/*

 * Copyright (c) 2013, 2016, 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.

 *

 * 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).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package crules;

import java.util.Arrays;

import java.util.HashMap;

import java.util.HashSet;

import java.util.List;

import java.util.Map;

import java.util.Set;

import com.sun.source.util.JavacTask;

import com.sun.source.util.TaskEvent.Kind;

import com.sun.tools.javac.tree.JCTree.JCVariableDecl;

import com.sun.tools.javac.tree.TreeScanner;

import static com.sun.tools.javac.code.Flags.ENUM;

import static com.sun.tools.javac.code.Flags.FINAL;

import static com.sun.tools.javac.code.Flags.STATIC;

import static com.sun.tools.javac.code.Flags.SYNTHETIC;

import static com.sun.tools.javac.code.Kinds.Kind.*;

/**This analyzer guards against non-final static fields.*/

public class MutableFieldsAnalyzer extends AbstractCodingRulesAnalyzer {

    public MutableFieldsAnalyzer(JavacTask task) {

        super(task);

        treeVisitor = new MutableFieldsVisitor();

        eventKind = Kind.ANALYZE;

    }

    private boolean ignoreField(String className, String field) {

        Set<String> fieldsToIgnore = classFieldsToIgnoreMap.get(className);

        return (fieldsToIgnore) != null && fieldsToIgnore.contains(field);

    }

    class MutableFieldsVisitor extends TreeScanner {

        @Override

        public void visitVarDef(JCVariableDecl tree) {

            boolean isJavacPack = tree.sym.outermostClass().fullname.toString()

                    .contains(packageToCheck);

            if (isJavacPack &&

                (tree.sym.flags() & SYNTHETIC) == 0 &&

                tree.sym.owner.kind == TYP) {

                if (!ignoreField(tree.sym.owner.flatName().toString(),

                        tree.getName().toString())) {

                    boolean enumClass = (tree.sym.owner.flags() & ENUM) != 0;

                    boolean nonFinalStaticEnumField =

                            (tree.sym.flags() & (ENUM | FINAL)) == 0;

                    boolean nonFinalStaticField =

                            (tree.sym.flags() & STATIC) != 0 &&

                            (tree.sym.flags() & FINAL) == 0;

                    if (enumClass ? nonFinalStaticEnumField : nonFinalStaticField) {

                        messages.error(tree, "crules.err.var.must.be.final", tree);

                    }

                }

            }

            super.visitVarDef(tree);

        }

    }

    private static final String packageToCheck = "com.sun.tools.javac";

    private static final Map<String, Set<String>> classFieldsToIgnoreMap =

                new HashMap<>();

    private static void ignoreFields(String className, String... fieldNames) {

        classFieldsToIgnoreMap.put(className, new HashSet<>(Arrays.asList(fieldNames)));

    };

    static {

        ignoreFields("com.sun.tools.javac.util.JCDiagnostic", "fragmentFormatter");

        ignoreFields("com.sun.tools.javac.util.JavacMessages", "defaultBundle", "defaultMessages");

        ignoreFields("com.sun.tools.javac.file.JRTIndex", "sharedInstance");

        ignoreFields("com.sun.tools.javac.main.JavaCompiler", "versionRB");

        ignoreFields("com.sun.tools.javac.code.Type", "moreInfo");

        ignoreFields("com.sun.tools.javac.util.SharedNameTable", "freelist");

        ignoreFields("com.sun.tools.javac.util.Log", "useRawMessages");

        ignoreFields("com.sun.tools.javac.util.JDK9Wrappers$ModuleFinder",

                "moduleFinderClass", "ofMethod");

        ignoreFields("com.sun.tools.javac.util.JDK9Wrappers$Configuration",

                "configurationClass", "resolveRequiresAndUsesMethod");

        ignoreFields("com.sun.tools.javac.util.JDK9Wrappers$Layer",

                "layerClass", "bootMethod", "defineModulesWithOneLoaderMethod", "configurationMethod");

        ignoreFields("com.sun.tools.javac.util.JDK9Wrappers$ServiceLoaderHelper",

                "loadMethod");

        ignoreFields("com.sun.tools.javac.util.ModuleHelper",

                "addExportsMethod", "getUnnamedModuleMethod", "getModuleMethod");

    }

}