/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 522337 2007-03-25 20:03:27Z mrglavas $

package javax.xml.xpath;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.Enumeration;

This class is duplicated for each JAXP subpackage so keep it in sync.
It is package private and therefore is not exposed as part of the JAXP
API.
Security related methods that only work on J2SE 1.2 and newer.
/**
 * This class is duplicated for each JAXP subpackage so keep it in sync.
 * It is package private and therefore is not exposed as part of the JAXP
 * API.
 *
 * Security related methods that only work on J2SE 1.2 and newer.
 */
final class SecuritySupport  {
    
    private 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 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();
	}
    }

    static InputStream getURLInputStream(final URL url)
        throws IOException
    {
	try {
            return (InputStream)
                AccessController.doPrivileged(new PrivilegedExceptionAction() {
                    public Object run() throws IOException {
                        return url.openStream();
                    }
                });
	} catch (PrivilegedActionException e) {
	    throw (IOException)e.getException();
	}
    }

    static URL getResourceAsURL(final ClassLoader cl,
                                final String name)
    {
        return (URL)
            AccessController.doPrivileged(new PrivilegedAction() {
                public Object run() {
                    URL url;
                    if (cl == null) {
                        url = ClassLoader.getSystemResource(name);
                    } 
                    else {
                        url = cl.getResource(name);
                    }
                    return url;
                }
            });
    }

    static Enumeration getResources(final ClassLoader cl,
                                    final String name) throws IOException
    {
        try{
        return (Enumeration)
            AccessController.doPrivileged(new PrivilegedExceptionAction() {
                public Object run() throws IOException{
                    Enumeration enumeration;
                    if (cl == null) {
                        enumeration = ClassLoader.getSystemResources(name);
                    } 
                    else {
                        enumeration = cl.getResources(name);
                    }
                    return enumeration;
                }
            });
        }catch(PrivilegedActionException e){
            throw (IOException)e.getException();
        }
    }
    
    static InputStream getResourceAsStream(final ClassLoader cl,
                                           final String name)
    {
        return (InputStream)
            AccessController.doPrivileged(new PrivilegedAction() {
                public Object run() {
                    InputStream ris;
                    if (cl == null) {
                        ris = ClassLoader.getSystemResourceAsStream(name);
                    } else {
                        ris = cl.getResourceAsStream(name);
                    }
                    return ris;
                }
            });
    }

    static boolean doesFileExist(final File f) {
    return ((Boolean)
            AccessController.doPrivileged(new PrivilegedAction() {
                public Object run() {
                    return f.exists() ? Boolean.TRUE : Boolean.FALSE;
                }
            })).booleanValue();
    }

}