Java tutorial
/** * Copyright (C) 2011-2012 Turn, Inc. * * Licensed 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 com.bittorrent.mpetazzoni.client; import com.bittorrent.mpetazzoni.bencode.InvalidBEncodingException; import com.bittorrent.mpetazzoni.common.Torrent; import com.bittorrent.mpetazzoni.client.peer.PeerActivityListener; import com.bittorrent.mpetazzoni.client.peer.SharingPeer; import com.bittorrent.mpetazzoni.client.storage.TorrentByteStorage; import com.bittorrent.mpetazzoni.client.storage.FileStorage; import com.bittorrent.mpetazzoni.client.storage.FileCollectionStorage; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.nio.ByteBuffer; import java.util.ArrayList; import java.util.BitSet; import java.util.Collections; import java.util.LinkedList; import java.util.List; import java.util.Random; import java.util.SortedSet; import java.util.TreeSet; import java.util.concurrent.Callable; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.Future; import org.apache.commons.io.FileUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * A torrent shared by the BitTorrent client. * * <p> * The {@link SharedTorrent} class extends the Torrent class with all the data * and logic required by the BitTorrent client implementation. * </p> * * <p> * <em>Note:</em> this implementation currently only supports single-file * torrents. * </p> * * @author mpetazzoni */ public class SharedTorrent extends Torrent implements PeerActivityListener { private static final Logger logger = LoggerFactory.getLogger(SharedTorrent.class); /** Randomly select the next piece to download from a peer from the * RAREST_PIECE_JITTER available from it. */ private static final int RAREST_PIECE_JITTER = 42; /** End-game trigger ratio. * * <p> * Eng-game behavior (requesting already requested pieces from available * and ready peers to try to speed-up the end of the transfer) will only be * enabled when the ratio of completed pieces over total pieces in the * torrent is over this value. * </p> */ private static final float ENG_GAME_COMPLETION_RATIO = 0.95f; private Random random; private boolean stop; private long uploaded; private long downloaded; private long left; private final TorrentByteStorage bucket; private final int pieceLength; private final ByteBuffer piecesHashes; private boolean initialized; private Piece[] pieces; private SortedSet<Piece> rarest; private BitSet completedPieces; private BitSet requestedPieces; private double maxUploadRate = 0.0; private double maxDownloadRate = 0.0; /** * Create a new shared torrent from a base Torrent object. * * <p> * This will recreate a SharedTorrent object from the provided Torrent * object's encoded meta-info data. * </p> * * @param torrent The Torrent object. * @param destDir The destination directory or location of the torrent * files. * @throws FileNotFoundException If the torrent file location or * destination directory does not exist and can't be created. * @throws IOException If the torrent file cannot be read or decoded. */ public SharedTorrent(Torrent torrent, File destDir) throws FileNotFoundException, IOException { this(torrent, destDir, false); } /** * Create a new shared torrent from a base Torrent object. * * <p> * This will recreate a SharedTorrent object from the provided Torrent * object's encoded meta-info data. * </p> * * @param torrent The Torrent object. * @param destDir The destination directory or location of the torrent * files. * @param seeder Whether we're a seeder for this torrent or not (disables * validation). * @throws FileNotFoundException If the torrent file location or * destination directory does not exist and can't be created. * @throws IOException If the torrent file cannot be read or decoded. */ public SharedTorrent(Torrent torrent, File destDir, boolean seeder) throws FileNotFoundException, IOException { this(torrent.getEncoded(), destDir, seeder); } /** * Create a new shared torrent from meta-info binary data. * * @param torrent The meta-info byte data. * @param destDir The destination directory or location of the torrent * files. * @throws FileNotFoundException If the torrent file location or * destination directory does not exist and can't be created. * @throws IOException If the torrent file cannot be read or decoded. */ public SharedTorrent(byte[] torrent, File destDir) throws FileNotFoundException, IOException { this(torrent, destDir, false); } /** * Create