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Direct CCoins references

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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.
This commit is contained in:
Pieter Wuille 2012-07-08 19:04:05 +02:00
parent 64dd46fd05
commit 13c51f20f6
3 changed files with 67 additions and 61 deletions
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102
src/main.cpp
View file

@ -170,6 +170,7 @@ CBlockIndex *CCoinsView::GetBestBlock() { return NULL; }
bool CCoinsView::SetBestBlock(CBlockIndex *pindex) { return false; } bool CCoinsView::SetBestBlock(CBlockIndex *pindex) { return false; }
bool CCoinsView::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return false; } bool CCoinsView::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return false; }
CCoinsViewBacked::CCoinsViewBacked(CCoinsView &viewIn) : base(&viewIn) { } CCoinsViewBacked::CCoinsViewBacked(CCoinsView &viewIn) : base(&viewIn) { }
bool CCoinsViewBacked::GetCoins(uint256 txid, CCoins &coins) { return base->GetCoins(txid, coins); } 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); } 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; 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) { bool CCoinsViewCache::SetCoins(uint256 txid, const CCoins &coins) {
cacheCoins[txid] = coins; cacheCoins[txid] = coins;
return true; return true;
} }
bool CCoinsViewCache::HaveCoins(uint256 txid) { bool CCoinsViewCache::HaveCoins(uint256 txid) {
return cacheCoins.count(txid) || base->HaveCoins(txid); return FetchCoins(txid) != cacheCoins.end();
} }
CBlockIndex *CCoinsViewCache::GetBestBlock() { CBlockIndex *CCoinsViewCache::GetBestBlock() {
@ -369,7 +387,7 @@ bool CTransaction::IsStandard() const
// expensive-to-check-upon-redemption script like: // expensive-to-check-upon-redemption script like:
// DUP CHECKSIG DROP ... repeated 100 times... OP_1 // DUP CHECKSIG DROP ... repeated 100 times... OP_1
// //
bool CTransaction::AreInputsStandard(CCoinsView& mapInputs) const bool CTransaction::AreInputsStandard(CCoinsViewCache& mapInputs) const
{ {
if (IsCoinBase()) if (IsCoinBase())
return true; // Coinbases don't use vin normally 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 // Check for non-standard pay-to-script-hash in inputs
if (!tx.AreInputsStandard(view) && !fTestNet) if (!tx.AreInputsStandard(view) && !fTestNet)
return error("CTxMemPool::accept() : nonstandard transaction input"); 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; const CCoins &coins = view.GetCoins(input.prevout.hash);
if (!view.GetCoins(input.prevout.hash, coins)) assert(coins.IsAvailable(input.prevout.n));
throw std::runtime_error("CTransaction::GetOutputFor() : prevout.hash not found"); return coins.vout[input.prevout.n];
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;
} }
int64 CTransaction::GetValueIn(CCoinsView& inputs) const int64 CTransaction::GetValueIn(CCoinsViewCache& inputs) const
{ {
if (IsCoinBase()) if (IsCoinBase())
return 0; return 0;
@ -1182,7 +1194,7 @@ int64 CTransaction::GetValueIn(CCoinsView& inputs) const
return nResult; return nResult;
} }
unsigned int CTransaction::GetP2SHSigOpCount(CCoinsView& inputs) const unsigned int CTransaction::GetP2SHSigOpCount(CCoinsViewCache& inputs) const
{ {
if (IsCoinBase()) if (IsCoinBase())
return 0; return 0;
@ -1190,27 +1202,23 @@ unsigned int CTransaction::GetP2SHSigOpCount(CCoinsView& inputs) const
unsigned int nSigOps = 0; unsigned int nSigOps = 0;
for (unsigned int i = 0; i < vin.size(); i++) 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()) if (prevout.scriptPubKey.IsPayToScriptHash())
nSigOps += prevout.scriptPubKey.GetSigOpCount(vin[i].scriptSig); nSigOps += prevout.scriptPubKey.GetSigOpCount(vin[i].scriptSig);
} }
return nSigOps; 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 // mark inputs spent
if (!IsCoinBase()) { if (!IsCoinBase()) {
BOOST_FOREACH(const CTxIn &txin, vin) { BOOST_FOREACH(const CTxIn &txin, vin) {
CCoins coins; CCoins &coins = inputs.GetCoins(txin.prevout.hash);
if (!inputs.GetCoins(txin.prevout.hash, coins))
return error("UpdateCoins() : cannot find prevtx");
CTxInUndo undo; CTxInUndo undo;
if (!coins.Spend(txin.prevout, undo)) if (!coins.Spend(txin.prevout, undo))
return error("UpdateCoins() : cannot spend input"); return error("UpdateCoins() : cannot spend input");
txundo.vprevout.push_back(undo); 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; return true;
} }
bool CTransaction::HaveInputs(CCoinsView &inputs) const bool CTransaction::HaveInputs(CCoinsViewCache &inputs) const
{ {
if (!IsCoinBase()) { if (!IsCoinBase()) {
// first check whether information about the prevout hash is available // 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 // then check whether the actual outputs are available
