/*

  * 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) 2013 Jeremy Long. All Rights Reserved.

  */

 package org.owasp.dependencycheck.utils;

 import java.io.BufferedInputStream;

 import java.io.BufferedOutputStream;

 import java.io.Closeable;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.FileOutputStream;

 import java.io.FilenameFilter;

 import java.io.IOException;

 import java.io.InputStream;

 import java.util.zip.ZipEntry;

 import java.util.zip.ZipInputStream;

 import org.apache.commons.compress.archivers.ArchiveEntry;

 import org.apache.commons.compress.archivers.ArchiveInputStream;

 import org.apache.commons.compress.archivers.zip.ZipArchiveInputStream;

 import org.owasp.dependencycheck.Engine;

 import org.owasp.dependencycheck.analyzer.exception.AnalysisException;

 import org.owasp.dependencycheck.analyzer.exception.ArchiveExtractionException;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 /**

  * Set of utilities to extract files from archives.

  *

  * @author Jeremy Long

  */

 public final class ExtractionUtil {

     /**

      * The logger.

      */

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

     /**

      * The buffer size to use when extracting files from the archive.

      */

     private static final int BUFFER_SIZE = 4096;

     /**

      * Private constructor for a utility class.

      */

     private ExtractionUtil() {

     }

     /**

      * Extracts the contents of an archive into the specified directory.

      *

      * @param archive an archive file such as a WAR or EAR

      * @param extractTo a directory to extract the contents to

      * @throws ExtractionException thrown if an exception occurs while extracting the files

      */

     public static void extractFiles(File archive, File extractTo) throws ExtractionException {

         extractFiles(archive, extractTo, null);

     }

     /**

      * Extracts the contents of an archive into the specified directory. The files are only extracted if they are supported by the

      * analyzers loaded into the specified engine. If the engine is specified as null then all files are extracted.

      *

      * @param archive an archive file such as a WAR or EAR

      * @param extractTo a directory to extract the contents to

      * @param engine the scanning engine

      * @throws ExtractionException thrown if there is an error extracting the files

      */

     public static void extractFiles(File archive, File extractTo, Engine engine) throws ExtractionException {

         if (archive == null || extractTo == null) {

             return;

         }

         FileInputStream fis = null;

         ZipInputStream zis = null;

         try {

             fis = new FileInputStream(archive);

         } catch (FileNotFoundException ex) {

             LOGGER.debug("", ex);

             throw new ExtractionException("Archive file was not found.", ex);

         }

         zis = new ZipInputStream(new BufferedInputStream(fis));

         ZipEntry entry;

         try {

             while ((entry = zis.getNextEntry()) != null) {

                 if (entry.isDirectory()) {

                     final File d = new File(extractTo, entry.getName());

                     if (!d.exists() && !d.mkdirs()) {

                         final String msg = String.format("Unable to create '%s'.", d.getAbsolutePath());

                         throw new ExtractionException(msg);

                     }

                 } else {

                     final File file = new File(extractTo, entry.getName());

                     if (engine == null || engine.accept(file)) {

                         BufferedOutputStream bos = null;

                         FileOutputStream fos;

                         try {

                             fos = new FileOutputStream(file);

                             bos = new BufferedOutputStream(fos, BUFFER_SIZE);

                             transferUsingBuffer(zis, bos);

                         } catch (FileNotFoundException ex) {

                             LOGGER.debug("", ex);

                             final String msg = String.format("Unable to find file '%s'.", file.getName());

                             throw new ExtractionException(msg, ex);

                         } catch (IOException ex) {

                             LOGGER.debug("", ex);

                             final String msg = String.format("IO Exception while parsing file '%s'.", file.getName());

                             throw new ExtractionException(msg, ex);

                         } finally {

                             closeStream(bos);

                         }

                     }

                 }

             }

         } catch (IOException ex) {

             final String msg = String.format("Exception reading archive '%s'.", archive.getName());

             LOGGER.debug("", ex);

             throw new ExtractionException(msg, ex);

         } finally {

             closeStream(zis);

         }

     }

     /**

      * Extracts the contents of an archive into the specified directory.

