001package org.apache.maven.plugins.enforcer.utils; 002 003/* 004 * Licensed to the Apache Software Foundation (ASF) under one 005 * or more contributor license agreements. See the NOTICE file 006 * distributed with this work for additional information 007 * regarding copyright ownership. The ASF licenses this file 008 * to you under the Apache License, Version 2.0 (the 009 * "License"); you may not use this file except in compliance 010 * with the License. You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, 015 * software distributed under the License is distributed on an 016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 017 * KIND, either express or implied. See the License for the 018 * specific language governing permissions and limitations 019 * under the License. 020 */ 021 022import java.io.FilterReader; 023import java.io.IOException; 024import java.io.Reader; 025 026/** 027 * Converts Unix line separators to Windows ones and vice-versa. 028 */ 029public class NormalizeLineSeparatorReader 030 extends FilterReader 031{ 032 033 private static final int EOL = -1; 034 035 /** 036 * Type representing either Unix or Windows line separators 037 */ 038 public enum LineSeparator 039 { 040 WINDOWS( "\r\n", null ), UNIX( "\n", '\r' ); 041 042 private final char[] separatorChars; 043 044 private final Character notPrecededByChar; 045 046 LineSeparator( String separator, Character notPrecededByChar ) 047 { 048 separatorChars = separator.toCharArray(); 049 this.notPrecededByChar = notPrecededByChar; 050 } 051 052 enum MatchResult 053 { 054 NO_MATCH, 055 POTENTIAL_MATCH, 056 MATCH; 057 } 058 059 /** 060 * Checks if two given characters match the line separator represented by this object. 061 * @param currentCharacter the character to check against 062 * @param previousCharacter optional previous character (may be {@code null}) 063 * @return one of {@link MatchResult} 064 */ 065 public MatchResult matches( char currentCharacter, Character previousCharacter ) 066 { 067 int len = separatorChars.length; 068 if ( currentCharacter == separatorChars[len - 1] ) 069 { 070 if ( len > 1 ) 071 { 072 if ( previousCharacter == null || previousCharacter != separatorChars[len - 1] ) 073 { 074 return MatchResult.NO_MATCH; 075 } 076 } 077 if ( notPrecededByChar != null ) 078 { 079 if ( previousCharacter != null && notPrecededByChar == previousCharacter ) 080 { 081 return MatchResult.NO_MATCH; 082 } 083 } 084 return MatchResult.MATCH; 085 } 086 else if ( len > 1 && currentCharacter == separatorChars[len - 2] ) 087 { 088 return MatchResult.POTENTIAL_MATCH; 089 } 090 return MatchResult.NO_MATCH; 091 } 092 }; 093 094 final LineSeparator lineSeparator; 095 096 Character bufferedCharacter; 097 098 Character previousCharacter; 099 100 public NormalizeLineSeparatorReader( Reader reader, LineSeparator lineSeparator ) 101 { 102 super( reader ); 103 this.lineSeparator = lineSeparator; 104 bufferedCharacter = null; 105 } 106 107 @Override 108 public int read( char[] cbuf, int off, int len ) 109 throws IOException 110 { 111 int n; 112 for ( n = off; n < off + len; n++ ) 113 { 114 int readResult = read(); 115 if ( readResult == EOL ) 116 { 117 return n == 0 ? EOL : n; 118 } 119 else 120 { 121 cbuf[n] = (char) readResult; 122 } 123 } 124 return n; 125 } 126 127 @Override 128 public int read() 129 throws IOException 130 { 131 // spool buffered characters, if any 132 if ( bufferedCharacter != null ) 133 { 134 char localBuffer = bufferedCharacter; 135 bufferedCharacter = null; 136 return localBuffer; 137 } 138 int readResult = super.read(); 139 if ( readResult == EOL ) 140 { 141 return readResult; 142 } 143 char currentCharacter = (char) readResult; 144 if ( lineSeparator == LineSeparator.UNIX ) 145 { 146 switch ( LineSeparator.WINDOWS.matches( currentCharacter, previousCharacter ) ) 147 { 148 case MATCH: 149 return lineSeparator.separatorChars[0]; 150 case POTENTIAL_MATCH: 151 previousCharacter = currentCharacter; 152 return read(); 153 default: 154 // fall-through 155 } 156 } 157 else 158 { // WINDOWS 159 // if current is unix, convert 160 switch ( LineSeparator.UNIX.matches( currentCharacter, previousCharacter ) ) 161 { 162 case MATCH: 163 bufferedCharacter = lineSeparator.separatorChars[1]; 164 // set buffered character and return current 165 return lineSeparator.separatorChars[0]; 166 case POTENTIAL_MATCH: 167 // invalid option 168 throw new IllegalStateException( "No potential matches expected for Unix line separator" ); 169 default: 170 // fall-through 171 } 172 } 173 previousCharacter = currentCharacter; 174 return currentCharacter; 175 } 176 177}