Line data    Source code

       1             : // Copyright (c) 2016-2020 The Bitcoin Core developers
       2             : // Distributed under the MIT software license, see the accompanying
       3             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4             : 
       5             : #ifndef BITCOIN_BLOCKENCODINGS_H
       6             : #define BITCOIN_BLOCKENCODINGS_H
       7             : 
       8             : #include <primitives/block.h>
       9             : 
      10             : 
      11             : class CTxMemPool;
      12             : 
      13             : // Transaction compression schemes for compact block relay can be introduced by writing
      14             : // an actual formatter here.
      15             : using TransactionCompression = DefaultFormatter;
      16             : 
      17           5 : class DifferenceFormatter
      18             : {
      19           5 :     uint64_t m_shift = 0;
      20             : 
      21             : public:
      22             :     template<typename Stream, typename I>
      23           5 :     void Ser(Stream& s, I v)
      24             :     {
      25           5 :         if (v < m_shift || v >= std::numeric_limits<uint64_t>::max()) throw std::ios_base::failure("differential value overflow");
      26           5 :         WriteCompactSize(s, v - m_shift);
      27           5 :         m_shift = uint64_t(v) + 1;
      28           5 :     }
      29             :     template<typename Stream, typename I>
      30           9 :     void Unser(Stream& s, I& v)
      31             :     {
      32           9 :         uint64_t n = ReadCompactSize(s);
      33           9 :         m_shift += n;
      34           9 :         if (m_shift < n || m_shift >= std::numeric_limits<uint64_t>::max() || m_shift < std::numeric_limits<I>::min() || m_shift > std::numeric_limits<I>::max()) throw std::ios_base::failure("differential value overflow");
      35           8 :         v = I(m_shift++);
      36           8 :     }
      37             : };
      38             : 
      39             : class BlockTransactionsRequest {
      40             : public:
      41             :     // A BlockTransactionsRequest message
      42             :     uint256 blockhash;
      43             :     std::vector<uint16_t> indexes;
      44             : 
      45          15 :     SERIALIZE_METHODS(BlockTransactionsRequest, obj)
      46             :     {
      47           5 :         READWRITE(obj.blockhash, Using<VectorFormatter<DifferenceFormatter>>(obj.indexes));
      48           5 :     }
      49             : };
      50             : 
      51             : class BlockTransactions {
      52             : public:
      53             :     // A BlockTransactions message
      54             :     uint256 blockhash;
      55             :     std::vector<CTransactionRef> txn;
      56             : 
      57           0 :     BlockTransactions() {}
      58           0 :     explicit BlockTransactions(const BlockTransactionsRequest& req) :
      59           0 :         blockhash(req.blockhash), txn(req.indexes.size()) {}
      60             : 
      61           0 :     SERIALIZE_METHODS(BlockTransactions, obj)
      62             :     {
      63           0 :         READWRITE(obj.blockhash, Using<VectorFormatter<TransactionCompression>>(obj.txn));
      64           0 :     }
      65             : };
      66             : 
      67             : // Dumb serialization/storage-helper for CBlockHeaderAndShortTxIDs and PartiallyDownloadedBlock
      68             : struct PrefilledTransaction {
      69             :     // Used as an offset since last prefilled tx in CBlockHeaderAndShortTxIDs,
      70             :     // as a proper transaction-in-block-index in PartiallyDownloadedBlock
      71             :     uint16_t index;
      72             :     CTransactionRef tx;
      73             : 
      74          81 :     SERIALIZE_METHODS(PrefilledTransaction, obj) { READWRITE(COMPACTSIZE(obj.index), Using<TransactionCompression>(obj.tx)); }
      75             : };
      76             : 
      77             : typedef enum ReadStatus_t
      78             : {
      79             :     READ_STATUS_OK,
      80             :     READ_STATUS_INVALID, // Invalid object, peer is sending bogus crap
      81             :     READ_STATUS_FAILED, // Failed to process object
      82             :     READ_STATUS_CHECKBLOCK_FAILED, // Used only by FillBlock to indicate a
      83             :                                    // failure in CheckBlock.
      84             : } ReadStatus;
      85             : 
      86             : class CBlockHeaderAndShortTxIDs {
      87             : private:
      88             :     mutable uint64_t shorttxidk0, shorttxidk1;
      89             :     uint64_t nonce;
      90             : 
      91             :     void FillShortTxIDSelector() const;
      92             : 
      93             :     friend class PartiallyDownloadedBlock;
      94             : 
      95             : protected:
      96             :     std::vector<uint64_t> shorttxids;
      97             :     std::vector<PrefilledTransaction> prefilledtxn;
      98             : 
      99             : public:
     100             :     static constexpr int SHORTTXIDS_LENGTH = 6;
     101             : 
     102             :     CBlockHeader header;
     103             : 
     104             :     // Dummy for deserialization
     105          14 :     CBlockHeaderAndShortTxIDs() {}
     106             : 
     107             :     CBlockHeaderAndShortTxIDs(const CBlock& block);
     108             : 
     109             :     uint64_t GetShortID(const uint256& txhash) const;
     110             : 
     111          11 :     size_t BlockTxCount() const { return shorttxids.size() + prefilledtxn.size(); }
     112             : 
     113          45 :     SERIALIZE_METHODS(CBlockHeaderAndShortTxIDs, obj)
     114             :     {
     115          15 :         READWRITE(obj.header, obj.nonce, Using<VectorFormatter<CustomUintFormatter<SHORTTXIDS_LENGTH>>>(obj.shorttxids), obj.prefilledtxn);
     116             :         if (ser_action.ForRead()) {
     117           7 :             if (obj.BlockTxCount() > std::numeric_limits<uint16_t>::max()) {
     118           0 :                 throw std::ios_base::failure("indexes overflowed 16 bits");
     119             :             }
     120           7 :             obj.FillShortTxIDSelector();
     121             :         }
     122          15 :     }
     123             : };
     124             : 
     125             : class PartiallyDownloadedBlock {
     126             : protected:
     127             :     std::vector<CTransactionRef> txn_available;
     128           4 :     size_t prefilled_count = 0, mempool_count = 0, extra_count = 0;
     129             :     const CTxMemPool* pool;
     130             : public:
     131             :     CBlockHeader header;
     132          12 :     explicit PartiallyDownloadedBlock(CTxMemPool* poolIn) : pool(poolIn) {}
     133             : 
     134             :     // extra_txn is a list of extra transactions to look at, in <hash, reference> form
     135             :     ReadStatus InitData(const CBlockHeaderAndShortTxIDs& cmpctblock, const std::vector<std::pair<uint256, CTransactionRef>>& extra_txn);
     136             :     bool IsTxAvailable(size_t index) const;
     137             :     ReadStatus FillBlock(CBlock& block, const std::vector<CTransactionRef>& vtx_missing);
     138             : };
     139             : 
     140             : #endif // BITCOIN_BLOCKENCODINGS_H