public override void OnBlocksDownloaded(Peer peer, Block block, int blocksLeft)
{
if (blocksLeft == 0)
{
DoneDownload();
_done.Release();
}
if (blocksLeft < 0 || _originalBlocksLeft <= 0)
return;
var pct = 100.0 - (100.0*(blocksLeft/(double) _originalBlocksLeft));
if ((int) pct != _lastPercent)
{
Progress(pct, UnixTime.FromUnixTime(block.TimeSeconds*1000));
_lastPercent = (int) pct;
}
}
/// <summary>
/// Creates a new StoredBlock, calculating the additional fields by adding to the values in this block.
/// </summary>
/// <exception cref="VerificationException"/>
public StoredBlock Build(Block block)
{
// Stored blocks track total work done in this chain, because the canonical chain is the one that represents
// the largest amount of work done not the tallest.
var chainWork = _chainWork.Add(block.GetWork());
var height = _height + 1;
return new StoredBlock(block.CloneAsHeader(), chainWork, height);
}
/// <summary>
/// Returns a solved block that builds on top of this one. This exists for unit tests.
/// </summary>
internal Block CreateNextBlock(Address to, uint time)
{
var b = new Block(Params);
b.DifficultyTarget = _difficultyTarget;
b.AddCoinbaseTransaction(_emptyBytes);
// Add a transaction paying 50 coins to the "to" address.
var t = new Transaction(Params);
t.AddOutput(new TransactionOutput(Params, t, Utils.ToNanoCoins(50, 0), to));
// The input does not really need to be a valid signature, as long as it has the right general form.
var input = new TransactionInput(Params, t, Script.CreateInputScript(_emptyBytes, _emptyBytes));
// Importantly the outpoint hash cannot be zero as that's how we detect a coinbase transaction in isolation
// but it must be unique to avoid 'different' transactions looking the same.
var counter = new byte[32];
counter[0] = (byte) _txCounter++;
input.Outpoint.Hash = new Sha256Hash(counter);
t.AddInput(input);
b.AddTransaction(t);
b.PrevBlockHash = Hash;
b.TimeSeconds = time;
b.Solve();
b.VerifyHeader();
return b;
}
public StoredBlock(Block header, BigInteger chainWork, uint height)
{
_header = header;
_chainWork = chainWork;
_height = height;
}
/// <summary>
/// Returns a copy of the block, but without any transactions.
/// </summary>
public Block CloneAsHeader()
{
var block = new Block(Params);
block._nonce = _nonce;
block._prevBlockHash = _prevBlockHash.Duplicate();
block._merkleRoot = MerkleRoot.Duplicate();
block._version = _version;
block._time = _time;
block._difficultyTarget = _difficultyTarget;
block.Transactions = null;
block._hash = Hash.Duplicate();
return block;
}
/// <summary>
/// For the transactions in the given block, update the txToWalletMap such that each wallet maps to a list of
/// transactions for which it is relevant.
/// </summary>
/// <exception cref="VerificationException"/>
private void ScanTransactions(Block block, IDictionary<Wallet, List<Transaction>> walletToTxMap)
{
foreach (var tx in block.Transactions)
{
try
{
foreach (var wallet in _wallets)
{
var shouldReceive = false;
foreach (var output in tx.Outputs)
{
// TODO: Handle more types of outputs, not just regular to address outputs.
if (output.ScriptPubKey.IsSentToIp) continue;
// This is not thread safe as a key could be removed between the call to isMine and receive.
if (output.IsMine(wallet))
{
shouldReceive = true;
break;
}
}
// Coinbase transactions don't have anything useful in their inputs (as they create coins out of thin air).
if (!shouldReceive && !tx.IsCoinBase)
{
foreach (var i in tx.Inputs)
{
var pubkey = i.ScriptSig.PubKey;
// This is not thread safe as a key could be removed between the call to isPubKeyMine and receive.
if (wallet.IsPubKeyMine(pubkey))
{
shouldReceive = true;
}
}
}
if (!shouldReceive) continue;
List<Transaction> txList;
if (!walletToTxMap.TryGetValue(wallet, out txList))
{
txList = new List<Transaction>();
walletToTxMap[wallet] = txList;
}
txList.Add(tx);
}
}
catch (ScriptException e)
{
// We don't want scripts we don't understand to break the block chain so just note that this tx was
// not scanned here and continue.
