Lint.java revision 2571:10fc81ac75b4 
1/*
2 * Copyright (c) 2005, 2013, 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.EnumSet;
29import java.util.Map;
30import java.util.concurrent.ConcurrentHashMap;
31
32import com.sun.tools.javac.code.Symbol.*;
33import com.sun.tools.javac.util.Context;
34import com.sun.tools.javac.util.List;
35import com.sun.tools.javac.util.Options;
36import com.sun.tools.javac.util.Pair;
37
38/**
39 * A class for handling -Xlint suboptions and @SuppresssWarnings.
40 *
41 *  <p><b>This is NOT part of any supported API.
42 *  If you write code that depends on this, you do so at your own risk.
43 *  This code and its internal interfaces are subject to change or
44 *  deletion without notice.</b>
45 */
46public class Lint
47{
48    /** The context key for the root Lint object. */
49    protected static final Context.Key<Lint> lintKey = new Context.Key<>();
50
51    /** Get the root Lint instance. */
52    public static Lint instance(Context context) {
53        Lint instance = context.get(lintKey);
54        if (instance == null)
55            instance = new Lint(context);
56        return instance;
57    }
58
59    /**
60     * Returns the result of combining the values in this object with
61     * the given annotation.
62     */
63    public Lint augment(Attribute.Compound attr) {
64        return augmentor.augment(this, attr);
65    }
66
67
68    /**
69     * Returns the result of combining the values in this object with
70     * the metadata on the given symbol.
71     */
72    public Lint augment(Symbol sym) {
73        Lint l = augmentor.augment(this, sym.getDeclarationAttributes());
74        if (sym.isDeprecated()) {
75            if (l == this)
76                l = new Lint(this);
77            l.values.remove(LintCategory.DEPRECATION);
78            l.suppressedValues.add(LintCategory.DEPRECATION);
79        }
80        return l;
81    }
82
83    private final AugmentVisitor augmentor;
84
85    private final EnumSet<LintCategory> values;
86    private final EnumSet<LintCategory> suppressedValues;
87
88    private static final Map<String, LintCategory> map = new ConcurrentHashMap<>(20);
89
90    protected Lint(Context context) {
91        // initialize values according to the lint options
92        Options options = Options.instance(context);
93        values = EnumSet.noneOf(LintCategory.class);
94        for (Map.Entry<String, LintCategory> e: map.entrySet()) {
95            if (options.lint(e.getKey()))
96                values.add(e.getValue());
97        }
98
99        suppressedValues = EnumSet.noneOf(LintCategory.class);
100
101        context.put(lintKey, this);
102        augmentor = new AugmentVisitor(context);
103    }
104
105    protected Lint(Lint other) {
106        this.augmentor = other.augmentor;
107        this.values = other.values.clone();
108        this.suppressedValues = other.suppressedValues.clone();
109    }
110
111    @Override
112    public String toString() {
113        return "Lint:[values" + values + " suppressedValues" + suppressedValues + "]";
114    }
115
116    /**
117     * Categories of warnings that can be generated by the compiler.
118     */
119    public enum LintCategory {
120        /**
121         * Warn when code refers to a auxiliary class that is hidden in a source file (ie source file name is
122         * different from the class name, and the type is not properly nested) and the referring code
123         * is not located in the same source file.
124         */
125        AUXILIARYCLASS("auxiliaryclass"),
126
127        /**
128         * Warn about use of unnecessary casts.
129         */
130        CAST("cast"),
131
132        /**
133         * Warn about issues related to classfile contents
134         */
135        CLASSFILE("classfile"),
136
137        /**
138         * Warn about use of deprecated items.
139         */
140        DEPRECATION("deprecation"),
141
142        /**
143         * Warn about items which are documented with an {@code @deprecated} JavaDoc
144         * comment, but which do not have {@code @Deprecated} annotation.
145         */
146        DEP_ANN("dep-ann"),
147
148        /**
149         * Warn about division by constant integer 0.
150         */
151        DIVZERO("divzero"),
152
153        /**
154         * Warn about empty statement after if.
155         */
156        EMPTY("empty"),
157
158        /**
159         * Warn about falling through from one case of a switch statement to the next.
160         */
161        FALLTHROUGH("fallthrough"),
162
163        /**
164         * Warn about finally clauses that do not terminate normally.
165         */
166        FINALLY("finally"),
167
168        /**
169         * Warn about issues relating to use of command line options
170         */
171        OPTIONS("options"),
172
173        /**
174         * Warn about issues regarding method overloads.
175         */
176        OVERLOADS("overloads"),
177
178        /**
179         * Warn about issues regarding method overrides.
