比特币源码解析－交易确认
图1 交易确认
主要描述bool CTransaction::ConnectInputs(CTxDB& txdb, map& mapTestPool, CDiskTxPos posThisTx, int nHeight, int64& nFees, bool fBlock, bool fMiner, int64 nMinFee)函数的功能。
当前交易不是创币交易
if (!IsCoinBase())
{
}
遍历输入交易并获取输入交易的COutPoint信息
for (int i = 0; i < vin.size(); i++)
{
COutPoint prevout = vin[i].prevout;
}
判断交易信息
如果当前矿工标志位为1，从mapTestPool中获取交易索引信息，否则从从交易数据库中判断前一个输出是否存在.
CTxIndex txindex;
bool fFound = true;
if (fMiner && mapTestPool.count(prevout.hash))
{
// Get txindex from current proposed changes
txindex = mapTestPool[prevout.hash];
}
else
{
// Read txindex from txdb
fFound = txdb.ReadTxIndex(prevout.hash, txindex);
}
if (!fFound && (fBlock || fMiner))
return fMiner ? false : error("ConnectInputs() : %s prev tx %s index entry not found", GetHash().ToString().substr(0,6).c_str(), prevout.hash.ToString().substr(0,6).c_str());
获取前一个交易信息
// Read txPrev
CTransaction txPrev;
if (!fFound || txindex.pos == CDiskTxPos(1,1,1))
{
// Get prev tx from single transactions in memory
CRITICAL_BLOCK(cs_mapTransactions)
{
if (!mapTransactions.count(prevout.hash))
return error("ConnectInputs() : %s mapTransactions prev not found %s", GetHash().ToString().substr(0,6).c_str(), prevout.hash.ToString().substr(0,6).c_str());
txPrev = mapTransactions[prevout.hash];
}
if (!fFound)
txindex.vSpent.resize(txPrev.vout.size());
}
else
{
// Get prev tx from disk
if (!txPrev.ReadFromDisk(txindex.pos))
return error("ConnectInputs() : %s ReadFromDisk prev tx %s failed", GetHash().ToString().substr(0,6).c_str(), prevout.hash.ToString().substr(0,6).c_str());
}
校验前一交易信息
如果前一交易是创币交易，则是否被足够多的区块确认
if (prevout.n >= txPrev.vout.size() || prevout.n >= txindex.vSpent.size())
return error("ConnectInputs() : %s prevout.n out of range %d %d %d", GetHash().ToString().substr(0,6).c_str(), prevout.n, txPrev.vout.size(), txindex.vSpent.size());
// If prev is coinbase, check that it's matured
if (txPrev.IsCoinBase())
for (CBlockIndex* pindex = pindexBest; pindex && nBestHeight - pindex->nHeight < COINBASE_MATURITY-1; pindex = pindex->pprev)
if (pindex->nBlockPos == txindex.pos.nBlockPos && pindex->nFile == txindex.pos.nFile)
return error("ConnectInputs() : tried to spend coinbase at depth %d", nBestHeight - pindex->nHeight);
校验签名信息并确认交易未被花费
// Verify signature
if (!VerifySignature(txPrev, *this, i))
return error("ConnectInputs() : %s VerifySignature failed", GetHash().ToString().substr(0,6).c_str());
// Check for conflicts
if (!txindex.vSpent[prevout.n].IsNull())
return fMiner ? false : error("ConnectInputs() : %s prev tx already used at %s", GetHash().ToString().substr(0,6).c_str(), txindex.vSpent[prevout.n].ToString().c_str());
// Mark outpoints as spent
txindex.vSpent[prevout.n] = posThisTx;
更新交易信息
if (fBlock)
txdb.UpdateTxIndex(prevout.hash, txindex);
else if (fMiner)
mapTestPool[prevout.hash] = txindex;
nValueIn += txPrev.vout[prevout.n].nValue;
轮询交易结束，计算交易手续费，且不小于最低手续费
int64 nTxFee = nValueIn - GetValueOut();
if (nTxFee < 0)
return error("ConnectInputs() : %s nTxFee < 0", GetHash().ToString().substr(0,6).c_str());
if (nTxFee < nMinFee)
return false;
nFees += nTxFee;
当前交易是创币交易
如果是创币交易并且当前是区块标志位fBlock为1则保存到交易数据库中，如果当前是矿工标志位fMiner为1则保存到mapTestPool中
if (fBlock)
{
// Add transaction to disk index
if (!txdb.AddTxIndex(*this, posThisTx, nHeight))
return error("ConnectInputs() : AddTxPos failed");
}
else if (fMiner)
{
// Add transaction to test pool
mapTestPool[GetHash()] = CTxIndex(CDiskTxPos(1,1,1), vout.size());
}