/*
 * Copyright (c) 2005, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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package com.sun.tools.javac.code;

import java.util.Arrays;
import java.util.EnumSet;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import com.sun.tools.javac.code.Symbol.*;
import com.sun.tools.javac.main.Option;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.Options;
import com.sun.tools.javac.util.Pair;

A class for handling -Xlint suboptions and @SuppressWarnings.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/**
 * A class for handling -Xlint suboptions and @SuppressWarnings.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class Lint
{
    
The context key for the root Lint object. /** The context key for the root Lint object. */
    protected static final Context.Key<Lint> lintKey = new Context.Key<>();

    
Get the root Lint instance. /** Get the root Lint instance. */
    public static Lint instance(Context context) {
        Lint instance = context.get(lintKey);
        if (instance == null)
            instance = new Lint(context);
        return instance;
    }

    
Returns the result of combining the values in this object with
the given annotation.
/**
     * Returns the result of combining the values in this object with
     * the given annotation.
     */
    public Lint augment(Attribute.Compound attr) {
        return augmentor.augment(this, attr);
    }


    
Returns the result of combining the values in this object with
the metadata on the given symbol.
/**
     * Returns the result of combining the values in this object with
     * the metadata on the given symbol.
     */
    public Lint augment(Symbol sym) {
        Lint l = augmentor.augment(this, sym.getDeclarationAttributes());
        if (sym.isDeprecated()) {
            if (l == this)
                l = new Lint(this);
            l.values.remove(LintCategory.DEPRECATION);
            l.suppressedValues.add(LintCategory.DEPRECATION);
        }
        return l;
    }

    
Returns a new Lint that has the given LintCategorys suppressed.
Params:
lc – one or more categories to be suppressed/**
     * Returns a new Lint that has the given LintCategorys suppressed.
     * @param lc one or more categories to be suppressed
     */
    public Lint suppress(LintCategory... lc) {
        Lint l = new Lint(this);
        l.values.removeAll(Arrays.asList(lc));
        l.suppressedValues.addAll(Arrays.asList(lc));
        return l;
    }

    private final AugmentVisitor augmentor;

    private final EnumSet<LintCategory> values;
    private final EnumSet<LintCategory> suppressedValues;

    private static final Map<String, LintCategory> map = new ConcurrentHashMap<>(20);

    protected Lint(Context context) {
        // initialize values according to the lint options
        Options options = Options.instance(context);

        if (options.isSet(Option.XLINT) || options.isSet(Option.XLINT_CUSTOM, "all")) {
            // If -Xlint or -Xlint:all is given, enable all categories by default
            values = EnumSet.allOf(LintCategory.class);
        } else if (options.isSet(Option.XLINT_CUSTOM, "none")) {
            // if -Xlint:none is given, disable all categories by default
            values = EnumSet.noneOf(LintCategory.class);
        } else {
            // otherwise, enable on-by-default categories
            values = EnumSet.noneOf(LintCategory.class);

            Source source = Source.instance(context);
            if (source.compareTo(Source.JDK9) >= 0) {
                values.add(LintCategory.DEP_ANN);
            }
            values.add(LintCategory.REQUIRES_TRANSITIVE_AUTOMATIC);
            values.add(LintCategory.OPENS);
            values.add(LintCategory.MODULE);
            values.add(LintCategory.REMOVAL);
            if (!options.isSet(Option.PREVIEW)) {
                values.add(LintCategory.PREVIEW);
            }
            values.add(LintCategory.SYNCHRONIZATION);
        }

        // Look for specific overrides
        for (LintCategory lc : LintCategory.values()) {
            if (options.isSet(Option.XLINT_CUSTOM, lc.option)) {
                values.add(lc);
            } else if (options.isSet(Option.XLINT_CUSTOM, "-" + lc.option)) {
                values.remove(lc);
            }
        }

        suppressedValues = EnumSet.noneOf(LintCategory.class);

        context.put(lintKey, this);
        augmentor = new AugmentVisitor(context);
    }

    protected Lint(Lint other) {
        this.augmentor = other.augmentor;
        this.values = other.values.clone();
        this.suppressedValues = other.suppressedValues.clone();
    }

    @Override
    public String toString() {
        return "Lint:[values" + values + " suppressedValues" + suppressedValues + "]";
    }