for (unsigned int i = 0; i < vin.size(); i++) { for (unsigned int i = 0; i < vin.size(); i++) {
const COutPoint &prevout = vin[i].prevout; const COutPoint &prevout = vin[i].prevout;
CCoins coins; const CCoins &coins = inputs.GetCoins(prevout.hash);
inputs.GetCoins(prevout.hash, coins);
if (!coins.IsAvailable(prevout.n)) if (!coins.IsAvailable(prevout.n))
return false; return false;
} }
@ -1243,28 +1250,25 @@ bool CTransaction::HaveInputs(CCoinsView &inputs) const
return true; 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()) 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 nValueIn = 0;
int64 nFees = 0; int64 nFees = 0;
for (unsigned int i = 0; i < vin.size(); i++) for (unsigned int i = 0; i < vin.size(); i++)
{ {
const COutPoint &prevout = vin[i].prevout; const COutPoint &prevout = vin[i].prevout;
CCoins coins; const CCoins &coins = inputs.GetCoins(prevout.hash);
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());
// If prev is coinbase, check that it's matured // If prev is coinbase, check that it's matured
if (coins.IsCoinBase()) { if (coins.IsCoinBase()) {
CBlockIndex *pindexBlock = inputs.GetBestBlock();
if (pindexBlock->nHeight - coins.nHeight < COINBASE_MATURITY) if (pindexBlock->nHeight - coins.nHeight < COINBASE_MATURITY)
return error("CheckInputs() : tried to spend coinbase at depth %d", pindexBlock->nHeight - coins.nHeight); 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())) { (csmode == CS_AFTER_CHECKPOINT && inputs.GetBestBlock()->nHeight >= Checkpoints::GetTotalBlocksEstimate())) {
for (unsigned int i = 0; i < vin.size(); i++) { for (unsigned int i = 0; i < vin.size(); i++) {
const COutPoint &prevout = vin[i].prevout; const COutPoint &prevout = vin[i].prevout;
CCoins coins; const CCoins &coins = inputs.GetCoins(prevout.hash);
inputs.GetCoins(prevout.hash, coins);
// Verify signature // Verify signature
if (!VerifySignature(coins, *this, i, fStrictPayToScriptHash, fStrictEncodings, 0)) { 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()); assert(pindex == view.GetBestBlock());
@ -1391,17 +1394,16 @@ bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsView &view)
uint256 hash = tx.GetHash(); uint256 hash = tx.GetHash();
// check that all outputs are available // check that all outputs are available
CCoins outs; if (!view.HaveCoins(hash))
if (!view.GetCoins(hash, outs))
return error("DisconnectBlock() : outputs still spent? database corrupted"); return error("DisconnectBlock() : outputs still spent? database corrupted");
CCoins &outs = view.GetCoins(hash);
CCoins outsBlock = CCoins(tx, pindex->nHeight); CCoins outsBlock = CCoins(tx, pindex->nHeight);
if (outs != outsBlock) if (outs != outsBlock)
return error("DisconnectBlock() : added transaction mismatch? database corrupted"); return error("DisconnectBlock() : added transaction mismatch? database corrupted");
// remove outputs // remove outputs
if (!view.SetCoins(hash, CCoins())) outs = CCoins();
return error("DisconnectBlock() : cannot delete coin outputs");
// restore inputs // restore inputs
if (i > 0) { // not coinbases 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 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 // Check it again in case a previous version let a bad block in
if (!CheckBlock(!fJustCheck, !fJustCheck)) if (!CheckBlock(!fJustCheck, !fJustCheck))
@ -1467,8 +1469,7 @@ bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsView &view, bool fJustCheck
if (fEnforceBIP30) { if (fEnforceBIP30) {
for (unsigned int i=0; i<vtx.size(); i++) { for (unsigned int i=0; i<vtx.size(); i++) {
uint256 hash = GetTxHash(i); uint256 hash = GetTxHash(i);
CCoins coins; if (view.HaveCoins(hash) && !view.GetCoins(hash).IsPruned())
if (view.GetCoins(hash, coins) && !coins.IsPruned())
return error("ConnectBlock() : tried to overwrite transaction"); return error("ConnectBlock() : tried to overwrite transaction");
} }
} }
@ -3719,7 +3720,7 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
std::make_heap(vecPriority.begin(), vecPriority.end(), comparer); std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
} }
if (!tx.CheckInputs(viewTemp, CS_ALWAYS, true, false)) if (!tx.HaveInputs(viewTemp))
continue; continue;
int64 nTxFees = tx.GetValueIn(viewTemp)-tx.GetValueOut(); int64 nTxFees = tx.GetValueIn(viewTemp)-tx.GetValueOut();
@ -3728,6 +3729,9 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS) if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
continue; continue;
if (!tx.CheckInputs(viewTemp, CS_ALWAYS, true, false))
continue;
CTxUndo txundo; CTxUndo txundo;
uint256 hash = tx.GetHash(); uint256 hash = tx.GetHash();
if (!tx.UpdateCoins(viewTemp, txundo, pindexPrev->nHeight+1, hash)) if (!tx.UpdateCoins(viewTemp, txundo, pindexPrev->nHeight+1, hash))

