Source code

001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2026 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.site;
021
022import java.io.IOException;
023import java.nio.file.Files;
024import java.nio.file.Path;
025import java.util.ArrayList;
026import java.util.Collection;
027import java.util.List;
028import java.util.Locale;
029import java.util.regex.Pattern;
030import java.util.stream.Collectors;
031
032import org.apache.maven.doxia.macro.AbstractMacro;
033import org.apache.maven.doxia.macro.Macro;
034import org.apache.maven.doxia.macro.MacroExecutionException;
035import org.apache.maven.doxia.macro.MacroRequest;
036import org.apache.maven.doxia.sink.Sink;
037import org.codehaus.plexus.component.annotations.Component;
038
039/**
040 * A macro that inserts a snippet of code or configuration from a file.
041 */
042@Component(role = Macro.class, hint = "example")
043public class ExampleMacro extends AbstractMacro {
044
045    /** Starting delimiter for config snippets. */
046    private static final String XML_CONFIG_START = "/*xml";
047
048    /** Ending delimiter for config snippets. */
049    private static final String XML_CONFIG_END = "*/";
050
051    /** Starting delimiter for code snippets. */
052    private static final String CODE_SNIPPET_START = "// xdoc section -- start";
053
054    /** Ending delimiter for code snippets. */
055    private static final String CODE_SNIPPET_END = "// xdoc section -- end";
056
057    /** The pattern of xml code blocks. */
058    private static final Pattern XML_PATTERN = Pattern.compile(
059            "^\\s*(<!DOCTYPE\\s+.*?>|<\\?xml\\s+.*?>|<module\\s+.*?>)\\s*",
060            Pattern.DOTALL
061    );
062
063    /** The path of the last file. */
064    private String lastPath = "";
065
066    /** The line contents of the last file. */
067    private List<String> lastLines = new ArrayList<>();
068
069    @Override
070    public void execute(Sink sink, MacroRequest request) throws MacroExecutionException {
071        final String path = (String) request.getParameter("path");
072        final String type = (String) request.getParameter("type");
073
074        List<String> lines = lastLines;
075        if (!path.equals(lastPath)) {
076            lines = readFile("src/xdocs-examples/" + path);
077            lastPath = path;
078            lastLines = lines;
079        }
080
081        if ("config".equals(type)) {
082            final String config = getConfigSnippet(lines);
083
084            if (config.isBlank()) {
085                final String message = String.format(Locale.ROOT,
086                        "Empty config snippet from %s, check"
087                                + " for xml config snippet delimiters in input file.", path
088                );
089                throw new MacroExecutionException(message);
090            }
091
092            writeSnippet(sink, config);
093        }
094        else if ("code".equals(type)) {
095            String code = getCodeSnippet(lines);
096            // Replace tabs with spaces for FileTabCharacterCheck examples
097            if (path.contains("filetabcharacter")) {
098                code = code.replace("\t", "  ");
099            }
100
101            if (code.isBlank()) {
102                final String message = String.format(Locale.ROOT,
103                        "Empty code snippet from %s, check"
104                                + " for code snippet delimiters in input file.", path
105                );
106                throw new MacroExecutionException(message);
107            }
108
109            writeSnippet(sink, code);
110        }
111        else if ("raw".equals(type)) {
112            final String content = String.join(ModuleJavadocParsingUtil.NEWLINE, lines);
113            writeSnippet(sink, content);
114        }
115        else {
116            final String message = String.format(Locale.ROOT, "Unknown example type: %s", type);
117            throw new MacroExecutionException(message);
118        }
119    }
120
121    /**
122     * Read the file at the given path and returns its contents as a list of lines.
123     *
124     * @param path the path to the file to read.
125     * @return the contents of the file as a list of lines.
126     * @throws MacroExecutionException if the file could not be read.
127     */
128    private static List<String> readFile(String path) throws MacroExecutionException {
129        try {
130            final Path exampleFilePath = Path.of(path);
131            return Files.readAllLines(exampleFilePath);
132        }
133        catch (IOException ioException) {
134            final String message = String.format(Locale.ROOT, "Failed to read %s", path);
135            throw new MacroExecutionException(message, ioException);
136        }
137    }
138
139    /**
140     * Extract a configuration snippet from the given lines. Config delimiters use the whole
141     * line for themselves and have no indentation. We use equals() instead of contains()
142     * to be more strict because some examples contain those delimiters. If the delimiters
143     * are not found, returns the entire file content.
