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Direct CCoins references

To prevent excessive copying of CCoins in and out of the CCoinsView
implementations, introduce a GetCoins() function in CCoinsViewCache
with returns a direct reference. The block validation and connection
logic is updated to require caching CCoinsViews, and exploits the
GetCoins() function heavily.
tags/v0.15.1
Pieter Wuille 8 years ago
parent
commit
13c51f20f6
3 changed files with 67 additions and 61 deletions
  1. 53
    49
      src/main.cpp
  2. 14
    9
      src/main.h
  3. 0
    3
      src/test/transaction_tests.cpp

+ 53
- 49
src/main.cpp View File

@@ -170,6 +170,7 @@ CBlockIndex *CCoinsView::GetBestBlock() { return NULL; }
bool CCoinsView::SetBestBlock(CBlockIndex *pindex) { return false; }
bool CCoinsView::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return false; }


CCoinsViewBacked::CCoinsViewBacked(CCoinsView &viewIn) : base(&viewIn) { }
bool CCoinsViewBacked::GetCoins(uint256 txid, CCoins &coins) { return base->GetCoins(txid, coins); }
bool CCoinsViewBacked::SetCoins(uint256 txid, const CCoins &coins) { return base->SetCoins(txid, coins); }
@@ -193,13 +194,30 @@ bool CCoinsViewCache::GetCoins(uint256 txid, CCoins &coins) {
return false;
}

std::map<uint256,CCoins>::iterator CCoinsViewCache::FetchCoins(uint256 txid) {
std::map<uint256,CCoins>::iterator it = cacheCoins.find(txid);
if (it != cacheCoins.end())
return it;
CCoins tmp;
if (!base->GetCoins(txid,tmp))
return it;
std::pair<std::map<uint256,CCoins>::iterator,bool> ret = cacheCoins.insert(std::make_pair(txid, tmp));
return ret.first;
}

CCoins &CCoinsViewCache::GetCoins(uint256 txid) {
std::map<uint256,CCoins>::iterator it = FetchCoins(txid);
assert(it != cacheCoins.end());
return it->second;
}

bool CCoinsViewCache::SetCoins(uint256 txid, const CCoins &coins) {
cacheCoins[txid] = coins;
return true;
}

bool CCoinsViewCache::HaveCoins(uint256 txid) {
return cacheCoins.count(txid) || base->HaveCoins(txid);
return FetchCoins(txid) != cacheCoins.end();
}

CBlockIndex *CCoinsViewCache::GetBestBlock() {
@@ -369,7 +387,7 @@ bool CTransaction::IsStandard() const
// expensive-to-check-upon-redemption script like:
// DUP CHECKSIG DROP ... repeated 100 times... OP_1
//
bool CTransaction::AreInputsStandard(CCoinsView& mapInputs) const
bool CTransaction::AreInputsStandard(CCoinsViewCache& mapInputs) const
{
if (IsCoinBase())
return true; // Coinbases don't use vin normally
@@ -683,6 +701,9 @@ bool CTxMemPool::accept(CTransaction &tx, bool fCheckInputs,
}
}

if (!tx.HaveInputs(view))
return error("CTxMemPool::accept() : inputs already spent");

// Check for non-standard pay-to-script-hash in inputs
if (!tx.AreInputsStandard(view) && !fTestNet)
return error("CTxMemPool::accept() : nonstandard transaction input");
@@ -1154,23 +1175,14 @@ void CBlock::UpdateTime(const CBlockIndex* pindexPrev)



CTxOut CTransaction::GetOutputFor(const CTxIn& input, CCoinsView& view)
const CTxOut &CTransaction::GetOutputFor(const CTxIn& input, CCoinsViewCache& view)
{
CCoins coins;
if (!view.GetCoins(input.prevout.hash, coins))
throw std::runtime_error("CTransaction::GetOutputFor() : prevout.hash not found");

if (input.prevout.n >= coins.vout.size())
throw std::runtime_error("CTransaction::GetOutputFor() : prevout.n out of range or already spent");

const CTxOut &out = coins.vout[input.prevout.n];
if (out.IsNull())
throw std::runtime_error("CTransaction::GetOutputFor() : already spent");

return out;
const CCoins &coins = view.GetCoins(input.prevout.hash);
assert(coins.IsAvailable(input.prevout.n));
return coins.vout[input.prevout.n];
}