      *

      * @param archive an archive file such as a WAR or EAR

      * @param destination a directory to extract the contents to

      * @param filter determines which files get extracted

      * @throws ExtractionException thrown if the archive is not found

      */

     public static void extractFilesUsingFilter(File archive, File destination,

             FilenameFilter filter) throws ExtractionException {

         if (archive == null || destination == null) {

             return;

         }

         FileInputStream fis = null;

         try {

             fis = new FileInputStream(archive);

         } catch (FileNotFoundException ex) {

             LOGGER.debug("", ex);

             throw new ExtractionException("Archive file was not found.", ex);

         }

         try {

             extractArchive(new ZipArchiveInputStream(new BufferedInputStream(

                     fis)), destination, filter);

         } catch (ArchiveExtractionException ex) {

             LOGGER.warn("Exception extracting archive '{}'.", archive.getName());

             LOGGER.debug("", ex);

         } finally {

             try {

                 fis.close();

             } catch (IOException ex) {

                 LOGGER.debug("", ex);

             }

         }

     }

     /**

      * Extracts files from an archive.

      *

      * @param input the archive to extract files from

      * @param destination the location to write the files too

      * @param filter determines which files get extracted

      * @throws ArchiveExtractionException thrown if there is an exception extracting files from the archive

      */

     private static void extractArchive(ArchiveInputStream input,

             File destination, FilenameFilter filter)

             throws ArchiveExtractionException {

         ArchiveEntry entry;

         try {

             while ((entry = input.getNextEntry()) != null) {

                 if (entry.isDirectory()) {

                     final File dir = new File(destination, entry.getName());

                     if (!dir.exists()) {

                         if (!dir.mkdirs()) {

                             final String msg = String.format(

                                     "Unable to create directory '%s'.",

                                     dir.getAbsolutePath());

                             throw new AnalysisException(msg);

                         }

                     }

                 } else {

                     extractFile(input, destination, filter, entry);

                 }

             }

         } catch (IOException ex) {

             throw new ArchiveExtractionException(ex);

         } catch (Throwable ex) {

             throw new ArchiveExtractionException(ex);

         } finally {

             closeStream(input);

         }

     }

     /**

      * Extracts a file from an archive (input stream) and correctly builds the directory structure.

      *

      * @param input the archive input stream

      * @param destination where to write the file

      * @param filter the file filter to apply to the files being extracted

      * @param entry the entry from the archive to extract

      * @throws ExtractionException thrown if there is an error reading from the archive stream

      */

     private static void extractFile(ArchiveInputStream input, File destination,

             FilenameFilter filter, ArchiveEntry entry) throws ExtractionException {

         final File file = new File(destination, entry.getName());

         if (filter.accept(file.getParentFile(), file.getName())) {

             LOGGER.debug("Extracting '{}'",

                     file.getPath());

             BufferedOutputStream bos = null;

             FileOutputStream fos = null;

             try {

                 createParentFile(file);

                 fos = new FileOutputStream(file);

                 bos = new BufferedOutputStream(fos, BUFFER_SIZE);

                 transferUsingBuffer(input, bos);

             } catch (FileNotFoundException ex) {

                 LOGGER.debug("", ex);

                 final String msg = String.format("Unable to find file '%s'.",

                         file.getName());

                 throw new ExtractionException(msg, ex);

             } catch (IOException ex) {

                 LOGGER.debug("", ex);

                 final String msg = String

                         .format("IO Exception while parsing file '%s'.",

                                 file.getName());

                 throw new ExtractionException(msg, ex);

             } finally {

                 closeStream(bos);

                 closeStream(fos);

             }

         }

     }

     /**

      * Transfers data from one stream to another using a buffer.

      *

      * @param input the input stream

      * @param bos the output stream

      * @throws IOException thrown if there is an error reading/writing to the streams

      */

     private static void transferUsingBuffer(InputStream input,

             BufferedOutputStream bos) throws IOException {

         int count;

         final byte[] data = new byte[BUFFER_SIZE];

         while ((count = input.read(data, 0, BUFFER_SIZE)) != -1) {

             bos.write(data, 0, count);

         }

         bos.flush();

     }

     /**

      * Closes the stream.

      *

      * @param stream the stream to close

      */

     private static void closeStream(Closeable stream) {

         if (stream != null) {

             try {

                 stream.close();

             } catch (IOException ex) {

                 LOGGER.trace("", ex);

             }

         }

     }

     /**

      * Ensures the parent path is correctly created on disk so that the file can be extracted to the correct location.

      *

      * @param file the file path

      * @throws ExtractionException thrown if the parent paths could not be created

      */

     private static void createParentFile(final File file)

             throws ExtractionException {

         final File parent = file.getParentFile();

         if (!parent.isDirectory()) {

             if (!parent.mkdirs()) {

                 final String msg = String.format(

                         "Unable to build directory '%s'.",

                         parent.getAbsolutePath());

                 throw new ExtractionException(msg);

             }

         }

     }

 }