144     *
145     * @param lines the lines to extract the snippet from.
146     * @return the configuration snippet.
147     */
148    private static String getConfigSnippet(Collection<String> lines) {
149        final String snippet = lines.stream()
150                .dropWhile(line -> !XML_CONFIG_START.equals(line))
151                .skip(1)
152                .takeWhile(line -> !XML_CONFIG_END.equals(line))
153                .collect(Collectors.joining(ModuleJavadocParsingUtil.NEWLINE));
154
155        // If no snippet was found (markers not present), return the entire file content
156        final String result;
157        if (snippet.isBlank()) {
158            result = String.join(ModuleJavadocParsingUtil.NEWLINE, lines);
159        }
160        else {
161            result = snippet;
162        }
163
164        return result;
165    }
166
167    /**
168     * Extract a code snippet from the given lines. Code delimiters can be indented, so
169     * we use contains() instead of equals(). If the delimiters are not found, returns
170     * the file content excluding the XML config block (if present).
171     *
172     * @param lines the lines to extract the snippet from.
173     * @return the code snippet.
174     */
175    private static String getCodeSnippet(Collection<String> lines) {
176        final String snippet = lines.stream()
177                .dropWhile(line -> !line.contains(CODE_SNIPPET_START))
178                .skip(1)
179                .takeWhile(line -> !line.contains(CODE_SNIPPET_END))
180                .collect(Collectors.joining(ModuleJavadocParsingUtil.NEWLINE));
181
182        // If no snippet was found (markers not present), return the file content
183        // excluding the XML config block (if present)
184        final String result;
185        if (snippet.isBlank()) {
186            final List<String> linesList = new ArrayList<>(lines);
187            final int configEndIndex = linesList.indexOf(XML_CONFIG_END);
188            if (configEndIndex >= 0) {
189                // XML config block is present, return content after it
190                result = String.join(ModuleJavadocParsingUtil.NEWLINE,
191                        linesList.stream()
192                                .skip(configEndIndex + 1)
193                                .toList());
194            }
195            else {
196                // No XML config block, return entire file
197                result = String.join(ModuleJavadocParsingUtil.NEWLINE, linesList);
198            }
199        }
200        else {
201            result = snippet;
202        }
203
204        return result;
205    }
206
207    /**
208     * Writes the given snippet inside a formatted source block.
209     *
210     * @param sink the sink to write to.
211     * @param snippet the snippet to write.
212     */
213    private static void writeSnippet(Sink sink, String snippet) {
214        sink.rawText("<div class=\"wrapper\">");
215        final boolean isXml = isXml(snippet);
216
217        final String languageClass;
218        if (isXml) {
219            languageClass = "language-xml";
220        }
221        else {
222            languageClass = "language-java";
223        }
224        sink.rawText("<pre class=\"prettyprint\"><code class=\"" + languageClass + "\">"
225            + ModuleJavadocParsingUtil.NEWLINE);
226        sink.rawText(escapeHtml(snippet).trim() + ModuleJavadocParsingUtil.NEWLINE);
227        sink.rawText("</code></pre>");
228        sink.rawText("</div>");
229    }
230
231    /**
232     * Escapes HTML special characters in the snippet.
233     *
234     * @param snippet the snippet to escape.
235     * @return the escaped snippet.
236     */
237    private static String escapeHtml(String snippet) {
238        return snippet.replace("&", "&amp;")
239                .replace("<", "&lt;")
240                .replace(">", "&gt;");
241    }
242
243    /**
244     * Determines if the given snippet is likely an XML fragment.
245     *
246     * @param snippet the code snippet to analyze.
247     * @return {@code true} if the snippet appears to be XML, otherwise {@code false}.
248     */
249    private static boolean isXml(String snippet) {
250        return XML_PATTERN.matcher(snippet.trim()).matches();
251    }
252}