public override void ValidateTransaction(ChainedHeader chainedHeader, LoadedTx loadedTx)
{
if (ValidateTransactionAction == null)
base.ValidateTransaction(chainedHeader, loadedTx);
else
ValidateTransactionAction(chainedHeader, loadedTx);
}
//TODO
//public virtual void ValidateBlock(ChainedBlock chainedBlock, ChainStateBuilder chainStateBuilder)
//{
// //TODO
// if (BypassValidation)
// return;
// // calculate the next required target
// var requiredTarget = GetRequiredNextTarget(chainStateBuilder.Chain);
// // validate block's target against the required target
// var blockTarget = chainedBlock.Header.CalculateTarget();
// if (blockTarget > requiredTarget)
// {
// throw new ValidationException(chainedBlock.Hash, "Failing block {0} at height {1}: Block target {2} did not match required target of {3}".Format2(chainedBlock.Hash.ToHexNumberString(), chainedBlock.Height, blockTarget.ToHexNumberString(), requiredTarget.ToHexNumberString()));
// }
// // validate block's proof of work against its stated target
// if (chainedBlock.Hash > blockTarget || chainedBlock.Hash > requiredTarget)
// {
// throw new ValidationException(chainedBlock.Hash, "Failing block {0} at height {1}: Block did not match its own target of {2}".Format2(chainedBlock.Hash.ToHexNumberString(), chainedBlock.Height, blockTarget.ToHexNumberString()));
// }
// // ensure there is at least 1 transaction
// if (chainedBlock.Transactions.Length == 0)
// {
// throw new ValidationException(chainedBlock.Hash, "Failing block {0} at height {1}: Zero transactions present".Format2(chainedBlock.Hash.ToHexNumberString(), chainedBlock.Height));
// }
// //TODO apply real coinbase rule
// // https://github.com/bitcoin/bitcoin/blob/481d89979457d69da07edd99fba451fd42a47f5c/src/core.h#L219
// var coinbaseTx = chainedBlock.Transactions[0];
// // check that coinbase has only one input
// if (coinbaseTx.Inputs.Length != 1)
// {
// throw new ValidationException(chainedBlock.Hash, "Failing block {0} at height {1}: Coinbase transaction does not have exactly one input".Format2(chainedBlock.Hash.ToHexNumberString(), chainedBlock.Height));
// }
// var blockTxIndices = new Dictionary<UInt256, int>();
// for (var i = 0; i < chainedBlock.Transactions.Length; i++)
// blockTxIndices.Add(chainedBlock.Transactions[i].Hash, i);
// // validate transactions
// long blockUnspentValue = 0L;
// for (var txIndex = 1; txIndex < chainedBlock.Transactions.Length; txIndex++)
// {
// var tx = chainedBlock.Transactions[txIndex];
// long txUnspentValue;
// ValidateTransaction(chainedBlock, tx, txIndex, chainStateBuilder, out txUnspentValue, blockTxIndices);
// blockUnspentValue += txUnspentValue;
// }
// // calculate the expected reward in coinbase
// var expectedReward = (long)(50 * SATOSHI_PER_BTC);
// if (chainedBlock.Height / 210000 <= 32)
// expectedReward /= (long)Math.Pow(2, chainedBlock.Height / 210000);
// expectedReward += blockUnspentValue;
// // calculate the actual reward in coinbase
// var actualReward = 0L;
// foreach (var txOutput in coinbaseTx.Outputs)
// actualReward += (long)txOutput.Value;
// // ensure coinbase has correct reward
// if (actualReward > expectedReward)
// {
// throw new ValidationException(chainedBlock.Hash, "Failing block {0} at height {1}: Coinbase value is greater than reward + fees".Format2(chainedBlock.Hash.ToHexNumberString(), chainedBlock.Height));
// }
// // all validation has passed
//}
public virtual void ValidateTransaction(ChainedHeader chainedHeader, LoadedTx loadedTx)
{
var tx = loadedTx.Transaction;
var txIndex = loadedTx.TxIndex;
if (loadedTx.IsCoinbase)
{
// TODO coinbase tx validation
}
else
{
// verify spend amounts
var txInputValue = (UInt64)0;
var txOutputValue = (UInt64)0;
for (var inputIndex = 0; inputIndex < tx.Inputs.Length; inputIndex++)
{
var input = tx.Inputs[inputIndex];
var prevOutput = loadedTx.GetInputPrevTxOutput(inputIndex);
// add transactions previous value to unspent amount (used to calculate allowed coinbase reward)
txInputValue += prevOutput.Value;
}
for (var outputIndex = 0; outputIndex < tx.Outputs.Length; outputIndex++)
{
// remove transactions spend value from unspent amount (used to calculate allowed coinbase reward)
var output = tx.Outputs[outputIndex];
txOutputValue += output.Value;
}
// ensure that amount being output from transaction isn't greater than amount being input
if (txOutputValue > txInputValue)
{
throw new ValidationException(chainedHeader.Hash, $"Failing tx {tx.Hash}: Transaction output value is greater than input value");
}
// calculate fee value (unspent amount)
var feeValue = (long)(txInputValue - txOutputValue);
// sanity check
if (feeValue < 0)
{
throw new ValidationException(chainedHeader.Hash);
}
}
// all validation has passed
}