public static void ClaimPreloadGas(NeoSystem system, Neo.Wallets.Wallet wallet, Random random)
{
void SubmitTransaction(Func <Snapshot, WalletAccount, Transaction?> factory)
{
using var snapshot = Blockchain.Singleton.GetSnapshot();
var validators = snapshot.GetValidators();
if (validators.Length != 1)
{
throw new InvalidOperationException("Preload only supported for single-node blockchains");
}
var account = wallet.GetAccounts().Single(a => a.Contract.Script.IsMultiSigContract());
var tx = factory(snapshot, account);
if (tx == null)
{
throw new Exception("Attempted to submit null preload transaction");
}
var context = new ContractParametersContext(tx);
wallet.Sign(context);
if (!context.Completed)
{
throw new InvalidOperationException("could not complete signing of preload transaction");
}
var block = CreatePreloadBlock(wallet, random, tx);
var result = system.Blockchain.Ask <RelayResultReason>(block).Result;
if (result != RelayResultReason.Succeed)
{
throw new Exception($"Preload {tx.Type} transaction failed {result}");
}
}
SubmitTransaction((snapshot, account) => NodeUtility.MakeTransferTransaction(snapshot,
ImmutableHashSet.Create(account.ScriptHash), account.ScriptHash, Blockchain.GoverningToken.Hash, null));
// There needs to be least one block after the transfer transaction before submitting a GAS claim
var block = CreatePreloadBlock(wallet, random);
var result = system.Blockchain.Ask <RelayResultReason>(block).Result;
if (result != RelayResultReason.Succeed)
{
throw new Exception($"Preload transfer suffix block failed {result}");
}
SubmitTransaction((snapshot, account) => NodeUtility.MakeClaimTransaction(snapshot, account.ScriptHash,
Blockchain.GoverningToken.Hash));
}
// Since ConensusContext's constructor is internal, it can't be used from neo-express.
// CreatePreloadBlock replicates the following logic for creating an empty block with ConensusContext
// var ctx = new Neo.Consensus.ConsensusContext(wallet, store);
// ctx.Reset(0);
// ctx.MakePrepareRequest();
// ctx.MakeCommit();
// ctx.Save();
// Block block = ctx.CreateBlock();
static Block CreatePreloadBlock(Neo.Wallets.Wallet wallet, Random random, Transaction?transaction = null)
{
using var snapshot = Blockchain.Singleton.GetSnapshot();
var validators = snapshot.GetValidators();
if (validators.Length != 1)
{
throw new InvalidOperationException("Preload only supported for single-node blockchains");
}
var amountNetFee = Block.CalculateNetFee(Enumerable.Empty <Transaction>());
if (amountNetFee != Fixed8.Zero)
{
throw new InvalidOperationException("amountNetFee must be zero");
}
var keyPair = wallet.GetAccount(validators[0]).GetKey();
var prevHash = snapshot.CurrentBlockHash;
var prevBlock = snapshot.GetBlock(prevHash);
var nonce = NextNonce(random);
var minerTx = new MinerTransaction
{
Nonce = (uint)(nonce % (uint.MaxValue + 1ul)),
Attributes = Array.Empty <TransactionAttribute>(),
Inputs = Array.Empty <CoinReference>(),
Outputs = Array.Empty <TransactionOutput>(),
Witnesses = Array.Empty <Witness>()
};
var blockTransactions = transaction == null ? new Transaction[] { minerTx } : new Transaction[] { minerTx, transaction };
var txHashes = blockTransactions.Select(tx => tx.Hash).ToArray();
var merkleRoot = MerkleTree.ComputeRoot(txHashes);
var nextConsensus = Blockchain.GetConsensusAddress(snapshot.GetValidators(blockTransactions).ToArray());
var consensusData = nonce;
var block = new Block()
{
Version = 0,
PrevHash = prevHash,
MerkleRoot = merkleRoot,
Timestamp = prevBlock.Timestamp + 1,
Index = prevBlock.Index + 1,
ConsensusData = nonce,
NextConsensus = nextConsensus,
Transactions = Array.Empty <Transaction>(),
};
var commit = new Neo.Consensus.Commit()
{
ViewNumber = 0,
Signature = block.Sign(keyPair)
};
var payload = new ConsensusPayload
{
Version = 0,
PrevHash = prevHash,
BlockIndex = block.Index,
ValidatorIndex = (ushort)0,
Data = Neo.IO.Helper.ToArray(commit)
};
{
var sc = new ContractParametersContext(payload);
wallet.Sign(sc);
payload.Witness = sc.GetWitnesses()[0];
}
{
var m = validators.Length - ((validators.Length - 1) / 3);
Contract contract = Contract.CreateMultiSigContract(m, validators);
ContractParametersContext sc = new ContractParametersContext(block);
for (int i = 0, j = 0; i < validators.Length && j < m; i++)
{
sc.AddSignature(contract, validators[0], payload.GetDeserializedMessage <Neo.Consensus.Commit>().Signature);
j++;
}
block.Witness = sc.GetWitnesses()[0];
block.Transactions = blockTransactions;
}
return(block);
}
