Java tutorial
/* * Copyright 2011-2014 the original author or authors. * * 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 mintcoin.wallet.service; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.net.InetSocketAddress; import java.util.ArrayList; import java.util.Arrays; import java.util.Date; import java.util.EnumSet; import java.util.LinkedList; import java.util.List; import java.util.Set; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicBoolean; import java.util.concurrent.atomic.AtomicInteger; import java.util.concurrent.atomic.AtomicLong; import javax.annotation.CheckForNull; import javax.annotation.Nonnull; import javax.annotation.Nullable; import mintcoin.wallet.AddressBookProvider; import mintcoin.wallet.Configuration; import mintcoin.wallet.Constants; import mintcoin.wallet.WalletApplication; import mintcoin.wallet.WalletBalanceWidgetProvider; import mintcoin.wallet.service.BlockchainState.Impediment; import mintcoin.wallet.ui.WalletActivity; import mintcoin.wallet.util.CrashReporter; import mintcoin.wallet.util.ThrottlingWalletChangeListener; import mintcoin.wallet.util.WalletUtils; import org.bitcoinj.core.AbstractPeerEventListener; import org.bitcoinj.core.Address; import org.bitcoinj.core.Block; import org.bitcoinj.core.BlockChain; import org.bitcoinj.core.CheckpointManager; import org.bitcoinj.core.Coin; import org.bitcoinj.core.Peer; import org.bitcoinj.core.PeerEventListener; import org.bitcoinj.core.PeerGroup; import org.bitcoinj.core.Sha256Hash; import org.bitcoinj.core.StoredBlock; import org.bitcoinj.core.Transaction; import org.bitcoinj.core.TransactionConfidence.ConfidenceType; import org.bitcoinj.core.Wallet; import org.bitcoinj.core.WalletEventListener; import org.bitcoinj.net.discovery.DnsDiscovery; import org.bitcoinj.net.discovery.PeerDiscovery; import org.bitcoinj.net.discovery.PeerDiscoveryException; import org.bitcoinj.store.BlockStore; import org.bitcoinj.store.BlockStoreException; import org.bitcoinj.store.SPVBlockStore; import org.bitcoinj.utils.MonetaryFormat; import org.bitcoinj.utils.Threading; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import android.annotation.SuppressLint; import android.app.Notification; import android.app.NotificationManager; import android.app.PendingIntent; import android.content.BroadcastReceiver; import android.content.ComponentCallbacks2; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.content.SharedPreferences; import android.content.SharedPreferences.OnSharedPreferenceChangeListener; import android.net.ConnectivityManager; import android.net.Uri; import android.os.Binder; import android.os.Handler; import android.os.IBinder; import android.os.PowerManager; import android.os.PowerManager.WakeLock; import android.support.v4.content.LocalBroadcastManager; import android.text.format.DateUtils; import mintcoin.wallet.R; /** * @author Andreas Schildbach */ public class BlockchainServiceImpl extends android.app.Service implements BlockchainService { private WalletApplication application; private Configuration config; private BlockStore blockStore; private File blockChainFile; private BlockChain blockChain; @CheckForNull private PeerGroup peerGroup; private final Handler handler = new Handler(); private final Handler delayHandler = new Handler(); private WakeLock wakeLock; private PeerConnectivityListener peerConnectivityListener; private NotificationManager nm; private static final int NOTIFICATION_ID_CONNECTED = 0; private static final int NOTIFICATION_ID_COINS_RECEIVED = 1; private final Set<Impediment> impediments = EnumSet.noneOf(Impediment.class); private int notificationCount = 0; private Coin notificationAccumulatedAmount = Coin.ZERO; private final List<Address> notificationAddresses = new LinkedList<Address>(); private AtomicInteger transactionsReceived = new