1/*
2 * Copyright (c) 2005, 2017, 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.javac.code;
27
28import java.util.Arrays;
29import java.util.EnumSet;
30import java.util.Map;
31import java.util.concurrent.ConcurrentHashMap;
32
33import com.sun.tools.javac.code.Symbol.*;
34import com.sun.tools.javac.main.Option;
35import com.sun.tools.javac.util.Context;
36import com.sun.tools.javac.util.List;
37import com.sun.tools.javac.util.Options;
38import com.sun.tools.javac.util.Pair;
39
40/**
41 * A class for handling -Xlint suboptions and @SuppresssWarnings.
42 *
43 *  <p><b>This is NOT part of any supported API.
44 *  If you write code that depends on this, you do so at your own risk.
45 *  This code and its internal interfaces are subject to change or
46 *  deletion without notice.</b>
47 */
48public class Lint
49{
50    /** The context key for the root Lint object. */
51    protected static final Context.Key<Lint> lintKey = new Context.Key<>();
52
53    /** Get the root Lint instance. */
54    public static Lint instance(Context context) {
55        Lint instance = context.get(lintKey);
56        if (instance == null)
57            instance = new Lint(context);
58        return instance;
59    }
60
61    /**
62     * Returns the result of combining the values in this object with
63     * the given annotation.
64     */
65    public Lint augment(Attribute.Compound attr) {
66        return augmentor.augment(this, attr);
67    }
68
69
70    /**
71     * Returns the result of combining the values in this object with
72     * the metadata on the given symbol.
73     */
74    public Lint augment(Symbol sym) {
75        Lint l = augmentor.augment(this, sym.getDeclarationAttributes());
76        if (sym.isDeprecated()) {
77            if (l == this)
78                l = new Lint(this);
79            l.values.remove(LintCategory.DEPRECATION);
80            l.suppressedValues.add(LintCategory.DEPRECATION);
81        }
82        return l;
83    }
84
85    /**
86     * Returns a new Lint that has the given LintCategorys suppressed.
87     * @param lc one or more categories to be suppressed
88     */
89    public Lint suppress(LintCategory... lc) {
90        Lint l = new Lint(this);
91        l.values.removeAll(Arrays.asList(lc));
92        l.suppressedValues.addAll(Arrays.asList(lc));
93        return l;
94    }
95
96    private final AugmentVisitor augmentor;
97
98    private final EnumSet<LintCategory> values;
99    private final EnumSet<LintCategory> suppressedValues;
100
101    private static final Map<String, LintCategory> map = new ConcurrentHashMap<>(20);
102
103    protected Lint(Context context) {
104        // initialize values according to the lint options
105        Options options = Options.instance(context);
106
107        if (options.isSet(Option.XLINT) || options.isSet(Option.XLINT_CUSTOM, "all")) {
108            // If -Xlint or -Xlint:all is given, enable all categories by default
109            values = EnumSet.allOf(LintCategory.class);
110        } else if (options.isSet(Option.XLINT_CUSTOM, "none")) {
111            // if -Xlint:none is given, disable all categories by default
112            values = EnumSet.noneOf(LintCategory.class);
113        } else {
114            // otherwise, enable on-by-default categories
115            values = EnumSet.noneOf(LintCategory.class);
116
117            Source source = Source.instance(context);
118            if (source.compareTo(Source.JDK1_9) >= 0) {
119                values.add(LintCategory.DEP_ANN);
120            }
121            values.add(LintCategory.REQUIRES_TRANSITIVE_AUTOMATIC);
122            values.add(LintCategory.OPENS);
123            values.add(LintCategory.MODULE);
124            values.add(LintCategory.REMOVAL);
125        }
126
127        // Look for specific overrides
128        for (LintCategory lc : LintCategory.values()) {
129            if (options.isSet(Option.XLINT_CUSTOM, lc.option)) {
130                values.add(lc);
131            } else if (options.isSet(Option.XLINT_CUSTOM, "-" + lc.option)) {
132                values.remove(lc);
133            }
134        }
135
136        suppressedValues = EnumSet.noneOf(LintCategory.class);
137
138        context.put(lintKey, this);
139        augmentor = new AugmentVisitor(context);
140    }
141
142    protected Lint(Lint other) {
143        this.augmentor = other.augmentor;
144        this.values = other.values.clone();
145        this.suppressedValues = other.suppressedValues.clone();
146    }
147
148    @Override
149    public String toString() {
150        return "Lint:[values" + values + " suppressedValues" + suppressedValues + "]";
151    }
152
153    /**
154     * Categories of warnings that can be generated by the compiler.
155     */
156    public enum LintCategory {
157        /**
158         * Warn when code refers to a auxiliary class that is hidden in a source file (ie source file name is
159         * different from the class name, and the type is not properly nested) and the referring code
160         * is not located in the same source file.
161         */
162        AUXILIARYCLASS("auxiliaryclass"),
163
164        /**
165         * Warn about use of unnecessary casts.
166         */
167        CAST("cast"),
168
169        /**
170         * Warn about issues related to classfile contents
171         */
172        CLASSFILE("classfile"),
173
174        /**
175         * Warn about use of deprecated items.
176         */
177        DEPRECATION("deprecation"),
178
179        /**
180         * Warn about items which are documented with an {@code @deprecated} JavaDoc
181         * comment, but which do not have {@code @Deprecated} annotation.
182         */
183        DEP_ANN("dep-ann"),
184
185        /**
186         * Warn about division by constant integer 0.
187         */
188        DIVZERO("divzero"),
189
190        /**
191         * Warn about empty statement after if.
192         */
193        EMPTY("empty"),
194
195        /**
196         * Warn about issues regarding module exports.
