PackTar.java

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package org.gffs.compression;
 
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Iterator;
 
import org.apache.commons.compress.archivers.ArchiveEntry;
import org.apache.commons.compress.archivers.ArchiveOutputStream;
import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;
import org.apache.commons.compress.compressors.gzip.GzipCompressorOutputStream;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.filefilter.IOFileFilter;
import org.apache.commons.io.filefilter.TrueFileFilter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
 
public class PackTar
{
  static private Log _logger = LogFactory.getLog(PackTar.class);
 
  public static String stripOutPrefix(String prefix, String longName) throws IOException
  {
    int indy = longName.indexOf(prefix, 0);
    if (indy < 0)
      throw new IOException("failure to find prefix in string, prefix=" + prefix + " and string=" + longName);
    return longName.substring(indy + prefix.length());
  }
 
  public static void compressArchive(ArchiveOutputStream tarOut, String prefix, File source) throws IOException
  {
    _logger.debug("entered into compress archive on source " + source + " prefix " + prefix + " and tarout " + tarOut);
 
    if (!source.exists()) {
      // Don't unpack into an existing directory.
      String msg = "Directory " + source.getAbsolutePath() + " doesn't exist yet. Cannot pack.";
      _logger.error(msg);
      throw new IOException(msg);
    }
 
    // traverse the whole tree of the directory (or just write this directly if it's a file).
    if (source.isFile()) {
      String choppedName = stripOutPrefix(prefix, source.getPath());
      if (_logger.isDebugEnabled())
        _logger.debug("adding a file to the archive (chopped): " + choppedName);
      ArchiveEntry f = tarOut.createArchiveEntry(source, choppedName);
      tarOut.putArchiveEntry(f);
      IOUtils.copy(new FileInputStream(source), tarOut);
      tarOut.closeArchiveEntry();
    } else if (source.isDirectory()) {
      // traverse the directory tree at just this height and add everything recursively.
 
      if (_logger.isDebugEnabled())
        _logger.debug("iterating over a directory to add its contents to the archive: " + source);
 
      Iterator<File> spidey = FileUtils.iterateFiles(source, new IOFileFilter()
      {
        @Override
        public boolean accept(File arg0)
        {
          return true;
        }
 
        @Override
        public boolean accept(File arg0, String arg1)
        {
          return true;
        }
      }, TrueFileFilter.INSTANCE);
 
      File item = null;
      while (spidey.hasNext()) {
        item = spidey.next();
 
        if (_logger.isTraceEnabled())
          _logger.debug("recursing on item: " + item);
 
        compressArchive(tarOut, prefix, item);
      }
    } else {
      String msg = "source is not a file or directory although it exists.  unknown how to process.";
      _logger.error(msg);
      throw new IOException(msg);
    }
 
  }
 
  public static String findAppropriatePrefix(String toChop)
  {
    if (toChop.endsWith("/"))
      return toChop; // already ready.
    else
      return toChop + "/"; // add a slash on the end.
  }
 
  public synchronized static void compressTarGZ(File tarFile, File dest) throws IOException
  {
    TarArchiveOutputStream tarOut = new TarArchiveOutputStream(new GzipCompressorOutputStream(new FileOutputStream(tarFile)));
    compressArchive(tarOut, findAppropriatePrefix(dest.getPath()), dest);
    tarOut.close();
  }
 
  public synchronized static void compressTar(File tarFile, File dest) throws IOException
  {
    TarArchiveOutputStream tarOut = new TarArchiveOutputStream(new FileOutputStream(tarFile));
    compressArchive(tarOut, findAppropriatePrefix(dest.getPath()), dest);
    tarOut.close();
  }
 
  public synchronized static void compressZip(File zipFile, File dest) throws IOException
  {
    ZipArchiveOutputStream tarOut = new ZipArchiveOutputStream(new FileOutputStream(zipFile));
    compressArchive(tarOut, findAppropriatePrefix(dest.getPath()), dest);
    tarOut.close();
  }
 
  static public void main(String[] args) throws Throwable
  {
    // future: could use our cool code above to handle any archive type they pass.
    if (args.length != 2) {
      System.err.println("USAGE: PackTar {tar.gz file} {source location}");
      System.exit(1);
    }
 
    try {
      PackTar.compressTarGZ(new File(args[0]), new File(args[1]));
    } catch (Throwable t) {
      _logger.error("failed to compress tar file " + args[0] + " from " + args[1]);
      System.exit(1);
    }
 
    System.out.println("successfully compressed archive file " + args[0] + " from " + args[1]);
  }
 
}