/*

  * This file is part of dependency-check-core.

  *

  * 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.

  *

  * Copyright (c) 2014 Jeremy Long. All Rights Reserved.

  */

 package org.owasp.dependencycheck.data.nvdcve;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import java.io.File;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.net.URLClassLoader;

 import java.security.AccessController;

 import java.security.PrivilegedAction;

 import java.sql.Driver;

 import java.sql.DriverManager;

 import java.sql.SQLException;

 import java.util.ArrayList;

 import java.util.List;

 /**

  * DriverLoader is a utility class that is used to load database drivers.

  *

  * @author Jeremy Long

  */

 public final class DriverLoader {

     /**

      * The logger.

      */

     private static final Logger LOGGER = LoggerFactory.getLogger(DriverLoader.class);

     /**

      * Private constructor for a utility class.

      */

     private DriverLoader() {

     }

     /**

      * Loads the specified class using the system class loader and registers the driver with the driver manager.

      *

      * @param className the fully qualified name of the desired class

      * @return the loaded Driver

      * @throws DriverLoadException thrown if the driver cannot be loaded

      */

     public static Driver load(String className) throws DriverLoadException {

         final ClassLoader loader = DriverLoader.class.getClassLoader(); //ClassLoader.getSystemClassLoader();

         return load(className, loader);

     }

     /**

      * Loads the specified class by registering the supplied paths to the class loader and then registers the driver

      * with the driver manager. The pathToDriver argument is added to the class loader so that an external driver can be

      * loaded. Note, the pathToDriver can contain a semi-colon separated list of paths so any dependencies can be added

      * as needed. If a path in the pathToDriver argument is a directory all files in the directory are added to the

      * class path.

      *

      * @param className the fully qualified name of the desired class

      * @param pathToDriver the path to the JAR file containing the driver; note, this can be a semi-colon separated list

      * of paths

      * @return the loaded Driver

      * @throws DriverLoadException thrown if the driver cannot be loaded

      */

     public static Driver load(String className, String pathToDriver) throws DriverLoadException {

         final URLClassLoader parent = (URLClassLoader) ClassLoader.getSystemClassLoader();

         final List<URL> urls = new ArrayList<URL>();

         final String[] paths = pathToDriver.split(File.pathSeparator);

         for (String path : paths) {

             final File file = new File(path);

             if (file.isDirectory()) {

                 final File[] files = file.listFiles();

                 for (File f : files) {

                     try {

                         urls.add(f.toURI().toURL());

                     } catch (MalformedURLException ex) {

                         LOGGER.debug("Unable to load database driver '{}'; invalid path provided '{}'",

                             className, f.getAbsoluteFile(), ex);

                         throw new DriverLoadException("Unable to load database driver. Invalid path provided", ex);

                     }

                 }

             } else if (file.exists()) {

                 try {

                     urls.add(file.toURI().toURL());

                 } catch (MalformedURLException ex) {

                     LOGGER.debug("Unable to load database driver '{}'; invalid path provided '{}'",

                         className, file.getAbsoluteFile(), ex);

                     throw new DriverLoadException("Unable to load database driver. Invalid path provided", ex);

                 }

             }

         }

         final URLClassLoader loader = AccessController.doPrivileged(new PrivilegedAction<URLClassLoader>() {

             @Override

             public URLClassLoader run() {

                 return new URLClassLoader(urls.toArray(new URL[urls.size()]), parent);

             }

         });

         return load(className, loader);

     }

     /**

      * Loads the specified class using the supplied class loader and registers the driver with the driver manager.

      *

      * @param className the fully qualified name of the desired class

      * @param loader the class loader to use when loading the driver

      * @return the loaded Driver

      * @throws DriverLoadException thrown if the driver cannot be loaded

      */

     private static Driver load(String className, ClassLoader loader) throws DriverLoadException {

         try {

             final Class c = Class.forName(className, true, loader);

             //final Class c = loader.loadClass(className);

             final Driver driver = (Driver) c.newInstance();

             final Driver shim = new DriverShim(driver);

             //using the DriverShim to get around the fact that the DriverManager won't register a driver not in the base class path

             DriverManager.registerDriver(shim);

             return shim;

         } catch (ClassNotFoundException ex) {

             final String msg = String.format("Unable to load database driver '%s'", className);

             LOGGER.debug(msg, ex);

             throw new DriverLoadException(msg, ex);

         } catch (InstantiationException ex) {

             final String msg = String.format("Unable to load database driver '%s'", className);

             LOGGER.debug(msg, ex);

             throw new DriverLoadException(msg, ex);

         } catch (IllegalAccessException ex) {

             final String msg = String.format("Unable to load database driver '%s'", className);

             LOGGER.debug(msg, ex);

             throw new DriverLoadException(msg, ex);

         } catch (SQLException ex) {

             final String msg = String.format("Unable to load database driver '%s'", className);

             LOGGER.debug(msg, ex);

             throw new DriverLoadException(msg, ex);

         }

     }

 }