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.StatelessCheck;
029import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
030import com.puppycrawl.tools.checkstyle.api.FileText;
031
032/**
033 * <p>
034 * Checks that there is a newline at the end of each file.
035 * </p>
036 * <p>
037 * An example of how to configure the check is:
038 * </p>
039 * <pre>
040 * &lt;module name="NewlineAtEndOfFile"/&gt;</pre>
041 * <p>
042 * This will check against the platform-specific default line separator.
043 * </p>
044 * <p>
045 * It is also possible to enforce the use of a specific line-separator across
046 * platforms, with the 'lineSeparator' property:
047 * </p>
048 * <pre>
049 * &lt;module name="NewlineAtEndOfFile"&gt;
050 *   &lt;property name="lineSeparator" value="lf"/&gt;
051 * &lt;/module&gt;</pre>
052 * <p>
053 * Valid values for the 'lineSeparator' property are 'system' (system default),
054 * 'crlf' (windows), 'cr' (mac), 'lf' (unix) and 'lf_cr_crlf' (lf, cr or crlf).
055 * </p>
056 *
057 * @author Christopher Lenz
058 * @author lkuehne
059 */
060@StatelessCheck
061public class NewlineAtEndOfFileCheck
062    extends AbstractFileSetCheck {
063
064    /**
065     * A key is pointing to the warning message text in "messages.properties"
066     * file.
067     */
068    public static final String MSG_KEY_UNABLE_OPEN = "unable.open";
069
070    /**
071     * A key is pointing to the warning message text in "messages.properties"
072     * file.
073     */
074    public static final String MSG_KEY_NO_NEWLINE_EOF = "noNewlineAtEOF";
075
076    /** The line separator to check against. */
077    private LineSeparatorOption lineSeparator = LineSeparatorOption.SYSTEM;
078
079    @Override
080    protected void processFiltered(File file, FileText fileText) {
081        try {
082            readAndCheckFile(file);
083        }
084        catch (final IOException ignored) {
085            log(0, MSG_KEY_UNABLE_OPEN, file.getPath());
086        }
087    }
088
089    /**
090     * Sets the line separator to one of 'crlf', 'lf','cr', 'lf_cr_crlf' or 'system'.
091     *
092     * @param lineSeparatorParam The line separator to set
093     * @throws IllegalArgumentException If the specified line separator is not
094     *         one of 'crlf', 'lf', 'cr', 'lf_cr_crlf' or 'system'
095     */
096    public void setLineSeparator(String lineSeparatorParam) {
097        try {
098            lineSeparator =
099                Enum.valueOf(LineSeparatorOption.class, lineSeparatorParam.trim()
100                    .toUpperCase(Locale.ENGLISH));
101        }
102        catch (IllegalArgumentException iae) {
103            throw new IllegalArgumentException("unable to parse " + lineSeparatorParam, iae);
104        }
105    }
106
107    /**
108     * Reads the file provided and checks line separators.
109     * @param file the file to be processed
110     * @throws IOException When an IO error occurred while reading from the
111     *         file provided
112     */
113    private void readAndCheckFile(File file) throws IOException {
114        // Cannot use lines as the line separators have been removed!
115        final RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r");
116        boolean threw = true;
117        try {
118            if (!endsWithNewline(randomAccessFile)) {
119                log(0, MSG_KEY_NO_NEWLINE_EOF, file.getPath());
120            }
121            threw = false;
122        }
123        finally {
124            Closeables.close(randomAccessFile, threw);
125        }
126    }
127
128    /**
129     * Checks whether the content provided by the Reader ends with the platform
130     * specific line separator.
131     * @param randomAccessFile The reader for the content to check
132     * @return boolean Whether the content ends with a line separator
133     * @throws IOException When an IO error occurred while reading from the
134     *         provided reader
135     */
136    private boolean endsWithNewline(RandomAccessFile randomAccessFile)
137            throws IOException {
138        final boolean result;
139        final int len = lineSeparator.length();
140        if (randomAccessFile.length() < len) {
141            result = false;
142        }
143        else {
144            randomAccessFile.seek(randomAccessFile.length() - len);
145            final byte[] lastBytes = new byte[len];
146            final int readBytes = randomAccessFile.read(lastBytes);
147            if (readBytes != len) {
148                throw new IOException("Unable to read " + len + " bytes, got "
149                        + readBytes);
150            }
151            result = lineSeparator.matches(lastBytes);
152        }
153        return result;
154    }
155}