197         */
198        EXPORTS("exports"),
199
200        /**
201         * Warn about falling through from one case of a switch statement to the next.
202         */
203        FALLTHROUGH("fallthrough"),
204
205        /**
206         * Warn about finally clauses that do not terminate normally.
207         */
208        FINALLY("finally"),
209
210        /**
211         * Warn about module system related issues.
212         */
213        MODULE("module"),
214
215        /**
216         * Warn about issues regarding module opens.
217         */
218        OPENS("opens"),
219
220        /**
221         * Warn about issues relating to use of command line options
222         */
223        OPTIONS("options"),
224
225        /**
226         * Warn about issues regarding method overloads.
227         */
228        OVERLOADS("overloads"),
229
230        /**
231         * Warn about issues regarding method overrides.
232         */
233        OVERRIDES("overrides"),
234
235        /**
236         * Warn about invalid path elements on the command line.
237         * Such warnings cannot be suppressed with the SuppressWarnings
238         * annotation.
239         */
240        PATH("path"),
241
242        /**
243         * Warn about issues regarding annotation processing.
244         */
245        PROCESSING("processing"),
246
247        /**
248         * Warn about unchecked operations on raw types.
249         */
250        RAW("rawtypes"),
251
252        /**
253         * Warn about use of deprecated-for-removal items.
254         */
255        REMOVAL("removal"),
256
257        /**
258         * Warn about use of automatic modules in the requires clauses.
259         */
260        REQUIRES_AUTOMATIC("requires-automatic"),
261
262        /**
263         * Warn about automatic modules in requires transitive.
264         */
265        REQUIRES_TRANSITIVE_AUTOMATIC("requires-transitive-automatic"),
266
267        /**
268         * Warn about Serializable classes that do not provide a serial version ID.
269         */
270        SERIAL("serial"),
271
272        /**
273         * Warn about issues relating to use of statics
274         */
275        STATIC("static"),
276
277        /**
278         * Warn about issues relating to use of try blocks (i.e. try-with-resources)
279         */
280        TRY("try"),
281
282        /**
283         * Warn about unchecked operations on raw types.
284         */
285        UNCHECKED("unchecked"),
286
287        /**
288         * Warn about potentially unsafe vararg methods
289         */
290        VARARGS("varargs");
291
292        LintCategory(String option) {
293            this(option, false);
294        }
295
296        LintCategory(String option, boolean hidden) {
297            this.option = option;
298            this.hidden = hidden;
299            map.put(option, this);
300        }
301
302        static LintCategory get(String option) {
303            return map.get(option);
304        }
305
306        public final String option;
307        public final boolean hidden;
308    }
309
310    /**
311     * Checks if a warning category is enabled. A warning category may be enabled
312     * on the command line, or by default, and can be temporarily disabled with
313     * the SuppressWarnings annotation.
314     */
315    public boolean isEnabled(LintCategory lc) {
316        return values.contains(lc);
317    }
318
319    /**
320     * Checks is a warning category has been specifically suppressed, by means
321     * of the SuppressWarnings annotation, or, in the case of the deprecated
322     * category, whether it has been implicitly suppressed by virtue of the
323     * current entity being itself deprecated.
324     */
325    public boolean isSuppressed(LintCategory lc) {
326        return suppressedValues.contains(lc);
327    }
328
329    protected static class AugmentVisitor implements Attribute.Visitor {
330        private final Context context;
331        private Symtab syms;
332        private Lint parent;
333        private Lint lint;
334
335        AugmentVisitor(Context context) {
336            // to break an ugly sequence of initialization dependencies,
337            // we defer the initialization of syms until it is needed
338            this.context = context;
339        }
340
341        Lint augment(Lint parent, Attribute.Compound attr) {
342            initSyms();
343            this.parent = parent;
344            lint = null;
345            attr.accept(this);
346            return (lint == null ? parent : lint);
347        }
348
349        Lint augment(Lint parent, List<Attribute.Compound> attrs) {
350            initSyms();
351            this.parent = parent;
352            lint = null;
353            for (Attribute.Compound a: attrs) {
354                a.accept(this);
355            }
356            return (lint == null ? parent : lint);
357        }
358
359        private void initSyms() {
360            if (syms == null)
361                syms = Symtab.instance(context);
362        }
363
364        private void suppress(LintCategory lc) {
365            if (lint == null)
366                lint = new Lint(parent);
367            lint.suppressedValues.add(lc);
368            lint.values.remove(lc);
369        }
370
371        public void visitConstant(Attribute.Constant value) {
372            if (value.type.tsym == syms.stringType.tsym) {
373                LintCategory lc = LintCategory.get((String) (value.value));
374                if (lc != null)
375                    suppress(lc);
376            }
377        }
378
379        public void visitClass(Attribute.Class clazz) {
380        }
381
382        // If we find a @SuppressWarnings annotation, then we continue
383        // walking the tree, in order to suppress the individual warnings
384        // specified in the @SuppressWarnings annotation.
385        public void visitCompound(Attribute.Compound compound) {
386            if (compound.type.tsym == syms.suppressWarningsType.tsym) {
387                for (List<Pair<MethodSymbol,Attribute>> v = compound.values;
388                     v.nonEmpty(); v = v.tail) {
389                    Pair<MethodSymbol,Attribute> value = v.head;
390                    if (value.fst.name.toString().equals("value"))
391                        value.snd.accept(this);
392                }
393
394            }
395        }
396
397        public void visitArray(Attribute.Array array) {
398            for (Attribute value : array.values)
399                value.accept(this);
400        }
401
402        public void visitEnum(Attribute.Enum e) {
403        }
404
405        public void visitError(Attribute.Error e) {
406        }
407    }
408}
409