/*

 * Copyright (c) 2017, 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).

 *

 * 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

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 */

package javax.xml.bind;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.lang.Module;

import java.util.ArrayList;

import java.util.List;

import java.util.logging.Level;

import java.util.logging.Logger;

/**

 * Propagates openness of JAXB annottated classess packages to JAXB impl module.

 *

 * @author Roman Grigoriadi

 */

class ModuleUtil {

    private static Logger logger = Logger.getLogger("javax.xml.bind");

    /**

     * Resolves classes from context path.

     * Only one class per package is needed to access its {@link java.lang.Module}

     */

    static Class[] getClassesFromContextPath(String contextPath, ClassLoader classLoader) throws JAXBException {

        List<Class> classes = new ArrayList<>();

        if (contextPath == null || contextPath.isEmpty()){

          return classes.toArray(new Class[]{});

        }

        String [] tokens = contextPath.split(":");

        for (String pkg : tokens){

           // look for ObjectFactory and load it

           final Class<?> o;

           try {

               o = classLoader.loadClass(pkg+".ObjectFactory");

               classes.add(o);

               continue;

           } catch (ClassNotFoundException e) {

               // not necessarily an error

           }

           // look for jaxb.index and load the list of classes

           try {

               final Class firstByJaxbIndex = findFirstByJaxbIndex(pkg, classLoader);

               if (firstByJaxbIndex != null) {

                   classes.add(firstByJaxbIndex);

               }

           } catch (IOException e) {

               throw new JAXBException(e);

           }

        }

        if (logger.isLoggable(Level.FINE)) {

            logger.log(Level.FINE, "Resolved classes from context path: {0}", classes);

        }

        return classes.toArray(new Class[]{});

    }

    /**

     * Find first class in package by {@code jaxb.index} file.

     */

    static Class findFirstByJaxbIndex(String pkg, ClassLoader classLoader) throws IOException, JAXBException {

        final String resource = pkg.replace('.', '/') + "/jaxb.index";

        final InputStream resourceAsStream = classLoader.getResourceAsStream(resource);

        if (resourceAsStream == null) {

            return null;

        }

        BufferedReader in =

                new BufferedReader(new InputStreamReader(resourceAsStream, "UTF-8"));

        try {

            String className = in.readLine();

            while (className != null) {

                className = className.trim();

                if (className.startsWith("#") || (className.length() == 0)) {

                    className = in.readLine();

                    continue;

                }

                try {

                    return classLoader.loadClass(pkg + '.' + className);

                } catch (ClassNotFoundException e) {

                    throw new JAXBException(Messages.format(Messages.ERROR_LOAD_CLASS, className, pkg), e);

                }

            }

        } finally {

            in.close();

        }

        return null;

    }

    /**

     * Implementation may be defined in other module than {@code java.xml.bind}. In that case openness

     * {@linkplain Module#isOpen open} of classes should be delegated to implementation module.

     *

     * @param classes used to resolve module for {@linkplain Module#addOpens(String, Module)}

     * @param factorySPI used to resolve {@link Module} of the implementation.

     *

     * @throws JAXBException if ony of a classes package is not open to {@code java.xml.bind} module.

     */

    static void delegateAddOpensToImplModule(Class[] classes, Class<?> factorySPI) throws JAXBException {

        final Module implModule = factorySPI.getModule();

        Module jaxbModule = JAXBContext.class.getModule();

        for (Class cls : classes) {

            final Module classModule = cls.getModule();

            final String packageName = cls.getPackageName();

            //no need for unnamed

            if (!classModule.isNamed()) {

                continue;

            }

            //report error if they are not open to java.xml.bind

            if (!classModule.isOpen(packageName, jaxbModule)) {

                throw new JAXBException(Messages.format(Messages.JAXB_CLASSES_NOT_OPEN,

                                                        packageName, cls.getName(), classModule.getName()));

            }

            //propagate openness to impl module

            classModule.addOpens(packageName, implModule);

            if (logger.isLoggable(Level.FINE)) {

                logger.log(Level.FINE, "Propagating openness of package {0} in {1} to {2}.",

                           new String[]{ packageName, classModule.getName(), implModule.getName() });

            }

        }

    }

}