1 ////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code for adherence to a set of rules.
3 // Copyright (C) 2001-2020 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 lines of the file, without terminators.
82 */
83 private final String[] lines;
84
85 /**
86 * The full text contents of the file.
87 *
88 * <p>Field is not final to ease reaching full test coverage.
89 *
90 * @noinspection FieldMayBeFinal
91 */
92 private String fullText;
93
94 /**
95 * The first position of each line within the full text.
96 */
97 private int[] lineBreaks;
98
99 /**
100 * Copy constructor.
101 * @param fileText to make copy of
102 */
103 public FileText" href="../../../../../com/puppycrawl/tools/checkstyle/api/FileText.html#FileText">FileText(FileText fileText) {
104 file = fileText.file;
105 charset = fileText.charset;
106 fullText = fileText.fullText;
107 lines = fileText.lines.clone();
108 if (fileText.lineBreaks == null) {
109 lineBreaks = null;
110 }
111 else {
112 lineBreaks = fileText.lineBreaks.clone();
113 }
114 }
115
116 /**
117 * Compatibility constructor.
118 *
119 * <p>This constructor reconstructs the text of the file by joining
120 * lines with linefeed characters. This process does not restore
121 * the original line terminators and should therefore be avoided.
122 *
123 * @param file the name of the file
124 * @param lines the lines of the text, without terminators
125 * @throws NullPointerException if the lines array is null
126 */
127 public FileText(File file, List<String> lines) {
128 final StringBuilder buf = new StringBuilder(1024);
129 for (final String line : lines) {
130 buf.append(line).append('\n');
131 }
132
133 this.file = file;
134 charset = null;
135 fullText = buf.toString();
136 this.lines = lines.toArray(CommonUtil.EMPTY_STRING_ARRAY);
137 }
138
139 /**
140 * Creates a new file text representation.
141 *
142 * <p>The file will be read using the specified encoding, replacing
143 * malformed input and unmappable characters with the default
144 * replacement character.
145 *
146 * @param file the name of the file
147 * @param charsetName the encoding to use when reading the file
148 * @throws NullPointerException if the text is null
149 * @throws IOException if the file could not be read
150 */
151 public FileText(File file, String charsetName) throws IOException {
152 this.file = file;
153
154 // We use our own decoder, to be sure we have complete control
155 // about replacements.
156 final CharsetDecoder decoder;
157 try {
158 charset = Charset.forName(charsetName);
159 decoder = charset.newDecoder();
160 decoder.onMalformedInput(CodingErrorAction.REPLACE);
161 decoder.onUnmappableCharacter(CodingErrorAction.REPLACE);
162 }
163 catch (final UnsupportedCharsetException ex) {
164 final String message = "Unsupported charset: " + charsetName;
165 throw new IllegalStateException(message, ex);
166 }
167
168 fullText = readFile(file, decoder);
169
170 // Use the BufferedReader to break down the lines as this
171 // is about 30% faster than using the
172 // LINE_TERMINATOR.split(fullText, -1) method
173 try (BufferedReader reader = new BufferedReader(new StringReader(fullText))) {
174 final ArrayList<String> textLines = new ArrayList<>();
175 while (true) {
176 final String line = reader.readLine();
177 if (line == null) {
178 break;
179 }
180 textLines.add(line);
181 }
182 lines = textLines.toArray(CommonUtil.EMPTY_STRING_ARRAY);
183 }
184 }
185
186 /**
187 * Reads file using specific decoder and returns all its content as a String.
188 *
189 * @param inputFile File to read
190 * @param decoder Charset decoder
191 * @return File's text
192 * @throws IOException Unable to open or read the file
193 * @throws FileNotFoundException when inputFile does not exists
194 */
195 private static String readFile(final File inputFile, final CharsetDecoder decoder)
196 throws IOException {
197 if (!inputFile.exists()) {
198 throw new FileNotFoundException(inputFile.getPath() + " (No such file or directory)");
199 }
200 final StringBuilder buf = new StringBuilder(1024);
201 final InputStream stream = Files.newInputStream(inputFile.toPath());
202 try (Reader reader = new InputStreamReader(stream, decoder)) {
203 final char[] chars = new char[READ_BUFFER_SIZE];
204 while (true) {
205 final int len = reader.read(chars);
206 if (len == -1) {
207 break;
208 }
209 buf.append(chars, 0, len);
210 }
211 }
212 return buf.toString();
213 }
214
215 /**
216 * Retrieves a line of the text by its number.
217 * The returned line will not contain a trailing terminator.
218 * @param lineNo the number of the line to get, starting at zero
219 * @return the line with the given number
220 */
221 public String get(final int lineNo) {
222 return lines[lineNo];
223 }
224
225 /**
226 * Get the name of the file.
227 *
228 * @return an object containing the name of the file
229 */
230 public File getFile() {
231 return file;
232 }
233
234 /**
235 * Get the character set which was used to read the file.
236 * Will be {@code null} for a file reconstructed from its lines.
237 *
238 * @return the charset used when the file was read
239 */
240 public Charset getCharset() {
241 return charset;
242 }
243
244 /**
245 * Retrieve the full text of the file.
246 *
247 * @return the full text of the file
248 */
249 public CharSequence getFullText() {
250 return fullText;
251 }
252
253 /**
254 * Returns an array of all lines.
255 * {@code text.toLinesArray()} is equivalent to
256 * {@code text.toArray(new String[text.size()])}.
257 *
258 * @return an array of all lines of the text
259 */
260 public String[] toLinesArray() {
261 return lines.clone();
262 }
263
264 /**
265 * Determine line and column numbers in full text.
266 *
267 * @param pos the character position in the full text
268 * @return the line and column numbers of this character
269 */
270 public LineColumn lineColumn(int pos) {
271 final int[] lineBreakPositions = findLineBreaks();
272 int lineNo = Arrays.binarySearch(lineBreakPositions, pos);
273 if (lineNo < 0) {
274 // we have: lineNo = -(insertion point) - 1
275 // we want: lineNo = (insertion point) - 1
276 lineNo = -lineNo - 2;
277 }
278 final int startOfLine = lineBreakPositions[lineNo];
279 final int columnNo = pos - startOfLine;
280 // now we have lineNo and columnNo, both starting at zero.
281 return new LineColumn(lineNo + 1, columnNo);
282 }
283
284 /**
285 * Find positions of line breaks in the full text.
286 * @return an array giving the first positions of each line.
287 */
288 private int[] findLineBreaks() {
289 if (lineBreaks == null) {
290 final int[] lineBreakPositions = new int[size() + 1];
291 lineBreakPositions[0] = 0;
292 int lineNo = 1;
293 final Matcher matcher = LINE_TERMINATOR.matcher(fullText);
294 while (matcher.find()) {
295 lineBreakPositions[lineNo] = matcher.end();
296 lineNo++;
297 }
298 if (lineNo < lineBreakPositions.length) {
299 lineBreakPositions[lineNo] = fullText.length();
300 }
301 lineBreaks = lineBreakPositions;
302 }
303 return lineBreaks;
304 }
305
306 /**
307 * Counts the lines of the text.
308 *
309 * @return the number of lines in the text
310 */
311 public int size() {
312 return lines.length;
313 }
314
315 }