/*
 * 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.
 */
/*
 * $Id: SecuritySupport.java,v 1.1.2.1 2005/08/01 02:08:48 jeffsuttor Exp $
 */

package com.sun.org.apache.xalan.internal.utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

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;
import java.util.Properties;

/**
 * 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;
    }

    public 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);
            }
        });
    }

    public static String getSystemProperty(final String propName, final String def) {
        return (String) AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                return System.getProperty(propName, def);
            }
        });
    }

    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(ObjectFactory.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 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();
    }

    /**
     * Read from $java.home/lib/jaxp.properties for the specified property
     * The program
     *
     * @param propertyId the Id of the property
     * @return the value of the property
     */
    static String readJAXPProperty(String propertyId) {
        String value = null;
        InputStream is = null;
        try {
            if (firstTime) {
                synchronized (cacheProps) {
                    if (firstTime) {
                        String configFile = getSystemProperty("java.home") + File.separator +
                            "lib" + File.separator + "jaxp.properties";
                        File f = new File(configFile);
                        if (getFileExists(f)) {
                            is = getFileInputStream(f);
                            cacheProps.load(is);
                        }
                        firstTime = false;
                    }
                }
            }
            value = cacheProps.getProperty(propertyId);

        }
        catch (Exception ex) {}
        finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException ex) {}
            }
        }
        return value;
    }

    /**
     * Cache for properties in java.home/lib/jaxp.properties
     */
    static final Properties cacheProps = new Properties();

    /**
     * Flag indicating if the program has tried reading java.home/lib/jaxp.properties
     */
    static volatile boolean firstTime = true;

    private SecuritySupport() {
    }
}
