/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 2002-2004 The Apache Software Foundation.

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.sun.org.apache.bcel.internal.util;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FilenameFilter;

import java.io.InputStream;

import java.lang.ClassLoader;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.security.PrivilegedActionException;

import java.security.PrivilegedExceptionAction;

import java.util.ListResourceBundle;

import java.util.Locale;

import java.util.MissingResourceException;

import java.util.ResourceBundle;

/**

 * This class is duplicated for each subpackage so keep it in sync. It is

 * package private and therefore is not exposed as part of any API.

 *

 * @xerces.internal

 */

public final class SecuritySupport {

    private static final SecuritySupport securitySupport = new SecuritySupport();

    /**

     * Return an instance of this class.

     */

    public static SecuritySupport getInstance() {

        return securitySupport;

    }

    static ClassLoader getContextClassLoader() {

        return (ClassLoader) AccessController.doPrivileged(new PrivilegedAction() {

            public Object run() {

                ClassLoader cl = null;

                try {

                    cl = Thread.currentThread().getContextClassLoader();

                } catch (SecurityException ex) {

                }

                return cl;

            }

        });

    }

    static ClassLoader getSystemClassLoader() {

        return (ClassLoader) AccessController.doPrivileged(new PrivilegedAction() {

            public Object run() {

                ClassLoader cl = null;

                try {

                    cl = ClassLoader.getSystemClassLoader();

                } catch (SecurityException ex) {

                }

                return cl;

            }

        });

    }

    static ClassLoader getParentClassLoader(final ClassLoader cl) {

        return (ClassLoader) AccessController.doPrivileged(new PrivilegedAction() {

            public Object run() {

                ClassLoader parent = null;

                try {

                    parent = cl.getParent();

                } catch (SecurityException ex) {

                }

                // eliminate loops in case of the boot

                // ClassLoader returning itself as a parent

                return (parent == cl) ? null : parent;

            }

        });

    }

    public static String getSystemProperty(final String propName) {

        return (String) AccessController.doPrivileged(new PrivilegedAction() {

            public Object run() {

                return System.getProperty(propName);

            }

        });

    }

    static FileInputStream getFileInputStream(final File file)

            throws FileNotFoundException {

        try {

            return (FileInputStream) AccessController.doPrivileged(new PrivilegedExceptionAction() {

                public Object run() throws FileNotFoundException {

                    return new FileInputStream(file);

                }

            });

        } catch (PrivilegedActionException e) {

            throw (FileNotFoundException) e.getException();

        }

    }

    /**

     * Return resource using the same classloader for the ObjectFactory by

     * default or bootclassloader when Security Manager is in place

     */

    public static InputStream getResourceAsStream(final String name) {

        if (System.getSecurityManager() != null) {

            return getResourceAsStream(null, name);

        } else {

            return getResourceAsStream(findClassLoader(), name);

        }

    }

    public static InputStream getResourceAsStream(final ClassLoader cl,

            final String name) {

        return (InputStream) AccessController.doPrivileged(new PrivilegedAction() {

            public Object run() {

                InputStream ris;

                if (cl == null) {

                    ris = Object.class.getResourceAsStream("/" + name);

                } else {

                    ris = cl.getResourceAsStream(name);

                }

                return ris;

            }

        });

    }

    /**

     * Gets a resource bundle using the specified base name, the default locale,

     * and the caller's class loader.

     *

     * @param bundle the base name of the resource bundle, a fully qualified

     * class name

     * @return a resource bundle for the given base name and the default locale

     */

    public static ListResourceBundle getResourceBundle(String bundle) {

        return getResourceBundle(bundle, Locale.getDefault());

    }

    /**

     * Gets a resource bundle using the specified base name and locale, and the

     * caller's class loader.

     *

     * @param bundle the base name of the resource bundle, a fully qualified

     * class name

     * @param locale the locale for which a resource bundle is desired

     * @return a resource bundle for the given base name and locale

     */

    public static ListResourceBundle getResourceBundle(final String bundle, final Locale locale) {

        return AccessController.doPrivileged(new PrivilegedAction<ListResourceBundle>() {

            public ListResourceBundle run() {

                try {

                    return (ListResourceBundle) ResourceBundle.getBundle(bundle, locale);

                } catch (MissingResourceException e) {

                    try {

                        return (ListResourceBundle) ResourceBundle.getBundle(bundle, new Locale("en", "US"));

                    } catch (MissingResourceException e2) {

                        throw new MissingResourceException(

                                "Could not load any resource bundle by " + bundle, bundle, "");

                    }

                }

            }

        });

    }

    public static String[] getFileList(final File f, final FilenameFilter filter) {

        return ((String[]) AccessController.doPrivileged(new PrivilegedAction() {

            public Object run() {

                return f.list(filter);

            }

        }));

    }

    public static boolean getFileExists(final File f) {

        return ((Boolean) AccessController.doPrivileged(new PrivilegedAction() {

            public Object run() {

                return f.exists() ? Boolean.TRUE : Boolean.FALSE;

            }

        })).booleanValue();

    }

    static long getLastModified(final File f) {

        return ((Long) AccessController.doPrivileged(new PrivilegedAction() {

            public Object run() {

                return new Long(f.lastModified());

            }

        })).longValue();

    }

    /**

     * Figure out which ClassLoader to use.

     */

    public static ClassLoader findClassLoader()

    {

        if (System.getSecurityManager()!=null) {

            //this will ensure bootclassloader is used

            return null;

        } else {

            return SecuritySupport.class.getClassLoader();

        }

    } // findClassLoader():ClassLoader

    private SecuritySupport() {

    }

}