Refactor peg-in witness construction to it's own function

Also changes to Use CVectorWriter instead of casting for peg-in value serialization

src/pegins.cpp

@@ -496,3 +496,45 @@ std::vector<std::pair<CScript, CScript>> GetValidFedpegScripts(const CBlockIndex
     fedpegscripts.resize(std::min(fedpegscripts.size(), params.total_valid_epochs));
     return fedpegscripts;
 }
+
+template<typename T_tx_ref, typename T_merkle_block>
+CScriptWitness CreatePeginWitnessInner(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const T_tx_ref& tx_ref, const T_merkle_block& merkle_block)
+{
+    std::vector<unsigned char> value_bytes;
+    CVectorWriter ss_val(0, 0, value_bytes, 0);
+    try {
+        ss_val << value;
+    } catch (...) {
+        throw std::ios_base::failure("Amount serialization is invalid.");
+    }
+
+    // Strip witness data for proof inclusion since only TXID-covered fields matters
+    CDataStream ss_tx(SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
+    ss_tx << tx_ref;
+    std::vector<unsigned char> tx_data_stripped(ss_tx.begin(), ss_tx.end());
+
+    // Serialize merkle block
+    CDataStream ss_txout_proof(SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
+    ss_txout_proof << merkle_block;
+    std::vector<unsigned char> txout_proof_bytes(ss_txout_proof.begin(), ss_txout_proof.end());
+
+    // Construct pegin proof
+    CScriptWitness pegin_witness;
+    std::vector<std::vector<unsigned char> >& stack = pegin_witness.stack;
+    stack.push_back(value_bytes);
+    stack.push_back(std::vector<unsigned char>(asset.begin(), asset.end()));
+    stack.push_back(std::vector<unsigned char>(genesis_hash.begin(), genesis_hash.end()));
+    stack.push_back(std::vector<unsigned char>(claim_script.begin(), claim_script.end()));
+    stack.push_back(tx_data_stripped);
+    stack.push_back(txout_proof_bytes);
+    return pegin_witness;
+}
+
+CScriptWitness CreatePeginWitness(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const CTransactionRef& tx_ref, const CMerkleBlock& merkle_block)
+{
+    return CreatePeginWitnessInner(value, asset, genesis_hash, claim_script, tx_ref, merkle_block);
+}
+CScriptWitness CreatePeginWitness(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const Sidechain::Bitcoin::CTransactionRef& tx_ref, const Sidechain::Bitcoin::CMerkleBlock& merkle_block)
+{
+    return CreatePeginWitnessInner(value, asset, genesis_hash, claim_script, tx_ref, merkle_block);
+}

src/pegins.h

@@ -7,7 +7,9 @@
 
 #include <amount.h>
 #include <consensus/params.h>
+#include <merkleblock.h>
 #include <primitives/bitcoin/transaction.h>
+#include <primitives/bitcoin/merkleblock.h>
 #include <primitives/transaction.h>
 #include <script/script.h>
 #include <chain.h>
@@ -38,4 +40,9 @@ bool MatchLiquidWatchman(const CScript& script);
  * scriptPubKey for the script, the second is the witnessScript. */
 std::vector<std::pair<CScript, CScript>> GetValidFedpegScripts(const CBlockIndex* pblockindex, const Consensus::Params& params, bool nextblock_validation);
 
+/** Create the peg-in witness stack */
+CScriptWitness CreatePeginWitness(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const CTransactionRef& tx_ref, const CMerkleBlock& merkle_block);
+CScriptWitness CreatePeginWitness(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const Sidechain::Bitcoin::CTransactionRef& tx_ref, const Sidechain::Bitcoin::CMerkleBlock& merkle_block);
+
+
 #endif // BITCOIN_PEGINS_H

src/wallet/rpcwallet.cpp

@@ -5530,19 +5530,6 @@ static UniValue createrawpegin(const JSONRPCRequest& request, T_tx_ref& txBTCRef
         throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Amounts to pegin must be explicit and asset must be %s", Params().GetConsensus().parent_pegged_asset.GetHex()));
     }
 
-    CDataStream stream(0, 0);
-    try {
-        stream << value;
-    } catch (...) {
-        throw JSONRPCError(RPC_INVALID_PARAMETER, "Amount serialization is invalid.");
-    }
-    // Need to reinterpret bytes as unsigned chars before adding to witness
-    char* buf = stream.data();
-    unsigned char* membuf = reinterpret_cast<unsigned char*>(buf);
-    std::vector<unsigned char> value_bytes(membuf, membuf + stream.size());
-
-    uint256 genesisBlockHash = Params().ParentGenesisBlockHash();
-
     // Manually construct peg-in transaction, sign it, and send it off.
     // Decrement the output value as much as needed given the total vsize to
     // pay the fees.
@@ -5566,20 +5553,8 @@ static UniValue createrawpegin(const JSONRPCRequest& request, T_tx_ref& txBTCRef
     mtx.vout.push_back(CTxOut(Params().GetConsensus().pegged_asset, value, GetScriptForDestination(wpkhash)));
     mtx.vout.push_back(CTxOut(Params().GetConsensus().pegged_asset, 0, CScript()));
 
-    // Strip witness data for proof inclusion since only TXID-covered fields matters
-    CDataStream ssTxBack(SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
-    ssTxBack << txBTC;
-    std::vector<unsigned char> tx_data_stripped(ssTxBack.begin(), ssTxBack.end());
-
     // Construct pegin proof
-    CScriptWitness pegin_witness;
-    std::vector<std::vector<unsigned char> >& stack = pegin_witness.stack;
-    stack.push_back(value_bytes);
-    stack.push_back(std::vector<unsigned char>(Params().GetConsensus().pegged_asset.begin(), Params().GetConsensus().pegged_asset.end()));
-    stack.push_back(std::vector<unsigned char>(genesisBlockHash.begin(), genesisBlockHash.end()));
-    stack.push_back(std::vector<unsigned char>(witness_script.begin(), witness_script.end()));
-    stack.push_back(tx_data_stripped);
-    stack.push_back(txOutProofData);
+    CScriptWitness pegin_witness = CreatePeginWitness(value, Params().GetConsensus().pegged_asset, Params().ParentGenesisBlockHash(), witness_script, txBTCRef, merkleBlock);
 
     // Peg-in witness isn't valid, even though the block header is(without depth check)
     // We re-check depth before returning with more descriptive result