0a22a52918
Transaction selection for mining tracks ancestor feerates that are modified based on transactions that have already been selected. This commit de-duplicates the code so that the ancestor feerate sorting used by the mempool can also be directly applied to the miner.
460 lines
18 KiB
C++
460 lines
18 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2017 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include <miner.h>
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#include <amount.h>
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#include <chain.h>
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#include <chainparams.h>
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#include <coins.h>
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#include <consensus/consensus.h>
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#include <consensus/tx_verify.h>
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#include <consensus/merkle.h>
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#include <consensus/validation.h>
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#include <hash.h>
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#include <validation.h>
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#include <net.h>
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#include <policy/feerate.h>
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#include <policy/policy.h>
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#include <pow.h>
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#include <primitives/transaction.h>
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#include <script/standard.h>
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#include <timedata.h>
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#include <util.h>
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#include <utilmoneystr.h>
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#include <validationinterface.h>
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#include <algorithm>
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#include <queue>
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#include <utility>
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//////////////////////////////////////////////////////////////////////////////
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//
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// BitcoinMiner
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//
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//
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// Unconfirmed transactions in the memory pool often depend on other
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// transactions in the memory pool. When we select transactions from the
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// pool, we select by highest fee rate of a transaction combined with all
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// its ancestors.
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uint64_t nLastBlockTx = 0;
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uint64_t nLastBlockWeight = 0;
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int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
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{
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int64_t nOldTime = pblock->nTime;
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int64_t nNewTime = std::max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
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if (nOldTime < nNewTime)
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pblock->nTime = nNewTime;
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// Updating time can change work required on testnet:
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if (consensusParams.fPowAllowMinDifficultyBlocks)
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pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, consensusParams);
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return nNewTime - nOldTime;
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}
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BlockAssembler::Options::Options() {
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blockMinFeeRate = CFeeRate(DEFAULT_BLOCK_MIN_TX_FEE);
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nBlockMaxWeight = DEFAULT_BLOCK_MAX_WEIGHT;
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}
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BlockAssembler::BlockAssembler(const CChainParams& params, const Options& options) : chainparams(params)
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{
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blockMinFeeRate = options.blockMinFeeRate;
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// Limit weight to between 4K and MAX_BLOCK_WEIGHT-4K for sanity:
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nBlockMaxWeight = std::max<size_t>(4000, std::min<size_t>(MAX_BLOCK_WEIGHT - 4000, options.nBlockMaxWeight));
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}
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static BlockAssembler::Options DefaultOptions(const CChainParams& params)
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{
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// Block resource limits
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// If neither -blockmaxsize or -blockmaxweight is given, limit to DEFAULT_BLOCK_MAX_*
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// If only one is given, only restrict the specified resource.
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// If both are given, restrict both.
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BlockAssembler::Options options;
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options.nBlockMaxWeight = gArgs.GetArg("-blockmaxweight", DEFAULT_BLOCK_MAX_WEIGHT);
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if (gArgs.IsArgSet("-blockmintxfee")) {
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CAmount n = 0;
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ParseMoney(gArgs.GetArg("-blockmintxfee", ""), n);
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options.blockMinFeeRate = CFeeRate(n);
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} else {
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options.blockMinFeeRate = CFeeRate(DEFAULT_BLOCK_MIN_TX_FEE);
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}
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return options;
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}
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BlockAssembler::BlockAssembler(const CChainParams& params) : BlockAssembler(params, DefaultOptions(params)) {}
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void BlockAssembler::resetBlock()
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{
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inBlock.clear();
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// Reserve space for coinbase tx
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nBlockWeight = 4000;
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nBlockSigOpsCost = 400;
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fIncludeWitness = false;
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// These counters do not include coinbase tx
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nBlockTx = 0;
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nFees = 0;
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}
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std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& scriptPubKeyIn, bool fMineWitnessTx)