180         */
181        OVERRIDES("overrides"),
182
183        /**
184         * Warn about invalid path elements on the command line.
185         * Such warnings cannot be suppressed with the SuppressWarnings
186         * annotation.
187         */
188        PATH("path"),
189
190        /**
191         * Warn about issues regarding annotation processing.
192         */
193        PROCESSING("processing"),
194
195        /**
196         * Warn about unchecked operations on raw types.
197         */
198        RAW("rawtypes"),
199
200        /**
201         * Warn about Serializable classes that do not provide a serial version ID.
202         */
203        SERIAL("serial"),
204
205        /**
206         * Warn about issues relating to use of statics
207         */
208        STATIC("static"),
209
210        /**
211         * Warn about proprietary API that may be removed in a future release.
212         */
213        SUNAPI("sunapi", true),
214
215        /**
216         * Warn about issues relating to use of try blocks (i.e. try-with-resources)
217         */
218        TRY("try"),
219
220        /**
221         * Warn about unchecked operations on raw types.
222         */
223        UNCHECKED("unchecked"),
224
225        /**
226         * Warn about potentially unsafe vararg methods
227         */
228        VARARGS("varargs");
229
230        LintCategory(String option) {
231            this(option, false);
232        }
233
234        LintCategory(String option, boolean hidden) {
235            this.option = option;
236            this.hidden = hidden;
237            map.put(option, this);
238        }
239
240        static LintCategory get(String option) {
241            return map.get(option);
242        }
243
244        public final String option;
245        public final boolean hidden;
246    }
247
248    /**
249     * Checks if a warning category is enabled. A warning category may be enabled
250     * on the command line, or by default, and can be temporarily disabled with
251     * the SuppressWarnings annotation.
252     */
253    public boolean isEnabled(LintCategory lc) {
254        return values.contains(lc);
255    }
256
257    /**
258     * Checks is a warning category has been specifically suppressed, by means
259     * of the SuppressWarnings annotation, or, in the case of the deprecated
260     * category, whether it has been implicitly suppressed by virtue of the
261     * current entity being itself deprecated.
262     */
263    public boolean isSuppressed(LintCategory lc) {
264        return suppressedValues.contains(lc);
265    }
266
267    protected static class AugmentVisitor implements Attribute.Visitor {
268        private final Context context;
269        private Symtab syms;
270        private Lint parent;
271        private Lint lint;
272
273        AugmentVisitor(Context context) {
274            // to break an ugly sequence of initialization dependencies,
275            // we defer the initialization of syms until it is needed
276            this.context = context;
277        }
278
279        Lint augment(Lint parent, Attribute.Compound attr) {
280            initSyms();
281            this.parent = parent;
282            lint = null;
283            attr.accept(this);
284            return (lint == null ? parent : lint);
285        }
286
287        Lint augment(Lint parent, List<Attribute.Compound> attrs) {
288            initSyms();
289            this.parent = parent;
290            lint = null;
291            for (Attribute.Compound a: attrs) {
292                a.accept(this);
293            }
294            return (lint == null ? parent : lint);
295        }
296
297        private void initSyms() {
298            if (syms == null)
299                syms = Symtab.instance(context);
300        }
301
302        private void suppress(LintCategory lc) {
303            if (lint == null)
304                lint = new Lint(parent);
305            lint.suppressedValues.add(lc);
306            lint.values.remove(lc);
307        }
308
309        public void visitConstant(Attribute.Constant value) {
310            if (value.type.tsym == syms.stringType.tsym) {
311                LintCategory lc = LintCategory.get((String) (value.value));
312                if (lc != null)
313                    suppress(lc);
314            }
315        }
316
317        public void visitClass(Attribute.Class clazz) {
318        }
319
320        // If we find a @SuppressWarnings annotation, then we continue
321        // walking the tree, in order to suppress the individual warnings
322        // specified in the @SuppressWarnings annotation.
323        public void visitCompound(Attribute.Compound compound) {
324            if (compound.type.tsym == syms.suppressWarningsType.tsym) {
325                for (List<Pair<MethodSymbol,Attribute>> v = compound.values;
326                     v.nonEmpty(); v = v.tail) {
327                    Pair<MethodSymbol,Attribute> value = v.head;
328                    if (value.fst.name.toString().equals("value"))
329                        value.snd.accept(this);
330                }
331
332            }
333        }
334
335        public void visitArray(Attribute.Array array) {
336            for (Attribute value : array.values)
337                value.accept(this);
338        }
339
340        public void visitEnum(Attribute.Enum e) {
341        }
342
343        public void visitError(Attribute.Error e) {
344        }
345    }
346}
347