Line data    Source code

       1             : // Copyright (c) 2018-2020 The Zcash developers
       2             : // Copyright (c) 2020-2021 The PIVX Core developers
       3             : // Distributed under the MIT software license, see the accompanying
       4             : // file COPYING or https://www.opensource.org/licenses/mit-license.php .
       5             : 
       6             : #ifndef PIVX_SAPLING_TRANSACTION_BUILDER_H
       7             : #define PIVX_SAPLING_TRANSACTION_BUILDER_H
       8             : 
       9             : #include "coins.h"
      10             : #include "consensus/params.h"
      11             : #include "keystore.h"
      12             : #include "optional.h"
      13             : #include "primitives/transaction.h"
      14             : #include "script/script.h"
      15             : #include "script/standard.h"
      16             : #include "uint256.h"
      17             : #include "sapling/address.h"
      18             : #include "sapling/incrementalmerkletree.h"
      19             : #include "sapling/note.h"
      20             : #include "sapling/noteencryption.h"
      21             : 
      22         192 : struct SpendDescriptionInfo {
      23             :     libzcash::SaplingExpandedSpendingKey expsk;
      24             :     libzcash::SaplingNote note;
      25             :     uint256 alpha;
      26             :     uint256 anchor;
      27             :     SaplingWitness witness;
      28             : 
      29             :     SpendDescriptionInfo(
      30             :         const libzcash::SaplingExpandedSpendingKey& _expsk,
      31             :         const libzcash::SaplingNote& _note,
      32             :         const uint256& _anchor,
      33             :         const SaplingWitness& _witness);
      34             : };
      35             : 
      36        3821 : struct OutputDescriptionInfo {
      37             :     uint256 ovk;
      38             :     libzcash::SaplingNote note;
      39             :     std::array<unsigned char, ZC_MEMO_SIZE> memo;
      40             : 
      41        2396 :     OutputDescriptionInfo(
      42             :         const uint256& _ovk,
      43             :         const libzcash::SaplingNote& _note,
      44        2396 :         const std::array<unsigned char, ZC_MEMO_SIZE>& _memo):
      45             :             ovk(_ovk),
      46             :             note(_note),
      47        2396 :             memo(_memo)
      48             :     {}
      49             : 
      50             :     Optional<OutputDescription> Build(void* ctx);
      51             : };
      52             : 
      53        9591 : struct TransparentInputInfo {
      54             :     CScript scriptPubKey;
      55             :     CAmount value;
      56             : 
      57        2374 :     TransparentInputInfo(const CScript& _scriptPubKey, CAmount _value):
      58             :         scriptPubKey(_scriptPubKey),
      59        2374 :         value(_value)
      60             :     {}
      61             : };
      62             : 
      63             : // Dummy constants used during fee-calculation loop
      64             : extern const OutputDescription DUMMY_SHIELD_OUT;
      65             : extern const SpendDescription DUMMY_SHIELD_SPEND;
      66             : extern const SaplingTxData::binding_sig_t DUMMY_SHIELD_BINDSIG;
      67             : 
      68             : class TransactionBuilderResult {
      69             : private:
      70             :     Optional<CTransaction> maybeTx;
      71             :     Optional<std::string> maybeError;
      72             : public:
      73             :     TransactionBuilderResult() = delete;
      74             :     explicit TransactionBuilderResult(const CTransaction& tx);
      75             :     explicit TransactionBuilderResult(const std::string& error);
      76             :     bool IsTx();
      77             :     bool IsError();
      78             :     CTransaction GetTxOrThrow();
      79             :     Optional<CTransaction> GetTx();
      80             :     std::string GetError();
      81             : };
      82             : 
      83             : class TransactionBuilder
      84             : {
      85             : private:
      86             :     Consensus::Params consensusParams;
      87             :     const CKeyStore* keystore;
      88             :     CMutableTransaction mtx;
      89             :     CAmount fee = -1;   // Verified in Build(). Must be set before.
      90             : 
      91             :     std::vector<SpendDescriptionInfo> spends;
      92             :     std::vector<OutputDescriptionInfo> outputs;
      93             :     std::vector<TransparentInputInfo> tIns;
      94             : 
      95             :     Optional<std::pair<uint256, libzcash::SaplingPaymentAddress>> saplingChangeAddr;
      96             :     Optional<CTxDestination> tChangeAddr;
      97             : 
      98             : public:
      99             :     explicit TransactionBuilder(
     100             :         const Consensus::Params& consensusParams,
     101             :         CKeyStore* keyStore = nullptr);
     102             : 
     103             :     void Clear();
     104             : 
     105             :     void SetFee(CAmount _fee);
     106             : 
     107             :     // Throws if the anchor does not match the anchor used by
     108             :     // previously-added Sapling spends.
     109             :     void AddSaplingSpend(
     110             :         const libzcash::SaplingExpandedSpendingKey& expsk,
     111             :         const libzcash::SaplingNote& note,
     112             :         const uint256& anchor,
     113             :         const SaplingWitness& witness);
     114             : 
     115             :     void AddSaplingOutput(
     116             :         const uint256& ovk,
     117             :         const libzcash::SaplingPaymentAddress& to,
     118             :         CAmount value,
     119             :         const std::array<unsigned char, ZC_MEMO_SIZE>& memo);
     120             : 
     121          72 :     void AddSaplingOutput(
     122             :         const uint256& ovk,
     123             :         const libzcash::SaplingPaymentAddress& to,
     124             :         CAmount value)
     125             :     {
     126          72 :         const std::array<unsigned char, ZC_MEMO_SIZE> memo = {{0xF6}};
     127          72 :         AddSaplingOutput(ovk, to, value, memo);
     128          72 :     }
     129             : 
     130             :     // Assumes that the value correctly corresponds to the provided UTXO.
     131             :     void AddTransparentInput(const COutPoint& utxo, const CScript& scriptPubKey, CAmount value);
     132             : 
     133             :     void AddTransparentOutput(const CTxOut& out);
     134             :     void AddTransparentOutput(const CTxDestination& dest, CAmount value);
     135             : 
     136             :     void SendChangeTo(const libzcash::SaplingPaymentAddress& changeAddr, const uint256& ovk);
     137             : 
     138             :     void SendChangeTo(const CTxDestination& changeAddr);
     139             : 
     140             :     TransactionBuilderResult Build(bool fDummySig = false);
     141             :     // Add Sapling Spend/Output descriptions, binding sig, and transparent signatures
     142             :     TransactionBuilderResult ProveAndSign();
     143             :     // Add dummy Sapling Spend/Output descriptions, binding sig, and transparent signatures
     144             :     TransactionBuilderResult AddDummySignatures();
     145             :     // Remove Sapling Spend/Output descriptions, binding sig, and transparent signatures
     146             :     void ClearProofsAndSignatures();
     147             : };
     148             : 
     149             : #endif // PIVX_SAPLING_TRANSACTION_BUILDER_H