From 6a4bd809d3d79209ef43ee55304e744d23409582 Mon Sep 17 00:00:00 2001
From: CryptoManiac <balthazar@yandex.ru>
Date: Wed, 16 Jul 2014 03:26:55 +0400
Subject: [PATCH] Replace VerifyScript with CScriptCheck

CScriptCheck is a closure representing a script check.
---
 src/main.cpp |   18 ++++++++----------
 src/main.h   |   29 +++++++++++++++++++++++++++--
 2 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 48b9d30..a0d3531 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1458,18 +1458,16 @@ unsigned int CTransaction::GetP2SHSigOpCount(const MapPrevTx& inputs) const
     return nSigOps;
 }
 
+bool CScriptCheck::operator()() const {
+    const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
+    if (!VerifyScript(scriptSig, scriptPubKey, *ptxTo, nIn, nFlags, nHashType))
+        return error("CScriptCheck() : %s VerifySignature failed", ptxTo->GetHash().ToString().substr(0,10).c_str());
+    return true;
+}
+
 bool VerifySignature(const CTransaction& txFrom, const CTransaction& txTo, unsigned int nIn, unsigned int flags, int nHashType)
 {
-    assert(nIn < txTo.vin.size());
-    const CTxIn& txin = txTo.vin[nIn];
-    if (txin.prevout.n >= txFrom.vout.size())
-        return false;
-    const CTxOut& txout = txFrom.vout[txin.prevout.n];
-
-    if (txin.prevout.hash != txFrom.GetHash())
-        return false;
-
-    return VerifyScript(txin.scriptSig, txout.scriptPubKey, txTo, nIn, flags, nHashType);
+    return CScriptCheck(txFrom, txTo, nIn, flags, nHashType)();
 }
 
 bool CTransaction::ConnectInputs(CTxDB& txdb, MapPrevTx inputs, map<uint256, CTxIndex>& mapTestPool, const CDiskTxPos& posThisTx,
diff --git a/src/main.h b/src/main.h
index 081661e..dc8499a 100644
--- a/src/main.h
+++ b/src/main.h
@@ -132,8 +132,6 @@ bool VerifySignature(const CTransaction& txFrom, const CTransaction& txTo, unsig
 
 
 
-
-
 bool GetWalletFile(CWallet* pwallet, std::string &strWalletFileOut);
 
 /** Position on disk for a particular transaction. */
@@ -707,6 +705,33 @@ protected:
     const CTxOut& GetOutputFor(const CTxIn& input, const MapPrevTx& inputs) const;
 };
 
+/** Closure representing one script verification
+ *  Note that this stores references to the spending transaction */
+class CScriptCheck
+{
+private:
+    CScript scriptPubKey;
+    const CTransaction *ptxTo;
+    unsigned int nIn;
+    unsigned int nFlags;
+    int nHashType;
+
+public:
+    CScriptCheck() {}
+    CScriptCheck(const CTransaction& txFromIn, const CTransaction& txToIn, unsigned int nInIn, unsigned int nFlagsIn, int nHashTypeIn) :
+        scriptPubKey(txFromIn.vout[txToIn.vin[nInIn].prevout.n].scriptPubKey),
+        ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), nHashType(nHashTypeIn) { }
+
+    bool operator()() const;
+
+    void swap(CScriptCheck &check) {
+        scriptPubKey.swap(check.scriptPubKey);
+        std::swap(ptxTo, check.ptxTo);
+        std::swap(nIn, check.nIn);
+        std::swap(nFlags, check.nFlags);
+        std::swap(nHashType, check.nHashType);
+    }
+};
 
 
 
-- 
1.7.1