    
Categories of warnings that can be generated by the compiler.
/**
     * Categories of warnings that can be generated by the compiler.
     */
    public enum LintCategory {
        
Warn when code refers to a auxiliary class that is hidden in a source file (ie source file name is
different from the class name, and the type is not properly nested) and the referring code
is not located in the same source file.
/**
         * Warn when code refers to a auxiliary class that is hidden in a source file (ie source file name is
         * different from the class name, and the type is not properly nested) and the referring code
         * is not located in the same source file.
         */
        AUXILIARYCLASS("auxiliaryclass"),

        
Warn about use of unnecessary casts.
/**
         * Warn about use of unnecessary casts.
         */
        CAST("cast"),

        
Warn about issues related to classfile contents
/**
         * Warn about issues related to classfile contents
         */
        CLASSFILE("classfile"),

        
Warn about use of deprecated items.
/**
         * Warn about use of deprecated items.
         */
        DEPRECATION("deprecation"),

        
Warn about items which are documented with an @deprecated JavaDoc comment, but which do not have @Deprecated annotation. /**
         * Warn about items which are documented with an {@code @deprecated} JavaDoc
         * comment, but which do not have {@code @Deprecated} annotation.
         */
        DEP_ANN("dep-ann"),

        
Warn about division by constant integer 0.
/**
         * Warn about division by constant integer 0.
         */
        DIVZERO("divzero"),

        
Warn about empty statement after if.
/**
         * Warn about empty statement after if.
         */
        EMPTY("empty"),

        
Warn about issues regarding module exports.
/**
         * Warn about issues regarding module exports.
         */
        EXPORTS("exports"),

        
Warn about falling through from one case of a switch statement to the next.
/**
         * Warn about falling through from one case of a switch statement to the next.
         */
        FALLTHROUGH("fallthrough"),

        
Warn about finally clauses that do not terminate normally.
/**
         * Warn about finally clauses that do not terminate normally.
         */
        FINALLY("finally"),

        
Warn about compiler generation of a default constructor.
/**
          * Warn about compiler generation of a default constructor.
          */
        MISSING_EXPLICIT_CTOR("missing-explicit-ctor"),

        
Warn about module system related issues.
/**
         * Warn about module system related issues.
         */
        MODULE("module"),

        
Warn about issues regarding module opens.
/**
         * Warn about issues regarding module opens.
         */
        OPENS("opens"),

        
Warn about issues relating to use of command line options
/**
         * Warn about issues relating to use of command line options
         */
        OPTIONS("options"),

        
Warn about issues regarding method overloads.
/**
         * Warn about issues regarding method overloads.
         */
        OVERLOADS("overloads"),

        
Warn about issues regarding method overrides.
/**
         * Warn about issues regarding method overrides.
         */
        OVERRIDES("overrides"),

        
Warn about invalid path elements on the command line.
Such warnings cannot be suppressed with the SuppressWarnings
annotation.
/**
         * Warn about invalid path elements on the command line.
         * Such warnings cannot be suppressed with the SuppressWarnings
         * annotation.
         */
        PATH("path"),

        
Warn about issues regarding annotation processing.
/**
         * Warn about issues regarding annotation processing.
         */
        PROCESSING("processing"),

        
Warn about unchecked operations on raw types.
/**
         * Warn about unchecked operations on raw types.
         */
        RAW("rawtypes"),

        
Warn about use of deprecated-for-removal items.
/**
         * Warn about use of deprecated-for-removal items.
         */
        REMOVAL("removal"),

        
Warn about use of automatic modules in the requires clauses.
/**
         * Warn about use of automatic modules in the requires clauses.
         */
        REQUIRES_AUTOMATIC("requires-automatic"),

        
Warn about automatic modules in requires transitive.
/**
         * Warn about automatic modules in requires transitive.
         */
        REQUIRES_TRANSITIVE_AUTOMATIC("requires-transitive-automatic"),

        
Warn about Serializable classes that do not provide a serial version ID.
/**
         * Warn about Serializable classes that do not provide a serial version ID.
         */
        SERIAL("serial"),

        
Warn about issues relating to use of statics
/**
         * Warn about issues relating to use of statics
         */
        STATIC("static"),

        
Warn about synchronization attempts on instances of @ValueBased classes.
/**
         * Warn about synchronization attempts on instances of @ValueBased classes.
         */
        SYNCHRONIZATION("synchronization"),

