Checker.java revision 3831:209b0eab0e1f 
1/*
2 * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package com.sun.tools.doclint;
27
28import java.io.IOException;
29import java.io.StringWriter;
30import java.net.URI;
31import java.net.URISyntaxException;
32import java.util.Deque;
33import java.util.EnumSet;
34import java.util.HashMap;
35import java.util.HashSet;
36import java.util.LinkedList;
37import java.util.List;
38import java.util.Map;
39import java.util.Set;
40import java.util.regex.Matcher;
41import java.util.regex.Pattern;
42
43import javax.lang.model.element.Element;
44import javax.lang.model.element.ElementKind;
45import javax.lang.model.element.ExecutableElement;
46import javax.lang.model.element.Name;
47import javax.lang.model.element.VariableElement;
48import javax.lang.model.type.TypeKind;
49import javax.lang.model.type.TypeMirror;
50import javax.tools.Diagnostic.Kind;
51import javax.tools.JavaFileObject;
52
53import com.sun.source.doctree.AttributeTree;
54import com.sun.source.doctree.AuthorTree;
55import com.sun.source.doctree.DocCommentTree;
56import com.sun.source.doctree.DocRootTree;
57import com.sun.source.doctree.DocTree;
58import com.sun.source.doctree.EndElementTree;
59import com.sun.source.doctree.EntityTree;
60import com.sun.source.doctree.ErroneousTree;
61import com.sun.source.doctree.IdentifierTree;
62import com.sun.source.doctree.InheritDocTree;
63import com.sun.source.doctree.LinkTree;
64import com.sun.source.doctree.LiteralTree;
65import com.sun.source.doctree.ParamTree;
66import com.sun.source.doctree.ProvidesTree;
67import com.sun.source.doctree.ReferenceTree;
68import com.sun.source.doctree.ReturnTree;
69import com.sun.source.doctree.SerialDataTree;
70import com.sun.source.doctree.SerialFieldTree;
71import com.sun.source.doctree.SinceTree;
72import com.sun.source.doctree.StartElementTree;
73import com.sun.source.doctree.TextTree;
74import com.sun.source.doctree.ThrowsTree;
75import com.sun.source.doctree.UnknownBlockTagTree;
76import com.sun.source.doctree.UnknownInlineTagTree;
77import com.sun.source.doctree.UsesTree;
78import com.sun.source.doctree.ValueTree;
79import com.sun.source.doctree.VersionTree;
80import com.sun.source.tree.Tree;
81import com.sun.source.util.DocTreePath;
82import com.sun.source.util.DocTreePathScanner;
83import com.sun.source.util.TreePath;
84import com.sun.tools.doclint.HtmlTag.AttrKind;
85import com.sun.tools.javac.tree.DocPretty;
86import com.sun.tools.javac.util.Assert;
87import com.sun.tools.javac.util.DefinedBy;
88import com.sun.tools.javac.util.DefinedBy.Api;
89import com.sun.tools.javac.util.StringUtils;
90
91import static com.sun.tools.doclint.Messages.Group.*;
92
93
94/**
95 * Validate a doc comment.
96 *
97 * <p><b>This is NOT part of any supported API.
98 * If you write code that depends on this, you do so at your own
99 * risk.  This code and its internal interfaces are subject to change
100 * or deletion without notice.</b></p>
101 */
102public class Checker extends DocTreePathScanner<Void, Void> {
103    final Env env;
104
105    Set<Element> foundParams = new HashSet<>();
106    Set<TypeMirror> foundThrows = new HashSet<>();
107    Map<Element, Set<String>> foundAnchors = new HashMap<>();
108    boolean foundInheritDoc = false;
109    boolean foundReturn = false;
110
111    public enum Flag {
112        TABLE_HAS_CAPTION,
113        HAS_ELEMENT,
114        HAS_HEADING,
115        HAS_INLINE_TAG,
116        HAS_TEXT,
117        REPORTED_BAD_INLINE
118    }
119
120    static class TagStackItem {
121        final DocTree tree; // typically, but not always, StartElementTree
122        final HtmlTag tag;
123        final Set<HtmlTag.Attr> attrs;
124        final Set<Flag> flags;
125        TagStackItem(DocTree tree, HtmlTag tag) {
126            this.tree = tree;
127            this.tag = tag;
128            attrs = EnumSet.noneOf(HtmlTag.Attr.class);
129            flags = EnumSet.noneOf(Flag.class);
130        }
131        @Override
132        public String toString() {
133            return String.valueOf(tag);
134        }
135    }
136
137    private final Deque<TagStackItem> tagStack; // TODO: maybe want to record starting tree as well
138    private HtmlTag currHeaderTag;
139
140    private final int implicitHeaderLevel;
141
142    // <editor-fold defaultstate="collapsed" desc="Top level">
143
144    Checker(Env env) {
145        this.env = Assert.checkNonNull(env);
146        tagStack = new LinkedList<>();
147        implicitHeaderLevel = env.implicitHeaderLevel;
148    }
149
150    public Void scan(DocCommentTree tree, TreePath p) {
151        env.initTypes();
152        env.setCurrent(p, tree);
153
154        boolean isOverridingMethod = !env.currOverriddenMethods.isEmpty();
155        JavaFileObject fo = p.getCompilationUnit().getSourceFile();
156
157        if (p.getLeaf().getKind() == Tree.Kind.PACKAGE) {
158            // If p points to a package, the implied declaration is the
159            // package declaration (if any) for the compilation unit.
