Transaction hash caching

Use CBlock's vMerkleTree to cache transaction hashes, and pass them
along as argument in more function calls. During initial block download,
this results in every transaction's hash to be only computed once.

src/main.cpp

@@ -111,10 +111,10 @@ void static EraseFromWallets(uint256 hash)
 }
 
 // make sure all wallets know about the given transaction, in the given block
-void SyncWithWallets(const CTransaction& tx, const CBlock* pblock, bool fUpdate)
+void SyncWithWallets(const uint256 &hash, const CTransaction& tx, const CBlock* pblock, bool fUpdate)
 {
     BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
-        pwallet->AddToWalletIfInvolvingMe(tx, pblock, fUpdate);
+        pwallet->AddToWalletIfInvolvingMe(hash, tx, pblock, fUpdate);
 }
 
 // notify wallets about a new best chain
@@ -1197,10 +1197,8 @@ unsigned int CTransaction::GetP2SHSigOpCount(CCoinsView& inputs) const
     return nSigOps;
 }
 
-bool CTransaction::UpdateCoins(CCoinsView &inputs, CTxUndo &txundo, int nHeight) const
+bool CTransaction::UpdateCoins(CCoinsView &inputs, CTxUndo &txundo, int nHeight, const uint256 &txhash) const
 {
-    uint256 hash = GetHash();
-
     // mark inputs spent
     if (!IsCoinBase()) {
         BOOST_FOREACH(const CTxIn &txin, vin) {
@@ -1217,7 +1215,7 @@ bool CTransaction::UpdateCoins(CCoinsView &inputs, CTxUndo &txundo, int nHeight)
     }
 
     // add outputs
-    if (!inputs.SetCoins(hash, CCoins(*this, nHeight)))
+    if (!inputs.SetCoins(txhash, CCoins(*this, nHeight)))
         return error("UpdateCoins() : cannot update output");
 
     return true;
@@ -1467,8 +1465,8 @@ bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsView &view, bool fJustCheck
     bool fEnforceBIP30 = !((pindex->nHeight==91842 && pindex->GetBlockHash() == uint256("0x00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec")) ||
                            (pindex->nHeight==91880 && pindex->GetBlockHash() == uint256("0x00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721")));
     if (fEnforceBIP30) {
-        BOOST_FOREACH(CTransaction& tx, vtx) {
-            uint256 hash = tx.GetHash();
+        for (unsigned int i=0; i<vtx.size(); i++) {
+            uint256 hash = GetTxHash(i);
             CCoins coins;
             if (view.GetCoins(hash, coins) && !coins.IsPruned())
                 return error("ConnectBlock() : tried to overwrite transaction");
@@ -1483,8 +1481,10 @@ bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsView &view, bool fJustCheck
 
     int64 nFees = 0;
     unsigned int nSigOps = 0;
-    BOOST_FOREACH(CTransaction& tx, vtx)
+    for (unsigned int i=0; i<vtx.size(); i++)
     {
+        const CTransaction &tx = vtx[i];
+
         nSigOps += tx.GetLegacySigOpCount();
         if (nSigOps > MAX_BLOCK_SIGOPS)
             return DoS(100, error("ConnectBlock() : too many sigops"));
@@ -1511,7 +1511,7 @@ bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsView &view, bool fJustCheck
         }
 
         CTxUndo txundo;
-        if (!tx.UpdateCoins(view, txundo, pindex->nHeight))
+        if (!tx.UpdateCoins(view, txundo, pindex->nHeight, GetTxHash(i)))
             return error("ConnectBlock() : UpdateInputs failed");
         if (!tx.IsCoinBase())
             blockundo.vtxundo.push_back(txundo);
@@ -1542,8 +1542,8 @@ bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsView &view, bool fJustCheck
         return false;
 
     // Watch for transactions paying to me
-    BOOST_FOREACH(CTransaction& tx, vtx)
-        SyncWithWallets(tx, this, true);
+    for (unsigned int i=0; i<vtx.size(); i++)
+        SyncWithWallets(GetTxHash(i), vtx[i], this, true);
 
     return true;
 }
@@ -1755,7 +1755,7 @@ bool CBlock::AddToBlockIndex(const CDiskBlockPos &pos)
         // Notify UI to display prev block's coinbase if it was ours
         static uint256 hashPrevBestCoinBase;
         UpdatedTransaction(hashPrevBestCoinBase);
-        hashPrevBestCoinBase = vtx[0].GetHash();
+        hashPrevBestCoinBase = GetTxHash(0);
     }
 
     uiInterface.NotifyBlocksChanged();
@@ -1876,10 +1876,10 @@ bool CBlock::CheckBlock(bool fCheckPOW, bool fCheckMerkleRoot) const
 