a new shared torrent from meta-info binary data. * * @param torrent The meta-info byte data. * @param parent The parent directory or location the torrent files. * @param seeder Whether we're a seeder for this torrent or not (disables * validation). * @throws FileNotFoundException If the torrent file location or * destination directory does not exist and can't be created. * @throws IOException If the torrent file cannot be read or decoded. */ public SharedTorrent(byte[] torrent, File parent, boolean seeder) throws FileNotFoundException, IOException { super(torrent, seeder); if (parent == null || !parent.isDirectory()) { throw new IllegalArgumentException("Invalid parent directory!"); } String parentPath = parent.getCanonicalPath(); try { this.pieceLength = this.decoded_info.get("piece length").getInt(); this.piecesHashes = ByteBuffer.wrap(this.decoded_info.get("pieces").getBytes()); if (this.piecesHashes.capacity() / Torrent.PIECE_HASH_SIZE * (long) this.pieceLength < this.getSize()) { throw new IllegalArgumentException( "Torrent size does not " + "match the number of pieces and the piece size!"); } } catch (InvalidBEncodingException ibee) { throw new IllegalArgumentException("Error reading torrent meta-info fields!"); } List<FileStorage> files = new LinkedList<FileStorage>(); long offset = 0L; for (Torrent.TorrentFile file : this.files) { File actual = new File(parent, file.file.getPath()); if (!actual.getCanonicalPath().startsWith(parentPath)) { throw new SecurityException("Torrent file path attempted " + "to break directory jail!"); } actual.getParentFile().mkdirs(); files.add(new FileStorage(actual, offset, file.size)); offset += file.size; } this.bucket = new FileCollectionStorage(files, this.getSize()); this.random = new Random(System.currentTimeMillis()); this.stop = false; this.uploaded = 0; this.downloaded = 0; this.left = this.getSize(); this.initialized = false; this.pieces = new Piece[0]; this.rarest = Collections.synchronizedSortedSet(new TreeSet<Piece>()); this.completedPieces = new BitSet(); this.requestedPieces = new BitSet(); } /** * Create a new shared torrent from the given torrent file. * * @param source The <code>.torrent</code> file to read the torrent * meta-info from. * @param parent The parent directory or location of the torrent files. * @throws IOException When the torrent file cannot be read or decoded. */ public static SharedTorrent fromFile(File source, File parent) throws IOException { byte[] data = FileUtils.readFileToByteArray(source); return new SharedTorrent(data, parent); } public double getMaxUploadRate() { return this.maxUploadRate; } /** * Set the maximum upload rate (in kB/second) for this * torrent. A setting of <= 0.0 disables rate limiting. * * @param rate The maximum upload rate */ public void setMaxUploadRate(double rate) { this.maxUploadRate = rate; } public double getMaxDownloadRate() { return this.maxDownloadRate; } /** * Set the maximum download rate (in kB/second) for this * torrent. A setting of <= 0.0 disables rate limiting. * * @param rate The maximum download rate */ public void setMaxDownloadRate(double rate) { this.maxDownloadRate = rate; } /** * Get the number of bytes uploaded for this torrent. */ public long getUploaded() { return this.uploaded; } /** * Get the number of bytes downloaded for this torrent. * * <p> * <b>Note:</b> this could be more than the torrent's length, and should * not be used to determine a completion percentage. * </p> */ public long getDownloaded() { return this.downloaded; } /** * Get the number of bytes left to download for this torrent. */ public long getLeft() { return this.left; } /** * Tells whether this torrent has been fully initialized yet. */ public boolean isInitialized() { return this.initialized; } /** * Stop the torrent initialization as soon as possible. */ public void stop() { this.stop = true; } /** * Build this torrent's pieces array. * * <p> * Hash and verify any potentially present local data and create this * torrent's pieces array from their respective hash provided in the * torrent meta-info. * </p> * * <p> * This function should be called soon after the constructor to initialize * the pieces array. * </p> */ public synchronized void init() throws InterruptedException, IOException { if (this.isInitialized()) { throw new IllegalStateException("Torrent was already initialized!"); } int threads = getHashingThreadsCount(); int