001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2025 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;
021
022import java.io.OutputStream;
023import java.io.OutputStreamWriter;
024import java.io.PrintWriter;
025import java.io.StringWriter;
026import java.nio.charset.StandardCharsets;
027import java.util.ArrayList;
028import java.util.Collections;
029import java.util.List;
030import java.util.Map;
031import java.util.concurrent.ConcurrentHashMap;
032
033import com.puppycrawl.tools.checkstyle.api.AuditEvent;
034import com.puppycrawl.tools.checkstyle.api.AuditListener;
035import com.puppycrawl.tools.checkstyle.api.AutomaticBean;
036import com.puppycrawl.tools.checkstyle.api.SeverityLevel;
037
038/**
039 * Simple XML logger.
040 * It outputs everything in UTF-8 (default XML encoding is UTF-8) in case
041 * we want to localize error messages or simply that file names are
042 * localized and takes care about escaping as well.
043 */
044// -@cs[AbbreviationAsWordInName] We can not change it as,
045// check's name is part of API (used in configurations).
046public class XMLLogger
047    extends AbstractAutomaticBean
048    implements AuditListener {
049
050    /** Decimal radix. */
051    private static final int BASE_10 = 10;
052
053    /** Hex radix. */
054    private static final int BASE_16 = 16;
055
056    /** Some known entities to detect. */
057    private static final String[] ENTITIES = {"gt", "amp", "lt", "apos",
058                                              "quot", };
059
060    /** Close output stream in auditFinished. */
061    private final boolean closeStream;
062
063    /** Holds all messages for the given file. */
064    private final Map<String, FileMessages> fileMessages =
065            new ConcurrentHashMap<>();
066
067    /**
068     * Helper writer that allows easy encoding and printing.
069     */
070    private final PrintWriter writer;
071
072    /**
073     * Creates a new {@code XMLLogger} instance.
074     * Sets the output to a defined stream.
075     *
076     * @param outputStream the stream to write logs to.
077     * @param outputStreamOptions if {@code CLOSE} stream should be closed in auditFinished()
078     * @throws IllegalArgumentException if outputStreamOptions is null.
079     * @noinspection deprecation
080     * @noinspectionreason We are forced to keep AutomaticBean compatability
081     *     because of maven-checkstyle-plugin. Until #12873.
082     */
083    public XMLLogger(OutputStream outputStream,
084                     AutomaticBean.OutputStreamOptions outputStreamOptions) {
085        this(outputStream, OutputStreamOptions.valueOf(outputStreamOptions.name()));
086    }
087
088    /**
089     * Creates a new {@code XMLLogger} instance.
090     * Sets the output to a defined stream.
091     *
092     * @param outputStream the stream to write logs to.
093     * @param outputStreamOptions if {@code CLOSE} stream should be closed in auditFinished()
094     * @throws IllegalArgumentException if outputStreamOptions is null.
095     */
096    public XMLLogger(OutputStream outputStream, OutputStreamOptions outputStreamOptions) {
097        writer = new PrintWriter(new OutputStreamWriter(outputStream, StandardCharsets.UTF_8));
098        if (outputStreamOptions == null) {
099            throw new IllegalArgumentException("Parameter outputStreamOptions can not be null");
100        }
101        closeStream = outputStreamOptions == OutputStreamOptions.CLOSE;
102    }
103
104    @Override
105    protected void finishLocalSetup() {
106        // No code by default
107    }
108
109    @Override
110    public void auditStarted(AuditEvent event) {
111        writer.println("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
112
113        final String version = XMLLogger.class.getPackage().getImplementationVersion();
114
115        writer.println("<checkstyle version=\"" + version + "\">");
116    }
117
118    @Override
119    public void auditFinished(AuditEvent event) {
120        writer.println("</checkstyle>");
121        if (closeStream) {
122            writer.close();
123        }
124        else {
125            writer.flush();
126        }
127    }
128
129    @Override
130    public void fileStarted(AuditEvent event) {
131        fileMessages.put(event.getFileName(), new FileMessages());
132    }
133
134    @Override
135    public void fileFinished(AuditEvent event) {
136        final String fileName = event.getFileName();
137        final FileMessages messages = fileMessages.remove(fileName);
138        writeFileMessages(fileName, messages);
139    }
140
141    /**
142     * Prints the file section with all file errors and exceptions.
143     *
144     * @param fileName The file name, as should be printed in the opening file tag.
145     * @param messages The file messages.
146     */
147    private void writeFileMessages(String fileName, FileMessages messages) {
148        writeFileOpeningTag(fileName);
149        if (messages != null) {
150            for (AuditEvent errorEvent : messages.getErrors()) {
151                writeFileError(errorEvent);
152            }
153            for (Throwable exception : messages.getExceptions()) {
154                writeException(exception);
155            }
156        }
157        writeFileClosingTag();
158    }
159
160    /**
161     * Prints the "file" opening tag with the given filename.
162     *
163     * @param fileName The filename to output.
164     */
165    private void writeFileOpeningTag(String fileName) {
166        writer.println("<file name=\"" + encode(fileName) + "\">");
167    }
168
169    /**
170     * Prints the "file" closing tag.