     // Check for duplicate txids. This is caught by ConnectInputs(),
     // but catching it earlier avoids a potential DoS attack:
+    BuildMerkleTree();
     set<uint256> uniqueTx;
-    BOOST_FOREACH(const CTransaction& tx, vtx)
-    {
-        uniqueTx.insert(tx.GetHash());
+    for (unsigned int i=0; i<vtx.size(); i++) {
+        uniqueTx.insert(GetTxHash(i));
     }
     if (uniqueTx.size() != vtx.size())
         return DoS(100, error("CheckBlock() : duplicate transaction"));
@@ -2914,7 +2914,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         bool fMissingInputs = false;
         if (tx.AcceptToMemoryPool(true, &fMissingInputs))
         {
-            SyncWithWallets(tx, NULL, true);
+            SyncWithWallets(inv.hash, tx, NULL, true);
             RelayMessage(inv, vMsg);
             mapAlreadyAskedFor.erase(inv);
             vWorkQueue.push_back(inv.hash);
@@ -2937,7 +2937,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                     if (tx.AcceptToMemoryPool(true, &fMissingInputs2))
                     {
                         printf("   accepted orphan tx %s\n", inv.hash.ToString().substr(0,10).c_str());
-                        SyncWithWallets(tx, NULL, true);
+                        SyncWithWallets(inv.hash, tx, NULL, true);
                         RelayMessage(inv, vMsg);
                         mapAlreadyAskedFor.erase(inv);
                         vWorkQueue.push_back(inv.hash);
@@ -3729,7 +3729,8 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
                 continue;
 
             CTxUndo txundo;
-            if (!tx.UpdateCoins(viewTemp, txundo, pindexPrev->nHeight+1))
+            uint256 hash = tx.GetHash();
+            if (!tx.UpdateCoins(viewTemp, txundo, pindexPrev->nHeight+1, hash))
                 continue;
 
             // push changes from the second layer cache to the first one
@@ -3749,7 +3750,6 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
             }
 
             // Add transactions that depend on this one to the priority queue
-            uint256 hash = tx.GetHash();
             if (mapDependers.count(hash))
             {
                 BOOST_FOREACH(COrphan* porphan, mapDependers[hash])

src/main.h

@@ -91,7 +91,7 @@ class CCoinsView;
 
 void RegisterWallet(CWallet* pwalletIn);
 void UnregisterWallet(CWallet* pwalletIn);
-void SyncWithWallets(const CTransaction& tx, const CBlock* pblock = NULL, bool fUpdate = false);
+void SyncWithWallets(const uint256 &hash, const CTransaction& tx, const CBlock* pblock = NULL, bool fUpdate = false);
 bool ProcessBlock(CNode* pfrom, CBlock* pblock);
 bool CheckDiskSpace(uint64 nAdditionalBytes=0);
 FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly = false);
@@ -577,7 +577,7 @@ public:
     bool CheckInputs(CCoinsView &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;
+    bool UpdateCoins(CCoinsView &view, CTxUndo &txundo, int nHeight, const uint256 &txhash) const;
 
     // Context-independent validity checks
     bool CheckTransaction() const;
@@ -1111,6 +1111,12 @@ public:
         return (vMerkleTree.empty() ? 0 : vMerkleTree.back());
     }
 
+    const uint256 &GetTxHash(unsigned int nIndex) const {
+        assert(vMerkleTree.size() > 0); // BuildMerkleTree must have been called first
+        assert(nIndex < vtx.size());
+        return vMerkleTree[nIndex];
+    }
+
     std::vector<uint256> GetMerkleBranch(int nIndex) const
     {
         if (vMerkleTree.empty())

src/rpcrawtransaction.cpp

@@ -517,7 +517,7 @@ Value sendrawtransaction(const Array& params, bool fHelp)
         // Not in block, but already in the memory pool; will drop
         // through to re-relay it.
     } else {
-        SyncWithWallets(tx, NULL, true);
+        SyncWithWallets(hashTx, tx, NULL, true);
     }
     RelayMessage(CInv(MSG_TX, hashTx), tx);
 

src/wallet.cpp

@@ -479,9 +479,8 @@ bool CWallet::AddToWallet(const CWalletTx& wtxIn)
 // Add a transaction to the wallet, or update it.
 // pblock is optional, but should be provided if the transaction is known to be in a block.
 // If fUpdate is true, existing transactions will be updated.
-bool CWallet::AddToWalletIfInvolvingMe(const CTransaction& tx, const CBlock* pblock, bool fUpdate, bool fFindBlock)
+bool CWallet::AddToWalletIfInvolvingMe(const uint256 &hash, const CTransaction& tx, const CBlock* pblock, bool fUpdate, bool fFindBlock)
 {
-    uint256 hash = tx.GetHash();
     {
         LOCK(cs_wallet);
         bool fExisted = mapWallet.count(hash);
@@ -756,7 +755,7 @@ int CWallet::ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate)
             block.ReadFromDisk(pindex, true);
             BOOST_FOREACH(CTransaction& tx, block.vtx)
             {
-                if (AddToWalletIfInvolvingMe(tx, &block, fUpdate))
+                if (AddToWalletIfInvolvingMe(tx.GetHash(), tx, &block, fUpdate))
                     ret++;
             }
             pindex = pindex->pnext;

src/wallet.h

@@ -162,7 +162,7 @@ public:
 
     void MarkDirty();
     bool AddToWallet(const CWalletTx& wtxIn);
-    bool AddToWalletIfInvolvingMe(const CTransaction& tx, const CBlock* pblock, bool fUpdate = false, bool fFindBlock = false);
+    bool AddToWalletIfInvolvingMe(const uint256 &hash, const CTransaction& tx, const CBlock* pblock, bool fUpdate = false, bool fFindBlock = false);
     bool EraseFromWallet(uint256 hash);
     void WalletUpdateSpent(const CTransaction& prevout);
     int ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate = false);