001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2019 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks;
021
022import java.io.File;
023import java.io.IOException;
024import java.io.RandomAccessFile;
025import java.util.Locale;
026
027import com.puppycrawl.tools.checkstyle.StatelessCheck;
028import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
029import com.puppycrawl.tools.checkstyle.api.FileText;
030
031/**
032 * <p>
033 * Checks that there is a newline at the end of each file.
034 * </p>
035 * <p>
036 * An example of how to configure the check is:
037 * </p>
038 * <pre>
039 * &lt;module name="NewlineAtEndOfFile"/&gt;</pre>
040 * <p>
041 * This will check against the platform-specific default line separator.
042 * </p>
043 * <p>
044 * It is also possible to enforce the use of a specific line-separator across
045 * platforms, with the 'lineSeparator' property:
046 * </p>
047 * <pre>
048 * &lt;module name="NewlineAtEndOfFile"&gt;
049 *   &lt;property name="lineSeparator" value="lf"/&gt;
050 * &lt;/module&gt;</pre>
051 * <p>
052 * Valid values for the 'lineSeparator' property are 'system' (system default),
053 * 'crlf' (windows), 'cr' (mac), 'lf' (unix) and 'lf_cr_crlf' (lf, cr or crlf).
054 * </p>
055 *
056 */
057@StatelessCheck
058public class NewlineAtEndOfFileCheck
059    extends AbstractFileSetCheck {
060
061    /**
062     * A key is pointing to the warning message text in "messages.properties"
063     * file.
064     */
065    public static final String MSG_KEY_UNABLE_OPEN = "unable.open";
066
067    /**
068     * A key is pointing to the warning message text in "messages.properties"
069     * file.
070     */
071    public static final String MSG_KEY_NO_NEWLINE_EOF = "noNewlineAtEOF";
072
073    /** The line separator to check against. */
074    private LineSeparatorOption lineSeparator = LineSeparatorOption.SYSTEM;
075
076    @Override
077    protected void processFiltered(File file, FileText fileText) {
078        try {
079            readAndCheckFile(file);
080        }
081        catch (final IOException ignored) {
082            log(1, MSG_KEY_UNABLE_OPEN, file.getPath());
083        }
084    }
085
086    /**
087     * Sets the line separator to one of 'crlf', 'lf','cr', 'lf_cr_crlf' or 'system'.
088     *
089     * @param lineSeparatorParam The line separator to set
090     * @throws IllegalArgumentException If the specified line separator is not
091     *         one of 'crlf', 'lf', 'cr', 'lf_cr_crlf' or 'system'
092     */
093    public void setLineSeparator(String lineSeparatorParam) {
094        lineSeparator =
095            Enum.valueOf(LineSeparatorOption.class, lineSeparatorParam.trim()
096                .toUpperCase(Locale.ENGLISH));
097    }
098
099    /**
100     * Reads the file provided and checks line separators.
101     * @param file the file to be processed
102     * @throws IOException When an IO error occurred while reading from the
103     *         file provided
104     */
105    private void readAndCheckFile(File file) throws IOException {
106        // Cannot use lines as the line separators have been removed!
107        try (RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r")) {
108            if (!endsWithNewline(randomAccessFile)) {
109                log(1, MSG_KEY_NO_NEWLINE_EOF, file.getPath());
110            }
111        }
112    }
113
114    /**
115     * Checks whether the content provided by the Reader ends with the platform
116     * specific line separator.
117     * @param randomAccessFile The reader for the content to check
118     * @return boolean Whether the content ends with a line separator
119     * @throws IOException When an IO error occurred while reading from the
120     *         provided reader
121     */
122    private boolean endsWithNewline(RandomAccessFile randomAccessFile)
123            throws IOException {
124        final boolean result;
125        final int len = lineSeparator.length();
126        if (randomAccessFile.length() < len) {
127            result = false;
128        }
129        else {
130            randomAccessFile.seek(randomAccessFile.length() - len);
131            final byte[] lastBytes = new byte[len];
132            final int readBytes = randomAccessFile.read(lastBytes);
133            if (readBytes != len) {
134                throw new IOException("Unable to read " + len + " bytes, got "
135                        + readBytes);
136            }
137            result = lineSeparator.matches(lastBytes);
138        }
139        return result;
140    }
141
142}