TransactionBuilder: Add support for transparent inputs and outputs

src/transaction_builder.h

@@ -6,7 +6,10 @@
 #define TRANSACTION_BUILDER_H
 
 #include "consensus/params.h"
+#include "keystore.h"
 #include "primitives/transaction.h"
+#include "script/script.h"
+#include "script/standard.h"
 #include "uint256.h"
 #include "zcash/Address.hpp"
 #include "zcash/IncrementalMerkleTree.hpp"
@@ -40,18 +43,29 @@ struct OutputDescriptionInfo {
         std::array<unsigned char, ZC_MEMO_SIZE> memo) : ovk(ovk), note(note), memo(memo) {}
 };
 
+struct TransparentInputInfo {
+    CScript scriptPubKey;
+    CAmount value;
+
+    TransparentInputInfo(
+        CScript scriptPubKey,
+        CAmount value) : scriptPubKey(scriptPubKey), value(value) {}
+};
+
 class TransactionBuilder
 {
 private:
     Consensus::Params consensusParams;
     int nHeight;
+    const CKeyStore* keystore;
     CMutableTransaction mtx;
 
     std::vector<SpendDescriptionInfo> spends;
     std::vector<OutputDescriptionInfo> outputs;
+    std::vector<TransparentInputInfo> tIns;
 
 public:
-    TransactionBuilder(const Consensus::Params& consensusParams, int nHeight);
+    TransactionBuilder(const Consensus::Params& consensusParams, int nHeight, CKeyStore* keyStore = nullptr);
 
     // Returns false if the anchor does not match the anchor used by
     // previously-added Sapling spends.
@@ -67,6 +81,11 @@ public:
         CAmount value,
         std::array<unsigned char, ZC_MEMO_SIZE> memo);
 
+    // Assumes that the value correctly corresponds to the provided UTXO.
+    void AddTransparentInput(COutPoint utxo, CScript scriptPubKey, CAmount value);
+
+    bool AddTransparentOutput(CTxDestination& to, CAmount value);
+
     boost::optional<CTransaction> Build();
 };