AtomicInteger(); private long serviceCreatedAt; private boolean resetBlockchainOnShutdown = false; private static final int MIN_COLLECT_HISTORY = 2; private static final int IDLE_BLOCK_TIMEOUT_MIN = 2; private static final int IDLE_TRANSACTION_TIMEOUT_MIN = 9; private static final int MAX_HISTORY_SIZE = Math.max(IDLE_TRANSACTION_TIMEOUT_MIN, IDLE_BLOCK_TIMEOUT_MIN); private static final long APPWIDGET_THROTTLE_MS = DateUtils.SECOND_IN_MILLIS; private static final long BLOCKCHAIN_STATE_BROADCAST_THROTTLE_MS = DateUtils.SECOND_IN_MILLIS; private static final Logger log = LoggerFactory.getLogger(BlockchainServiceImpl.class); private final WalletEventListener walletEventListener = new ThrottlingWalletChangeListener( APPWIDGET_THROTTLE_MS) { @Override public void onThrottledWalletChanged() { WalletBalanceWidgetProvider.updateWidgets(BlockchainServiceImpl.this, application.getWallet()); } @Override public void onCoinsReceived(final Wallet wallet, final Transaction tx, final Coin prevBalance, final Coin newBalance) { transactionsReceived.incrementAndGet(); final int bestChainHeight = blockChain.getBestChainHeight(); final Address from = WalletUtils.getFirstFromAddress(tx); final Coin amount = tx.getValue(wallet); final ConfidenceType confidenceType = tx.getConfidence().getConfidenceType(); handler.post(new Runnable() { @Override public void run() { final boolean isReceived = amount.signum() > 0; final boolean replaying = bestChainHeight < config.getBestChainHeightEver(); final boolean isReplayedTx = confidenceType == ConfidenceType.BUILDING && replaying; if (isReceived && !isReplayedTx) notifyCoinsReceived(from, amount); } }); } @Override public void onCoinsSent(final Wallet wallet, final Transaction tx, final Coin prevBalance, final Coin newBalance) { transactionsReceived.incrementAndGet(); } }; private void notifyCoinsReceived(@Nullable final Address from, @Nonnull final Coin amount) { if (notificationCount == 1) nm.cancel(NOTIFICATION_ID_COINS_RECEIVED); notificationCount++; notificationAccumulatedAmount = notificationAccumulatedAmount.add(amount); if (from != null && !notificationAddresses.contains(from)) notificationAddresses.add(from); final MonetaryFormat btcFormat = config.getFormat(); final String packageFlavor = application.applicationPackageFlavor(); final String msgSuffix = packageFlavor != null ? " [" + packageFlavor + "]" : ""; final String tickerMsg = getString(R.string.notification_coins_received_msg, btcFormat.format(amount)) + msgSuffix; final String msg = getString(R.string.notification_coins_received_msg, btcFormat.format(notificationAccumulatedAmount)) + msgSuffix; final StringBuilder text = new StringBuilder(); for (final Address address : notificationAddresses) { if (text.length() > 0) text.append(", "); final String addressStr = address.toString(); final String label = AddressBookProvider.resolveLabel(getApplicationContext(), addressStr); text.append(label != null ? label : addressStr); } final Notification.Builder notification = new Notification.Builder(this); notification.setSmallIcon(R.drawable.stat_notify_received); notification.setTicker(tickerMsg); notification.setContentTitle(msg); if (text.length() > 0) notification.setContentText(text); notification .setContentIntent(PendingIntent.getActivity(this, 0, new Intent(this, WalletActivity.class), 0)); notification.setNumber(notificationCount == 1 ? 