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 53 /** 54 * Write Git style pkt-line formatting to an output stream. 55 * <p> 56 * This class is not thread safe and may issue multiple writes to the underlying 57 * stream for each method call made. 58 * <p> 59 * This class performs no buffering on its own. This makes it suitable to 60 * interleave writes performed by this class with writes performed directly 61 * against the underlying OutputStream. 62 */ 63 public class PacketLineOut { 64 private final OutputStream out; 65 66 private final byte[] lenbuffer; 67 68 private boolean flushOnEnd; 69 70 /** 71 * Create a new packet line writer. 72 * 73 * @param outputStream 74 * stream. 75 */ 76 public PacketLineOut(final OutputStream outputStream) { 77 out = outputStream; 78 lenbuffer = new byte[5]; 79 flushOnEnd = true; 80 } 81 82 /** 83 * Set the flush behavior during {@link #end()}. 84 * 85 * @param flushOnEnd 86 * if true, a flush-pkt written during {@link #end()} also 87 * flushes the underlying stream. 88 */ 89 public void setFlushOnEnd(boolean flushOnEnd) { 90 this.flushOnEnd = flushOnEnd; 91 } 92 93 /** 94 * Write a UTF-8 encoded string as a single length-delimited packet. 95 * 96 * @param s 97 * string to write. 98 * @throws IOException 99 * the packet could not be written, the stream is corrupted as 100 * the packet may have been only partially written. 101 */ 102 public void writeString(final String s) throws IOException { 103 writePacket(Constants.encode(s)); 104 } 105 106 /** 107 * Write a binary packet to the stream. 108 * 109 * @param packet 110 * the packet to write; the length of the packet is equal to the 111 * size of the byte array. 112 * @throws IOException 113 * the packet could not be written, the stream is corrupted as 114 * the packet may have been only partially written. 115 */ 116 public void writePacket(final byte[] packet) throws IOException { 117 formatLength(packet.length + 4); 118 out.write(lenbuffer, 0, 4); 119 out.write(packet); 120 } 121 122 /** 123 * Write a packet end marker, sometimes referred to as a flush command. 124 * <p> 125 * Technically this is a magical packet type which can be detected 126 * separately from an empty string or an empty packet. 127 * <p> 128 * Implicitly performs a flush on the underlying OutputStream to ensure the 129 * peer will receive all data written thus far. 130 * 131 * @throws IOException 132 * the end marker could not be written, the stream is corrupted 133 * as the end marker may have been only partially written. 134 */ 135 public void end() throws IOException { 136 formatLength(0); 137 out.write(lenbuffer, 0, 4); 138 if (flushOnEnd) 139 flush(); 140 } 141 142 /** 143 * Flush the underlying OutputStream. 144 * <p> 145 * Performs a flush on the underlying OutputStream to ensure the peer will 146 * receive all data written thus far. 147 * 148 * @throws IOException 149 * the underlying stream failed to flush. 150 */ 151 public void flush() throws IOException { 152 out.flush(); 153 } 154 155 private static final byte[] hexchar = { '0', '1', '2', '3', '4', '5', '6', 156 '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; 157 158 private void formatLength(int w) { 159 formatLength(lenbuffer, w); 160 } 161 162 static void formatLength(byte[] lenbuffer, int w) { 163 int o = 3; 164 while (o >= 0 && w != 0) { 165 lenbuffer[o--] = hexchar[w & 0xf]; 166 w >>>= 4; 167 } 168 while (o >= 0) 169 lenbuffer[o--] = '0'; 170 } 171 }