160            // Handle this case specially, because doc comments are only
161            // expected in package-info files.
162            boolean isPkgInfo = fo.isNameCompatible("package-info", JavaFileObject.Kind.SOURCE);
163            if (tree == null) {
164                if (isPkgInfo)
165                    reportMissing("dc.missing.comment");
166                return null;
167            } else {
168                if (!isPkgInfo)
169                    reportReference("dc.unexpected.comment");
170            }
171        } else if (tree != null && fo.isNameCompatible("package", JavaFileObject.Kind.HTML)) {
172            // a package.html file with a DocCommentTree
173            if (tree.getFullBody().isEmpty()) {
174                reportMissing("dc.missing.comment");
175                return null;
176            }
177        } else {
178            if (tree == null) {
179                if (!isSynthetic() && !isOverridingMethod)
180                    reportMissing("dc.missing.comment");
181                return null;
182            }
183        }
184
185        tagStack.clear();
186        currHeaderTag = null;
187
188        foundParams.clear();
189        foundThrows.clear();
190        foundInheritDoc = false;
191        foundReturn = false;
192
193        scan(new DocTreePath(p, tree), null);
194
195        if (!isOverridingMethod) {
196            switch (env.currElement.getKind()) {
197                case METHOD:
198                case CONSTRUCTOR: {
199                    ExecutableElement ee = (ExecutableElement) env.currElement;
200                    checkParamsDocumented(ee.getTypeParameters());
201                    checkParamsDocumented(ee.getParameters());
202                    switch (ee.getReturnType().getKind()) {
203                        case VOID:
204                        case NONE:
205                            break;
206                        default:
207                            if (!foundReturn
208                                    && !foundInheritDoc
209                                    && !env.types.isSameType(ee.getReturnType(), env.java_lang_Void)) {
210                                reportMissing("dc.missing.return");
211                            }
212                    }
213                    checkThrowsDocumented(ee.getThrownTypes());
214                }
215            }
216        }
217
218        return null;
219    }
220
221    private void reportMissing(String code, Object... args) {
222        env.messages.report(MISSING, Kind.WARNING, env.currPath.getLeaf(), code, args);
223    }
224
225    private void reportReference(String code, Object... args) {
226        env.messages.report(REFERENCE, Kind.WARNING, env.currPath.getLeaf(), code, args);
227    }
228
229    @Override @DefinedBy(Api.COMPILER_TREE)
230    public Void visitDocComment(DocCommentTree tree, Void ignore) {
231        super.visitDocComment(tree, ignore);
232        for (TagStackItem tsi: tagStack) {
233            warnIfEmpty(tsi, null);
234            if (tsi.tree.getKind() == DocTree.Kind.START_ELEMENT
235                    && tsi.tag.endKind == HtmlTag.EndKind.REQUIRED) {
236                StartElementTree t = (StartElementTree) tsi.tree;
237                env.messages.error(HTML, t, "dc.tag.not.closed", t.getName());
238            }
239        }
240        return null;
241    }
242    // </editor-fold>
243
244    // <editor-fold defaultstate="collapsed" desc="Text and entities.">
245
246    @Override @DefinedBy(Api.COMPILER_TREE)
247    public Void visitText(TextTree tree, Void ignore) {
248        if (hasNonWhitespace(tree)) {
249            checkAllowsText(tree);
250            markEnclosingTag(Flag.HAS_TEXT);
251        }
252        return null;
253    }
254
255    @Override @DefinedBy(Api.COMPILER_TREE)
256    public Void visitEntity(EntityTree tree, Void ignore) {
257        checkAllowsText(tree);
258        markEnclosingTag(Flag.HAS_TEXT);
259        String name = tree.getName().toString();
260        if (name.startsWith("#")) {
261            int v = StringUtils.toLowerCase(name).startsWith("#x")
262                    ? Integer.parseInt(name.substring(2), 16)
263                    : Integer.parseInt(name.substring(1), 10);
264            if (!Entity.isValid(v)) {
265                env.messages.error(HTML, tree, "dc.entity.invalid", name);
266            }
267        } else if (!Entity.isValid(name)) {
268            env.messages.error(HTML, tree, "dc.entity.invalid", name);
269        }
270        return null;
271    }
272
273    void checkAllowsText(DocTree tree) {
274        TagStackItem top = tagStack.peek();
275        if (top != null
276                && top.tree.getKind() == DocTree.Kind.START_ELEMENT
277                && !top.tag.acceptsText()) {
278            if (top.flags.add(Flag.REPORTED_BAD_INLINE)) {
279                env.messages.error(HTML, tree, "dc.text.not.allowed",
280                        ((StartElementTree) top.tree).getName());
281            }
282        }
283    }
284
285    // </editor-fold>
286
287    // <editor-fold defaultstate="collapsed" desc="HTML elements">
288
289    @Override @DefinedBy(Api.COMPILER_TREE)
290    public Void visitStartElement(StartElementTree tree, Void ignore) {
291        final Name treeName = tree.getName();
292        final HtmlTag t = HtmlTag.get(treeName);
293        if (t == null) {
294            env.messages.error(HTML, tree, "dc.tag.unknown", treeName);
295        } else if (t.allowedVersion != HtmlVersion.ALL && t.allowedVersion != env.htmlVersion) {
296            env.messages.error(HTML, tree, "dc.tag.not.supported", treeName);