        
Warn about issues relating to use of text blocks
/**
         * Warn about issues relating to use of text blocks
         */
        TEXT_BLOCKS("text-blocks"),

        
Warn about issues relating to use of try blocks (i.e. try-with-resources)
/**
         * Warn about issues relating to use of try blocks (i.e. try-with-resources)
         */
        TRY("try"),

        
Warn about unchecked operations on raw types.
/**
         * Warn about unchecked operations on raw types.
         */
        UNCHECKED("unchecked"),

        
Warn about potentially unsafe vararg methods
/**
         * Warn about potentially unsafe vararg methods
         */
        VARARGS("varargs"),

        
Warn about use of preview features.
/**
         * Warn about use of preview features.
         */
        PREVIEW("preview");

        LintCategory(String option) {
            this(option, false);
        }

        LintCategory(String option, boolean hidden) {
            this.option = option;
            this.hidden = hidden;
            map.put(option, this);
        }

        static LintCategory get(String option) {
            return map.get(option);
        }

        public final String option;
        public final boolean hidden;
    }

    
Checks if a warning category is enabled. A warning category may be enabled
on the command line, or by default, and can be temporarily disabled with
the SuppressWarnings annotation.
/**
     * Checks if a warning category is enabled. A warning category may be enabled
     * on the command line, or by default, and can be temporarily disabled with
     * the SuppressWarnings annotation.
     */
    public boolean isEnabled(LintCategory lc) {
        return values.contains(lc);
    }

    
Checks is a warning category has been specifically suppressed, by means
of the SuppressWarnings annotation, or, in the case of the deprecated
category, whether it has been implicitly suppressed by virtue of the
current entity being itself deprecated.
/**
     * Checks is a warning category has been specifically suppressed, by means
     * of the SuppressWarnings annotation, or, in the case of the deprecated
     * category, whether it has been implicitly suppressed by virtue of the
     * current entity being itself deprecated.
     */
    public boolean isSuppressed(LintCategory lc) {
        return suppressedValues.contains(lc);
    }

    protected static class AugmentVisitor implements Attribute.Visitor {
        private final Context context;
        private Symtab syms;
        private Lint parent;
        private Lint lint;

        AugmentVisitor(Context context) {
            // to break an ugly sequence of initialization dependencies,
            // we defer the initialization of syms until it is needed
            this.context = context;
        }

        Lint augment(Lint parent, Attribute.Compound attr) {
            initSyms();
            this.parent = parent;
            lint = null;
            attr.accept(this);
            return (lint == null ? parent : lint);
        }

        Lint augment(Lint parent, List<Attribute.Compound> attrs) {
            initSyms();
            this.parent = parent;
            lint = null;
            for (Attribute.Compound a: attrs) {
                a.accept(this);
            }
            return (lint == null ? parent : lint);
        }

        private void initSyms() {
            if (syms == null)
                syms = Symtab.instance(context);
        }

        private void suppress(LintCategory lc) {
            if (lint == null)
                lint = new Lint(parent);
            lint.suppressedValues.add(lc);
            lint.values.remove(lc);
        }

        public void visitConstant(Attribute.Constant value) {
            if (value.type.tsym == syms.stringType.tsym) {
                LintCategory lc = LintCategory.get((String) (value.value));
                if (lc != null)
                    suppress(lc);
            }
        }

        public void visitClass(Attribute.Class clazz) {
        }

        // If we find a @SuppressWarnings annotation, then we continue
        // walking the tree, in order to suppress the individual warnings
        // specified in the @SuppressWarnings annotation.
        public void visitCompound(Attribute.Compound compound) {
            if (compound.type.tsym == syms.suppressWarningsType.tsym) {
                for (List<Pair<MethodSymbol,Attribute>> v = compound.values;
                     v.nonEmpty(); v = v.tail) {
                    Pair<MethodSymbol,Attribute> value = v.head;
                    if (value.fst.name.toString().equals("value"))
                        value.snd.accept(this);
                }

            }
        }

        public void visitArray(Attribute.Array array) {
            for (Attribute value : array.values)
                value.accept(this);
        }

        public void visitEnum(Attribute.Enum e) {
        }

        public void visitError(Attribute.Error e) {
        }
    }
}