1// Copyright (c) 2009-2010 Satoshi Nakamoto
2// Copyright (c) 2009-present 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 <coins.h>
10#include <compressor.h>
11#include <consensus/consensus.h>
12#include <primitives/transaction.h>
13#include <serialize.h>
14
15/** Formatter for undo information for a CTxIn
16 *
17 *  Contains the prevout's CTxOut being spent, and its metadata as well
18 *  (coinbase or not, height). The serialization contains a dummy value of
19 *  zero. This is compatible with older versions which expect to see
20 *  the transaction version there.
21 */
22struct TxInUndoFormatter
23{
24    template<typename Stream>
25    void Ser(Stream &s, const Coin& txout) {
26        uint32_t nCode{(uint32_t{txout.nHeight} << 1) | uint32_t{txout.fCoinBase}};
27        ::Serialize(s, VARINT(nCode));
28        if (txout.nHeight > 0) {
29            // Required to maintain compatibility with older undo format.
30            ::Serialize(s, (unsigned char)0);
31        }
32        ::Serialize(s, Using<TxOutCompression>(txout.out));
33    }
34
35    template<typename Stream>
36    void Unser(Stream &s, Coin& txout) {
37        uint32_t nCode = 0;
38        ::Unserialize(s, VARINT(nCode));
39        txout.nHeight = nCode >> 1;
40        txout.fCoinBase = nCode & 1;
41        if (txout.nHeight > 0) {
42            // Old versions stored the version number for the last spend of
43            // a transaction's outputs. Non-final spends were indicated with
44            // height = 0.
45            unsigned int nVersionDummy;
46            ::Unserialize(s, VARINT(nVersionDummy));
47        }
48        ::Unserialize(s, Using<TxOutCompression>(txout.out));
49    }
50};
51
52/** Undo information for a CTransaction */
53class CTxUndo
54{
55public:
56    // undo information for all txins
57    std::vector<Coin> vprevout;
58
59    SERIALIZE_METHODS(CTxUndo, obj) { READWRITE(Using<VectorFormatter<TxInUndoFormatter>>(obj.vprevout)); }
60};
61
62/** Undo information for a CBlock */
63class CBlockUndo
64{
65public:
66    std::vector<CTxUndo> vtxundo; // for all but the coinbase
67
68    SERIALIZE_METHODS(CBlockUndo, obj) { READWRITE(obj.vtxundo); }
69};
70
71#endif // BITCOIN_UNDO_H
72