/// <summary>
/// Checks and computes stake.
/// </summary>
/// <param name="context">Context that contains variety of information regarding blocks validation and execution.</param>
/// <exception cref="ConsensusErrors.PrevStakeNull">Thrown if previous stake is not found.</exception>
/// <exception cref="ConsensusErrors.SetStakeEntropyBitFailed">Thrown if failed to set stake entropy bit.</exception>
private void CheckAndComputeStake(RuleContext context)
{
this.logger.LogTrace("()");
ChainedBlock chainedBlock = context.BlockValidationContext.ChainedBlock;
Block block = context.BlockValidationContext.Block;
BlockStake blockStake = context.Stake.BlockStake;
// Verify hash target and signature of coinstake tx.
if (BlockStake.IsProofOfStake(block))
{
ChainedBlock prevChainedBlock = chainedBlock.Previous;
BlockStake prevBlockStake = this.stakeChain.Get(prevChainedBlock.HashBlock);
if (prevBlockStake == null)
{
ConsensusErrors.PrevStakeNull.Throw();
}
// Only do proof of stake validation for blocks that are after the assumevalid block or after the last checkpoint.
if (!context.SkipValidation)
{
this.StakeValidator.CheckProofOfStake(context.Stake, prevChainedBlock, prevBlockStake, block.Transactions[1], chainedBlock.Header.Bits.ToCompact());
}
else
{
this.logger.LogTrace("POS validation skipped for block at height {0}.", chainedBlock.Height);
}
}
// PoW is checked in CheckBlock().
if (BlockStake.IsProofOfWork(block))
{
context.Stake.HashProofOfStake = chainedBlock.Header.GetPoWHash();
}
// Compute stake entropy bit for stake modifier.
if (!blockStake.SetStakeEntropyBit(blockStake.GetStakeEntropyBit()))
{
this.logger.LogTrace("(-)[STAKE_ENTROPY_BIT_FAIL]");
ConsensusErrors.SetStakeEntropyBitFailed.Throw();
}
// Record proof hash value.
blockStake.HashProof = context.Stake.HashProofOfStake;
int lastCheckpointHeight = this.Checkpoints.GetLastCheckpointHeight();
if (chainedBlock.Height > lastCheckpointHeight)
{
// Compute stake modifier.
ChainedBlock prevChainedBlock = chainedBlock.Previous;
BlockStake blockStakePrev = prevChainedBlock == null ? null : this.stakeChain.Get(prevChainedBlock.HashBlock);
blockStake.StakeModifierV2 = this.StakeValidator.ComputeStakeModifierV2(prevChainedBlock, blockStakePrev, blockStake.IsProofOfWork() ? chainedBlock.HashBlock : blockStake.PrevoutStake.Hash);
}
else if (chainedBlock.Height == lastCheckpointHeight)
{
// Copy checkpointed stake modifier.
CheckpointInfo checkpoint = this.Checkpoints.GetCheckpoint(lastCheckpointHeight);
blockStake.StakeModifierV2 = checkpoint.StakeModifierV2;
this.logger.LogTrace("Last checkpoint stake modifier V2 loaded: '{0}'.", blockStake.StakeModifierV2);
}
else
{
this.logger.LogTrace("POS stake modifier computation skipped for block at height {0} because it is not above last checkpoint block height {1}.", chainedBlock.Height, lastCheckpointHeight);
}
this.logger.LogTrace("(-)[OK]");
}
/// <inheritdoc />
public override void CheckBlock(RuleContext context)
{
this.logger.LogTrace("()");
base.CheckBlock(context);
Block block = context.BlockValidationContext.Block;
// Check timestamp.
if (block.Header.Time > this.FutureDrift(this.dateTimeProvider.GetAdjustedTimeAsUnixTimestamp()))
{
// The block can be valid only after its time minus the future drift.
context.BlockValidationContext.RejectUntil = Utils.UnixTimeToDateTime(block.Header.Time - this.FutureDrift(0)).UtcDateTime;
this.logger.LogTrace("(-)[TIME_TOO_FAR]");
ConsensusErrors.BlockTimestampTooFar.Throw();
}
if (BlockStake.IsProofOfStake(block))
{
// Coinbase output should be empty if proof-of-stake block.
if ((block.Transactions[0].Outputs.Count != 1) || !block.Transactions[0].Outputs[0].IsEmpty)
{
this.logger.LogTrace("(-)[COINBASE_NOT_EMPTY]");
ConsensusErrors.BadStakeBlock.Throw();
}
// Second transaction must be coinstake, the rest must not be.
if (!block.Transactions[1].IsCoinStake)
{
this.logger.LogTrace("(-)[NO_COINSTAKE]");
ConsensusErrors.BadStakeBlock.Throw();
}
if (block.Transactions.Skip(2).Any(t => t.IsCoinStake))
{
this.logger.LogTrace("(-)[MULTIPLE_COINSTAKE]");
ConsensusErrors.BadMultipleCoinstake.Throw();
}
}
// Check proof-of-stake block signature.
if (!this.CheckBlockSignature(block))
{
this.logger.LogTrace("(-)[BAD_SIGNATURE]");
ConsensusErrors.BadBlockSignature.Throw();
}
// Check transactions.
foreach (Transaction transaction in block.Transactions)
{
// Check transaction timestamp.
if (block.Header.Time < transaction.Time)
{
this.logger.LogTrace("Block contains transaction with timestamp {0}, which is greater than block's timestamp {1}.", transaction.Time, block.Header.Time);
this.logger.LogTrace("(-)[TX_TIME_MISMATCH]");
ConsensusErrors.BlockTimeBeforeTrx.Throw();
}
}
this.logger.LogTrace("(-)[OK]");
}