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{
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int64_t nTimeStart = GetTimeMicros();
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resetBlock();
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pblocktemplate.reset(new CBlockTemplate());
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if(!pblocktemplate.get())
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return nullptr;
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pblock = &pblocktemplate->block; // pointer for convenience
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// Add dummy coinbase tx as first transaction
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pblock->vtx.emplace_back();
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pblocktemplate->vTxFees.push_back(-1); // updated at end
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pblocktemplate->vTxSigOpsCost.push_back(-1); // updated at end
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LOCK2(cs_main, mempool.cs);
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CBlockIndex* pindexPrev = chainActive.Tip();
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assert(pindexPrev != nullptr);
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nHeight = pindexPrev->nHeight + 1;
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pblock->nVersion = ComputeBlockVersion(pindexPrev, chainparams.GetConsensus());
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// -regtest only: allow overriding block.nVersion with
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// -blockversion=N to test forking scenarios
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if (chainparams.MineBlocksOnDemand())
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pblock->nVersion = gArgs.GetArg("-blockversion", pblock->nVersion);
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pblock->nTime = GetAdjustedTime();
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const int64_t nMedianTimePast = pindexPrev->GetMedianTimePast();
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nLockTimeCutoff = (STANDARD_LOCKTIME_VERIFY_FLAGS & LOCKTIME_MEDIAN_TIME_PAST)
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? nMedianTimePast
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: pblock->GetBlockTime();
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// Decide whether to include witness transactions
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// This is only needed in case the witness softfork activation is reverted
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// (which would require a very deep reorganization) or when
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// -promiscuousmempoolflags is used.
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// TODO: replace this with a call to main to assess validity of a mempool
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// transaction (which in most cases can be a no-op).
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fIncludeWitness = IsWitnessEnabled(pindexPrev, chainparams.GetConsensus()) && fMineWitnessTx;
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int nPackagesSelected = 0;
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int nDescendantsUpdated = 0;
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addPackageTxs(nPackagesSelected, nDescendantsUpdated);
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int64_t nTime1 = GetTimeMicros();
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nLastBlockTx = nBlockTx;
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nLastBlockWeight = nBlockWeight;
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// Create coinbase transaction.
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CMutableTransaction coinbaseTx;
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coinbaseTx.vin.resize(1);
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coinbaseTx.vin[0].prevout.SetNull();
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coinbaseTx.vout.resize(1);
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coinbaseTx.vout[0].scriptPubKey = scriptPubKeyIn;
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coinbaseTx.vout[0].nValue = nFees + GetBlockSubsidy(nHeight, chainparams.GetConsensus());
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coinbaseTx.vin[0].scriptSig = CScript() << nHeight << OP_0;
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pblock->vtx[0] = MakeTransactionRef(std::move(coinbaseTx));
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pblocktemplate->vchCoinbaseCommitment = GenerateCoinbaseCommitment(*pblock, pindexPrev, chainparams.GetConsensus());
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pblocktemplate->vTxFees[0] = -nFees;
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LogPrintf("CreateNewBlock(): block weight: %u txs: %u fees: %ld sigops %d\n", GetBlockWeight(*pblock), nBlockTx, nFees, nBlockSigOpsCost);
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// Fill in header
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pblock->hashPrevBlock = pindexPrev->GetBlockHash();
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UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev);
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pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, chainparams.GetConsensus());
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pblock->nNonce = 0;
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pblocktemplate->vTxSigOpsCost[0] = WITNESS_SCALE_FACTOR * GetLegacySigOpCount(*pblock->vtx[0]);
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CValidationState state;
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if (!TestBlockValidity(state, chainparams, *pblock, pindexPrev, false, false)) {
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throw std::runtime_error(strprintf("%s: TestBlockValidity failed: %s", __func__, FormatStateMessage(state)));
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}
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int64_t nTime2 = GetTimeMicros();
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LogPrint(BCLog::BENCH, "CreateNewBlock() packages: %.2fms (%d packages, %d updated descendants), validity: %.2fms (total %.2fms)\n", 0.001 * (nTime1 - nTimeStart), nPackagesSelected, nDescendantsUpdated, 0.001 * (nTime2 - nTime1), 0.001 * (nTime2 - nTimeStart));
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return std::move(pblocktemplate);
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}
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void BlockAssembler::onlyUnconfirmed(CTxMemPool::setEntries& testSet)
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{
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for (CTxMemPool::setEntries::iterator iit = testSet.begin(); iit != testSet.end(); ) {
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// Only test txs not already in the block
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if (inBlock.count(*iit)) {
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testSet.erase(iit++);
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}
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else {
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iit++;
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}
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}
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}
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bool BlockAssembler::TestPackage(uint64_t packageSize, int64_t packageSigOpsCost) const
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{
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// TODO: switch to weight-based accounting for packages instead of vsize-based accounting.
