Consensus: Refactor: Separate Consensus::CheckTxInputs and GetSpendHeight in CheckInputs

Author: jtimon

src/main.cpp

@@ -1379,22 +1379,21 @@ bool CScriptCheck::operator()() {
     return true;
 }
 
-bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, std::vector<CScriptCheck> *pvChecks)
+int GetSpendHeight(const CCoinsViewCache& inputs)
 {
-    if (!tx.IsCoinBase())
-    {
-        if (pvChecks)
-            pvChecks->reserve(tx.vin.size());
+    LOCK(cs_main);
+    CBlockIndex* pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
+    return pindexPrev->nHeight + 1;
+}
 
+namespace Consensus {
+bool CheckTxInputs(const CTransaction& tx, CValidationState& state, const CCoinsViewCache& inputs, int nSpendHeight)
+{
         // 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 (!inputs.HaveInputs(tx))
             return state.Invalid(error("CheckInputs(): %s inputs unavailable", tx.GetHash().ToString()));
 
-        // While checking, GetBestBlock() refers to the parent block.
-        // This is also true for mempool checks.
-        CBlockIndex *pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
-        int nSpendHeight = pindexPrev->nHeight + 1;
         CAmount nValueIn = 0;
         CAmount nFees = 0;
         for (unsigned int i = 0; i < tx.vin.size(); i++)
@@ -1433,6 +1432,19 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsVi
         if (!MoneyRange(nFees))
             return state.DoS(100, error("CheckInputs(): nFees out of range"),
                              REJECT_INVALID, "bad-txns-fee-outofrange");
+    return true;
+}
+}// namespace Consensus
+
+bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, std::vector<CScriptCheck> *pvChecks)
+{
+    if (!tx.IsCoinBase())
+    {
+        if (!Consensus::CheckTxInputs(tx, state, inputs, GetSpendHeight(inputs)))
+            return false;
+
+        if (pvChecks)
+            pvChecks->reserve(tx.vin.size());
 
         // The first loop above does all the inexpensive checks.
         // Only if ALL inputs pass do we perform expensive ECDSA signature checks.

src/main.h

@@ -507,4 +507,11 @@ extern CCoinsViewCache *pcoinsTip;
 /** Global variable that points to the active block tree (protected by cs_main) */
 extern CBlockTreeDB *pblocktree;
 
+/**
+ * Return the spend height, which is one more than the inputs.GetBestBlock().
+ * While checking, GetBestBlock() refers to the parent block. (protected by cs_main)
+ * This is also true for mempool checks.
+ */
+int GetSpendHeight(const CCoinsViewCache& inputs);
+
 #endif // BITCOIN_MAIN_H