297        } else {
298            boolean done = false;
299            for (TagStackItem tsi: tagStack) {
300                if (tsi.tag.accepts(t)) {
301                    while (tagStack.peek() != tsi) {
302                        warnIfEmpty(tagStack.peek(), null);
303                        tagStack.pop();
304                    }
305                    done = true;
306                    break;
307                } else if (tsi.tag.endKind != HtmlTag.EndKind.OPTIONAL) {
308                    done = true;
309                    break;
310                }
311            }
312            if (!done && HtmlTag.BODY.accepts(t)) {
313                while (!tagStack.isEmpty()) {
314                    warnIfEmpty(tagStack.peek(), null);
315                    tagStack.pop();
316                }
317            }
318
319            markEnclosingTag(Flag.HAS_ELEMENT);
320            checkStructure(tree, t);
321
322            // tag specific checks
323            switch (t) {
324                // check for out of sequence headers, such as <h1>...</h1>  <h3>...</h3>
325                case H1: case H2: case H3: case H4: case H5: case H6:
326                    checkHeader(tree, t);
327                    break;
328            }
329
330            if (t.flags.contains(HtmlTag.Flag.NO_NEST)) {
331                for (TagStackItem i: tagStack) {
332                    if (t == i.tag) {
333                        env.messages.warning(HTML, tree, "dc.tag.nested.not.allowed", treeName);
334                        break;
335                    }
336                }
337            }
338        }
339
340        // check for self closing tags, such as <a id="name"/>
341        if (tree.isSelfClosing()) {
342            env.messages.error(HTML, tree, "dc.tag.self.closing", treeName);
343        }
344
345        try {
346            TagStackItem parent = tagStack.peek();
347            TagStackItem top = new TagStackItem(tree, t);
348            tagStack.push(top);
349
350            super.visitStartElement(tree, ignore);
351
352            // handle attributes that may or may not have been found in start element
353            if (t != null) {
354                switch (t) {
355                    case CAPTION:
356                        if (parent != null && parent.tag == HtmlTag.TABLE)
357                            parent.flags.add(Flag.TABLE_HAS_CAPTION);
358                        break;
359
360                    case H1: case H2: case H3: case H4: case H5: case H6:
361                        if (parent != null && (parent.tag == HtmlTag.SECTION || parent.tag == HtmlTag.ARTICLE)) {
362                            parent.flags.add(Flag.HAS_HEADING);
363                        }
364                        break;
365
366                    case IMG:
367                        if (!top.attrs.contains(HtmlTag.Attr.ALT))
368                            env.messages.error(ACCESSIBILITY, tree, "dc.no.alt.attr.for.image");
369                        break;
370                }
371            }
372
373            return null;
374        } finally {
375
376            if (t == null || t.endKind == HtmlTag.EndKind.NONE)
377                tagStack.pop();
378        }
379    }
380
381    private void checkStructure(StartElementTree tree, HtmlTag t) {
382        Name treeName = tree.getName();
383        TagStackItem top = tagStack.peek();
384        switch (t.blockType) {
385            case BLOCK:
386                if (top == null || top.tag.accepts(t))
387                    return;
388
389                switch (top.tree.getKind()) {
390                    case START_ELEMENT: {
391                        if (top.tag.blockType == HtmlTag.BlockType.INLINE) {
392                            Name name = ((StartElementTree) top.tree).getName();
393                            env.messages.error(HTML, tree, "dc.tag.not.allowed.inline.element",
394                                    treeName, name);
395                            return;
396                        }
397                    }
398                    break;
399
400                    case LINK:
401                    case LINK_PLAIN: {
402                        String name = top.tree.getKind().tagName;
403                        env.messages.error(HTML, tree, "dc.tag.not.allowed.inline.tag",
404                                treeName, name);
405                        return;
406                    }
407                }
408                break;
409
410            case INLINE:
411                if (top == null || top.tag.accepts(t))
412                    return;
413                break;
414
415            case LIST_ITEM:
416            case TABLE_ITEM:
417                if (top != null) {
418                    // reset this flag so subsequent bad inline content gets reported
419                    top.flags.remove(Flag.REPORTED_BAD_INLINE);
420                    if (top.tag.accepts(t))
421                        return;
422                }
423                break;
424
425            case OTHER:
426                env.messages.error(HTML, tree, "dc.tag.not.allowed", treeName);
427                return;
428        }
429
430        env.messages.error(HTML, tree, "dc.tag.not.allowed.here", treeName);
431    }
432
433    private void checkHeader(StartElementTree tree, HtmlTag tag) {
434        // verify the new tag
435        if (getHeaderLevel(tag) > getHeaderLevel(currHeaderTag) + 1) {
436            if (currHeaderTag == null) {
437                env.messages.error(ACCESSIBILITY, tree, "dc.tag.header.sequence.1", tag);
438            } else {
