src/transaction_builder.h

   1 // Copyright (c) 2018 The Zcash developers
   2 // Distributed under the MIT software license, see the accompanying
   3 // file COPYING or https://www.opensource.org/licenses/mit-license.php .
   4
   5 #ifndef TRANSACTION_BUILDER_H
   6 #define TRANSACTION_BUILDER_H
   7
   8 #include "coins.h"
   9 #include "consensus/params.h"
  10 #include "keystore.h"
  11 #include "primitives/transaction.h"
  12 #include "script/script.h"
  13 #include "script/standard.h"
  14 #include "uint256.h"
  15 #include "zcash/Address.hpp"
  16 #include "zcash/IncrementalMerkleTree.hpp"
  17 #include "zcash/JoinSplit.hpp"
  18 #include "zcash/Note.hpp"
  19 #include "zcash/NoteEncryption.hpp"
  20
  21 #include <boost/optional.hpp>
  22
  23 struct SpendDescriptionInfo {
  24     libzcash::SaplingExpandedSpendingKey expsk;
  25     libzcash::SaplingNote note;
  26     uint256 alpha;
  27     uint256 anchor;
  28     SaplingWitness witness;
  29
  30     SpendDescriptionInfo(
  31         libzcash::SaplingExpandedSpendingKey expsk,
  32         libzcash::SaplingNote note,
  33         uint256 anchor,
  34         SaplingWitness witness);
  35 };
  36
  37 struct OutputDescriptionInfo {
  38     uint256 ovk;
  39     libzcash::SaplingNote note;
  40     std::array<unsigned char, ZC_MEMO_SIZE> memo;
  41
  42     OutputDescriptionInfo(
  43         uint256 ovk,
  44         libzcash::SaplingNote note,
  45         std::array<unsigned char, ZC_MEMO_SIZE> memo) : ovk(ovk), note(note), memo(memo) {}
  46 };
  47
  48 struct TransparentInputInfo {
  49     CScript scriptPubKey;
  50     CAmount value;
  51
  52     TransparentInputInfo(
  53         CScript scriptPubKey,
  54         CAmount value) : scriptPubKey(scriptPubKey), value(value) {}
  55 };
  56
  57 class TransactionBuilderResult {
  58 private:
  59     boost::optional<CTransaction> maybeTx;
  60     boost::optional<std::string> maybeError;
  61 public:
  62     TransactionBuilderResult() = delete;
  63     TransactionBuilderResult(const CTransaction& tx);
  64     TransactionBuilderResult(const std::string& error);
  65     bool IsTx();
  66     bool IsError();
  67     CTransaction GetTxOrThrow();
  68     std::string GetError();
  69 };
  70
  71 class TransactionBuilder
  72 {
  73 private:
  74     Consensus::Params consensusParams;
  75     int nHeight;
  76     const CKeyStore* keystore;
  77     ZCJoinSplit* sproutParams;
  78     const CCoinsViewCache* coinsView;
  79     CCriticalSection* cs_coinsView;
  80     CMutableTransaction mtx;
  81     CAmount fee = 10000;
  82
  83     std::vector<SpendDescriptionInfo> spends;
  84     std::vector<OutputDescriptionInfo> outputs;
  85     std::vector<libzcash::JSInput> jsInputs;
  86     std::vector<libzcash::JSOutput> jsOutputs;
  87     std::vector<TransparentInputInfo> tIns;
  88
  89     boost::optional<std::pair<uint256, libzcash::SaplingPaymentAddress>> saplingChangeAddr;
  90     boost::optional<libzcash::SproutPaymentAddress> sproutChangeAddr;
  91     boost::optional<CTxDestination> tChangeAddr;
  92
  93 public:
  94     TransactionBuilder() {}
  95     TransactionBuilder(
  96         const Consensus::Params& consensusParams,
  97         int nHeight,
  98         int nExpiryDelta,
  99         CKeyStore* keyStore = nullptr,
 100         ZCJoinSplit* sproutParams = nullptr,
 101         CCoinsViewCache* coinsView = nullptr,
 102         CCriticalSection* cs_coinsView = nullptr);
 103
 104     void SetFee(CAmount fee);
 105
 106     // Throws if the anchor does not match the anchor used by
 107     // previously-added Sapling spends.
 108     void AddSaplingSpend(
 109         libzcash::SaplingExpandedSpendingKey expsk,
 110         libzcash::SaplingNote note,
 111         uint256 anchor,
 112         SaplingWitness witness);
 113
 114     void AddSaplingOutput(
 115         uint256 ovk,
 116         libzcash::SaplingPaymentAddress to,
 117         CAmount value,
 118         std::array<unsigned char, ZC_MEMO_SIZE> memo = {{0xF6}});
 119
 120     // Throws if the anchor does not match the anchor used by
 121     // previously-added Sprout inputs.
 122     void AddSproutInput(
 123         libzcash::SproutSpendingKey sk,
 124         libzcash::SproutNote note,
 125         SproutWitness witness);
 126
 127     void AddSproutOutput(
 128         libzcash::SproutPaymentAddress to,
 129         CAmount value,
 130         std::array<unsigned char, ZC_MEMO_SIZE> memo = {{0xF6}});
 131
 132     // Assumes that the value correctly corresponds to the provided UTXO.
 133     void AddTransparentInput(COutPoint utxo, CScript scriptPubKey, CAmount value);
 134
 135     void AddTransparentOutput(CTxDestination& to, CAmount value);
 136
 137     void SendChangeTo(libzcash::SaplingPaymentAddress changeAddr, uint256 ovk);
 138
 139     void SendChangeTo(libzcash::SproutPaymentAddress);
 140
 141     void SendChangeTo(CTxDestination& changeAddr);
 142
 143     TransactionBuilderResult Build();
 144
 145 private:
 146     void CreateJSDescriptions();
 147
 148     void CreateJSDescription(
 149         uint64_t vpub_old,
 150         uint64_t vpub_new,
 151         std::array<libzcash::JSInput, ZC_NUM_JS_INPUTS> vjsin,
 152         std::array<libzcash::JSOutput, ZC_NUM_JS_OUTPUTS> vjsout,
 153         std::array<size_t, ZC_NUM_JS_INPUTS>& inputMap,
 154         std::array<size_t, ZC_NUM_JS_OUTPUTS>& outputMap);
 155 };
 156
 157 #endif /* TRANSACTION_BUILDER_H */