org.apache.hadoop.fs.tar.TarFSUtils.java Source code

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Here is the source code for org.apache.hadoop.fs.tar.TarFSUtils.java

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/**
 * Licensed to 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 org.apache.hadoop.fs.tar;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URISyntaxException;

import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

/**
 * Common utilities for a TAR file system
 * @author joydip
 *
 */
public class TarFSUtils {

    public static FileSystem getHadoopFS(URI sample) throws URISyntaxException, IOException {

        return getHadoopFS(sample, new Configuration());
    }

    public static FileSystem getHadoopFS(URI sample, Configuration conf) throws IOException {

        return FileSystem.get(sample, conf);
    }

    @Deprecated
    public static FSDataInputStream openHadoopIS(FileSystem fs, URI file) throws IOException {

        Path f = new Path(file);
        return fs.open(f);
    }

    @Deprecated
    public static TarArchiveInputStream createTarInputStream(FileSystem fs, String tarFile, long offset)
            throws URISyntaxException, IOException {

        return createTarInputStream(fs, new Path(tarFile), offset);
    }

    public static TarArchiveInputStream createTarInputStream(FileSystem fs, Path tarPath, long offset)
            throws URISyntaxException, IOException {

        FSDataInputStream fsdis = fs.open(tarPath);
        fsdis.seek(offset);
        return new TarArchiveInputStream(new BufferedInputStream(fsdis));
    }

    @Deprecated
    public static TarArchiveInputStream createTarInputStream(InputStream in) throws IOException {
        return new TarArchiveInputStream(in);
    }

    private static byte[] getFirstFewBytes(InputStream in, int n) throws IOException {
        byte[] b = new byte[n];

        if (in.markSupported()) {
            in.mark(n);
            int bytesRead = in.read(b);
            in.reset();

            if (bytesRead < n)
                return null;
        } else
            throw new IOException("Mark must be supported");

        return b;
    }

    /**
     * Returns true if the file pointed by filename is a valid gunzip compressed file.
     * @param filename
     * @param in an inputstream to the file.
     * @return
     * @throws IOException
     */
    public static boolean isGZ(String filename, InputStream in) throws IOException {

        File f = new File(filename);
        if (!f.isFile())
            return false;

        if (filename.endsWith(".gz") || filename.endsWith(".tgz")) {
            byte[] b = getFirstFewBytes(in, 3);
            if (b == null)
                return false;

            if ((b[0] & 0xff) == 0x1f && (b[1] & 0xff) == 0x8b)
                return true;
            else
                return false;
        }

        else
            return false;

    }

}