Use const CCoinsView's at some places.

At some places where it is possible (e. g., CheckInputs), use a const
version of CCoinsView instead of a non-const one.

src/main.cpp

@@ -644,7 +644,7 @@ bool IsFinalTx(const CTransaction &tx, int nBlockHeight, int64_t nBlockTime)
 // 2. P2SH scripts with a crazy number of expensive
 //    CHECKSIG/CHECKMULTISIG operations
 //
-bool AreInputsStandard(const CTransaction& tx, CCoinsViewCache& mapInputs)
+bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
 {
     if (tx.IsCoinBase())
         return true; // Coinbases don't use vin normally
@@ -717,7 +717,7 @@ unsigned int GetLegacySigOpCount(const CTransaction& tx)
     return nSigOps;
 }
 
-unsigned int GetP2SHSigOpCount(const CTransaction& tx, CCoinsViewCache& inputs)
+unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& inputs)
 {
     if (tx.IsCoinBase())
         return 0;
@@ -1470,7 +1470,7 @@ bool VerifySignature(const CCoins& txFrom, const CTransaction& txTo, unsigned in
     return CScriptCheck(txFrom, txTo, nIn, flags, nHashType)();
 }
 
-bool CheckInputs(const CTransaction& tx, CValidationState &state, CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, std::vector<CScriptCheck> *pvChecks)
+bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, std::vector<CScriptCheck> *pvChecks)
 {
     if (!tx.IsCoinBase())
     {

src/main.h

@@ -265,7 +265,7 @@ int64_t GetMinRelayFee(const CTransaction& tx, unsigned int nBytes, bool fAllowF
     @param[in] mapInputs    Map of previous transactions that have outputs we're spending
     @return True if all inputs (scriptSigs) use only standard transaction forms
 */
-bool AreInputsStandard(const CTransaction& tx, CCoinsViewCache& mapInputs);
+bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs);
 
 /** Count ECDSA signature operations the old-fashioned (pre-0.6) way
     @return number of sigops this transaction's outputs will produce when spent
@@ -279,13 +279,13 @@ unsigned int GetLegacySigOpCount(const CTransaction& tx);
     @return maximum number of sigops required to validate this transaction's inputs
     @see CTransaction::FetchInputs
  */
-unsigned int GetP2SHSigOpCount(const CTransaction& tx, CCoinsViewCache& mapInputs);
+unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& mapInputs);
 
 
 // Check whether all inputs of this transaction are valid (no double spends, scripts & sigs, amounts)
 // This does not modify the UTXO set. If pvChecks is not NULL, script checks are pushed onto it
 // instead of being performed inline.
-bool CheckInputs(const CTransaction& tx, CValidationState &state, CCoinsViewCache &view, bool fScriptChecks = true,
+bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &view, bool fScriptChecks = true,
                  unsigned int flags = STANDARD_SCRIPT_VERIFY_FLAGS,
                  std::vector<CScriptCheck> *pvChecks = NULL);
 

src/txmempool.cpp

@@ -484,7 +484,7 @@ void CTxMemPool::clear()
     ++nTransactionsUpdated;
 }
 
-void CTxMemPool::check(CCoinsViewCache *pcoins) const
+void CTxMemPool::check(const CCoinsViewCache *pcoins) const
 {
     if (!fSanityCheck)
         return;
@@ -505,7 +505,7 @@ void CTxMemPool::check(CCoinsViewCache *pcoins) const
                 const CTransaction& tx2 = it2->second.GetTx();
                 assert(tx2.vout.size() > txin.prevout.n && !tx2.vout[txin.prevout.n].IsNull());
             } else {
-                CCoins &coins = pcoins->GetCoins(txin.prevout.hash);
+                const CCoins &coins = pcoins->GetCoins(txin.prevout.hash);
                 assert(coins.IsAvailable(txin.prevout.n));
             }
             // Check whether its inputs are marked in mapNextTx.

src/txmempool.h

@@ -85,7 +85,7 @@ public:
      * all inputs are in the mapNextTx array). If sanity-checking is turned off,
      * check does nothing.
      */
-    void check(CCoinsViewCache *pcoins) const;
+    void check(const CCoinsViewCache *pcoins) const;
     void setSanityCheck(bool _fSanityCheck) { fSanityCheck = _fSanityCheck; }
 
     bool addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry);