// Taking the selected transaction receipts from consensus, CreateHeader removes bad
// transactions, adds necessary system transactions, emulate the transactions, calculate
// stateHash and finally returns a blockHeader
public BlockHeader?CreateHeader(
ulong index, IReadOnlyCollection <TransactionReceipt> receipts, ulong nonce, out TransactionReceipt[] receiptsTaken
)
{
Logger.LogTrace("CreateHeader");
if (_blockManager.GetHeight() >= index)
{
Logger.LogWarning("Block already produced");
receiptsTaken = new TransactionReceipt[] {};
return(null);
}
// we don't need to verify receipts here
// verfification will be done during emulation
// But we need to verify the hash as we map the receipts with its hash
// we skip the transactions with hash mismatch
receipts = receipts.Where(receipt =>
receipt.Transaction.FullHash(receipt.Signature, HardforkHeights.IsHardfork_9Active(index)).Equals(receipt.Hash)).ToList();
receipts = receipts.OrderBy(receipt => receipt, new ReceiptComparer())
.ToList();
var cycle = index / StakingContract.CycleDuration;
var indexInCycle = index % StakingContract.CycleDuration;
// try to add necessary system transactions at the end
if (cycle > 0 && indexInCycle == StakingContract.AttendanceDetectionDuration)
{
var txToAdd = DistributeCycleRewardsAndPenaltiesTxReceipt(index);
if (receipts.Select(x => x.Hash).Contains(txToAdd.Hash))
{
Logger.LogDebug("DistributeCycleRewardsAndPenaltiesTxReceipt is already in txPool");
}
else
{
receipts = receipts.Concat(new[] { txToAdd }).ToList();
}
}
else if (indexInCycle == StakingContract.VrfSubmissionPhaseDuration)
{
var txToAdd = FinishVrfLotteryTxReceipt(index);
if (receipts.Select(x => x.Hash).Contains(txToAdd.Hash))
{
Logger.LogDebug("FinishVrfLotteryTxReceipt is already in txPool");
}
else
{
receipts = receipts.Concat(new[] { txToAdd }).ToList();
}
}
else if (cycle > 0 && indexInCycle == 0)
{
var txToAdd = FinishCycleTxReceipt(index);
if (receipts.Select(x => x.Hash).Contains(txToAdd.Hash))
{
Logger.LogDebug("FinishCycleTxReceipt is already in txPool");
}
else
{
receipts = receipts.Concat(new[] { txToAdd }).ToList();
}
}
if (_blockManager.LatestBlock().Header.Index + 1 != index)
{
throw new InvalidOperationException(
$"Latest block is {_blockManager.LatestBlock().Header.Index} " +
$"with hash {_blockManager.LatestBlock().Hash.ToHex()}, " +
$"but we are trying to create block {index}");
}
var blockWithTransactions =
new BlockBuilder(_blockManager.LatestBlock().Header)
.WithTransactions(receipts)
.Build(nonce);
var(operatingError, removedTxs, stateHash, returnedTxs) =
_blockManager.Emulate(blockWithTransactions.Block, blockWithTransactions.Transactions);
var badReceipts = new HashSet <TransactionReceipt>(removedTxs.Concat(returnedTxs));
receiptsTaken = receipts.Where(receipt => !badReceipts.Contains(receipt)).ToArray();
blockWithTransactions = new BlockBuilder(_blockManager.LatestBlock().Header)
.WithTransactions(receiptsTaken)
.Build(nonce);
if (operatingError != OperatingError.Ok)
{
throw new InvalidOperationException($"Cannot assemble block: error {operatingError}");
}
return(new BlockHeader
{
Index = blockWithTransactions.Block.Header.Index,
MerkleRoot = blockWithTransactions.Block.Header.MerkleRoot,
Nonce = nonce,
PrevBlockHash = blockWithTransactions.Block.Header.PrevBlockHash,
StateHash = stateHash
});
}