/*

 * Copyright (c) 2010, 2013, 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

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

 * questions.

 */

/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file, and Oracle licenses the original version of this file under the BSD

 * license:

 */

/*

   Copyright 2009-2013 Attila Szegedi

*/

package jdk.dynalink.beans;

import java.lang.reflect.Modifier;

import java.security.AccessControlContext;

import java.security.AccessController;

import java.security.PrivilegedAction;

import jdk.dynalink.internal.AccessControlContextFactory;

/**

 * A utility class to check whether a given class is in a package with restricted access e.g. "sun.*" etc.

 */

class CheckRestrictedPackage {

    private static final AccessControlContext NO_PERMISSIONS_CONTEXT =

            AccessControlContextFactory.createAccessControlContext();

    /**

     * Returns true if the class is either not public, or it resides in a package with restricted access.

     * @param clazz the class to test

     * @return true if the class is either not public, or it resides in a package with restricted access.

     */

    static boolean isRestrictedClass(final Class<?> clazz) {

        if(!Modifier.isPublic(clazz.getModifiers())) {

            // Non-public classes are always restricted

            return true;

        }

        final String name = clazz.getName();

        final int i = name.lastIndexOf('.');

        if (i == -1) {

            // Classes in default package are never restricted

            return false;

        }

        final String pkgName = name.substring(0, i);

        final Module module = clazz.getModule();

        if (module != null && !module.isExported(pkgName)) {

            return true;

        }

        final SecurityManager sm = System.getSecurityManager();

        if(sm == null) {

            // No further restrictions if we don't have a security manager

            return false;

        }

        // Do a package access check from within an access control context with no permissions

        try {

            AccessController.doPrivileged(new PrivilegedAction<Void>() {

                @Override

                public Void run() {

                    sm.checkPackageAccess(pkgName);

                    return null;

                }

            }, NO_PERMISSIONS_CONTEXT);

        } catch(final SecurityException e) {

            return true;

        }

        return false;

    }

}