_log.Warn("Failed to parse a script: " + e);
}
}
}
/// <exception cref="BlockStoreException"/>
/// <exception cref="VerificationException"/>
/// <exception cref="ScriptException"/>
private bool Add(Block block, bool tryConnecting)
{
lock (this)
{
if (Environment.TickCount - _statsLastTime > 1000)
{
// More than a second passed since last stats logging.
_log.InfoFormat("{0} blocks per second", _statsBlocksAdded);
_statsLastTime = Environment.TickCount;
_statsBlocksAdded = 0;
}
// We check only the chain head for double adds here to avoid potentially expensive block chain misses.
if (block.Equals(_chainHead.Header))
{
// Duplicate add of the block at the top of the chain, can be a natural artifact of the download process.
return true;
}
// Does this block contain any transactions we might care about? Check this up front before verifying the
// blocks validity so we can skip the merkle root verification if the contents aren't interesting. This saves
// a lot of time for big blocks.
var contentsImportant = false;
var walletToTxMap = new Dictionary<Wallet, List<Transaction>>();
if (block.Transactions != null)
{
ScanTransactions(block, walletToTxMap);
contentsImportant = walletToTxMap.Count > 0;
}
// Prove the block is internally valid: hash is lower than target, etc. This only checks the block contents
// if there is a tx sending or receiving coins using an address in one of our wallets. And those transactions
// are only lightly verified: presence in a valid connecting block is taken as proof of validity. See the
// article here for more details: http://code.google.com/p/bitcoinj/wiki/SecurityModel
try
{
block.VerifyHeader();
if (contentsImportant)
block.VerifyTransactions();
}
catch (VerificationException e)
{
_log.Error("Failed to verify block:", e);
_log.Error(block.HashAsString);
throw;
}
// Try linking it to a place in the currently known blocks.
var storedPrev = _blockStore.Get(block.PrevBlockHash);
if (storedPrev == null)
{
// We can't find the previous block. Probably we are still in the process of downloading the chain and a
// block was solved whilst we were doing it. We put it to one side and try to connect it later when we
// have more blocks.
_log.WarnFormat("Block does not connect: {0}", block.HashAsString);
_unconnectedBlocks.Add(block);
return false;
}
// It connects to somewhere on the chain. Not necessarily the top of the best known chain.
//
// Create a new StoredBlock from this block. It will throw away the transaction data so when block goes
// out of scope we will reclaim the used memory.
var newStoredBlock = storedPrev.Build(block);
CheckDifficultyTransitions(storedPrev, newStoredBlock);
_blockStore.Put(newStoredBlock);
ConnectBlock(newStoredBlock, storedPrev, walletToTxMap);
if (tryConnecting)
TryConnectingUnconnected();
_statsBlocksAdded++;
return true;
}
}
/// <summary>
/// Processes a received block and tries to add it to the chain. If there's something wrong with the block an
/// exception is thrown. If the block is OK but cannot be connected to the chain at this time, returns false.
/// If the block can be connected to the chain, returns true.
/// </summary>
/// <exception cref="VerificationException"/>
/// <exception cref="ScriptException"/>
public bool Add(Block block)
{
lock (this)
{
return Add(block, true);
}
}
private static Block CreateGenesis(NetworkParameters n)
{
var genesisBlock = new Block(n);
var t = new Transaction(n);
// A script containing the difficulty bits and the following message:
//
// "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"
var bytes = Hex.Decode("04ffff001d0104455468652054696d65732030332f4a616e2f32303039204368616e63656c6c6f72206f6e206272696e6b206f66207365636f6e64206261696c6f757420666f722062616e6b73");
t.AddInput(new TransactionInput(n, t, bytes));
using (var scriptPubKeyBytes = new MemoryStream())
{
Script.WriteBytes(scriptPubKeyBytes, Hex.Decode("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5f"));
scriptPubKeyBytes.Write(Script.OpCheckSig);
t.AddOutput(new TransactionOutput(n, t, scriptPubKeyBytes.ToArray()));
}
genesisBlock.AddTransaction(t);
return genesisBlock;
}