nPieces = (int) (Math.ceil((double) this.getSize() / this.pieceLength)); int step = 10; this.pieces = new Piece[nPieces]; this.completedPieces = new BitSet(nPieces); this.piecesHashes.clear(); ExecutorService executor = Executors.newFixedThreadPool(threads); List<Future<Piece>> results = new LinkedList<Future<Piece>>(); try { logger.info("Analyzing local data for {} with {} threads ({} pieces)...", new Object[] { this.getName(), threads, nPieces }); for (int idx = 0; idx < nPieces; idx++) { byte[] hash = new byte[Torrent.PIECE_HASH_SIZE]; this.piecesHashes.get(hash); // The last piece may be shorter than the torrent's global piece // length. Let's make sure we get the right piece length in any // situation. long off = ((long) idx) * this.pieceLength; long len = Math.min(this.bucket.size() - off, this.pieceLength); this.pieces[idx] = new Piece(this.bucket, idx, off, len, hash, this.isSeeder()); Callable<Piece> hasher = new Piece.CallableHasher(this.pieces[idx]); results.add(executor.submit(hasher)); if (results.size() >= threads) { this.validatePieces(results); } if (idx / (float) nPieces * 100f > step) { logger.info(" ... {}% complete", step); step += 10; } } this.validatePieces(results); } finally { // Request orderly executor shutdown and wait for hashing tasks to // complete. executor.shutdown(); while (!executor.isTerminated()) { if (this.stop) { throw new InterruptedException("Torrent data analysis " + "interrupted."); } Thread.sleep(10); } } logger.debug("{}: we have {}/{} bytes ({}%) [{}/{} pieces].", new Object[] { this.getName(), (this.getSize() - this.left), this.getSize(), String.format("%.1f", (100f * (1f - this.left / (float) this.getSize()))), this.completedPieces.cardinality(), this.pieces.length }); this.initialized = true; } /** * Process the pieces enqueued for hash validation so far. * * @param results The list of {@link Future}s of pieces to process. */ private void validatePieces(List<Future<Piece>> results) throws IOException { try { for (Future<Piece> task : results) { Piece piece = task.get(); if (this.pieces[piece.getIndex()].isValid()) { this.completedPieces.set(piece.getIndex()); this.left -= piece.size(); } } results.clear(); } catch (Exception e) { throw new IOException("Error while hashing a torrent piece!", e); } } public synchronized void close() { try { this.bucket.close(); } catch (IOException ioe) { logger.error("Error closing torrent byte storage: {}", ioe.getMessage()); } } /** * Retrieve a piece object by index. * * @param index The index of the piece in this torrent. */ public Piece getPiece(int index) { if (this.pieces == null) { throw new IllegalStateException("Torrent not initialized yet."); } if (index >= this.pieces.length) { throw new IllegalArgumentException("Invalid piece index!"); } return this.pieces[index]; } /** * Get the number of pieces in this torrent. */ public int getPieceCount() { if (this.pieces == null) { throw new IllegalStateException("Torrent not initialized yet."); } return this.pieces.length; } /** * Return a copy of the bit field of available pieces for this torrent. * * <p> * Available pieces are pieces available in the swarm, and it does not * include our own pieces. * </p> */ public BitSet getAvailablePieces() { if (!this.isInitialized()) { throw new IllegalStateException("Torrent not yet initialized!"); } BitSet availablePieces = new BitSet(this.pieces.length); synchronized (this.pieces) { for (Piece piece : this.pieces) { if (piece.available()) { availablePieces.set(piece.getIndex()); } } } return availablePieces; } /** * Return a copy of the completed pieces bitset. */ public BitSet getCompletedPieces() { if (!this.isInitialized()) { throw new IllegalStateException("Torrent not yet initialized!"); } synchronized (this.completedPieces) { return (BitSet) this.completedPieces.clone(); } } /** * Return a copy of the requested pieces bitset. */ public BitSet getRequestedPieces() { if (!this.isInitialized()) { throw new IllegalStateException("Torrent not yet initialized!"); } synchronized (this.requestedPieces) { return (BitSet) this.requestedPieces.clone(); } } /** * Tells whether this torrent has been fully downloaded, or is fully * available locally. */ public synchronized boolean isComplete() { return this.pieces.length > 0 && this.completedPieces.cardinality() == this.pieces.length; } /** * Finalize the download of this torrent. * * <p> * This realizes