UntarUtility.java

/**
 * Copyright 2015 StreamSets Inc.
 *
 * Licensed under 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.streamsets.datacollector.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.LinkedList;
import java.util.List;
import java.util.zip.GZIPInputStream;

import org.apache.commons.compress.archivers.ArchiveException;
import org.apache.commons.compress.archivers.ArchiveStreamFactory;
import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class UntarUtility {
  private static final Logger LOG = LoggerFactory.getLogger(UntarUtility.class);

  /**
   * Untar an input file into an output file. The output file is created in the output folder, having the same name as
   * the input file, minus the '.tar' extension.
   * @param inputFile the input .tar file
   * @param outputDir the output directory file.
   * @throws IOException
   * @throws FileNotFoundException
   * @return The {@link List} of {@link File}s with the untared content.
   * @throws ArchiveException
   */
  private static List<File> unTar(final File inputFile, final File outputDir) throws FileNotFoundException,
    IOException, ArchiveException {

    LOG.info(String.format("Untaring %s to dir %s.", inputFile.getAbsolutePath(), outputDir.getAbsolutePath()));

    final List<File> untaredFiles = new LinkedList<File>();
    final InputStream is = new FileInputStream(inputFile);
    final TarArchiveInputStream debInputStream =
      (TarArchiveInputStream) new ArchiveStreamFactory().createArchiveInputStream("tar", is);
    TarArchiveEntry entry = null;
    while ((entry = (TarArchiveEntry) debInputStream.getNextEntry()) != null) {
      final File outputFile = new File(outputDir, entry.getName());
      if (entry.isDirectory()) {
        LOG.info(String.format("Attempting to write output directory %s.", outputFile.getAbsolutePath()));
        if (!outputFile.exists()) {
          LOG.info(String.format("Attempting to create output directory %s.", outputFile.getAbsolutePath()));
          if (!outputFile.mkdirs()) {
            throw new IllegalStateException(
              String.format("Couldn't create directory %s.", outputFile.getAbsolutePath()));
          }
        }
      } else {
        LOG.info(String.format("Creating output file %s.", outputFile.getAbsolutePath()));
        final OutputStream outputFileStream = new FileOutputStream(outputFile);
        IOUtils.copy(debInputStream, outputFileStream);
        outputFileStream.close();
      }
      untaredFiles.add(outputFile);
    }
    debInputStream.close();

    return untaredFiles;
  }

  /**
   * Ungzip an input file into an output file.
   * <p>
   * The output file is created in the output folder, having the same name as the input file, minus the '.gz' extension.
   * @param inputFile the input .gz file
   * @param outputDir the output directory file.
   * @throws IOException
   * @throws FileNotFoundException
   * @return The {@File} with the ungzipped content.
   * @throws ArchiveException
   */
  public static List<File> unGzip(final File inputFile, final File outputDir) throws FileNotFoundException, IOException, ArchiveException {
    LOG.info(String.format("Ungzipping %s to dir %s.", inputFile.getAbsolutePath(), outputDir.getAbsolutePath()));

    final File outputFile = new File(outputDir, inputFile.getName().substring(0, inputFile.getName().length() - 3));

    final GZIPInputStream in = new GZIPInputStream(new FileInputStream(inputFile));
    final FileOutputStream out = new FileOutputStream(outputFile);

    IOUtils.copy(in, out);

    in.close();
    out.close();

    return unTar(outputFile, outputDir);
  }
}