/*

  * 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) 2012 Jeremy Long. All Rights Reserved.

  */

 package org.owasp.dependencycheck.utils;

 import java.io.Closeable;

 import org.apache.commons.io.FilenameUtils;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import java.io.File;

 import java.io.IOException;

 import java.util.UUID;

 import org.apache.commons.lang3.SystemUtils;

 /**

  * A collection of utilities for processing information about files.

  *

  * @author Jeremy Long

  */

 public final class FileUtils {

     /**

      * The logger.

      */

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

     /**

      * Bit bucket for non-Windows systems

      */

     private static final String BIT_BUCKET_UNIX = "/dev/null";

     /**

      * Bit bucket for Windows systems (yes, only one 'L')

      */

     private static final String BIT_BUCKET_WIN = "NUL";

     /**

      * Private constructor for a utility class.

      */

     private FileUtils() {

     }

     /**

      * Returns the (lowercase) file extension for a specified file.

      *

      * @param fileName the file name to retrieve the file extension from.

      * @return the file extension.

      */

     public static String getFileExtension(String fileName) {

         final String fileExt = FilenameUtils.getExtension(fileName);

         return null == fileExt || fileExt.isEmpty() ? null : fileExt.toLowerCase();

     }

     /**

      * Deletes a file. If the File is a directory it will recursively delete the

      * contents.

      *

      * @param file the File to delete

      * @return true if the file was deleted successfully, otherwise false

      */

     public static boolean delete(File file) {

         final boolean success = org.apache.commons.io.FileUtils.deleteQuietly(file);

         if (!success) {

             LOGGER.debug("Failed to delete file: {}; attempting to delete on exit.", file.getPath());

             file.deleteOnExit();

         }

         return success;

     }

     /**

      * Creates a unique temporary directory in the given directory.

      *

      * @param base the base directory to create a temporary directory within

      * @return the temporary directory

      * @throws IOException thrown when a directory cannot be created within the

      * base directory

      */

     public static File createTempDirectory(File base) throws IOException {

         final File tempDir = new File(base, "dctemp" + UUID.randomUUID().toString());

         if (tempDir.exists()) {

             return createTempDirectory(base);

         }

         if (!tempDir.mkdirs()) {

             throw new IOException("Could not create temp directory `" + tempDir.getAbsolutePath() + "`");

         }

         return tempDir;

     }

     /**

      * Generates a new temporary file name that is guaranteed to be unique.

      *

      * @param prefix the prefix for the file name to generate

      * @param extension the extension of the generated file name

      * @return a temporary File

      * @throws java.io.IOException thrown if the temporary folder could not be

      * created

      */

     public static File getTempFile(String prefix, String extension) throws IOException {

         final File dir = Settings.getTempDirectory();

         final String tempFileName = String.format("%s%s.%s", prefix, UUID.randomUUID().toString(), extension);

         final File tempFile = new File(dir, tempFileName);

         if (tempFile.exists()) {

             return getTempFile(prefix, extension);

         }

         return tempFile;

     }

     /**

      * Return the bit bucket for the OS. '/dev/null' for Unix and 'NUL' for

      * Windows

      *

      * @return a String containing the bit bucket

      */

     public static String getBitBucket() {

         if (SystemUtils.IS_OS_WINDOWS) {

             return BIT_BUCKET_WIN;

         } else {

             return BIT_BUCKET_UNIX;

         }

     }

     /**

      * Close the given {@link Closeable} instance, ignoring nulls, and logging

      * any thrown {@link IOException}.

      *

      * @param closeable to be closed

      */

     public static void close(Closeable closeable) {

         if (null != closeable) {

             try {

                 closeable.close();

             } catch (IOException ex) {

                 LOGGER.trace("", ex);

             }

         }

     }

 }