the final, pre-seeding phase actions on this torrent, * which usually consists in putting the torrent data in their final form * and at their target location. * </p> * * @see TorrentByteStorage#finish */ public synchronized void finish() throws IOException { if (!this.isInitialized()) { throw new IllegalStateException("Torrent not yet initialized!"); } if (!this.isComplete()) { throw new IllegalStateException("Torrent download is not complete!"); } this.bucket.finish(); } public synchronized boolean isFinished() { return this.isComplete() && this.bucket.isFinished(); } /** * Return the completion percentage of this torrent. * * <p> * This is computed from the number of completed pieces divided by the * number of pieces in this torrent, times 100. * </p> */ public float getCompletion() { return this.isInitialized() ? (float) this.completedPieces.cardinality() / (float) this.pieces.length * 100.0f : 0.0f; } /** * Mark a piece as completed, decrementing the piece size in bytes from our * left bytes to download counter. */ public synchronized void markCompleted(Piece piece) { if (this.completedPieces.get(piece.getIndex())) { return; } // A completed piece means that's that much data left to download for // this torrent. this.left -= piece.size(); this.completedPieces.set(piece.getIndex()); } /** PeerActivityListener handler(s). *************************************/ /** * Peer choked handler. * * <p> * When a peer chokes, the requests made to it are canceled and we need to * mark the eventually piece we requested from it as available again for * download tentative from another peer. * </p> * * @param peer The peer that choked. */ @Override public synchronized void handlePeerChoked(SharingPeer peer) { Piece piece = peer.getRequestedPiece(); if (piece != null) { this.requestedPieces.set(piece.getIndex(), false); } logger.trace("Peer {} choked, we now have {} outstanding " + "request(s): {}", new Object[] { peer, this.requestedPieces.cardinality(), this.requestedPieces }); } /** * Peer ready handler. * * <p> * When a peer becomes ready to accept piece block requests, select a piece * to download and go for it. * </p> * * @param peer The peer that became ready. */ @Override public synchronized void handlePeerReady(SharingPeer peer) { BitSet interesting = peer.getAvailablePieces(); interesting.andNot(this.completedPieces); interesting.andNot(this.requestedPieces); logger.trace("Peer {} is ready and has {} interesting piece(s).", peer, interesting.cardinality()); // If we didn't find interesting pieces, we need to check if we're in // an end-game situation. If yes, we request an already requested piece // to try to speed up the end. if (interesting.cardinality() == 0) { interesting = peer.getAvailablePieces(); interesting.andNot(this.completedPieces); if (interesting.cardinality() == 0) { logger.trace("No interesting piece from {}!", peer); return; } if (this.completedPieces.cardinality() < ENG_GAME_COMPLETION_RATIO * this.pieces.length) { logger.trace("Not far along enough to warrant end-game mode."); return; } logger.trace("Possible end-game, we're about to request a piece " + "that was already requested from another peer."); } // Extract the RAREST_PIECE_JITTER rarest pieces from the interesting // pieces of this peer. ArrayList<Piece> choice = new ArrayList<Piece>(RAREST_PIECE_JITTER); synchronized (this.rarest) { for (Piece piece : this.rarest) { if (interesting.get(piece.getIndex())) { choice.add(piece); if (choice.size() >= RAREST_PIECE_JITTER) { break; } } } } Piece chosen = choice.get(this.random.nextInt(Math.min(choice.size(), RAREST_PIECE_JITTER))); this.requestedPieces.set(chosen.getIndex()); logger.trace("Requesting {} from {}, we now have {} " + "outstanding request(s): {}", new Object[] { chosen, peer, this.requestedPieces.cardinality(), this.requestedPieces }); peer.downloadPiece(chosen); } /** * Piece availability handler. * * <p> * Handle updates in piece availability from a peer's HAVE message. When * this happens, we need to mark that piece as available from the peer. * </p> * * @param peer The peer we got the update from. * @param piece The piece that became available. */ @Override public synchronized void handlePieceAvailability(SharingPeer peer, Piece piece) { // If we don't have this piece, tell the peer we're interested in // getting it from him. if (!this.completedPieces.get(piece.getIndex()) && !this.requestedPieces.get(piece.getIndex())) { peer.interesting(); } this.rarest.remove(piece); piece.seenAt(peer); this.rarest.add(piece); logger.trace("Peer {} contributes {} piece(s) [{}/{}/{}].", new Object[] { peer, peer.getAvailablePieces().cardinality(), this.completedPieces.cardinality(), this.getAvailablePieces().cardinality(), this.pieces.length }); if (!peer.isChoked() && peer.isInteresting() && !peer.isDownloading()) { this.handlePeerReady(peer); } } /** * Bit field availability handler. * * <p> * Handle updates in piece availability from a peer's BITFIELD message. * When this happens, we need to mark in all the pieces the peer has that * they can be reached through this peer, thus augmenting the global * availability of pieces. * </p> * * @param peer The peer we got the update from. * @param availablePieces The pieces availability bit field of the peer. */ @Override public synchronized void handleBitfieldAvailability(SharingPeer peer, BitSet availablePieces) { // Determine if the peer is interesting for us or not, and notify it. BitSet interesting = (BitSet) availablePieces.clone(); interesting.andNot(this.completedPieces); interesting.andNot(this.requestedPieces); if (interesting.cardinality() == 0) { peer.notInteresting(); } else { peer.interesting(); } // Record that the peer has all the pieces it told us it had. for (int i = availablePieces.nextSetBit(0); i >= 0; i = availablePieces.nextSetBit(i + 1)) { this.rarest.remove(this.pieces[i]); this.pieces[i].seenAt(peer); this.rarest.add(this.pieces[i]); } logger.trace("Peer {} contributes {} piece(s) ({} interesting) " + "[completed={}; available={}/{}].", new Object[] { peer, availablePieces.cardinality(), interesting.cardinality(), this.completedPieces.cardinality(), this.getAvailablePieces().cardinality(), this.pieces.length }); } /** * Piece upload completion handler. * * <p> * When a piece has been sent to a peer, we just record that we sent that * many bytes. If the piece is valid on the peer's side, it will send us a * HAVE message and we'll record that the piece is available on the peer at * that moment (see <code>handlePieceAvailability()</code>). * </p> * * @param peer The peer we got this piece from. * @param piece The piece in question. */ @Override public synchronized void handlePieceSent(SharingPeer peer, Piece piece) { logger.trace("Completed upload of {} to {}.", piece, peer); this.uploaded += piece.size(); } /** * Piece download completion handler. * * <p> * If the complete piece downloaded is valid, we can record in the torrent * completedPieces bit field that we know have this piece. * </p> * * @param peer The peer we got this piece from. * @param piece The piece in question. */ @Override public synchronized void handlePieceCompleted(SharingPeer peer, Piece piece) throws IOException { // Regardless of validity, record the number of bytes downloaded and // mark the piece as not requested anymore this.downloaded += piece.size(); this.requestedPieces.set(piece.getIndex(), false); logger.trace("We now have {} piece(s) and {} outstanding request(s): {}", new Object[] { this.completedPieces.cardinality(), this.requestedPieces.cardinality(), this.requestedPieces }); } /** * Peer disconnection handler. * * <p> * When a peer disconnects, we need to mark in all of the pieces it had * available that they can't be reached through this peer anymore. * </p> * * @param peer The peer we got this piece from. */ @Override public synchronized void handlePeerDisconnected(SharingPeer peer) { BitSet availablePieces = peer.getAvailablePieces(); for (int i = availablePieces.nextSetBit(0); i >= 0; i = availablePieces.nextSetBit(i + 1)) { this.rarest.remove(this.pieces[i]); this.pieces[i].noLongerAt(peer); this.rarest.add(this.pieces[i]); } Piece requested = peer.getRequestedPiece(); if (requested != null) { this.requestedPieces.set(requested.getIndex(), false); } logger.debug("Peer {} went away with {} piece(s) [completed={}; available={}/{}]", new Object[] { peer, availablePieces.cardinality(), this.completedPieces.cardinality(), this.getAvailablePieces().cardinality(), this.pieces.length }); logger.trace("We now have {} piece(s) and {} outstanding request(s): {}", new Object[] { this.completedPieces.cardinality(), this.requestedPieces.cardinality(), this.requestedPieces }); } @Override public synchronized void handleIOException(SharingPeer peer, IOException ioe) { /* Do nothing */ } }