src/undo.h

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2017 The Bitcoin Core developers
   3 // Distributed under the MIT software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #ifndef BITCOIN_UNDO_H
   7 #define BITCOIN_UNDO_H
   8
   9 #include <compressor.h>
  10 #include <consensus/consensus.h>
  11 #include <primitives/transaction.h>
  12 #include <serialize.h>
  13
  14 /** Undo information for a CTxIn
  15  *
  16  *  Contains the prevout's CTxOut being spent, and its metadata as well
  17  *  (coinbase or not, height). The serialization contains a dummy value of
  18  *  zero. This is be compatible with older versions which expect to see
  19  *  the transaction version there.
  20  */
  21 class TxInUndoSerializer
  22 {
  23     const Coin* txout;
  24
  25 public:
  26     template<typename Stream>
  27     void Serialize(Stream &s) const {
  28         ::Serialize(s, VARINT(txout->nHeight * 2 + (txout->fCoinBase ? 1 : 0)));
  29         if (txout->nHeight > 0) {
  30             // Required to maintain compatibility with older undo format.
  31             ::Serialize(s, (unsigned char)0);
  32         }
  33         ::Serialize(s, CTxOutCompressor(REF(txout->out)));
  34     }
  35
  36     explicit TxInUndoSerializer(const Coin* coin) : txout(coin) {}
  37 };
  38
  39 class TxInUndoDeserializer
  40 {
  41     Coin* txout;
  42
  43 public:
  44     template<typename Stream>
  45     void Unserialize(Stream &s) {
  46         unsigned int nCode = 0;
  47         ::Unserialize(s, VARINT(nCode));
  48         txout->nHeight = nCode / 2;
  49         txout->fCoinBase = nCode & 1;
  50         if (txout->nHeight > 0) {
  51             // Old versions stored the version number for the last spend of
  52             // a transaction's outputs. Non-final spends were indicated with
  53             // height = 0.
  54             int nVersionDummy;
  55             ::Unserialize(s, VARINT(nVersionDummy));
  56         }
  57         ::Unserialize(s, REF(CTxOutCompressor(REF(txout->out))));
  58     }
  59
  60     explicit TxInUndoDeserializer(Coin* coin) : txout(coin) {}
  61 };
  62
  63 static const size_t MIN_TRANSACTION_INPUT_WEIGHT = WITNESS_SCALE_FACTOR * ::GetSerializeSize(CTxIn(), SER_NETWORK, PROTOCOL_VERSION);
  64 static const size_t MAX_INPUTS_PER_BLOCK = MAX_BLOCK_WEIGHT / MIN_TRANSACTION_INPUT_WEIGHT;
  65
  66 /** Undo information for a CTransaction */
  67 class CTxUndo
  68 {
  69 public:
  70     // undo information for all txins
  71     std::vector<Coin> vprevout;
  72
  73     template <typename Stream>
  74     void Serialize(Stream& s) const {
  75         // TODO: avoid reimplementing vector serializer
  76         uint64_t count = vprevout.size();
  77         ::Serialize(s, COMPACTSIZE(REF(count)));
  78         for (const auto& prevout : vprevout) {
  79             ::Serialize(s, REF(TxInUndoSerializer(&prevout)));
  80         }
  81     }
  82
  83     template <typename Stream>
  84     void Unserialize(Stream& s) {
  85         // TODO: avoid reimplementing vector deserializer
  86         uint64_t count = 0;
  87         ::Unserialize(s, COMPACTSIZE(count));
  88         if (count > MAX_INPUTS_PER_BLOCK) {
  89             throw std::ios_base::failure("Too many input undo records");
  90         }
  91         vprevout.resize(count);
  92         for (auto& prevout : vprevout) {
  93             ::Unserialize(s, REF(TxInUndoDeserializer(&prevout)));
  94         }
  95     }
  96 };
  97
  98 /** Undo information for a CBlock */
  99 class CBlockUndo
 100 {
 101 public:
 102     std::vector<CTxUndo> vtxundo; // for all but the coinbase
 103
 104     ADD_SERIALIZE_METHODS;
 105
 106     template <typename Stream, typename Operation>
 107     inline void SerializationOp(Stream& s, Operation ser_action) {
 108         READWRITE(vtxundo);
 109     }
 110 };
 111
 112 #endif // BITCOIN_UNDO_H