/*
 * Copyright (c) 1997, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.istack.internal.tools;

import java.security.AccessController;
import java.security.PrivilegedAction;

/**
 * Class defined for safe calls of getClassLoader methods of any kind (context/system/class
 * classloader. This MUST be package private and defined in every package which
 * uses such invocations.
 * @author snajper
 */
class SecureLoader {

    static ClassLoader getContextClassLoader() {
        if (System.getSecurityManager() == null) {
            return Thread.currentThread().getContextClassLoader();
        } else {
            return AccessController.doPrivileged(
                    new PrivilegedAction<ClassLoader>() {
                        @Override
                        public ClassLoader run() {
                            return Thread.currentThread().getContextClassLoader();
                        }
                    });
        }
    }

    static ClassLoader getClassClassLoader(final Class c) {
        if (System.getSecurityManager() == null) {
            return c.getClassLoader();
        } else {
            return AccessController.doPrivileged(
                    new PrivilegedAction<ClassLoader>() {
                        @Override
                        public ClassLoader run() {
                            return c.getClassLoader();
                        }
                    });
        }
    }

    static ClassLoader getSystemClassLoader() {
        if (System.getSecurityManager() == null) {
            return ClassLoader.getSystemClassLoader();
        } else {
            return AccessController.doPrivileged(
                    new PrivilegedAction<ClassLoader>() {
                        @Override
                        public ClassLoader run() {
                            return ClassLoader.getSystemClassLoader();
                        }
                    });
        }
    }

    static ClassLoader getParentClassLoader(final ClassLoader cl) {
        if (System.getSecurityManager() == null) {
            return cl.getParent();
        } else {
            return AccessController.doPrivileged(
                    new PrivilegedAction<ClassLoader>() {
                        @Override
                        public ClassLoader run() {
                            return cl.getParent();
                        }
                    });
        }
    }

    static void setContextClassLoader(final ClassLoader cl) {
        if (System.getSecurityManager() == null) {
            Thread.currentThread().setContextClassLoader(cl);
        } else {
            AccessController.doPrivileged(
                    new PrivilegedAction<ClassLoader>() {
                        @Override
                        public ClassLoader run() {
                            Thread.currentThread().setContextClassLoader(cl);
                            return null;
                        }
                    });
        }
    }

}