TarBackupWriter.java

/*
 * @copyright 2013 Philip Warner
 * @license GNU General Public License
 * 
 * This file is part of Book Catalogue.
 *
 * Book Catalogue is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Book Catalogue is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Book Catalogue.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.eleybourn.bookcatalogue.backup.tar;

import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;

import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;

import android.content.SharedPreferences;

import com.eleybourn.bookcatalogue.backup.BackupContainer;
import com.eleybourn.bookcatalogue.backup.BackupInfo;
import com.eleybourn.bookcatalogue.backup.BackupUtils;
import com.eleybourn.bookcatalogue.backup.BackupWriterAbstract;
import com.eleybourn.bookcatalogue.booklist.BooklistStyle;
import com.eleybourn.bookcatalogue.database.SerializationUtils;

/**
 * Implementation of TAR-specific writer functions
 * 
 * @author pjw
 */
public class TarBackupWriter extends BackupWriterAbstract {
	private final TarBackupContainer mContainer;
	private TarArchiveOutputStream mOutput;
	private int mStyleCounter = 0;

	/**
	 * Constructor
	 * 
	 * @param container		Parent
	 * @throws IOException
	 */
	public TarBackupWriter(TarBackupContainer container) throws IOException {
		mContainer = container;
		// Open the archive for writing
		FileOutputStream out = new FileOutputStream(container.getFile());
		mOutput = new TarArchiveOutputStream(out);
	}

	/** 
	 * Accessor
	 */
	@Override
	public BackupContainer getContainer() {
		return mContainer;
	}


	/**
	 * Save the books export file
	 */
	@Override
	public void putBooks(File books) throws IOException {
		TarArchiveEntry entry = new TarArchiveEntry(new File(TarBackupContainer.BOOKS_FILE));
		entry.setModTime(books.lastModified());
		entry.setSize(books.length());
		mOutput.putArchiveEntry(entry);
		FileInputStream in = new FileInputStream(books);
		streamToArchive(in);
	}

	/**
	 * Save a cover file
	 */
	@Override
	public void putCoverFile(File source) throws IOException {
		TarArchiveEntry entry = new TarArchiveEntry(source.getName());
		entry.setModTime(source.lastModified());
		entry.setSize(source.length());
		mOutput.putArchiveEntry(entry);
		FileInputStream in = new FileInputStream(source);
		streamToArchive(in);
	}

	/**
	 * Save the INFO data
	 */
	@Override
	public void putInfo(BackupInfo info) throws IOException {
		ByteArrayOutputStream infoData = new ByteArrayOutputStream();
		BufferedWriter infoOut = new BufferedWriter(new OutputStreamWriter(infoData, TarBackupContainer.UTF8), TarBackupContainer.BUFFER_SIZE);
		BackupUtils.bundleToXml(infoOut, info.getBundle());
		infoOut.close();
		bytesToArchive(TarBackupContainer.INFO_FILE, infoData.toByteArray());
	}

	/**
	 * Save a Booklist style. We save them with increasing suffix counters to ensure uniqueness
	 */
	@Override
	public void putBooklistStyle(BooklistStyle style) throws IOException {
		// Turn the object into a byte array
		byte[] blob = SerializationUtils.serializeObject(style);
		mStyleCounter++;
		bytesToArchive(TarBackupContainer.STYLE_PREFIX + mStyleCounter, blob);
	}

	/**
	 * Save the preferences.
	 * 
	 * It would be nice to support groups (ie. more than one preference name), but ... we don't need it.
	 */
	@Override
	public void putPreferences(SharedPreferences prefs) throws IOException {
		// Turn the preferences into an XML file in a byte array
		ByteArrayOutputStream infoData = new ByteArrayOutputStream();
		BufferedWriter infoOut = new BufferedWriter(new OutputStreamWriter(infoData, TarBackupContainer.UTF8), TarBackupContainer.BUFFER_SIZE);
		BackupUtils.preferencesToXml(infoOut, prefs);
		infoOut.close();
		// Save them
		bytesToArchive(TarBackupContainer.PREFERENCES, infoData.toByteArray());
	}

	/**
	 * Utility routine to send the contents of a stream to the current archive entry
	 * 
	 * @param in			Stream to be saved
	 * 
	 * @throws IOException
	 */
	private void streamToArchive(InputStream in) throws IOException {
		try {
			byte[] buffer = new byte[TarBackupContainer.BUFFER_SIZE];
			while (true) {
				int cnt = in.read(buffer);
				if (cnt <= 0)
					break;
				mOutput.write(buffer, 0, cnt);
			}			
		} finally {
			try {
				in.close();
			} finally {
			}
			try {
				mOutput.closeArchiveEntry();		
			} finally {
			}
		}
		
	}

	/**
	 * Utility routine to save the passed bytes to an entry with the passed name
	 * 
	 * @param name		name of "file" in archive
	 * @param bytes		bytes to write
	 * 
	 * @throws IOException
	 */
	private void bytesToArchive(String name, byte[] bytes) throws IOException {
		TarArchiveEntry entry = new TarArchiveEntry(name);
		entry.setSize(bytes.length);
		mOutput.putArchiveEntry(entry);
		InputStream in = new ByteArrayInputStream(bytes);
		streamToArchive(in);
	}

	/**
	 * Cleanup
	 */
	@Override
	public void close() throws IOException {
		super.close();
		mOutput.close();
	}
}