1 ////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code for adherence to a set of rules.
3 // Copyright (C) 2001-2019 the original author or authors.
4 //
5 // This library is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU Lesser General Public
7 // License as published by the Free Software Foundation; either
8 // version 2.1 of the License, or (at your option) any later version.
9 //
10 // This library is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // Lesser General Public License for more details.
14 //
15 // You should have received a copy of the GNU Lesser General Public
16 // License along with this library; if not, write to the Free Software
17 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 ////////////////////////////////////////////////////////////////////////////////
19
20 package com.puppycrawl.tools.checkstyle.api;
21
22 import java.io.BufferedReader;
23 import java.io.File;
24 import java.io.FileNotFoundException;
25 import java.io.IOException;
26 import java.io.InputStream;
27 import java.io.InputStreamReader;
28 import java.io.Reader;
29 import java.io.StringReader;
30 import java.nio.charset.Charset;
31 import java.nio.charset.CharsetDecoder;
32 import java.nio.charset.CodingErrorAction;
33 import java.nio.charset.UnsupportedCharsetException;
34 import java.nio.file.Files;
35 import java.util.ArrayList;
36 import java.util.Arrays;
37 import java.util.List;
38 import java.util.regex.Matcher;
39 import java.util.regex.Pattern;
40
41 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
42
43 /**
44 * Represents the text contents of a file of arbitrary plain text type.
45 * <p>
46 * This class will be passed to instances of class FileSetCheck by
47 * Checker.
48 * </p>
49 *
50 */
51 public final class FileText {
52
53 /**
54 * The number of characters to read in one go.
55 */
56 private static final int READ_BUFFER_SIZE = 1024;
57
58 /**
59 * Regular expression pattern matching all line terminators.
60 */
61 private static final Pattern LINE_TERMINATOR = Pattern.compile("\\n|\\r\\n?");
62
63 // For now, we always keep both full text and lines array.
64 // In the long run, however, the one passed at initialization might be
65 // enough, while the other could be lazily created when requested.
66 // This would save memory but cost CPU cycles.
67
68 /**
69 * The name of the file.
70 * {@code null} if no file name is available for whatever reason.
71 */
72 private final File file;
73
74 /**
75 * The charset used to read the file.
76 * {@code null} if the file was reconstructed from a list of lines.
77 */
78 private final Charset charset;
79
80 /**
81 * The full text contents of the file.
82 */
83 private final String fullText;
84
85 /**
86 * The lines of the file, without terminators.
87 */
88 private final String[] lines;
89
90 /**
91 * The first position of each line within the full text.
92 */
93 private int[] lineBreaks;
94
95 /**
96 * Creates a new file text representation.
97 *
98 * <p>The file will be read using the specified encoding, replacing
99 * malformed input and unmappable characters with the default
100 * replacement character.
101 *
102 * @param file the name of the file
103 * @param charsetName the encoding to use when reading the file
104 * @throws NullPointerException if the text is null
105 * @throws IOException if the file could not be read
106 */
107 public FileText(File file, String charsetName) throws IOException {
108 this.file = file;
109
110 // We use our own decoder, to be sure we have complete control
111 // about replacements.
112 final CharsetDecoder decoder;
113 try {
114 charset = Charset.forName(charsetName);
115 decoder = charset.newDecoder();
116 decoder.onMalformedInput(CodingErrorAction.REPLACE);
117 decoder.onUnmappableCharacter(CodingErrorAction.REPLACE);
118 }
119 catch (final UnsupportedCharsetException ex) {
120 final String message = "Unsupported charset: " + charsetName;
121 throw new IllegalStateException(message, ex);
122 }
123
124 fullText = readFile(file, decoder);
125
126 // Use the BufferedReader to break down the lines as this
127 // is about 30% faster than using the
128 // LINE_TERMINATOR.split(fullText, -1) method
129 try (BufferedReader reader = new BufferedReader(new StringReader(fullText))) {
130 final ArrayList<String> textLines = new ArrayList<>();
131 while (true) {
132 final String line = reader.readLine();
133 if (line == null) {
134 break;
135 }
136 textLines.add(line);
137 }
138 lines = textLines.toArray(CommonUtil.EMPTY_STRING_ARRAY);
139 }
140 }
141
142 /**
143 * Copy constructor.
144 * @param fileText to make copy of
145 */
146 public FileText(FileText fileText) {
147 file = fileText.file;
148 charset = fileText.charset;
149 fullText = fileText.fullText;
150 lines = fileText.lines.clone();
151 if (fileText.lineBreaks == null) {
152 lineBreaks = null;
153 }
154 else {
155 lineBreaks = fileText.lineBreaks.clone();
156 }
157 }
158
159 /**
160 * Compatibility constructor.