int64 CTransaction::GetValueIn(CCoinsView& inputs) const
int64 CTransaction::GetValueIn(CCoinsViewCache& inputs) const
{
if (IsCoinBase())
return 0;
@@ -1182,7 +1194,7 @@ int64 CTransaction::GetValueIn(CCoinsView& inputs) const
return nResult;
}

unsigned int CTransaction::GetP2SHSigOpCount(CCoinsView& inputs) const
unsigned int CTransaction::GetP2SHSigOpCount(CCoinsViewCache& inputs) const
{
if (IsCoinBase())
return 0;
@@ -1190,27 +1202,23 @@ unsigned int CTransaction::GetP2SHSigOpCount(CCoinsView& inputs) const
unsigned int nSigOps = 0;
for (unsigned int i = 0; i < vin.size(); i++)
{
CTxOut prevout = GetOutputFor(vin[i], inputs);
const CTxOut &prevout = GetOutputFor(vin[i], inputs);
if (prevout.scriptPubKey.IsPayToScriptHash())
nSigOps += prevout.scriptPubKey.GetSigOpCount(vin[i].scriptSig);
}
return nSigOps;
}

bool CTransaction::UpdateCoins(CCoinsView &inputs, CTxUndo &txundo, int nHeight, const uint256 &txhash) const
bool CTransaction::UpdateCoins(CCoinsViewCache &inputs, CTxUndo &txundo, int nHeight, const uint256 &txhash) const
{
// mark inputs spent
if (!IsCoinBase()) {
BOOST_FOREACH(const CTxIn &txin, vin) {
CCoins coins;
if (!inputs.GetCoins(txin.prevout.hash, coins))
return error("UpdateCoins() : cannot find prevtx");
CCoins &coins = inputs.GetCoins(txin.prevout.hash);
CTxInUndo undo;
if (!coins.Spend(txin.prevout, undo))
return error("UpdateCoins() : cannot spend input");
txundo.vprevout.push_back(undo);
if (!inputs.SetCoins(txin.prevout.hash, coins))
return error("UpdateCoins() : cannot update input");
}
}

@@ -1221,7 +1229,7 @@ bool CTransaction::UpdateCoins(CCoinsView &inputs, CTxUndo &txundo, int nHeight,
return true;
}

bool CTransaction::HaveInputs(CCoinsView &inputs) const
bool CTransaction::HaveInputs(CCoinsViewCache &inputs) const
{
if (!IsCoinBase()) {
// first check whether information about the prevout hash is available
@@ -1234,8 +1242,7 @@ bool CTransaction::HaveInputs(CCoinsView &inputs) const
// then check whether the actual outputs are available
for (unsigned int i = 0; i < vin.size(); i++) {
const COutPoint &prevout = vin[i].prevout;
CCoins coins;
inputs.GetCoins(prevout.hash, coins);
const CCoins &coins = inputs.GetCoins(prevout.hash);
if (!coins.IsAvailable(prevout.n))
return false;
}
@@ -1243,28 +1250,25 @@ bool CTransaction::HaveInputs(CCoinsView &inputs) const
return true;
}

bool CTransaction::CheckInputs(CCoinsView &inputs, enum CheckSig_mode csmode, bool fStrictPayToScriptHash, bool fStrictEncodings) const
bool CTransaction::CheckInputs(CCoinsViewCache &inputs, enum CheckSig_mode csmode, bool fStrictPayToScriptHash, bool fStrictEncodings) const
{
if (!IsCoinBase())
{
// This doesn't trigger the DoS code on purpose; if it did, it would make it easier
// for an attacker to attempt to split the network.
if (!HaveInputs(inputs))
return error("CheckInputs() : %s inputs unavailable", GetHash().ToString().substr(0,10).c_str());

CBlockIndex *pindexBlock = inputs.GetBestBlock();
int64 nValueIn = 0;
int64 nFees = 0;
for (unsigned int i = 0; i < vin.size(); i++)
{
const COutPoint &prevout = vin[i].prevout;
CCoins coins;
if (!inputs.GetCoins(prevout.hash, coins))
return error("CheckInputs() : cannot find prevout tx");

