Add normalized transaction hash

Rebased-from: e7853a91cf646a6a4701158d148f036924575a97
Rebased-by:   Warren Togami <wtogami@gmail.com>

Original code from https://github.com/bitcoin/bitcoin/pull/3656

Warning
=======
This patch was rejected from Bitcoin Core and must be considered experimental.
Theoretically it is compatible with the de facto standard as utilized by
blockchain.info and a few vendors.

src/bitcoinrpc.cpp

@@ -260,6 +260,7 @@ static const CRPCCommand vRPCCommands[] =
     { "decoderawtransaction",   &decoderawtransaction,   false,     false,      false },
     { "signrawtransaction",     &signrawtransaction,     false,     false,      false },
     { "sendrawtransaction",     &sendrawtransaction,     false,     false,      false },
+    { "getnormalizedtxid",      &getnormalizedtxid,      true,      true,       false },
     { "gettxoutsetinfo",        &gettxoutsetinfo,        true,      false,      false },
     { "gettxout",               &gettxout,               true,      false,      false },
     { "lockunspent",            &lockunspent,            false,     false,      true },

src/bitcoinrpc.h

@@ -194,6 +194,7 @@ extern json_spirit::Value createrawtransaction(const json_spirit::Array& params,
 extern json_spirit::Value decoderawtransaction(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value signrawtransaction(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value sendrawtransaction(const json_spirit::Array& params, bool fHelp);
+extern json_spirit::Value getnormalizedtxid(const json_spirit::Array& params, bool fHelp);
 
 extern json_spirit::Value getblockcount(const json_spirit::Array& params, bool fHelp); // in rpcblockchain.cpp
 extern json_spirit::Value getbestblockhash(const json_spirit::Array& params, bool fHelp);

src/main.h

@@ -514,6 +514,11 @@ public:
         return SerializeHash(*this);
     }
 
+    uint256 GetNormalizedHash() const
+    {
+        return SignatureHash(CScript(), *this, 0, SIGHASH_ALL);
+    }
+
     bool IsFinal(int nBlockHeight=0, int64 nBlockTime=0) const
     {
         // Time based nLockTime implemented in 0.1.6

src/rpcrawtransaction.cpp

@@ -576,3 +576,25 @@ Value sendrawtransaction(const Array& params, bool fHelp)
 
     return hashTx.GetHex();
 }
+
+Value getnormalizedtxid(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() != 1)
+        throw runtime_error("blah");
+
+    // parse hex string from parameter
+    vector<unsigned char> txData(ParseHexV(params[0], "parameter"));
+    CDataStream ssData(txData, SER_NETWORK, PROTOCOL_VERSION);
+    CTransaction tx;
+
+    // deserialize binary data stream
+    try {
+        ssData >> tx;
+    }
+    catch (std::exception &e) {
+        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
+    }
+    uint256 hashNormalized = tx.GetNormalizedHash();
+
+    return hashNormalized.GetHex();
+}

src/rpcwallet.cpp

@@ -45,6 +45,7 @@ void WalletTxToJSON(const CWalletTx& wtx, Object& entry)
         entry.push_back(Pair("blocktime", (boost::int64_t)(mapBlockIndex[wtx.hashBlock]->nTime)));
     }
     entry.push_back(Pair("txid", wtx.GetHash().GetHex()));
+    entry.push_back(Pair("normtxid", wtx.GetNormalizedHash().GetHex()));
     entry.push_back(Pair("time", (boost::int64_t)wtx.GetTxTime()));
     entry.push_back(Pair("timereceived", (boost::int64_t)wtx.nTimeReceived));
     BOOST_FOREACH(const PAIRTYPE(string,string)& item, wtx.mapValue)

src/script.h

@@ -670,6 +670,7 @@ public:
 bool IsCanonicalPubKey(const std::vector<unsigned char> &vchPubKey);
 bool IsCanonicalSignature(const std::vector<unsigned char> &vchSig);
 
+uint256 SignatureHash(CScript scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType);
 bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, unsigned int flags, int nHashType);
 bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, std::vector<std::vector<unsigned char> >& vSolutionsRet);
 int ScriptSigArgsExpected(txnouttype t, const std::vector<std::vector<unsigned char> >& vSolutions);