0 : notificationCount); notification.setWhen(System.currentTimeMillis()); notification.setSound(Uri.parse("android.resource://" + getPackageName() + "/" + R.raw.coins_received)); nm.notify(NOTIFICATION_ID_COINS_RECEIVED, notification.getNotification()); } private final class PeerConnectivityListener extends AbstractPeerEventListener implements OnSharedPreferenceChangeListener { private int peerCount; private AtomicBoolean stopped = new AtomicBoolean(false); public PeerConnectivityListener() { config.registerOnSharedPreferenceChangeListener(this); } public void stop() { stopped.set(true); config.unregisterOnSharedPreferenceChangeListener(this); nm.cancel(NOTIFICATION_ID_CONNECTED); } @Override public void onPeerConnected(final Peer peer, final int peerCount) { this.peerCount = peerCount; changed(peerCount); } @Override public void onPeerDisconnected(final Peer peer, final int peerCount) { this.peerCount = peerCount; changed(peerCount); } @Override public void onSharedPreferenceChanged(final SharedPreferences sharedPreferences, final String key) { if (Configuration.PREFS_KEY_CONNECTIVITY_NOTIFICATION.equals(key)) changed(peerCount); } private void changed(final int numPeers) { if (stopped.get()) return; handler.post(new Runnable() { @Override public void run() { final boolean connectivityNotificationEnabled = config.getConnectivityNotificationEnabled(); if (!connectivityNotificationEnabled || numPeers == 0) { nm.cancel(NOTIFICATION_ID_CONNECTED); } else { final Notification.Builder notification = new Notification.Builder( BlockchainServiceImpl.this); notification.setSmallIcon(R.drawable.stat_sys_peers, numPeers > 4 ? 4 : numPeers); notification.setContentTitle(getString(R.string.app_name)); notification.setContentText(getString(R.string.notification_peers_connected_msg, numPeers)); notification.setContentIntent(PendingIntent.getActivity(BlockchainServiceImpl.this, 0, new Intent(BlockchainServiceImpl.this, WalletActivity.class), 0)); notification.setWhen(System.currentTimeMillis()); notification.setOngoing(true); nm.notify(NOTIFICATION_ID_CONNECTED, notification.getNotification()); } // send broadcast broadcastPeerState(numPeers); } }); } } private final PeerEventListener blockchainDownloadListener = new AbstractPeerEventListener() { private final AtomicLong lastMessageTime = new AtomicLong(0); @Override public void onBlocksDownloaded(final Peer peer, final Block block, final int blocksLeft) { config.maybeIncrementBestChainHeightEver(blockChain.getChainHead().getHeight()); delayHandler.removeCallbacksAndMessages(null); final long now = System.currentTimeMillis(); if (now - lastMessageTime.get() > BLOCKCHAIN_STATE_BROADCAST_THROTTLE_MS) delayHandler.post(runnable); else delayHandler.postDelayed(runnable, BLOCKCHAIN_STATE_BROADCAST_THROTTLE_MS); } private final Runnable runnable = new Runnable() { @Override public void run() { lastMessageTime.set(System.currentTimeMillis()); broadcastBlockchainState(); } }; }; private final BroadcastReceiver connectivityReceiver = new BroadcastReceiver() { @Override public void onReceive(final Context context, final Intent intent) { final String action = intent.getAction(); if (ConnectivityManager.CONNECTIVITY_ACTION.equals(action)) { final boolean hasConnectivity = !intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, false); log.info("network is " + (hasConnectivity ? "up" : "down")); if (hasConnectivity) impediments.remove(Impediment.NETWORK); else impediments.add(Impediment.NETWORK); check(); } else if (Intent.ACTION_DEVICE_STORAGE_LOW.equals(action)) { log.info("device storage low"); impediments.add(Impediment.STORAGE); check(); } else if (Intent.ACTION_DEVICE_STORAGE_OK.equals(action)) { log.info("device storage ok"); impediments.remove(Impediment.STORAGE); check(); } } @SuppressLint("Wakelock") private void check() { final Wallet wallet = application.getWallet(); if (impediments.isEmpty() && peerGroup == null) { log.debug("acquiring wakelock"); wakeLock.acquire(); // consistency check final int walletLastBlockSeenHeight = wallet.getLastBlockSeenHeight(); final int bestChainHeight = blockChain.getBestChainHeight(); if (walletLastBlockSeenHeight != -1 && walletLastBlockSeenHeight != bestChainHeight) { final String message = "wallet/blockchain out of sync: " + walletLastBlockSeenHeight + "/" + bestChainHeight; log.error(message); CrashReporter.saveBackgroundTrace(new RuntimeException(message), application.packageInfo()); } log.info("starting peergroup"); peerGroup = new PeerGroup(Constants.NETWORK_PARAMETERS, blockChain); peerGroup.setDownloadTxDependencies(false); // recursive implementation causes StackOverflowError peerGroup.addWallet(wallet); peerGroup.setUserAgent(Constants.USER_AGENT, application.packageInfo().versionName); peerGroup.addEventListener(peerConnectivityListener); final int maxConnectedPeers = application.maxConnectedPeers(); final String trustedPeerHost = config.getTrustedPeerHost(); final boolean hasTrustedPeer = !trustedPeerHost.isEmpty(); final boolean connectTrustedPeerOnly = hasTrustedPeer && config.getTrustedPeerOnly(); peerGroup.setMaxConnections(connectTrustedPeerOnly ? 1 : maxConnectedPeers); peerGroup.setConnectTimeoutMillis(Constants.PEER_TIMEOUT_MS); peerGroup.addPeerDiscovery(new PeerDiscovery() { private final PeerDiscovery normalPeerDiscovery = new DnsDiscovery( Constants.NETWORK_PARAMETERS); @Override public InetSocketAddress[] getPeers(final long timeoutValue, final TimeUnit timeoutUnit) throws PeerDiscoveryException { final List<InetSocketAddress> peers = new LinkedList<InetSocketAddress>(); boolean needsTrimPeersWorkaround = false; if (hasTrustedPeer) { log.info("trusted peer '" + trustedPeerHost + "'" + (connectTrustedPeerOnly ? " only" : "")); final InetSocketAddress addr = new InetSocketAddress(trustedPeerHost, Constants.NETWORK_PARAMETERS.getPort()); if (addr.getAddress() != null) { peers.add(addr); needsTrimPeersWorkaround = true; } } if (!connectTrustedPeerOnly) peers.addAll(Arrays.asList(normalPeerDiscovery.getPeers(timeoutValue, timeoutUnit))); // workaround because PeerGroup will shuffle peers if (needsTrimPeersWorkaround) while (peers.size() >= maxConnectedPeers) peers.remove(peers.size() - 1); return peers.toArray(new InetSocketAddress[0]); } @Override public void shutdown() { normalPeerDiscovery.shutdown(); } }); // start peergroup peerGroup.startAsync(); peerGroup.startBlockChainDownload(blockchainDownloadListener); } else if (!impediments.isEmpty() && peerGroup != null) { log.info("stopping peergroup"); peerGroup.removeEventListener(peerConnectivityListener); peerGroup.removeWallet(wallet); peerGroup.stopAsync(); peerGroup = null; log.debug("releasing wakelock"); wakeLock.release(); } broadcastBlockchainState(); } }; private final static class ActivityHistoryEntry { public final int numTransactionsReceived; public final int numBlocksDownloaded; public ActivityHistoryEntry(final int numTransactionsReceived, final int numBlocksDownloaded) { this.numTransactionsReceived = numTransactionsReceived; this.numBlocksDownloaded = numBlocksDownloaded; } @Override public String toString() { return numTransactionsReceived + "/" + numBlocksDownloaded; } } private final BroadcastReceiver tickReceiver = new BroadcastReceiver() { private int lastChainHeight = 0; private final List<ActivityHistoryEntry> activityHistory = new LinkedList<ActivityHistoryEntry>(); @Override public void onReceive(final Context context, final Intent intent) { final int chainHeight = blockChain.getBestChainHeight(); if (lastChainHeight > 0) { final int numBlocksDownloaded = chainHeight - lastChainHeight; final int numTransactionsReceived = transactionsReceived.getAndSet(0); // push history activityHistory.add(0, new ActivityHistoryEntry(numTransactionsReceived, numBlocksDownloaded)); // trim while (activityHistory.size() > MAX_HISTORY_SIZE) activityHistory.remove(activityHistory.size() - 1); // print final StringBuilder builder = new StringBuilder(); for (final ActivityHistoryEntry entry : activityHistory) { if (builder.length() > 0) builder.append(", "); builder.append(entry); } log.info("History of