// Check for conflicts (double-spend)
// This doesn't trigger the DoS code on purpose; if it did, it would make it easier
// for an attacker to attempt to split the network.
if (!coins.IsAvailable(prevout.n))
return error("CheckInputs() : %s prev tx already used", GetHash().ToString().substr(0,10).c_str());
const CCoins &coins = inputs.GetCoins(prevout.hash);

// If prev is coinbase, check that it's matured
if (coins.IsCoinBase()) {
CBlockIndex *pindexBlock = inputs.GetBestBlock();
if (pindexBlock->nHeight - coins.nHeight < COINBASE_MATURITY)
return error("CheckInputs() : tried to spend coinbase at depth %d", pindexBlock->nHeight - coins.nHeight);
}
@@ -1298,8 +1302,7 @@ bool CTransaction::CheckInputs(CCoinsView &inputs, enum CheckSig_mode csmode, bo
(csmode == CS_AFTER_CHECKPOINT && inputs.GetBestBlock()->nHeight >= Checkpoints::GetTotalBlocksEstimate())) {
for (unsigned int i = 0; i < vin.size(); i++) {
const COutPoint &prevout = vin[i].prevout;
CCoins coins;
inputs.GetCoins(prevout.hash, coins);
const CCoins &coins = inputs.GetCoins(prevout.hash);

// Verify signature
if (!VerifySignature(coins, *this, i, fStrictPayToScriptHash, fStrictEncodings, 0)) {
@@ -1367,7 +1370,7 @@ bool CTransaction::ClientCheckInputs() const



bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsView &view)
bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &view)
{
assert(pindex == view.GetBestBlock());

@@ -1391,17 +1394,16 @@ bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsView &view)
uint256 hash = tx.GetHash();

// check that all outputs are available
CCoins outs;
if (!view.GetCoins(hash, outs))
if (!view.HaveCoins(hash))
return error("DisconnectBlock() : outputs still spent? database corrupted");
CCoins &outs = view.GetCoins(hash);

CCoins outsBlock = CCoins(tx, pindex->nHeight);
if (outs != outsBlock)
return error("DisconnectBlock() : added transaction mismatch? database corrupted");

// remove outputs
if (!view.SetCoins(hash, CCoins()))
return error("DisconnectBlock() : cannot delete coin outputs");
outs = CCoins();

// restore inputs
if (i > 0) { // not coinbases
@@ -1441,7 +1443,7 @@ bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsView &view)

bool FindUndoPos(CChainDB &chaindb, int nFile, CDiskBlockPos &pos, unsigned int nAddSize);

bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsView &view, bool fJustCheck)
bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsViewCache &view, bool fJustCheck)
{
// Check it again in case a previous version let a bad block in
if (!CheckBlock(!fJustCheck, !fJustCheck))
@@ -1467,8 +1469,7 @@ bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsView &view, bool fJustCheck
if (fEnforceBIP30) {
for (unsigned int i=0; i<vtx.size(); i++) {
uint256 hash = GetTxHash(i);
CCoins coins;
if (view.GetCoins(hash, coins) && !coins.IsPruned())
if (view.HaveCoins(hash) && !view.GetCoins(hash).IsPruned())
return error("ConnectBlock() : tried to overwrite transaction");
}
}
@@ -3719,7 +3720,7 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
}

if (!tx.CheckInputs(viewTemp, CS_ALWAYS, true, false))
if (!tx.HaveInputs(viewTemp))
continue;

int64 nTxFees = tx.GetValueIn(viewTemp)-tx.GetValueOut();
@@ -3728,6 +3729,9 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
continue;

if (!tx.CheckInputs(viewTemp, CS_ALWAYS, true, false))
continue;

CTxUndo txundo;
uint256 hash = tx.GetHash();
if (!tx.UpdateCoins(viewTemp, txundo, pindexPrev->nHeight+1, hash))

+ 14
- 9
src/main.h View File

@@ -88,6 +88,7 @@ class CDiskBlockPos;
class CCoins;
class CTxUndo;
class CCoinsView;
class CCoinsViewCache;

void RegisterWallet(CWallet* pwalletIn);
void UnregisterWallet(CWallet* pwalletIn);
@@ -480,7 +481,7 @@ public:
@return True if all inputs (scriptSigs) use only standard transaction forms
@see CTransaction::FetchInputs
*/
bool AreInputsStandard(CCoinsView& mapInputs) const;
bool AreInputsStandard(CCoinsViewCache& mapInputs) const;

