src/main/java/org/apache/commons/compress/archivers/ArchiveStreamFactory.java

/*
 * 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.commons.compress.archivers;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Locale;

import org.apache.commons.compress.archivers.ar.ArArchiveInputStream;
import org.apache.commons.compress.archivers.ar.ArArchiveOutputStream;
import org.apache.commons.compress.archivers.cpio.CpioArchiveInputStream;
import org.apache.commons.compress.archivers.cpio.CpioArchiveOutputStream;
import org.apache.commons.compress.archivers.jar.JarArchiveInputStream;
import org.apache.commons.compress.archivers.jar.JarArchiveOutputStream;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
import org.apache.commons.compress.archivers.zip.ZipArchiveInputStream;
import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;

/**
 * <p>Factory to create Archive[In|Out]putStreams from names or the first bytes of
 * the InputStream. In order add other implementations you should extend
 * ArchiveStreamFactory and override the appropriate methods (and call their
 * implementation from super of course).</p>
 * 
 * Compressing a ZIP-File:
 * 
 * <pre>
 * final OutputStream out = new FileOutputStream(output); 
 * ArchiveOutputStream os = new ArchiveStreamFactory().createArchiveOutputStream("zip", out);
 * 
 * os.putArchiveEntry(new ZipArchiveEntry("testdata/test1.xml"));
 * IOUtils.copy(new FileInputStream(file1), os);
 * os.closeArchiveEntry();
 *
 * os.putArchiveEntry(new ZipArchiveEntry("testdata/test2.xml"));
 * IOUtils.copy(new FileInputStream(file2), os);
 * os.closeArchiveEntry();
 * os.close();
 * </pre>
 * 
 * Decompressing a ZIP-File:
 * 
 * <pre>
 * final InputStream is = new FileInputStream(input); 
 * ArchiveInputStream in = new ArchiveStreamFactory().createArchiveInputStream("zip", is);
 * ZipArchiveEntry entry = (ZipArchiveEntry)in.getNextEntry();
 * OutputStream out = new FileOutputStream(new File(dir, entry.getName()));
 * IOUtils.copy(in, out);
 * out.close();
 * in.close();
 * </pre>
 * 
 * @Immutable
 */
public class ArchiveStreamFactory {

    // constants used for case- and locale-insensitive comparisons.

    private static final String AR_LC = "ar";
    private static final String CPIO_LC = "cpio";
    private static final String JAR_LC = "jar";
    private static final String TAR_LC = "tar";
    private static final String ZIP_LC = "zip";

    /**
     * Create an archive input stream from an archiver name and an input stream.
     * 
     * @param archiverName the archive name, i.e. "ar", "zip", "tar", "jar" or "cpio"
     * @param in the input stream
     * @return the archive input stream
     * @throws ArchiveException if the archiver name is not known
     * @throws IllegalArgumentException if the archiver name or stream is null
     */
    public ArchiveInputStream createArchiveInputStream(
            final String archiverName, final InputStream in)
            throws ArchiveException {
        
        if (archiverName == null) {
            throw new IllegalArgumentException("Archivername must not be null.");
        }
        
        if (in == null) {
        	throw new IllegalArgumentException("InputStream must not be null.");
        }

        String archiverNameToCompare = archiverName.toLowerCase(Locale.ENGLISH);

        if (AR_LC.equals(archiverNameToCompare)) {
            return new ArArchiveInputStream(in);
        }
        if (ZIP_LC.equals(archiverNameToCompare)) {
            return new ZipArchiveInputStream(in);
        }
        if (TAR_LC.equals(archiverNameToCompare)) {
            return new TarArchiveInputStream(in);
        }
        if (JAR_LC.equals(archiverNameToCompare)) {
            return new JarArchiveInputStream(in);
        }
        if (CPIO_LC.equals(archiverNameToCompare)) {
            return new CpioArchiveInputStream(in);
        }
        
        throw new ArchiveException("Archiver: " + archiverName + " not found.");
    }

    /**
     * Create an archive output stream from an archiver name and an input stream.
     * 
     * @param archiverName the archive name, i.e. "ar", "zip", "tar", "jar" or "cpio"
     * @param out the output stream
     * @return the archive output stream
     * @throws ArchiveException if the archiver name is not known
     * @throws IllegalArgumentException if the archiver name or stream is null
     */
    public ArchiveOutputStream createArchiveOutputStream(
            final String archiverName, final OutputStream out)
            throws ArchiveException {
        if (archiverName == null) {
            throw new IllegalArgumentException("Archivername must not be null.");
        }
        if (out == null) {
        	throw new IllegalArgumentException("OutputStream must not be null.");
        }

        String archiverNameToCompare = archiverName.toLowerCase(Locale.ENGLISH);

        if (AR_LC.equals(archiverNameToCompare)) {
            return new ArArchiveOutputStream(out);
        }
        if (ZIP_LC.equals(archiverNameToCompare)) {
            return new ZipArchiveOutputStream(out);
        }
        if (TAR_LC.equals(archiverNameToCompare)) {
            return new TarArchiveOutputStream(out);
        }
        if (JAR_LC.equals(archiverNameToCompare)) {
            return new JarArchiveOutputStream(out);
        }
        if (CPIO_LC.equals(archiverNameToCompare)) {
            return new CpioArchiveOutputStream(out);
        }
        throw new ArchiveException("Archiver: " + archiverName + " not found.");
    }

    /**
     * Create an archive input stream from an input stream, autodetecting
     * the archive type from the first few bytes of the stream. The InputStream
     * must support marks, like BufferedInputStream.
     * 
     * @param in the input stream
     * @return the archive input stream
     * @throws ArchiveException if the archiver name is not known
     * @throws IllegalArgumentException if the stream is null or does not support mark
     */
    public ArchiveInputStream createArchiveInputStream(final InputStream in)
            throws ArchiveException {
        if (in == null) {
            throw new IllegalArgumentException("Stream must not be null.");
        }

        if (!in.markSupported()) {
            throw new IllegalArgumentException("Mark is not supported.");
        }

        final byte[] signature = new byte[12];
        in.mark(signature.length);
        try {
            int signatureLength = in.read(signature);
            in.reset();
            if (ZipArchiveInputStream.matches(signature, signatureLength)) {
                return new ZipArchiveInputStream(in);
            } else if (JarArchiveInputStream.matches(signature, signatureLength)) {
                return new JarArchiveInputStream(in);
            } else if (ArArchiveInputStream.matches(signature, signatureLength)) {
                return new ArArchiveInputStream(in);
            } else if (CpioArchiveInputStream.matches(signature, signatureLength)) {
                return new CpioArchiveInputStream(in);
            }
            // Tar needs a bigger buffer to check the signature; read the first block
            final byte[] tarheader = new byte[512];
            in.mark(tarheader.length);
            signatureLength = in.read(tarheader);
            in.reset();
            if (TarArchiveInputStream.matches(tarheader, signatureLength)) {
                return new TarArchiveInputStream(in);
            }
        } catch (IOException e) {
            throw new ArchiveException("Could not use reset and mark operations.", e);
        }

        throw new ArchiveException("No Archiver found for the stream signature");
    }
}