1 ////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code for adherence to a set of rules.
3 // Copyright (C) 2001-2019 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.checks;
21
22 import java.io.File;
23 import java.io.IOException;
24 import java.io.RandomAccessFile;
25 import java.util.Locale;
26
27 import com.puppycrawl.tools.checkstyle.StatelessCheck;
28 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
29 import com.puppycrawl.tools.checkstyle.api.FileText;
30
31 /**
32 * <p>
33 * Checks that there is a newline at the end of each file.
34 * </p>
35 * <p>
36 * An example of how to configure the check is:
37 * </p>
38 * <pre>
39 * <module name="NewlineAtEndOfFile"/></pre>
40 * <p>
41 * This will check against the platform-specific default line separator.
42 * </p>
43 * <p>
44 * It is also possible to enforce the use of a specific line-separator across
45 * platforms, with the 'lineSeparator' property:
46 * </p>
47 * <pre>
48 * <module name="NewlineAtEndOfFile">
49 * <property name="lineSeparator" value="lf"/>
50 * </module></pre>
51 * <p>
52 * Valid values for the 'lineSeparator' property are 'system' (system default),
53 * 'crlf' (windows), 'cr' (mac), 'lf' (unix) and 'lf_cr_crlf' (lf, cr or crlf).
54 * </p>
55 *
56 */
57 @StatelessCheck
58 public class NewlineAtEndOfFileCheck
59 extends AbstractFileSetCheck {
60
61 /**
62 * A key is pointing to the warning message text in "messages.properties"
63 * file.
64 */
65 public static final String MSG_KEY_UNABLE_OPEN = "unable.open";
66
67 /**
68 * A key is pointing to the warning message text in "messages.properties"
69 * file.
70 */
71 public static final String MSG_KEY_NO_NEWLINE_EOF = "noNewlineAtEOF";
72
73 /** The line separator to check against. */
74 private LineSeparatorOption lineSeparator = LineSeparatorOption.SYSTEM;
75
76 @Override
77 protected void processFiltered(File file, FileText fileText) {
78 try {
79 readAndCheckFile(file);
80 }
81 catch (final IOException ignored) {
82 log(1, MSG_KEY_UNABLE_OPEN, file.getPath());
83 }
84 }
85
86 /**
87 * Sets the line separator to one of 'crlf', 'lf','cr', 'lf_cr_crlf' or 'system'.
88 *
89 * @param lineSeparatorParam The line separator to set
90 * @throws IllegalArgumentException If the specified line separator is not
91 * one of 'crlf', 'lf', 'cr', 'lf_cr_crlf' or 'system'
92 */
93 public void setLineSeparator(String lineSeparatorParam) {
94 lineSeparator =
95 Enum.valueOf(LineSeparatorOption.class, lineSeparatorParam.trim()
96 .toUpperCase(Locale.ENGLISH));
97 }
98
99 /**
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 }