/** Count ECDSA signature operations the old-fashioned (pre-0.6) way
@return number of sigops this transaction's outputs will produce when spent
@@ -494,7 +495,7 @@ public:
@return maximum number of sigops required to validate this transaction's inputs
@see CTransaction::FetchInputs
*/
unsigned int GetP2SHSigOpCount(CCoinsView& mapInputs) const;
unsigned int GetP2SHSigOpCount(CCoinsViewCache& mapInputs) const;

/** Amount of bitcoins spent by this transaction.
@return sum of all outputs (note: does not include fees)
@@ -519,7 +520,7 @@ public:
@return Sum of value of all inputs (scriptSigs)
@see CTransaction::FetchInputs
*/
int64 GetValueIn(CCoinsView& mapInputs) const;
int64 GetValueIn(CCoinsViewCache& mapInputs) const;

static bool AllowFree(double dPriority)
{
@@ -570,14 +571,14 @@ public:
bool ClientCheckInputs() const;

// Check whether all prevouts of this transaction are present in the UTXO set represented by view
bool HaveInputs(CCoinsView &view) const;
bool HaveInputs(CCoinsViewCache &view) const;

// Check whether all inputs of this transaction are valid (no double spends, scripts & sigs, amounts)
// This does not modify the UTXO set
bool CheckInputs(CCoinsView &view, enum CheckSig_mode csmode, bool fStrictPayToScriptHash=true, bool fStrictEncodings=true) const;
bool CheckInputs(CCoinsViewCache &view, enum CheckSig_mode csmode, bool fStrictPayToScriptHash=true, bool fStrictEncodings=true) const;

// Apply the effects of this transaction on the UTXO set represented by view
bool UpdateCoins(CCoinsView &view, CTxUndo &txundo, int nHeight, const uint256 &txhash) const;
bool UpdateCoins(CCoinsViewCache &view, CTxUndo &txundo, int nHeight, const uint256 &txhash) const;

// Context-independent validity checks
bool CheckTransaction() const;
@@ -586,7 +587,7 @@ public:
bool AcceptToMemoryPool(bool fCheckInputs=true, bool* pfMissingInputs=NULL);

protected:
static CTxOut GetOutputFor(const CTxIn& input, CCoinsView& mapInputs);
static const CTxOut &GetOutputFor(const CTxIn& input, CCoinsViewCache& mapInputs);
};

/** wrapper for CTxOut that provides a more compact serialization */
@@ -1225,10 +1226,10 @@ public:


// Undo the effects of this block (with given index) on the UTXO set represented by coins
bool DisconnectBlock(CBlockIndex *pindex, CCoinsView &coins);
bool DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &coins);

// Apply the effects of this block (with given index) on the UTXO set represented by coins
bool ConnectBlock(CBlockIndex *pindex, CCoinsView &coins, bool fJustCheck=false);
bool ConnectBlock(CBlockIndex *pindex, CCoinsViewCache &coins, bool fJustCheck=false);

// Read a block from disk
bool ReadFromDisk(const CBlockIndex* pindex, bool fReadTransactions=true);
@@ -1759,11 +1760,15 @@ public:
bool GetCoins(uint256 txid, CCoins &coins);
bool SetCoins(uint256 txid, const CCoins &coins);
bool HaveCoins(uint256 txid);
CCoins &GetCoins(uint256 txid);
CBlockIndex *GetBestBlock();
bool SetBestBlock(CBlockIndex *pindex);
bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
bool Flush();
unsigned int GetCacheSize();

private:
std::map<uint256,CCoins>::iterator FetchCoins(uint256 txid);
};

/** CCoinsView that brings transactions from a memorypool into view.

+ 0
- 3
src/test/transaction_tests.cpp View File

@@ -256,9 +256,6 @@ BOOST_AUTO_TEST_CASE(test_GetThrow)
t1.vout.resize(2);
t1.vout[0].nValue = 90*CENT;
t1.vout[0].scriptPubKey << OP_1;

BOOST_CHECK_THROW(t1.AreInputsStandard(coinsDummy), runtime_error);
BOOST_CHECK_THROW(t1.GetValueIn(coinsDummy), runtime_error);
}

BOOST_AUTO_TEST_SUITE_END()

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