1 /* 2 * Copyright (C) 2012, Google Inc. and others 3 * 4 * This program and the accompanying materials are made available under the 5 * terms of the Eclipse Distribution License v. 1.0 which is available at 6 * https://www.eclipse.org/org/documents/edl-v10.php. 7 * 8 * SPDX-License-Identifier: BSD-3-Clause 9 */ 10 11 package org.eclipse.jgit.http.server; 12 13 import javax.servlet.http.HttpServletRequest; 14 15 /** 16 * Parses Git client User-Agent strings. 17 */ 18 public class ClientVersionUtil { 19 /** 20 * An invalid version of Git 21 * 22 * @return maximum version array, indicating an invalid version of Git. 23 */ invalidVersion()24 public static int[] invalidVersion() { 25 return new int[] { Integer.MAX_VALUE }; 26 } 27 28 /** 29 * Parse a Git client User-Agent header value. 30 * 31 * @param version 32 * git client version string, of the form "git/1.7.9". 33 * @return components of the version string. {@link #invalidVersion()} if 34 * the version string cannot be parsed. 35 */ parseVersion(String version)36 public static int[] parseVersion(String version) { 37 if (version != null && version.startsWith("git/")) 38 return splitVersion(version.substring("git/".length())); 39 return invalidVersion(); 40 } 41 splitVersion(String versionString)42 private static int[] splitVersion(String versionString) { 43 char[] str = versionString.toCharArray(); 44 int[] ver = new int[4]; 45 int end = 0; 46 int acc = 0; 47 for (int i = 0; i < str.length; i++) { 48 char c = str[i]; 49 if ('0' <= c && c <= '9') { 50 acc *= 10; 51 acc += c - '0'; 52 } else if (c == '.') { 53 if (end == ver.length) 54 ver = grow(ver); 55 ver[end++] = acc; 56 acc = 0; 57 } else if (c == 'g' && 0 < i && str[i - 1] == '.' && 0 < end) { 58 // Non-tagged builds may contain a mangled git describe output. 59 // "1.7.6.1.45.gbe0cc". The 45 isn't a valid component. Drop it. 60 ver[end - 1] = 0; 61 acc = 0; 62 break; 63 } else if (c == '-' && (i + 2) < str.length 64 && str[i + 1] == 'r' && str[i + 2] == 'c') { 65 // Release candidates aren't the same as a final release. 66 if (acc > 0) 67 acc--; 68 break; 69 } else 70 break; 71 } 72 if (acc != 0) { 73 if (end == ver.length) 74 ver = grow(ver); 75 ver[end++] = acc; 76 } else { 77 while (0 < end && ver[end - 1] == 0) 78 end--; 79 } 80 if (end < ver.length) { 81 int[] n = new int[end]; 82 System.arraycopy(ver, 0, n, 0, end); 83 ver = n; 84 } 85 return ver; 86 } 87 grow(int[] tmp)88 private static int[] grow(int[] tmp) { 89 int[] n = new int[tmp.length + 1]; 90 System.arraycopy(tmp, 0, n, 0, tmp.length); 91 return n; 92 } 93 94 /** 95 * Compare two version strings for natural ordering. 96 * 97 * @param a 98 * first parsed version string. 99 * @param b 100 * second parsed version string. 101 * @return < 0 if a is before b; 0 if a equals b; >0 if a is after b. 102 */ compare(int[] a, int[] b)103 public static int compare(int[] a, int[] b) { 104 for (int i = 0; i < a.length && i < b.length; i++) { 105 int cmp = a[i] - b[i]; 106 if (cmp != 0) 107 return cmp; 108 } 109 return a.length - b.length; 110 } 111 112 /** 113 * Convert a parsed version back to a string. 114 * 115 * @param ver 116 * the parsed version array. 117 * @return a string, e.g. "1.6.6.0". 118 */ toString(int[] ver)119 public static String toString(int[] ver) { 120 StringBuilder b = new StringBuilder(); 121 for (int v : ver) { 122 if (b.length() > 0) 123 b.append('.'); 124 b.append(v); 125 } 126 return b.toString(); 127 } 128 129 /** 130 * Check if a Git client has the known push status bug. 131 * <p> 132 * These buggy clients do not display the status report from a failed push 133 * over HTTP. 134 * 135 * @param version 136 * parsed version of the Git client software. 137 * @return true if the bug is present. 138 * @deprecated no widely used Git versions need this any more 139 */ 140 @Deprecated hasPushStatusBug(int[] version)141 public static boolean hasPushStatusBug(int[] version) { 142 return false; 143 } 144 145 /** 146 * Check if a Git client has the known chunked request body encoding bug. 147 * <p> 148 * Git 1.7.5 contains a unique bug where chunked requests are malformed. 149 * This applies to both fetch and push. 150 * 151 * @param version 152 * parsed version of the Git client software. 153 * @param request 154 * incoming HTTP request. 155 * @return true if the client has the chunked encoding bug. 156 * @deprecated no widely used Git versions need this any more 157 */ 158 @Deprecated hasChunkedEncodingRequestBug( int[] version, HttpServletRequest request)159 public static boolean hasChunkedEncodingRequestBug( 160 int[] version, HttpServletRequest request) { 161 return false; 162 } 163 ClientVersionUtil()164 private ClientVersionUtil() { 165 } 166 } 167