From 64dd46fd05de1dd8ff5066e192e1345f733c6a1f Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Sun, 8 Jul 2012 00:06:34 +0200
Subject: 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 | 40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

(limited to 'src/main.cpp')

diff --git a/src/main.cpp b/src/main.cpp
index c23aae320..a4f90dda7 100644
--- a/src/main.cpp
+++ b/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])
-- 
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