001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2017 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.google.common.io.Closeables;
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 * @author Christopher Lenz
057 * @author lkuehne
058 */
059public class NewlineAtEndOfFileCheck
060    extends AbstractFileSetCheck {
061
062    /**
063     * A key is pointing to the warning message text in "messages.properties"
064     * file.
065     */
066    public static final String MSG_KEY_UNABLE_OPEN = "unable.open";
067
068    /**
069     * A key is pointing to the warning message text in "messages.properties"
070     * file.
071     */
072    public static final String MSG_KEY_NO_NEWLINE_EOF = "noNewlineAtEOF";
073
074    /** The line separator to check against. */
075    private LineSeparatorOption lineSeparator = LineSeparatorOption.SYSTEM;
076
077    @Override
078    protected void processFiltered(File file, FileText fileText) {
079        try {
080            readAndCheckFile(file);
081        }
082        catch (final IOException ignored) {
083            log(0, MSG_KEY_UNABLE_OPEN, file.getPath());
084        }
085    }
086
087    /**
088     * Sets the line separator to one of 'crlf', 'lf','cr', 'lf_cr_crlf' or 'system'.
089     *
090     * @param lineSeparatorParam The line separator to set
091     * @throws IllegalArgumentException If the specified line separator is not
092     *         one of 'crlf', 'lf', 'cr', 'lf_cr_crlf' or 'system'
093     */
094    public void setLineSeparator(String lineSeparatorParam) {
095        try {
096            lineSeparator =
097                Enum.valueOf(LineSeparatorOption.class, lineSeparatorParam.trim()
098                    .toUpperCase(Locale.ENGLISH));
099        }
100        catch (IllegalArgumentException iae) {
101            throw new IllegalArgumentException("unable to parse " + lineSeparatorParam, iae);
102        }
103    }
104
105    /**
106     * Reads the file provided and checks line separators.
107     * @param file the file to be processed
108     * @throws IOException When an IO error occurred while reading from the
109     *         file provided
110     */
111    private void readAndCheckFile(File file) throws IOException {
112        // Cannot use lines as the line separators have been removed!
113        final RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r");
114        boolean threw = true;
115        try {
116            if (!endsWithNewline(randomAccessFile)) {
117                log(0, MSG_KEY_NO_NEWLINE_EOF, file.getPath());
118            }
119            threw = false;
120        }
121        finally {
122            Closeables.close(randomAccessFile, threw);
123        }
124    }
125
126    /**
127     * Checks whether the content provided by the Reader ends with the platform
128     * specific line separator.
129     * @param randomAccessFile The reader for the content to check
130     * @return boolean Whether the content ends with a line separator
131     * @throws IOException When an IO error occurred while reading from the
132     *         provided reader
133     */
134    private boolean endsWithNewline(RandomAccessFile randomAccessFile)
135            throws IOException {
136        final boolean result;
137        final int len = lineSeparator.length();
138        if (randomAccessFile.length() < len) {
139            result = false;
140        }
141        else {
142            randomAccessFile.seek(randomAccessFile.length() - len);
143            final byte[] lastBytes = new byte[len];
144            final int readBytes = randomAccessFile.read(lastBytes);
145            if (readBytes != len) {
146                throw new IOException("Unable to read " + len + " bytes, got "
147                        + readBytes);
148            }
149            result = lineSeparator.matches(lastBytes);
150        }
151        return result;
152    }
153}