171     */
172    private void writeFileClosingTag() {
173        writer.println("</file>");
174    }
175
176    @Override
177    public void addError(AuditEvent event) {
178        if (event.getSeverityLevel() != SeverityLevel.IGNORE) {
179            final String fileName = event.getFileName();
180            if (fileName == null || !fileMessages.containsKey(fileName)) {
181                writeFileError(event);
182            }
183            else {
184                final FileMessages messages = fileMessages.get(fileName);
185                messages.addError(event);
186            }
187        }
188    }
189
190    /**
191     * Outputs the given event to the writer.
192     *
193     * @param event An event to print.
194     */
195    private void writeFileError(AuditEvent event) {
196        writer.print("<error" + " line=\"" + event.getLine() + "\"");
197        if (event.getColumn() > 0) {
198            writer.print(" column=\"" + event.getColumn() + "\"");
199        }
200        writer.print(" severity=\""
201                + event.getSeverityLevel().getName()
202                + "\"");
203        writer.print(" message=\""
204                + encode(event.getMessage())
205                + "\"");
206        writer.print(" source=\"");
207        if (event.getModuleId() == null) {
208            writer.print(encode(event.getSourceName()));
209        }
210        else {
211            writer.print(encode(event.getModuleId()));
212        }
213        writer.println("\"/>");
214    }
215
216    @Override
217    public void addException(AuditEvent event, Throwable throwable) {
218        final String fileName = event.getFileName();
219        if (fileName == null || !fileMessages.containsKey(fileName)) {
220            writeException(throwable);
221        }
222        else {
223            final FileMessages messages = fileMessages.get(fileName);
224            messages.addException(throwable);
225        }
226    }
227
228    /**
229     * Writes the exception event to the print writer.
230     *
231     * @param throwable The
232     */
233    private void writeException(Throwable throwable) {
234        writer.println("<exception>");
235        writer.println("<![CDATA[");
236
237        final StringWriter stringWriter = new StringWriter();
238        final PrintWriter printer = new PrintWriter(stringWriter);
239        throwable.printStackTrace(printer);
240        writer.println(encode(stringWriter.toString()));
241
242        writer.println("]]>");
243        writer.println("</exception>");
244    }
245
246    /**
247     * Escape &lt;, &gt; &amp; &#39; and &quot; as their entities.
248     *
249     * @param value the value to escape.
250     * @return the escaped value if necessary.
251     */
252    public static String encode(String value) {
253        final StringBuilder sb = new StringBuilder(256);
254        for (int i = 0; i < value.length(); i++) {
255            final char chr = value.charAt(i);
256            switch (chr) {
257                case '<':
258                    sb.append("&lt;");
259                    break;
260                case '>':
261                    sb.append("&gt;");
262                    break;
263                case '\'':
264                    sb.append("&apos;");
265                    break;
266                case '\"':
267                    sb.append("&quot;");
268                    break;
269                case '&':
270                    sb.append("&amp;");
271                    break;
272                case '\r':
273                    break;
274                case '\n':
275                    sb.append("&#10;");
276                    break;
277                default:
278                    if (Character.isISOControl(chr)) {
279                        // true escape characters need '&' before, but it also requires XML 1.1
280                        // until https://github.com/checkstyle/checkstyle/issues/5168
281                        sb.append("#x");
282                        sb.append(Integer.toHexString(chr));
283                        sb.append(';');
284                    }
285                    else {
286                        sb.append(chr);
287                    }
288                    break;
289            }
290        }
291        return sb.toString();
292    }
293
294    /**
295     * Finds whether the given argument is character or entity reference.
296     *
297     * @param ent the possible entity to look for.
298     * @return whether the given argument a character or entity reference
299     */
300    public static boolean isReference(String ent) {
301        boolean reference = false;
302
303        if (ent.charAt(0) == '&' && ent.endsWith(";")) {
304            if (ent.charAt(1) == '#') {
305                // prefix is "&#"
306                int prefixLength = 2;
307
308                int radix = BASE_10;
309                if (ent.charAt(2) == 'x') {
310                    prefixLength++;
311                    radix = BASE_16;
312                }
313                try {
314                    Integer.parseInt(
315                        ent.substring(prefixLength, ent.length() - 1), radix);
316                    reference = true;
317                }
318                catch (final NumberFormatException ignored) {
319                    reference = false;
320                }
321            }
322            else {
323                final String name = ent.substring(1, ent.length() - 1);
324                for (String element : ENTITIES) {
325                    if (name.equals(element)) {
326                        reference = true;
327                        break;
328                    }
329                }
330            }
331        }
332
333        return reference;
334    }
335
336    /**
337     * The registered file messages.
338     */
339    private static final class FileMessages {
340
341        /** The file error events. */
342        private final List<AuditEvent> errors = new ArrayList<>();
343
344        /** The file exceptions. */
345        private final List<Throwable> exceptions = new ArrayList<>();
346
347        /**
348         * Returns the file error events.
349         *
350         * @return the file error events.
351         */
352        public List<AuditEvent> getErrors() {
353            return Collections.unmodifiableList(errors);
354        }
355
356        /**
357         * Adds the given error event to the messages.
358         *
359         * @param event the error event.
360         */
361        public void addError(AuditEvent event) {
362            errors.add(event);
363        }
364
365        /**
366         * Returns the file exceptions.
367         *
368         * @return the file exceptions.
369         */
370        public List<Throwable> getExceptions() {
371            return Collections.unmodifiableList(exceptions);
372        }
373
374        /**
375         * Adds the given exception to the messages.
376         *
377         * @param throwable the file exception
378         */
379        public void addException(Throwable throwable) {
380            exceptions.add(throwable);
381        }
382
383    }
384
385}