FileText.java
////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2021 the original author or authors.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
////////////////////////////////////////////////////////////////////////////////
package com.puppycrawl.tools.checkstyle.api;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CodingErrorAction;
import java.nio.charset.UnsupportedCharsetException;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
/**
* Represents the text contents of a file of arbitrary plain text type.
* <p>
* This class will be passed to instances of class FileSetCheck by
* Checker.
* </p>
*
*/
public final class FileText {
/**
* The number of characters to read in one go.
*/
private static final int READ_BUFFER_SIZE = 1024;
/**
* Regular expression pattern matching all line terminators.
*/
private static final Pattern LINE_TERMINATOR = Pattern.compile("\\n|\\r\\n?");
// For now, we always keep both full text and lines array.
// In the long run, however, the one passed at initialization might be
// enough, while the other could be lazily created when requested.
// This would save memory but cost CPU cycles.
/**
* The name of the file.
* {@code null} if no file name is available for whatever reason.
*/
private final File file;
/**
* The charset used to read the file.
* {@code null} if the file was reconstructed from a list of lines.
*/
private final Charset charset;
/**
* The lines of the file, without terminators.
*/
private final String[] lines;
/**
* The full text contents of the file.
*
* <p>Field is not final to ease reaching full test coverage.
*
* @noinspection FieldMayBeFinal
*/
private String fullText;
/**
* The first position of each line within the full text.
*/
private int[] lineBreaks;
/**
* Copy constructor.
*
* @param fileText to make copy of
*/
public FileText(FileText fileText) {
file = fileText.file;
charset = fileText.charset;
fullText = fileText.fullText;
lines = fileText.lines.clone();
if (fileText.lineBreaks == null) {
lineBreaks = null;
}
else {
lineBreaks = fileText.lineBreaks.clone();
}
}
/**
* Compatibility constructor.
*
* <p>This constructor reconstructs the text of the file by joining
* lines with linefeed characters. This process does not restore
* the original line terminators and should therefore be avoided.
*
* @param file the name of the file
* @param lines the lines of the text, without terminators
* @throws NullPointerException if the lines array is null
*/
public FileText(File file, List<String> lines) {
final StringBuilder buf = new StringBuilder(1024);
for (final String line : lines) {
buf.append(line).append('\n');
}
this.file = file;
charset = null;
fullText = buf.toString();
this.lines = lines.toArray(CommonUtil.EMPTY_STRING_ARRAY);
}
/**
* Creates a new file text representation.
*
* <p>The file will be read using the specified encoding, replacing
* malformed input and unmappable characters with the default
* replacement character.
*
* @param file the name of the file
* @param charsetName the encoding to use when reading the file
* @throws NullPointerException if the text is null
* @throws IllegalStateException if the charset is not supported.
* @throws IOException if the file could not be read
*/
public FileText(File file, String charsetName) throws IOException {
this.file = file;
// We use our own decoder, to be sure we have complete control
// about replacements.
final CharsetDecoder decoder;
try {
charset = Charset.forName(charsetName);
decoder = charset.newDecoder();
decoder.onMalformedInput(CodingErrorAction.REPLACE);
decoder.onUnmappableCharacter(CodingErrorAction.REPLACE);
}
catch (final UnsupportedCharsetException ex) {
final String message = "Unsupported charset: " + charsetName;
throw new IllegalStateException(message, ex);
}
fullText = readFile(file, decoder);
// Use the BufferedReader to break down the lines as this
// is about 30% faster than using the
// LINE_TERMINATOR.split(fullText, -1) method
try (BufferedReader reader = new BufferedReader(new StringReader(fullText))) {
final ArrayList<String> textLines = new ArrayList<>();
while (true) {
final String line = reader.readLine();
if (line == null) {
break;
}
textLines.add(line);
}
lines = textLines.toArray(CommonUtil.EMPTY_STRING_ARRAY);
}
}
/**
* Reads file using specific decoder and returns all its content as a String.
*
* @param inputFile File to read
* @param decoder Charset decoder
* @return File's text
* @throws IOException Unable to open or read the file
* @throws FileNotFoundException when inputFile does not exists
*/
private static String readFile(final File inputFile, final CharsetDecoder decoder)
throws IOException {
if (!inputFile.exists()) {
throw new FileNotFoundException(inputFile.getPath() + " (No such file or directory)");
}
final StringBuilder buf = new StringBuilder(1024);
final InputStream stream = Files.newInputStream(inputFile.toPath());
try (Reader reader = new InputStreamReader(stream, decoder)) {
final char[] chars = new char[READ_BUFFER_SIZE];
while (true) {
final int len = reader.read(chars);
if (len == -1) {
break;
}
buf.append(chars, 0, len);
}
}
return buf.toString();
}
/**
* Retrieves a line of the text by its number.
* The returned line will not contain a trailing terminator.
*
* @param lineNo the number of the line to get, starting at zero
* @return the line with the given number
*/
public String get(final int lineNo) {
return lines[lineNo];
}
/**
* Get the name of the file.
*
* @return an object containing the name of the file
*/
public File getFile() {
return file;
}
/**
* Get the character set which was used to read the file.
* Will be {@code null} for a file reconstructed from its lines.
*
* @return the charset used when the file was read
*/
public Charset getCharset() {
return charset;
}
/**
* Retrieve the full text of the file.
*
* @return the full text of the file
*/
public CharSequence getFullText() {
return fullText;
}
/**
* Returns an array of all lines.
* {@code text.toLinesArray()} is equivalent to
* {@code text.toArray(new String[text.size()])}.
*
* @return an array of all lines of the text
*/
public String[] toLinesArray() {
return lines.clone();
}
/**
* Determine line and column numbers in full text.
*
* @param pos the character position in the full text
* @return the line and column numbers of this character
*/
public LineColumn lineColumn(int pos) {
final int[] lineBreakPositions = findLineBreaks();
int lineNo = Arrays.binarySearch(lineBreakPositions, pos);
if (lineNo < 0) {
// we have: lineNo = -(insertion point) - 1
// we want: lineNo = (insertion point) - 1
lineNo = -lineNo - 2;
}
final int startOfLine = lineBreakPositions[lineNo];
final int columnNo = pos - startOfLine;
// now we have lineNo and columnNo, both starting at zero.
return new LineColumn(lineNo + 1, columnNo);
}
/**
* Find positions of line breaks in the full text.
*
* @return an array giving the first positions of each line.
*/
private int[] findLineBreaks() {
if (lineBreaks == null) {
final int[] lineBreakPositions = new int[size() + 1];
lineBreakPositions[0] = 0;
int lineNo = 1;
final Matcher matcher = LINE_TERMINATOR.matcher(fullText);
while (matcher.find()) {
lineBreakPositions[lineNo] = matcher.end();
lineNo++;
}
if (lineNo < lineBreakPositions.length) {
lineBreakPositions[lineNo] = fullText.length();
}
lineBreaks = lineBreakPositions;
}
return lineBreaks;
}
/**
* Counts the lines of the text.
*
* @return the number of lines in the text
*/
public int size() {
return lines.length;
}
}