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 * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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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 * 2 along with this work; if not, write to the Free Software Foundation,
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package com.sun.tools.doclint;


import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import java.util.regex.Pattern;

import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.Modifier;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.Elements;
import javax.lang.model.util.Types;
import javax.tools.Diagnostic.Kind;

import com.sun.source.doctree.DocCommentTree;
import com.sun.source.tree.CompilationUnitTree;
import com.sun.source.util.DocTrees;
import com.sun.source.util.JavacTask;
import com.sun.source.util.SourcePositions;
import com.sun.source.util.TreePath;
import com.sun.tools.javac.model.JavacTypes;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.util.MatchingUtils;
import com.sun.tools.javac.util.StringUtils;

Utility container for current execution environment,
providing the current declaration and its doc comment.
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.
/**
 * Utility container for current execution environment,
 * providing the current declaration and its doc comment.
 *
 * <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></p>
 */
public class Env {
    
Access kinds for declarations.
/**
     * Access kinds for declarations.
     */
    public enum AccessKind {
        PRIVATE,
        PACKAGE,
        PROTECTED,
        PUBLIC;

        static boolean accepts(String opt) {
            for (AccessKind g: values())
                if (opt.equals(StringUtils.toLowerCase(g.name()))) return true;
            return false;
        }

        static AccessKind of(Set<Modifier> mods) {
            if (mods.contains(Modifier.PUBLIC))
                return AccessKind.PUBLIC;
            else if (mods.contains(Modifier.PROTECTED))
                return AccessKind.PROTECTED;
            else if (mods.contains(Modifier.PRIVATE))
                return AccessKind.PRIVATE;
            else
                return AccessKind.PACKAGE;
        }
    }

    
Message handler. /** Message handler. */
    final Messages messages;

    Set<String> customTags;

    Set<Pattern> includePackages;
    Set<Pattern> excludePackages;

    HtmlVersion htmlVersion = HtmlVersion.HTML4;

    // Utility classes
    DocTrees trees;
    Elements elements;
    Types types;

    // Types used when analysing doc comments.
    TypeMirror java_lang_Error;
    TypeMirror java_lang_RuntimeException;
    TypeMirror java_lang_Throwable;
    TypeMirror java_lang_Void;

    
The path for the declaration containing the comment currently being analyzed. /** The path for the declaration containing the comment currently being analyzed. */
    TreePath currPath;
    
The element for the declaration containing the comment currently being analyzed. /** The element for the declaration containing the comment currently being analyzed. */
    Element currElement;
    
The comment current being analyzed. /** The comment current being analyzed. */
    DocCommentTree currDocComment;
    
The access kind of the declaration containing the comment currently being analyzed.
This is the minimum (most restrictive) access kind of the declaration itself
and that of its containers. For example, a public method in a private class is
noted as private.
/**
     * The access kind of the declaration containing the comment currently being analyzed.
     * This is the minimum (most restrictive) access kind of the declaration itself
     * and that of its containers. For example, a public method in a private class is
     * noted as private.
     */
    AccessKind currAccess;
    
The set of methods, if any, that the current declaration overrides. /** The set of methods, if any, that the current declaration overrides. */
    Set<? extends ExecutableElement> currOverriddenMethods;

    Env() {
        messages = new Messages(this);
    }

    void init(JavacTask task) {
        init(DocTrees.instance(task), task.getElements(), task.getTypes());
    }

    void init(DocTrees trees, Elements elements, Types types) {
        this.trees = trees;
        this.elements = elements;
        this.types = types;
    }

    void initTypes() {
        if (java_lang_Error != null)
            return ;

        java_lang_Error = elements.getTypeElement("java.lang.Error").asType();
        java_lang_RuntimeException = elements.getTypeElement("java.lang.RuntimeException").asType();
        java_lang_Throwable = elements.getTypeElement("java.lang.Throwable").asType();
        java_lang_Void = elements.getTypeElement("java.lang.Void").asType();
    }

    void setCustomTags(String cTags) {
        customTags = new LinkedHashSet<>();
        for (String s : cTags.split(DocLint.SEPARATOR)) {
            if (!s.isEmpty())
                customTags.add(s);
        }
    }

    void setCheckPackages(String packages) {
        includePackages = new HashSet<>();
        excludePackages = new HashSet<>();
        for (String pack : packages.split(DocLint.SEPARATOR)) {
            boolean excluded = false;
            if (pack.startsWith("-")) {
                pack = pack.substring(1);
                excluded = true;
            }
            if (pack.isEmpty())
                continue;
            Pattern pattern = MatchingUtils.validImportStringToPattern(pack);
            if (excluded) {
                excludePackages.add(pattern);
            } else {
                includePackages.add(pattern);
            }
        }
    }

    static boolean validatePackages(String packages) {
        for (String pack : packages.split(DocLint.SEPARATOR)) {
            if (pack.startsWith("-")) {
                pack = pack.substring(1);
            }
            if (!pack.isEmpty() && !MatchingUtils.isValidImportString(pack))
                return false;
        }
        return true;
    }

    void setHtmlVersion(HtmlVersion version) {
        htmlVersion = version;
    }

    
Set the current declaration and its doc comment. /** Set the current declaration and its doc comment. */
    void setCurrent(TreePath path, DocCommentTree comment) {
        currPath = path;
        currDocComment = comment;
        currElement = trees.getElement(currPath);
        currOverriddenMethods = ((JavacTypes) types).getOverriddenMethods(currElement);

        AccessKind ak = AccessKind.PUBLIC;
        for (TreePath p = path; p != null; p = p.getParentPath()) {
            Element e = trees.getElement(p);
            if (e != null && e.getKind() != ElementKind.PACKAGE && e.getKind() != ElementKind.MODULE) {
                ak = min(ak, AccessKind.of(e.getModifiers()));
            }
        }
        currAccess = ak;
    }

    AccessKind getAccessKind() {
        return currAccess;
    }

    long getPos(TreePath p) {
        return ((JCTree) p.getLeaf()).pos;
    }

    long getStartPos(TreePath p) {
        SourcePositions sp = trees.getSourcePositions();
        return sp.getStartPosition(p.getCompilationUnit(), p.getLeaf());
    }

    boolean shouldCheck(CompilationUnitTree unit) {
        if (includePackages == null)
            return true;

        String packageName =   unit.getPackageName() != null
                             ? unit.getPackageName().toString()
                             : "";

        if (!includePackages.isEmpty()) {
            boolean included = false;
            for (Pattern pack : includePackages) {
                if (pack.matcher(packageName).matches()) {
                    included = true;
                    break;
                }
            }
            if (!included)
                return false;
        }

        for (Pattern pack : excludePackages) {
            if (pack.matcher(packageName).matches()) {
                return false;
            }
        }

        return true;
    }

    private <T extends Comparable<T>> T min(T item1, T item2) {
        return (item1 == null) ? item2
                : (item2 == null) ? item1
                : item1.compareTo(item2) <= 0 ? item1 : item2;
    }
}