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if (nBlockWeight + WITNESS_SCALE_FACTOR * packageSize >= nBlockMaxWeight)
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return false;
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if (nBlockSigOpsCost + packageSigOpsCost >= MAX_BLOCK_SIGOPS_COST)
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return false;
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return true;
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}
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// Perform transaction-level checks before adding to block:
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// - transaction finality (locktime)
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// - premature witness (in case segwit transactions are added to mempool before
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// segwit activation)
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bool BlockAssembler::TestPackageTransactions(const CTxMemPool::setEntries& package)
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{
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for (const CTxMemPool::txiter it : package) {
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if (!IsFinalTx(it->GetTx(), nHeight, nLockTimeCutoff))
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return false;
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if (!fIncludeWitness && it->GetTx().HasWitness())
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return false;
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}
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return true;
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}
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void BlockAssembler::AddToBlock(CTxMemPool::txiter iter)
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{
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pblock->vtx.emplace_back(iter->GetSharedTx());
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pblocktemplate->vTxFees.push_back(iter->GetFee());
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pblocktemplate->vTxSigOpsCost.push_back(iter->GetSigOpCost());
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nBlockWeight += iter->GetTxWeight();
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++nBlockTx;
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nBlockSigOpsCost += iter->GetSigOpCost();
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nFees += iter->GetFee();
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inBlock.insert(iter);
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bool fPrintPriority = gArgs.GetBoolArg("-printpriority", DEFAULT_PRINTPRIORITY);
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if (fPrintPriority) {
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LogPrintf("fee %s txid %s\n",
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CFeeRate(iter->GetModifiedFee(), iter->GetTxSize()).ToString(),
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iter->GetTx().GetHash().ToString());
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}
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}
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int BlockAssembler::UpdatePackagesForAdded(const CTxMemPool::setEntries& alreadyAdded,
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indexed_modified_transaction_set &mapModifiedTx)
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{
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int nDescendantsUpdated = 0;
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for (const CTxMemPool::txiter it : alreadyAdded) {
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CTxMemPool::setEntries descendants;
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mempool.CalculateDescendants(it, descendants);
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// Insert all descendants (not yet in block) into the modified set
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for (CTxMemPool::txiter desc : descendants) {
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if (alreadyAdded.count(desc))
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continue;
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++nDescendantsUpdated;
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modtxiter mit = mapModifiedTx.find(desc);
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if (mit == mapModifiedTx.end()) {
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CTxMemPoolModifiedEntry modEntry(desc);
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modEntry.nSizeWithAncestors -= it->GetTxSize();
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modEntry.nModFeesWithAncestors -= it->GetModifiedFee();
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modEntry.nSigOpCostWithAncestors -= it->GetSigOpCost();
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mapModifiedTx.insert(modEntry);
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} else {
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mapModifiedTx.modify(mit, update_for_parent_inclusion(it));
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}
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}
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}
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return nDescendantsUpdated;
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}
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// Skip entries in mapTx that are already in a block or are present
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// in mapModifiedTx (which implies that the mapTx ancestor state is
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// stale due to ancestor inclusion in the block)
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// Also skip transactions that we've already failed to add. This can happen if
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// we consider a transaction in mapModifiedTx and it fails: we can then
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// potentially consider it again while walking mapTx. It's currently
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// guaranteed to fail again, but as a belt-and-suspenders check we put it in
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// failedTx and avoid re-evaluation, since the re-evaluation would be using
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// cached size/sigops/fee values that are not actually correct.
