the thread. The actual flush will
84 * happen at some future point in time, when the thread wakes up to process
85 * the request.
86 */
87 public void flush() {
88 flushCount.incrementAndGet();
89 interrupt();
90 }
91
92 /**
93 * Request that the thread terminate, and wait for it.
94 * <p>
95 * This method signals to the copy thread that it should stop as soon as
96 * there is no more IO occurring.
97 *
98 * @throws InterruptedException
99 * the calling thread was interrupted.
100 */
101 public void halt() throws InterruptedException {
102 for (;;) {
103 join(250 /* milliseconds */);
104 if (isAlive()) {
105 done = true;
106 interrupt();
107 } else
108 break;
109 }
110 }
111
112 @Override
113 public void run() {
114 try {
115 final byte[] buf = new byte[BUFFER_SIZE];
116 int flushCountBeforeRead = 0;
117 boolean readInterrupted = false;
118 for (;;) {
119 try {
120 if (readInterrupted) {
121 dst.flush();
122 readInterrupted = false;
123 if (!flushCount.compareAndSet(flushCountBeforeRead, 0)) {
124 // There was a flush() call since last blocked read.
125 // Set interrupt status, so next blocked read will throw
126 // an InterruptedIOException and we will flush again.
127 interrupt();
128 }
129 }
130
131 if (done)
132 break;
133
134 flushCountBeforeRead = flushCount.get();
135 final int n;
136 try {
137 n = src.read(buf);
138 } catch (InterruptedIOException wakey) {
139 readInterrupted = true;
140 continue;
141 }
142 if (n < 0)
143 break;
144
145 boolean writeInterrupted = false;
146 for (;;) {
147 try {
148 dst.write(buf, 0, n);
149 } catch (InterruptedIOException wakey) {
150 writeInterrupted = true;
151 continue;
152 }
153
154 // set interrupt status, which will be checked
155 // when we block in src.read
156 if (writeInterrupted || flushCount.get() > 0)
157 interrupt();
158 break;
159 }
160 } catch (IOException e) {
161 break;
162 }
163 }
164 } finally {
165 try {
166 src.close();
167 } catch (IOException e) {
168 // Ignore IO errors on close
169 }
170 try {
171 dst.close();
172 } catch (IOException e) {
173 // Ignore IO errors on close
174 }
175 }
176 }
177 }