439                env.messages.error(ACCESSIBILITY, tree, "dc.tag.header.sequence.2",
440                    tag, currHeaderTag);
441            }
442        }
443
444        currHeaderTag = tag;
445    }
446
447    private int getHeaderLevel(HtmlTag tag) {
448        if (tag == null)
449            return implicitHeaderLevel;
450        switch (tag) {
451            case H1: return 1;
452            case H2: return 2;
453            case H3: return 3;
454            case H4: return 4;
455            case H5: return 5;
456            case H6: return 6;
457            default: throw new IllegalArgumentException();
458        }
459    }
460
461    @Override @DefinedBy(Api.COMPILER_TREE)
462    public Void visitEndElement(EndElementTree tree, Void ignore) {
463        final Name treeName = tree.getName();
464        final HtmlTag t = HtmlTag.get(treeName);
465        if (t == null) {
466            env.messages.error(HTML, tree, "dc.tag.unknown", treeName);
467        } else if (t.endKind == HtmlTag.EndKind.NONE) {
468            env.messages.error(HTML, tree, "dc.tag.end.not.permitted", treeName);
469        } else {
470            boolean done = false;
471            while (!tagStack.isEmpty()) {
472                TagStackItem top = tagStack.peek();
473                if (t == top.tag) {
474                    switch (t) {
475                        case TABLE:
476                            if (!top.attrs.contains(HtmlTag.Attr.SUMMARY)
477                                    && !top.flags.contains(Flag.TABLE_HAS_CAPTION)) {
478                                env.messages.error(ACCESSIBILITY, tree,
479                                        "dc.no.summary.or.caption.for.table");
480                            }
481                            break;
482
483                        case SECTION:
484                        case ARTICLE:
485                            if (env.htmlVersion == HtmlVersion.HTML5 && !top.flags.contains(Flag.HAS_HEADING)) {
486                                env.messages.error(HTML, tree, "dc.tag.requires.heading", treeName);
487                            }
488                            break;
489                    }
490                    warnIfEmpty(top, tree);
491                    tagStack.pop();
492                    done = true;
493                    break;
494                } else if (top.tag == null || top.tag.endKind != HtmlTag.EndKind.REQUIRED) {
495                    tagStack.pop();
496                } else {
497                    boolean found = false;
498                    for (TagStackItem si: tagStack) {
499                        if (si.tag == t) {
500                            found = true;
501                            break;
502                        }
503                    }
504                    if (found && top.tree.getKind() == DocTree.Kind.START_ELEMENT) {
505                        env.messages.error(HTML, top.tree, "dc.tag.start.unmatched",
506                                ((StartElementTree) top.tree).getName());
507                        tagStack.pop();
508                    } else {
509                        env.messages.error(HTML, tree, "dc.tag.end.unexpected", treeName);
510                        done = true;
511                        break;
512                    }
513                }
514            }
515
516            if (!done && tagStack.isEmpty()) {
517                env.messages.error(HTML, tree, "dc.tag.end.unexpected", treeName);
518            }
519        }
520
521        return super.visitEndElement(tree, ignore);
522    }
523
524    void warnIfEmpty(TagStackItem tsi, DocTree endTree) {
525        if (tsi.tag != null && tsi.tree instanceof StartElementTree) {
526            if (tsi.tag.flags.contains(HtmlTag.Flag.EXPECT_CONTENT)
527                    && !tsi.flags.contains(Flag.HAS_TEXT)
528                    && !tsi.flags.contains(Flag.HAS_ELEMENT)
529                    && !tsi.flags.contains(Flag.HAS_INLINE_TAG)) {
530                DocTree tree = (endTree != null) ? endTree : tsi.tree;
531                Name treeName = ((StartElementTree) tsi.tree).getName();
532                env.messages.warning(HTML, tree, "dc.tag.empty", treeName);
533            }
534        }
535    }
536
537    // </editor-fold>
538
539    // <editor-fold defaultstate="collapsed" desc="HTML attributes">
540
541    @Override @DefinedBy(Api.COMPILER_TREE) @SuppressWarnings("fallthrough")
542    public Void visitAttribute(AttributeTree tree, Void ignore) {
543        HtmlTag currTag = tagStack.peek().tag;
544        if (currTag != null) {
545            Name name = tree.getName();
546            HtmlTag.Attr attr = currTag.getAttr(name);
547            if (attr != null) {
548                if (env.htmlVersion == HtmlVersion.HTML4 && attr.name().contains("-")) {
549                    env.messages.error(HTML, tree, "dc.attr.not.supported.html4", name);
550                }
551                boolean first = tagStack.peek().attrs.add(attr);
552                if (!first)
553                    env.messages.error(HTML, tree, "dc.attr.repeated", name);
554            }
555            AttrKind k = currTag.getAttrKind(name);
556            switch (env.htmlVersion) {
557                case HTML4:
558                    validateHtml4Attrs(tree, name, k);
559                    break;
560
561                case HTML5:
562                    validateHtml5Attrs(tree, name, k);
563                    break;
564            }
565
566            if (attr != null) {
567                switch (attr) {
568                    case NAME:
569                        if (currTag != HtmlTag.A) {
570                            break;
571                        }
572                        // fallthrough
573                    case ID:
574                        String value = getAttrValue(tree);
575                        if (value == null) {
576                            env.messages.error(HTML, tree, "dc.anchor.value.missing");
577                        } else {
578                            if (!validName.matcher(value).matches()) {
579                                env.messages.error(HTML, tree, "dc.invalid.anchor", value);
580                            }
581                            if (!checkAnchor(value)) {
582                                env.messages.error(HTML, tree, "dc.anchor.already.defined", value);
583                            }
584                        }
585                        break;
586
587                    case HREF:
588                        if (currTag == HtmlTag.A) {
589                            String v = getAttrValue(tree);
590                            if (v == null || v.isEmpty()) {
591                                env.messages.error(HTML, tree, "dc.attr.lacks.value");
592                            } else {
593                                Matcher m = docRoot.matcher(v);
594                                if (m.matches()) {
595                                    String rest = m.group(2);
596                                    if (!rest.isEmpty())
597                                        checkURI(tree, rest);
598                                } else {
599                                    checkURI(tree, v);
600                                }
601                            }
602                        }
603                        break;
604
605                    case VALUE:
606                        if (currTag == HtmlTag.LI) {
607                            String v = getAttrValue(tree);
608                            if (v == null || v.isEmpty()) {
609                                env.messages.error(HTML, tree, "dc.attr.lacks.value");
610                            } else if (!validNumber.matcher(v).matches()) {
611                                env.messages.error(HTML, tree, "dc.attr.not.number");
612                            }
613                        }
614                        break;
615
616                    case BORDER:
617                        if (currTag == HtmlTag.TABLE) {
618                            String v = getAttrValue(tree);
619                            try {
620                                if (env.htmlVersion == HtmlVersion.HTML5
621                                        && (v == null || (!v.isEmpty() && Integer.parseInt(v) != 1))) {
622                                    env.messages.error(HTML, tree, "dc.attr.table.border.html5", attr);
623                                }
624                            } catch (NumberFormatException ex) {
625                                env.messages.error(HTML, tree, "dc.attr.table.border.html5", attr);
626                            }
627                        }
628                        break;
629                }
630            }
631        }
632
633        // TODO: basic check on value
634
635        return super.visitAttribute(tree, ignore);
636    }
637
638    private void validateHtml4Attrs(AttributeTree tree, Name name, AttrKind k) {
639        switch (k) {
640            case ALL:
641            case HTML4:
642                break;
643
644            case INVALID:
645                env.messages.error(HTML, tree, "dc.attr.unknown", name);
646                break;
647
648            case OBSOLETE:
649                env.messages.warning(ACCESSIBILITY, tree, "dc.attr.obsolete", name);
650                break;
651
652            case USE_CSS:
653                env.messages.warning(ACCESSIBILITY, tree, "dc.attr.obsolete.use.css", name);
654                break;
655
656            case HTML5:
657                env.messages.error(HTML, tree, "dc.attr.not.supported.html4", name);
658                break;
659        }
660    }
661
662    private void validateHtml5Attrs(AttributeTree tree, Name name, AttrKind k) {
663        switch (k) {
664            case ALL:
665            case HTML5:
666                break;
667
668            case INVALID:
669            case OBSOLETE:
670            case USE_CSS:
671            case HTML4:
672                env.messages.error(HTML, tree, "dc.attr.not.supported.html5", name);
673                break;
674        }
675    }
676
677    private boolean checkAnchor(String name) {
678        Element e = getEnclosingPackageOrClass(env.currElement);
679        if (e == null)
680            return true;
681        Set<String> set = foundAnchors.get(e);
682        if (set == null)
683            foundAnchors.put(e, set = new HashSet<>());
684        return set.add(name);
685    }
686
687    private Element getEnclosingPackageOrClass(Element e) {
688        while (e != null) {
689            switch (e.getKind()) {
690                case CLASS:
691                case ENUM:
692                case INTERFACE:
693                case PACKAGE:
694                    return e;
695                default:
696                    e = e.getEnclosingElement();
697            }
698        }
699        return e;
700    }
701
702    // http://www.w3.org/TR/html401/types.html#type-name
703    private static final Pattern validName = Pattern.compile("[A-Za-z][A-Za-z0-9-_:.]*");
704
705    private static final Pattern validNumber = Pattern.compile("-?[0-9]+");
706
707    // pattern to remove leading {@docRoot}/?