161 *
162 * <p>This constructor reconstructs the text of the file by joining
163 * lines with linefeed characters. This process does not restore
164 * the original line terminators and should therefore be avoided.
165 *
166 * @param file the name of the file
167 * @param lines the lines of the text, without terminators
168 * @throws NullPointerException if the lines array is null
169 */
170 public FileText(File file, List<String> lines) {
171 final StringBuilder buf = new StringBuilder(1024);
172 for (final String line : lines) {
173 buf.append(line).append('\n');
174 }
175
176 this.file = file;
177 charset = null;
178 fullText = buf.toString();
179 this.lines = lines.toArray(CommonUtil.EMPTY_STRING_ARRAY);
180 }
181
182 /**
183 * Reads file using specific decoder and returns all its content as a String.
184 * @param inputFile File to read
185 * @param decoder Charset decoder
186 * @return File's text
187 * @throws IOException Unable to open or read the file
188 */
189 private static String readFile(final File inputFile, final CharsetDecoder decoder)
190 throws IOException {
191 if (!inputFile.exists()) {
192 throw new FileNotFoundException(inputFile.getPath() + " (No such file or directory)");
193 }
194 final StringBuilder buf = new StringBuilder(1024);
195 final InputStream stream = Files.newInputStream(inputFile.toPath());
196 try (Reader reader = new InputStreamReader(stream, decoder)) {
197 final char[] chars = new char[READ_BUFFER_SIZE];
198 while (true) {
199 final int len = reader.read(chars);
200 if (len == -1) {
201 break;
202 }
203 buf.append(chars, 0, len);
204 }
205 }
206 return buf.toString();
207 }
208
209 /**
210 * Get the name of the file.
211 * @return an object containing the name of the file
212 */
213 public File getFile() {
214 return file;
215 }
216
217 /**
218 * Get the character set which was used to read the file.
219 * Will be {@code null} for a file reconstructed from its lines.
220 * @return the charset used when the file was read
221 */
222 public Charset getCharset() {
223 return charset;
224 }
225
226 /**
227 * Retrieve the full text of the file.
228 * @return the full text of the file
229 */
230 public CharSequence getFullText() {
231 return fullText;
232 }
233
234 /**
235 * Returns an array of all lines.
236 * {@code text.toLinesArray()} is equivalent to
237 * {@code text.toArray(new String[text.size()])}.
238 * @return an array of all lines of the text
239 */
240 public String[] toLinesArray() {
241 return lines.clone();
242 }
243
244 /**
245 * Find positions of line breaks in the full text.
246 * @return an array giving the first positions of each line.
247 */
248 private int[] findLineBreaks() {
249 if (lineBreaks == null) {
250 final int[] lineBreakPositions = new int[size() + 1];
251 lineBreakPositions[0] = 0;
252 int lineNo = 1;
253 final Matcher matcher = LINE_TERMINATOR.matcher(fullText);
254 while (matcher.find()) {
255 lineBreakPositions[lineNo] = matcher.end();
256 lineNo++;
257 }
258 if (lineNo < lineBreakPositions.length) {
259 lineBreakPositions[lineNo] = fullText.length();
260 }
261 lineBreaks = lineBreakPositions;
262 }
263 return lineBreaks;
264 }
265
266 /**
267 * Determine line and column numbers in full text.
268 * @param pos the character position in the full text
269 * @return the line and column numbers of this character
270 */
271 public LineColumn lineColumn(int pos) {
272 final int[] lineBreakPositions = findLineBreaks();
273 int lineNo = Arrays.binarySearch(lineBreakPositions, pos);
274 if (lineNo < 0) {
275 // we have: lineNo = -(insertion point) - 1
276 // we want: lineNo = (insertion point) - 1
277 lineNo = -lineNo - 2;
278 }
279 final int startOfLine = lineBreakPositions[lineNo];
280 final int columnNo = pos - startOfLine;
281 // now we have lineNo and columnNo, both starting at zero.
282 return new LineColumn(lineNo + 1, columnNo);
283 }
284
285 /**
286 * Retrieves a line of the text by its number.
287 * The returned line will not contain a trailing terminator.
288 * @param lineNo the number of the line to get, starting at zero
289 * @return the line with the given number
290 */
291 public String get(final int lineNo) {
292 return lines[lineNo];
293 }
294
295 /**
296 * Counts the lines of the text.
297 * @return the number of lines in the text
298 */
299 public int size() {
300 return lines.length;
301 }
302
303 }