transactions/blocks: " + builder); // determine if block and transaction activity is idling boolean isIdle = false; if (activityHistory.size() >= MIN_COLLECT_HISTORY) { isIdle = true; for (int i = 0; i < activityHistory.size(); i++) { final ActivityHistoryEntry entry = activityHistory.get(i); final boolean blocksActive = entry.numBlocksDownloaded > 0 && i <= IDLE_BLOCK_TIMEOUT_MIN; final boolean transactionsActive = entry.numTransactionsReceived > 0 && i <= IDLE_TRANSACTION_TIMEOUT_MIN; if (blocksActive || transactionsActive) { isIdle = false; break; } } } // if idling, shutdown service if (isIdle) { log.info("idling detected, stopping service"); stopSelf(); } } lastChainHeight = chainHeight; } }; public class LocalBinder extends Binder { public BlockchainService getService() { return BlockchainServiceImpl.this; } } private final IBinder mBinder = new LocalBinder(); @Override public IBinder onBind(final Intent intent) { log.debug(".onBind()"); return mBinder; } @Override public boolean onUnbind(final Intent intent) { log.debug(".onUnbind()"); return super.onUnbind(intent); } @Override public void onCreate() { serviceCreatedAt = System.currentTimeMillis(); log.debug(".onCreate()"); super.onCreate(); nm = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE); final String lockName = getPackageName() + " blockchain sync"; final PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE); wakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, lockName); application = (WalletApplication) getApplication(); config = application.getConfiguration(); final Wallet wallet = application.getWallet(); peerConnectivityListener = new PeerConnectivityListener(); broadcastPeerState(0); blockChainFile = new File(getDir("blockstore", Context.MODE_PRIVATE), Constants.Files.BLOCKCHAIN_FILENAME); final boolean blockChainFileExists = blockChainFile.exists(); if (!blockChainFileExists) { log.info("blockchain does not exist, resetting wallet"); wallet.clearTransactions(0); wallet.setLastBlockSeenHeight(-1); // magic value wallet.setLastBlockSeenHash(null); } try { blockStore = new SPVBlockStore(Constants.NETWORK_PARAMETERS, blockChainFile); blockStore.getChainHead(); // detect corruptions as early as possible final long earliestKeyCreationTime = wallet.getEarliestKeyCreationTime(); if (!blockChainFileExists && earliestKeyCreationTime > 0) { try { final long start = System.currentTimeMillis(); final InputStream checkpointsInputStream = getAssets() .open(Constants.Files.CHECKPOINTS_FILENAME); CheckpointManager.checkpoint(Constants.NETWORK_PARAMETERS, checkpointsInputStream, blockStore, earliestKeyCreationTime); log.info("checkpoints loaded from '{}', took {}ms", Constants.Files.CHECKPOINTS_FILENAME, System.currentTimeMillis() - start); } catch (final IOException x) { log.error("problem reading checkpoints, continuing without", x); } } } catch (final BlockStoreException x) { blockChainFile.delete(); final String msg = "blockstore cannot be created"; log.error(msg, x); throw new Error(msg, x); } try { blockChain = new BlockChain(Constants.NETWORK_PARAMETERS, wallet, blockStore); } catch (final BlockStoreException x) { throw new Error("blockchain cannot be created", x); } final IntentFilter intentFilter = new IntentFilter(); intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION); intentFilter.addAction(Intent.ACTION_DEVICE_STORAGE_LOW); intentFilter.addAction(Intent.ACTION_DEVICE_STORAGE_OK); registerReceiver(connectivityReceiver, intentFilter); // implicitly start PeerGroup application.getWallet().addEventListener(walletEventListener, Threading.SAME_THREAD); registerReceiver(tickReceiver, new IntentFilter(Intent.ACTION_TIME_TICK)); } @Override public int onStartCommand(final Intent intent, final int flags, final int startId) { if (intent != null) { log.info("service start command: " + intent + (intent.hasExtra(Intent.EXTRA_ALARM_COUNT) ? " (alarm count: " + intent.getIntExtra(Intent.EXTRA_ALARM_COUNT, 0) + ")" : "")); final String action = intent.getAction(); if (BlockchainService.ACTION_CANCEL_COINS_RECEIVED.equals(action)) { notificationCount = 0; notificationAccumulatedAmount = Coin.ZERO; notificationAddresses.clear(); nm.cancel(NOTIFICATION_ID_COINS_RECEIVED); } else if (BlockchainService.ACTION_RESET_BLOCKCHAIN.equals(action)) { log.info("will remove blockchain on service shutdown"); resetBlockchainOnShutdown = true; stopSelf(); } else if (BlockchainService.ACTION_BROADCAST_TRANSACTION.equals(action)) { final Sha256Hash hash = new Sha256Hash( intent.getByteArrayExtra(BlockchainService.ACTION_BROADCAST_TRANSACTION_HASH)); final Transaction tx = application.getWallet().getTransaction(hash); if (peerGroup != null) { log.info("broadcasting transaction " + tx.getHashAsString()); peerGroup.broadcastTransaction(tx); } else { log.info("peergroup not available, not broadcasting transaction " + tx.getHashAsString()); } } } else { log.warn("service restart, although it was started as non-sticky"); } return START_NOT_STICKY; } @Override public void onDestroy() { log.debug(".onDestroy()"); WalletApplication.scheduleStartBlockchainService(this); unregisterReceiver(tickReceiver); application.getWallet().removeEventListener(walletEventListener); unregisterReceiver(connectivityReceiver); if (peerGroup != null) { peerGroup.removeEventListener(peerConnectivityListener); peerGroup.removeWallet(application.getWallet()); peerGroup.stopAsync(); peerGroup.awaitTerminated(); log.info("peergroup stopped"); } peerConnectivityListener.stop(); delayHandler.removeCallbacksAndMessages(null); try { blockStore.close(); } catch (final BlockStoreException x) { throw new RuntimeException(x); } application.saveWallet(); if (wakeLock.isHeld()) { log.debug("wakelock still held, releasing"); wakeLock.release(); } if (resetBlockchainOnShutdown) { log.info("removing blockchain"); blockChainFile.delete(); } super.onDestroy(); log.info( "service was up for " + ((System.currentTimeMillis() - serviceCreatedAt) / 1000 / 60) + " minutes"); } @Override public void onTrimMemory(final int level) { log.info("onTrimMemory({}) called", level); if (level >= ComponentCallbacks2.TRIM_MEMORY_BACKGROUND) { log.warn("low memory detected, stopping service"); stopSelf(); } } @Override public BlockchainState getBlockchainState() { final StoredBlock chainHead = blockChain.getChainHead(); final Date bestChainDate = chainHead.getHeader().getTime(); final int bestChainHeight = chainHead.getHeight(); final boolean replaying = chainHead.getHeight() < config.getBestChainHeightEver(); return new BlockchainState(bestChainDate, bestChainHeight, replaying, impediments); } @Override public List<Peer> getConnectedPeers() { if (peerGroup != null) return peerGroup.getConnectedPeers(); else return null; } @Override public List<StoredBlock> getRecentBlocks(final int maxBlocks) { final List<StoredBlock> blocks = new ArrayList<StoredBlock>(maxBlocks); try { StoredBlock block = blockChain.getChainHead(); while (block != null) { blocks.add(block); if (blocks.size() >= maxBlocks) break; block = block.getPrev(blockStore); } } catch (final BlockStoreException x) { // swallow } return blocks; } private void broadcastPeerState(final int numPeers) { final Intent broadcast = new Intent(ACTION_PEER_STATE); broadcast.setPackage(getPackageName()); broadcast.putExtra(ACTION_PEER_STATE_NUM_PEERS, numPeers); LocalBroadcastManager.getInstance(this).sendBroadcast(broadcast); } private void broadcastBlockchainState() { final Intent broadcast = new Intent(ACTION_BLOCKCHAIN_STATE); broadcast.setPackage(getPackageName()); getBlockchainState().putExtras(broadcast); LocalBroadcastManager.getInstance(this).sendBroadcast(broadcast); } }