708    private static final Pattern docRoot = Pattern.compile("(?i)(\\{@docRoot *\\}/?)?(.*)");
709
710    private String getAttrValue(AttributeTree tree) {
711        if (tree.getValue() == null)
712            return null;
713
714        StringWriter sw = new StringWriter();
715        try {
716            new DocPretty(sw).print(tree.getValue());
717        } catch (IOException e) {
718            // cannot happen
719        }
720        // ignore potential use of entities for now
721        return sw.toString();
722    }
723
724    private void checkURI(AttributeTree tree, String uri) {
725        try {
726            URI u = new URI(uri);
727        } catch (URISyntaxException e) {
728            env.messages.error(HTML, tree, "dc.invalid.uri", uri);
729        }
730    }
731    // </editor-fold>
732
733    // <editor-fold defaultstate="collapsed" desc="javadoc tags">
734
735    @Override @DefinedBy(Api.COMPILER_TREE)
736    public Void visitAuthor(AuthorTree tree, Void ignore) {
737        warnIfEmpty(tree, tree.getName());
738        return super.visitAuthor(tree, ignore);
739    }
740
741    @Override @DefinedBy(Api.COMPILER_TREE)
742    public Void visitDocRoot(DocRootTree tree, Void ignore) {
743        markEnclosingTag(Flag.HAS_INLINE_TAG);
744        return super.visitDocRoot(tree, ignore);
745    }
746
747    @Override @DefinedBy(Api.COMPILER_TREE)
748    public Void visitInheritDoc(InheritDocTree tree, Void ignore) {
749        markEnclosingTag(Flag.HAS_INLINE_TAG);
750        // TODO: verify on overridden method
751        foundInheritDoc = true;
752        return super.visitInheritDoc(tree, ignore);
753    }
754
755    @Override @DefinedBy(Api.COMPILER_TREE)
756    public Void visitLink(LinkTree tree, Void ignore) {
757        markEnclosingTag(Flag.HAS_INLINE_TAG);
758        // simulate inline context on tag stack
759        HtmlTag t = (tree.getKind() == DocTree.Kind.LINK)
760                ? HtmlTag.CODE : HtmlTag.SPAN;
761        tagStack.push(new TagStackItem(tree, t));
762        try {
763            return super.visitLink(tree, ignore);
764        } finally {
765            tagStack.pop();
766        }
767    }
768
769    @Override @DefinedBy(Api.COMPILER_TREE)
770    public Void visitLiteral(LiteralTree tree, Void ignore) {
771        markEnclosingTag(Flag.HAS_INLINE_TAG);
772        if (tree.getKind() == DocTree.Kind.CODE) {
773            for (TagStackItem tsi: tagStack) {
774                if (tsi.tag == HtmlTag.CODE) {
775                    env.messages.warning(HTML, tree, "dc.tag.code.within.code");
776                    break;
777                }
778            }
779        }
780        return super.visitLiteral(tree, ignore);
781    }
782
783    @Override @DefinedBy(Api.COMPILER_TREE)
784    @SuppressWarnings("fallthrough")
785    public Void visitParam(ParamTree tree, Void ignore) {
786        boolean typaram = tree.isTypeParameter();
787        IdentifierTree nameTree = tree.getName();
788        Element paramElement = nameTree != null ? env.trees.getElement(new DocTreePath(getCurrentPath(), nameTree)) : null;
789
790        if (paramElement == null) {
791            switch (env.currElement.getKind()) {
792                case CLASS: case INTERFACE: {
793                    if (!typaram) {
794                        env.messages.error(REFERENCE, tree, "dc.invalid.param");
795                        break;
796                    }
797                }
798                case METHOD: case CONSTRUCTOR: {
799                    env.messages.error(REFERENCE, nameTree, "dc.param.name.not.found");
800                    break;
801                }
802
803                default:
804                    env.messages.error(REFERENCE, tree, "dc.invalid.param");
805                    break;
806            }
807        } else {
808            foundParams.add(paramElement);
809        }
810
811        warnIfEmpty(tree, tree.getDescription());
812        return super.visitParam(tree, ignore);
813    }
814
815    private void checkParamsDocumented(List<? extends Element> list) {
816        if (foundInheritDoc)
817            return;
818
819        for (Element e: list) {
820            if (!foundParams.contains(e)) {
821                CharSequence paramName = (e.getKind() == ElementKind.TYPE_PARAMETER)
822                        ? "<" + e.getSimpleName() + ">"
823                        : e.getSimpleName();
824                reportMissing("dc.missing.param", paramName);
825            }
826        }
827    }
828
829    @Override @DefinedBy(Api.COMPILER_TREE)
830    public Void visitProvides(ProvidesTree tree, Void ignore) {
831        Element e = env.trees.getElement(env.currPath);
832        if (e.getKind() != ElementKind.MODULE) {
833            env.messages.error(REFERENCE, tree, "dc.invalid.provides");