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bool BlockAssembler::SkipMapTxEntry(CTxMemPool::txiter it, indexed_modified_transaction_set &mapModifiedTx, CTxMemPool::setEntries &failedTx)
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{
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assert (it != mempool.mapTx.end());
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return mapModifiedTx.count(it) || inBlock.count(it) || failedTx.count(it);
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}
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void BlockAssembler::SortForBlock(const CTxMemPool::setEntries& package, CTxMemPool::txiter entry, std::vector<CTxMemPool::txiter>& sortedEntries)
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{
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// Sort package by ancestor count
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// If a transaction A depends on transaction B, then A's ancestor count
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// must be greater than B's. So this is sufficient to validly order the
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// transactions for block inclusion.
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sortedEntries.clear();
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sortedEntries.insert(sortedEntries.begin(), package.begin(), package.end());
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std::sort(sortedEntries.begin(), sortedEntries.end(), CompareTxIterByAncestorCount());
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}
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// This transaction selection algorithm orders the mempool based
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// on feerate of a transaction including all unconfirmed ancestors.
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// Since we don't remove transactions from the mempool as we select them
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// for block inclusion, we need an alternate method of updating the feerate
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// of a transaction with its not-yet-selected ancestors as we go.
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// This is accomplished by walking the in-mempool descendants of selected
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// transactions and storing a temporary modified state in mapModifiedTxs.
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// Each time through the loop, we compare the best transaction in
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// mapModifiedTxs with the next transaction in the mempool to decide what
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// transaction package to work on next.
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void BlockAssembler::addPackageTxs(int &nPackagesSelected, int &nDescendantsUpdated)
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{
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// mapModifiedTx will store sorted packages after they are modified
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// because some of their txs are already in the block
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indexed_modified_transaction_set mapModifiedTx;
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// Keep track of entries that failed inclusion, to avoid duplicate work
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CTxMemPool::setEntries failedTx;
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// Start by adding all descendants of previously added txs to mapModifiedTx
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// and modifying them for their already included ancestors
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UpdatePackagesForAdded(inBlock, mapModifiedTx);
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CTxMemPool::indexed_transaction_set::index<ancestor_score>::type::iterator mi = mempool.mapTx.get<ancestor_score>().begin();
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CTxMemPool::txiter iter;
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// Limit the number of attempts to add transactions to the block when it is
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// close to full; this is just a simple heuristic to finish quickly if the
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// mempool has a lot of entries.
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const int64_t MAX_CONSECUTIVE_FAILURES = 1000;
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int64_t nConsecutiveFailed = 0;
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while (mi != mempool.mapTx.get<ancestor_score>().end() || !mapModifiedTx.empty())
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{
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// First try to find a new transaction in mapTx to evaluate.
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if (mi != mempool.mapTx.get<ancestor_score>().end() &&
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SkipMapTxEntry(mempool.mapTx.project<0>(mi), mapModifiedTx, failedTx)) {
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++mi;
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continue;
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}
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// Now that mi is not stale, determine which transaction to evaluate:
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// the next entry from mapTx, or the best from mapModifiedTx?
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bool fUsingModified = false;
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modtxscoreiter modit = mapModifiedTx.get<ancestor_score>().begin();
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if (mi == mempool.mapTx.get<ancestor_score>().end()) {
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// We're out of entries in mapTx; use the entry from mapModifiedTx
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iter = modit->iter;
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fUsingModified = true;
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} else {
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// Try to compare the mapTx entry to the mapModifiedTx entry
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iter = mempool.mapTx.project<0>(mi);
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if (modit != mapModifiedTx.get<ancestor_score>().end() &&
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CompareTxMemPoolEntryByAncestorFee()(*modit, CTxMemPoolModifiedEntry(iter))) {
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// The best entry in mapModifiedTx has higher score
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// than the one from mapTx.
