/*
* Syncany, www.syncany.org
* Copyright (C) 2011-2014 Philipp C. Heckel <philipp.heckel@gmail.com>
*
* This program 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.syncany.operations;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.commons.io.IOUtils;
import org.syncany.config.Config;
import org.syncany.config.LocalEventBus;
import org.syncany.database.MultiChunkEntry.MultiChunkId;
import org.syncany.operations.daemon.messages.DownDownloadFileSyncExternalEvent;
import org.syncany.plugins.transfer.StorageException;
import org.syncany.plugins.transfer.TransferManager;
import org.syncany.plugins.transfer.files.MultichunkRemoteFile;
/**
* The downloader uses a {@link TransferManager} to download a given set of multichunks,
* decrypt them and store them in the local cache folder.
*
* @author Philipp C. Heckel <philipp.heckel@gmail.com>
*/
public class Downloader {
private static final Logger logger = Logger.getLogger(Downloader.class.getSimpleName());
private Config config;
private TransferManager transferManager;
private LocalEventBus eventBus;
public Downloader(Config config, TransferManager transferManager) {
this.config = config;
this.transferManager = transferManager;
this.eventBus = LocalEventBus.getInstance();
}
/**
* Downloads the given multichunks from the remote storage and decrypts them
* to the local cache folder.
*/
public void downloadAndDecryptMultiChunks(Set<MultiChunkId> unknownMultiChunkIds) throws StorageException, IOException {
logger.log(Level.INFO, "Downloading and extracting multichunks ...");
int multiChunkNumber = 0;
for (MultiChunkId multiChunkId : unknownMultiChunkIds) {
File localEncryptedMultiChunkFile = config.getCache().getEncryptedMultiChunkFile(multiChunkId);
File localDecryptedMultiChunkFile = config.getCache().getDecryptedMultiChunkFile(multiChunkId);
MultichunkRemoteFile remoteMultiChunkFile = new MultichunkRemoteFile(multiChunkId);
multiChunkNumber++;
if (localDecryptedMultiChunkFile.exists()) {
logger.log(Level.INFO, " + Decrypted multichunk exists locally " + multiChunkId + ". No need to download it!");
}
else {
eventBus.post(new DownDownloadFileSyncExternalEvent(config.getLocalDir().getAbsolutePath(), "multichunk", multiChunkNumber,
unknownMultiChunkIds.size()));
logger.log(Level.INFO, " + Downloading multichunk " + multiChunkId + " ...");
transferManager.download(remoteMultiChunkFile, localEncryptedMultiChunkFile);
try {
logger.log(Level.INFO, " + Decrypting multichunk " + multiChunkId + " ...");
InputStream multiChunkInputStream = config.getTransformer().createInputStream(new FileInputStream(localEncryptedMultiChunkFile));
OutputStream decryptedMultiChunkOutputStream = new FileOutputStream(localDecryptedMultiChunkFile);
IOUtils.copy(multiChunkInputStream, decryptedMultiChunkOutputStream);
decryptedMultiChunkOutputStream.close();
multiChunkInputStream.close();
}
catch (IOException e) {
// Security: Deleting the multichunk if the decryption/extraction failed is important!
// If it is not deleted, the partially decrypted multichunk will reside in the
// local cache and the next 'down' will try to use it. If this is the only
// multichunk that has been tampered with, other changes might be applied to the
// file system! See https://github.com/syncany/syncany/issues/59#issuecomment-55154793
logger.log(Level.FINE, " -> FAILED: Decryption/extraction of multichunk failed, deleting " + multiChunkId + " ...");
localDecryptedMultiChunkFile.delete();
throw new IOException("Decryption/extraction of multichunk " + multiChunkId
+ " failed. The multichunk might have been tampered with!", e);
}
finally {
logger.log(Level.FINE, " + Locally deleting multichunk " + multiChunkId + " ...");
localEncryptedMultiChunkFile.delete();
}
}
}
transferManager.disconnect();
}
}