834        }
835        ReferenceTree serviceType = tree.getServiceType();
836        Element se = env.trees.getElement(new DocTreePath(getCurrentPath(), serviceType));
837        if (se == null) {
838            env.messages.error(REFERENCE, tree, "dc.service.not.found");
839        }
840        return super.visitProvides(tree, ignore);
841    }
842
843    @Override @DefinedBy(Api.COMPILER_TREE)
844    public Void visitReference(ReferenceTree tree, Void ignore) {
845        String sig = tree.getSignature();
846        if (sig.contains("<") || sig.contains(">"))
847            env.messages.error(REFERENCE, tree, "dc.type.arg.not.allowed");
848
849        Element e = env.trees.getElement(getCurrentPath());
850        if (e == null)
851            env.messages.error(REFERENCE, tree, "dc.ref.not.found");
852        return super.visitReference(tree, ignore);
853    }
854
855    @Override @DefinedBy(Api.COMPILER_TREE)
856    public Void visitReturn(ReturnTree tree, Void ignore) {
857        Element e = env.trees.getElement(env.currPath);
858        if (e.getKind() != ElementKind.METHOD
859                || ((ExecutableElement) e).getReturnType().getKind() == TypeKind.VOID)
860            env.messages.error(REFERENCE, tree, "dc.invalid.return");
861        foundReturn = true;
862        warnIfEmpty(tree, tree.getDescription());
863        return super.visitReturn(tree, ignore);
864    }
865
866    @Override @DefinedBy(Api.COMPILER_TREE)
867    public Void visitSerialData(SerialDataTree tree, Void ignore) {
868        warnIfEmpty(tree, tree.getDescription());
869        return super.visitSerialData(tree, ignore);
870    }
871
872    @Override @DefinedBy(Api.COMPILER_TREE)
873    public Void visitSerialField(SerialFieldTree tree, Void ignore) {
874        warnIfEmpty(tree, tree.getDescription());
875        return super.visitSerialField(tree, ignore);
876    }
877
878    @Override @DefinedBy(Api.COMPILER_TREE)
879    public Void visitSince(SinceTree tree, Void ignore) {
880        warnIfEmpty(tree, tree.getBody());
881        return super.visitSince(tree, ignore);
882    }
883
884    @Override @DefinedBy(Api.COMPILER_TREE)
885    public Void visitThrows(ThrowsTree tree, Void ignore) {
886        ReferenceTree exName = tree.getExceptionName();
887        Element ex = env.trees.getElement(new DocTreePath(getCurrentPath(), exName));
888        if (ex == null) {
889            env.messages.error(REFERENCE, tree, "dc.ref.not.found");
890        } else if (isThrowable(ex.asType())) {
891            switch (env.currElement.getKind()) {
892                case CONSTRUCTOR:
893                case METHOD:
894                    if (isCheckedException(ex.asType())) {
895                        ExecutableElement ee = (ExecutableElement) env.currElement;
896                        checkThrowsDeclared(exName, ex.asType(), ee.getThrownTypes());
897                    }
898                    break;
899                default:
900                    env.messages.error(REFERENCE, tree, "dc.invalid.throws");
901            }
902        } else {
903            env.messages.error(REFERENCE, tree, "dc.invalid.throws");
904        }
905        warnIfEmpty(tree, tree.getDescription());
906        return scan(tree.getDescription(), ignore);
907    }
908
909    private boolean isThrowable(TypeMirror tm) {
910        switch (tm.getKind()) {
911            case DECLARED:
912            case TYPEVAR:
913                return env.types.isAssignable(tm, env.java_lang_Throwable);
914        }
915        return false;
916    }
917
918    private void checkThrowsDeclared(ReferenceTree tree, TypeMirror t, List<? extends TypeMirror> list) {
919        boolean found = false;
920        for (TypeMirror tl : list) {
921            if (env.types.isAssignable(t, tl)) {
922                foundThrows.add(tl);
923                found = true;
924            }
925        }
926        if (!found)
927            env.messages.error(REFERENCE, tree, "dc.exception.not.thrown", t);
928    }
929
930    private void checkThrowsDocumented(List<? extends TypeMirror> list) {
931        if (foundInheritDoc)
932            return;
933
934        for (TypeMirror tl: list) {
935            if (isCheckedException(tl) && !foundThrows.contains(tl))
936                reportMissing("dc.missing.throws", tl);
937        }
938    }
939
940    @Override @DefinedBy(Api.COMPILER_TREE)
941    public Void visitUnknownBlockTag(UnknownBlockTagTree tree, Void ignore) {
942        checkUnknownTag(tree, tree.getTagName());
943        return super.visitUnknownBlockTag(tree, ignore);
944    }
945
946    @Override @DefinedBy(Api.COMPILER_TREE)
947    public Void visitUnknownInlineTag(UnknownInlineTagTree tree, Void ignore) {
948        checkUnknownTag(tree, tree.getTagName());
949        return super.visitUnknownInlineTag(tree, ignore);