23
src/main.h
View file

@ -88,6 +88,7 @@ class CDiskBlockPos;
class CCoins; class CCoins;
class CTxUndo; class CTxUndo;
class CCoinsView; class CCoinsView;
class CCoinsViewCache;
void RegisterWallet(CWallet* pwalletIn); void RegisterWallet(CWallet* pwalletIn);
void UnregisterWallet(CWallet* pwalletIn); void UnregisterWallet(CWallet* pwalletIn);
@ -480,7 +481,7 @@ public:
@return True if all inputs (scriptSigs) use only standard transaction forms @return True if all inputs (scriptSigs) use only standard transaction forms
@see CTransaction::FetchInputs @see CTransaction::FetchInputs
*/ */
bool AreInputsStandard(CCoinsView& mapInputs) const; bool AreInputsStandard(CCoinsViewCache& mapInputs) const;
/** Count ECDSA signature operations the old-fashioned (pre-0.6) way /** Count ECDSA signature operations the old-fashioned (pre-0.6) way
@return number of sigops this transaction's outputs will produce when spent @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 @return maximum number of sigops required to validate this transaction's inputs
@see CTransaction::FetchInputs @see CTransaction::FetchInputs
*/ */
unsigned int GetP2SHSigOpCount(CCoinsView& mapInputs) const; unsigned int GetP2SHSigOpCount(CCoinsViewCache& mapInputs) const;
/** Amount of bitcoins spent by this transaction. /** Amount of bitcoins spent by this transaction.
@return sum of all outputs (note: does not include fees) @return sum of all outputs (note: does not include fees)
@ -519,7 +520,7 @@ public:
@return Sum of value of all inputs (scriptSigs) @return Sum of value of all inputs (scriptSigs)
@see CTransaction::FetchInputs @see CTransaction::FetchInputs
*/ */
int64 GetValueIn(CCoinsView& mapInputs) const; int64 GetValueIn(CCoinsViewCache& mapInputs) const;
static bool AllowFree(double dPriority) static bool AllowFree(double dPriority)
{ {
@ -570,14 +571,14 @@ public:
bool ClientCheckInputs() const; bool ClientCheckInputs() const;
// Check whether all prevouts of this transaction are present in the UTXO set represented by view // 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) // Check whether all inputs of this transaction are valid (no double spends, scripts & sigs, amounts)
// This does not modify the UTXO set // 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 // 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 // Context-independent validity checks
bool CheckTransaction() const; bool CheckTransaction() const;
@ -586,7 +587,7 @@ public:
bool AcceptToMemoryPool(bool fCheckInputs=true, bool* pfMissingInputs=NULL); bool AcceptToMemoryPool(bool fCheckInputs=true, bool* pfMissingInputs=NULL);
protected: 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 */ /** 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 // 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 // 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 // Read a block from disk
bool ReadFromDisk(const CBlockIndex* pindex, bool fReadTransactions=true); bool ReadFromDisk(const CBlockIndex* pindex, bool fReadTransactions=true);
@ -1759,11 +1760,15 @@ public:
bool GetCoins(uint256 txid, CCoins &coins); bool GetCoins(uint256 txid, CCoins &coins);
bool SetCoins(uint256 txid, const CCoins &coins); bool SetCoins(uint256 txid, const CCoins &coins);
bool HaveCoins(uint256 txid); bool HaveCoins(uint256 txid);
CCoins &GetCoins(uint256 txid);
CBlockIndex *GetBestBlock(); CBlockIndex *GetBestBlock();
bool SetBestBlock(CBlockIndex *pindex); bool SetBestBlock(CBlockIndex *pindex);
bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex); bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
bool Flush(); bool Flush();
unsigned int GetCacheSize(); unsigned int GetCacheSize();
private:
std::map<uint256,CCoins>::iterator FetchCoins(uint256 txid);
}; };
/** CCoinsView that brings transactions from a memorypool into view. /** CCoinsView that brings transactions from a memorypool into view.

3
src/test/transaction_tests.cpp
View file

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