/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/*
 * 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.
 */

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.net.URL;

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();
        }
    }

    public static InputStream getResourceAsStream(final String name) {
        return (InputStream) AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                return SecuritySupport.class.getResourceAsStream("/"+name);
            }
        });
    }

    /**
     * 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();
    }

    /**
     * Strip off path from an URI
     *
     * @param uri an URI with full path
     * @return the file name only
     */
    public static String sanitizePath(String uri) {
        if (uri == null) {
            return "";
        }
        int i = uri.lastIndexOf("/");
        if (i > 0) {
            return uri.substring(i+1, uri.length());
        }
        return "";
    }

    /**
     * Check the protocol used in the systemId against allowed protocols
     *
     * @param systemId the Id of the URI
     * @param allowedProtocols a list of allowed protocols separated by comma
     * @param accessAny keyword to indicate allowing any protocol
     * @return the name of the protocol if rejected, null otherwise
     */
    public static String checkAccess(String systemId, String allowedProtocols, String accessAny) throws IOException {
        if (systemId == null || (allowedProtocols != null &&
                allowedProtocols.equalsIgnoreCase(accessAny))) {
            return null;
        }

        String protocol;
        if (systemId.indexOf(":")==-1) {
            protocol = "file";
        } else {
            URL url = new URL(systemId);
            protocol = url.getProtocol();
            if (protocol.equalsIgnoreCase("jar")) {
                String path = url.getPath();
                protocol = path.substring(0, path.indexOf(":"));
            }
        }

        if (isProtocolAllowed(protocol, allowedProtocols)) {
            //access allowed
            return null;
        } else {
            return protocol;
        }
    }

    /**
     * Check if the protocol is in the allowed list of protocols. The check
     * is case-insensitive while ignoring whitespaces.
     *
     * @param protocol a protocol
     * @param allowedProtocols a list of allowed protocols
     * @return true if the protocol is in the list
     */
    private static boolean isProtocolAllowed(String protocol, String allowedProtocols) {
         if (allowedProtocols == null) {
             return false;
         }
         String temp[] = allowedProtocols.split(",");
         for (String t : temp) {
             t = t.trim();
             if (t.equalsIgnoreCase(protocol)) {
                 return true;
             }
         }
         return false;
     }

    /**
     * Read JAXP system property in this order: system property,
     * $java.home/lib/jaxp.properties if the system property is not specified
     *
     * @param propertyId the Id of the property
     * @return the value of the property
     */
    public static String getJAXPSystemProperty(String sysPropertyId) {
        String accessExternal = getSystemProperty(sysPropertyId);
        if (accessExternal == null) {
            accessExternal = readJAXPProperty(sysPropertyId);
        }
        return accessExternal;
    }

    /**
     * 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 () {}
}