950    }
951
952    private void checkUnknownTag(DocTree tree, String tagName) {
953        if (env.customTags != null && !env.customTags.contains(tagName))
954            env.messages.error(SYNTAX, tree, "dc.tag.unknown", tagName);
955    }
956
957    @Override @DefinedBy(Api.COMPILER_TREE)
958    public Void visitUses(UsesTree tree, Void ignore) {
959        Element e = env.trees.getElement(env.currPath);
960        if (e.getKind() != ElementKind.MODULE) {
961            env.messages.error(REFERENCE, tree, "dc.invalid.uses");
962        }
963        ReferenceTree serviceType = tree.getServiceType();
964        Element se = env.trees.getElement(new DocTreePath(getCurrentPath(), serviceType));
965        if (se == null) {
966            env.messages.error(REFERENCE, tree, "dc.service.not.found");
967        }
968        return super.visitUses(tree, ignore);
969    }
970
971    @Override @DefinedBy(Api.COMPILER_TREE)
972    public Void visitValue(ValueTree tree, Void ignore) {
973        ReferenceTree ref = tree.getReference();
974        if (ref == null || ref.getSignature().isEmpty()) {
975            if (!isConstant(env.currElement))
976                env.messages.error(REFERENCE, tree, "dc.value.not.allowed.here");
977        } else {
978            Element e = env.trees.getElement(new DocTreePath(getCurrentPath(), ref));
979            if (!isConstant(e))
980                env.messages.error(REFERENCE, tree, "dc.value.not.a.constant");
981        }
982
983        markEnclosingTag(Flag.HAS_INLINE_TAG);
984        return super.visitValue(tree, ignore);
985    }
986
987    private boolean isConstant(Element e) {
988        if (e == null)
989            return false;
990
991        switch (e.getKind()) {
992            case FIELD:
993                Object value = ((VariableElement) e).getConstantValue();
994                return (value != null); // can't distinguish "not a constant" from "constant is null"
995            default:
996                return false;
997        }
998    }
999
1000    @Override @DefinedBy(Api.COMPILER_TREE)
1001    public Void visitVersion(VersionTree tree, Void ignore) {
1002        warnIfEmpty(tree, tree.getBody());
1003        return super.visitVersion(tree, ignore);
1004    }
1005
1006    @Override @DefinedBy(Api.COMPILER_TREE)
1007    public Void visitErroneous(ErroneousTree tree, Void ignore) {
1008        env.messages.error(SYNTAX, tree, null, tree.getDiagnostic().getMessage(null));
1009        return null;
1010    }
1011    // </editor-fold>
1012
1013    // <editor-fold defaultstate="collapsed" desc="Utility methods">
1014
1015    private boolean isCheckedException(TypeMirror t) {
1016        return !(env.types.isAssignable(t, env.java_lang_Error)
1017                || env.types.isAssignable(t, env.java_lang_RuntimeException));
1018    }
1019
1020    private boolean isSynthetic() {
1021        switch (env.currElement.getKind()) {
1022            case CONSTRUCTOR:
1023                // A synthetic default constructor has the same pos as the
1024                // enclosing class
1025                TreePath p = env.currPath;
1026                return env.getPos(p) == env.getPos(p.getParentPath());
1027        }
1028        return false;
1029    }
1030
1031    void markEnclosingTag(Flag flag) {
1032        TagStackItem top = tagStack.peek();
1033        if (top != null)
1034            top.flags.add(flag);
1035    }
1036
1037    String toString(TreePath p) {
1038        StringBuilder sb = new StringBuilder("TreePath[");
1039        toString(p, sb);
1040        sb.append("]");
1041        return sb.toString();
1042    }
1043
1044    void toString(TreePath p, StringBuilder sb) {
1045        TreePath parent = p.getParentPath();
1046        if (parent != null) {
1047            toString(parent, sb);
1048            sb.append(",");
1049        }
1050       sb.append(p.getLeaf().getKind()).append(":").append(env.getPos(p)).append(":S").append(env.getStartPos(p));
1051    }
1052
1053    void warnIfEmpty(DocTree tree, List<? extends DocTree> list) {
1054        for (DocTree d: list) {
1055            switch (d.getKind()) {
1056                case TEXT:
1057                    if (hasNonWhitespace((TextTree) d))
1058                        return;
1059                    break;
1060                default:
1061                    return;
1062            }
1063        }
1064        env.messages.warning(SYNTAX, tree, "dc.empty", tree.getKind().tagName);
1065    }
1066
1067    boolean hasNonWhitespace(TextTree tree) {
1068        String s = tree.getBody();
1069        for (int i = 0; i < s.length(); i++) {
1070            if (!Character.isWhitespace(s.charAt(i)))
1071                return true;
1072        }
1073        return false;
1074    }
1075
1076    // </editor-fold>
1077
1078}
1079