1 /*
2 * Copyright (C) 2008-2010, Google Inc.
3 * Copyright (C) 2008-2009, Robin Rosenberg <robin.rosenberg@dewire.com>
4 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
5 * and other copyright owners as documented in the project's IP log.
6 *
7 * This program and the accompanying materials are made available
8 * under the terms of the Eclipse Distribution License v1.0 which
9 * accompanies this distribution, is reproduced below, and is
10 * available at http://www.eclipse.org/org/documents/edl-v10.php
11 *
12 * All rights reserved.
13 *
14 * Redistribution and use in source and binary forms, with or
15 * without modification, are permitted provided that the following
16 * conditions are met:
17 *
18 * - Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 *
21 * - Redistributions in binary form must reproduce the above
22 * copyright notice, this list of conditions and the following
23 * disclaimer in the documentation and/or other materials provided
24 * with the distribution.
25 *
26 * - Neither the name of the Eclipse Foundation, Inc. nor the
27 * names of its contributors may be used to endorse or promote
28 * products derived from this software without specific prior
29 * written permission.
30 *
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
32 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
33 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
34 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
36 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
37 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
39 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
40 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
43 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44 */
45
46 package org.eclipse.jgit.transport;
47
48 import java.io.IOException;
49 import java.io.OutputStream;
50
51 import org.eclipse.jgit.lib.Constants;
52 import org.eclipse.jgit.util.RawParseUtils;
53 import org.slf4j.Logger;
54 import org.slf4j.LoggerFactory;
55
56 /**
57 * Write Git style pkt-line formatting to an output stream.
58 * <p>
59 * This class is not thread safe and may issue multiple writes to the underlying
60 * stream for each method call made.
61 * <p>
62 * This class performs no buffering on its own. This makes it suitable to
63 * interleave writes performed by this class with writes performed directly
64 * against the underlying OutputStream.
65 */
66 public class PacketLineOut {
67 private static final Logger log = LoggerFactory.getLogger(PacketLineOut.class);
68
69 private final OutputStream out;
70
71 private final byte[] lenbuffer;
72
73 private boolean flushOnEnd;
74
75 /**
76 * Create a new packet line writer.
77 *
78 * @param outputStream
79 * stream.
80 */
81 public PacketLineOut(final OutputStream outputStream) {
82 out = outputStream;
83 lenbuffer = new byte[5];
84 flushOnEnd = true;
85 }
86
87 /**
88 * Set the flush behavior during {@link #end()}.
89 *
90 * @param flushOnEnd
91 * if true, a flush-pkt written during {@link #end()} also
92 * flushes the underlying stream.
93 */
94 public void setFlushOnEnd(boolean flushOnEnd) {
95 this.flushOnEnd = flushOnEnd;
96 }
97
98 /**
99 * Write a UTF-8 encoded string as a single length-delimited packet.
100 *
101 * @param s
102 * string to write.
103 * @throws IOException
104 * the packet could not be written, the stream is corrupted as
105 * the packet may have been only partially written.
106 */
107 public void writeString(final String s) throws IOException {
108 writePacket(Constants.encode(s));
109 }
110
111 /**
112 * Write a binary packet to the stream.
113 *
114 * @param packet
115 * the packet to write; the length of the packet is equal to the
116 * size of the byte array.
117 * @throws IOException
118 * the packet could not be written, the stream is corrupted as
119 * the packet may have been only partially written.
120 */
121 public void writePacket(byte[] packet) throws IOException {
122 writePacket(packet, 0, packet.length);
123 }
124
125 /**
126 * Write a binary packet to the stream.
127 *
128 * @param buf
129 * the packet to write
130 * @param pos
131 * first index within {@code buf}.
132 * @param len
133 * number of bytes to write.
134 * @throws IOException
135 * the packet could not be written, the stream is corrupted as
136 * the packet may have been only partially written.
137 * @since 4.5
138 */
139 public void writePacket(byte[] buf, int pos, int len) throws IOException {
140 formatLength(len + 4);
141 out.write(lenbuffer, 0, 4);
142 out.write(buf, pos, len);
143 if (log.isDebugEnabled()) {
144 String s = RawParseUtils.decode(Constants.CHARSET, buf, pos, len);
145 log.debug("git> " + s); //$NON-NLS-1$
146 }
147 }
148
149 /**
150 * Write a packet end marker, sometimes referred to as a flush command.
151 * <p>
152 * Technically this is a magical packet type which can be detected
153 * separately from an empty string or an empty packet.
154 * <p>
155 * Implicitly performs a flush on the underlying OutputStream to ensure the
156 * peer will receive all data written thus far.
157 *
158 * @throws IOException
159 * the end marker could not be written, the stream is corrupted
160 * as the end marker may have been only partially written.
161 */
162 public void end() throws IOException {
163 formatLength(0);
164 out.write(lenbuffer, 0, 4);
165 log.debug("git> 0000"); //$NON-NLS-1$
166 if (flushOnEnd)
167 flush();
168 }
169
170 /**
171 * Flush the underlying OutputStream.
172 * <p>
173 * Performs a flush on the underlying OutputStream to ensure the peer will
174 * receive all data written thus far.
175 *
176 * @throws IOException
177 * the underlying stream failed to flush.
178 */
179 public void flush() throws IOException {
180 out.flush();
181 }
182
183 private static final byte[] hexchar = { '0', '1', '2', '3', '4', '5', '6',
184 '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
185
186 private void formatLength(int w) {
187 formatLength(lenbuffer, w);
188 }
189
190 static void formatLength(byte[] lenbuffer, int w) {
191 int o = 3;
192 while (o >= 0 && w != 0) {
193 lenbuffer[o--] = hexchar[w & 0xf];
194 w >>>= 4;
195 }
196 while (o >= 0)
197 lenbuffer[o--] = '0';
198 }
199 }