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// Switch which transaction (package) to consider
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iter = modit->iter;
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fUsingModified = true;
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} else {
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// Either no entry in mapModifiedTx, or it's worse than mapTx.
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// Increment mi for the next loop iteration.
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++mi;
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}
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}
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// We skip mapTx entries that are inBlock, and mapModifiedTx shouldn't
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// contain anything that is inBlock.
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assert(!inBlock.count(iter));
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uint64_t packageSize = iter->GetSizeWithAncestors();
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CAmount packageFees = iter->GetModFeesWithAncestors();
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int64_t packageSigOpsCost = iter->GetSigOpCostWithAncestors();
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if (fUsingModified) {
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packageSize = modit->nSizeWithAncestors;
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packageFees = modit->nModFeesWithAncestors;
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packageSigOpsCost = modit->nSigOpCostWithAncestors;
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}
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if (packageFees < blockMinFeeRate.GetFee(packageSize)) {
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// Everything else we might consider has a lower fee rate
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return;
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}
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if (!TestPackage(packageSize, packageSigOpsCost)) {
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if (fUsingModified) {
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// Since we always look at the best entry in mapModifiedTx,
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// we must erase failed entries so that we can consider the
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// next best entry on the next loop iteration
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mapModifiedTx.get<ancestor_score>().erase(modit);
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failedTx.insert(iter);
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}
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++nConsecutiveFailed;
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if (nConsecutiveFailed > MAX_CONSECUTIVE_FAILURES && nBlockWeight >
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nBlockMaxWeight - 4000) {
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// Give up if we're close to full and haven't succeeded in a while
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break;
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}
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continue;
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}
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CTxMemPool::setEntries ancestors;
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uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
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std::string dummy;
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mempool.CalculateMemPoolAncestors(*iter, ancestors, nNoLimit, nNoLimit, nNoLimit, nNoLimit, dummy, false);
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onlyUnconfirmed(ancestors);
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ancestors.insert(iter);
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// Test if all tx's are Final
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if (!TestPackageTransactions(ancestors)) {
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if (fUsingModified) {
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mapModifiedTx.get<ancestor_score>().erase(modit);
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failedTx.insert(iter);
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}
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continue;
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}
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// This transaction will make it in; reset the failed counter.
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nConsecutiveFailed = 0;
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// Package can be added. Sort the entries in a valid order.
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std::vector<CTxMemPool::txiter> sortedEntries;
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SortForBlock(ancestors, iter, sortedEntries);
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for (size_t i=0; i<sortedEntries.size(); ++i) {
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AddToBlock(sortedEntries[i]);
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// Erase from the modified set, if present
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mapModifiedTx.erase(sortedEntries[i]);
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}
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++nPackagesSelected;
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// Update transactions that depend on each of these
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nDescendantsUpdated += UpdatePackagesForAdded(ancestors, mapModifiedTx);
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}
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}
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void IncrementExtraNonce(CBlock* pblock, const CBlockIndex* pindexPrev, unsigned int& nExtraNonce)
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{
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// Update nExtraNonce
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static uint256 hashPrevBlock;
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if (hashPrevBlock != pblock->hashPrevBlock)
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{
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nExtraNonce = 0;
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hashPrevBlock = pblock->hashPrevBlock;
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}
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++nExtraNonce;
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unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
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CMutableTransaction txCoinbase(*pblock->vtx[0]);
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txCoinbase.vin[0].scriptSig = (CScript() << nHeight << CScriptNum(nExtraNonce)) + COINBASE_FLAGS;
|
|
assert(txCoinbase.vin[0].scriptSig.size() <= 100);
|
|
|
|
pblock->vtx[0] = MakeTransactionRef(std::move(txCoinbase));
|
|
pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
|
|
}
|