text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2014 The Bitcoin developers
  // Copyright (c) 2016-2020 The PIVX developers
  // Copyright (c) 2021 The DECENOMY Core Developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #ifndef BITCOIN_TXDB_H
  #define BITCOIN_TXDB_H
  
  #include "coins.h"
  #include "chain.h"
  #include "dbwrapper.h"
  #include "libzerocoin/Coin.h"
  #include "libzerocoin/CoinSpend.h"
  
  #include <map>
  #include <string>
  #include <utility>
  #include <vector>
  
  #include <boost/function.hpp>
  
  class CCoinsViewDBCursor;
  class uint256;
  
  //! Compensate for extra memory peak (x1.5-x1.9) at flush time.
  static constexpr int DB_PEAK_USAGE_FACTOR = 2;
  //! No need to periodic flush if at least this much space still available.
  static constexpr int MAX_BLOCK_COINSDB_USAGE = 10 * DB_PEAK_USAGE_FACTOR;
  
  //! -dbcache default (MiB)
  static const int64_t nDefaultDbCache = 100;
  //! max. -dbcache in (MiB)
  static const int64_t nMaxDbCache = sizeof(void*) > 4 ? 16384 : 1024;
  //! min. -dbcache in (MiB)
  static const int64_t nMinDbCache = 4;
  
  struct CDiskTxPos : public CDiskBlockPos
  {
      unsigned int nTxOffset; // after header
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action)
      {
          READWRITE(*(CDiskBlockPos*)this);
          READWRITE(VARINT(nTxOffset));
      }
  
      CDiskTxPos(const CDiskBlockPos& blockIn, unsigned int nTxOffsetIn) : CDiskBlockPos(blockIn.nFile, blockIn.nPos), nTxOffset(nTxOffsetIn)
      {
      }
  
      CDiskTxPos()
      {
          SetNull();
      }
  
      void SetNull()
      {
          CDiskBlockPos::SetNull();
          nTxOffset = 0;
      }
  };
  
  /** CCoinsView backed by the LevelDB coin database (chainstate/) */
  class CCoinsViewDB : public CCoinsView
  {
  protected:
      CDBWrapper db;
  
  public:
      CCoinsViewDB(size_t nCacheSize, bool fMemory = false, bool fWipe = false);
  
      bool GetCoin(const COutPoint& outpoint, Coin& coin) const override;
      bool HaveCoin(const COutPoint& outpoint) const override;
      uint256 GetBestBlock() const override;
      bool BatchWrite(CCoinsMap& mapCoins, const uint256& hashBlock) override;
      CCoinsViewCursor* Cursor() const override;
  
      //! Attempt to update from an older database format. Returns whether an error occurred.
      bool Upgrade();
      size_t EstimateSize() const override;
  };
  
  /** Specialization of CCoinsViewCursor to iterate over a CCoinsViewDB */
  class CCoinsViewDBCursor: public CCoinsViewCursor
  {
  public:
      ~CCoinsViewDBCursor() {}
  
      bool GetKey(COutPoint& key) const;
      bool GetValue(Coin& coin) const;
      unsigned int GetValueSize() const;
  
      bool Valid() const;
      void Next();
  
  private:
      CCoinsViewDBCursor(CDBIterator* pcursorIn, const uint256& hashBlockIn):
          CCoinsViewCursor(hashBlockIn), pcursor(pcursorIn) {}
      boost::scoped_ptr<CDBIterator> pcursor;
      std::pair<char, COutPoint> keyTmp;
  
      friend class CCoinsViewDB;
  };
  
  /** Access to the block database (blocks/index/) */
  class CBlockTreeDB : public CDBWrapper
  {
  public:
      CBlockTreeDB(size_t nCacheSize, bool fMemory = false, bool fWipe = false);
  
  private:
      CBlockTreeDB(const CBlockTreeDB&);
      void operator=(const CBlockTreeDB&);
  
  public:
      bool WriteBlockIndex(const CDiskBlockIndex& blockindex);
      bool WriteBatchSync(const std::vector<std::pair<int, const CBlockFileInfo*> >& fileInfo, int nLastFile, const std::vector<const CBlockIndex*>& blockinfo);
      bool ReadBlockFileInfo(int nFile, CBlockFileInfo& fileinfo);
      bool ReadLastBlockFile(int& nFile);
      bool WriteReindexing(bool fReindex);
      bool ReadReindexing(bool& fReindex);
      bool ReadTxIndex(const uint256& txid, CDiskTxPos& pos);
      bool WriteTxIndex(const std::vector<std::pair<uint256, CDiskTxPos> >& list);
      bool WriteFlag(const std::string& name, bool fValue);
      bool ReadFlag(const std::string& name, bool& fValue);
      bool WriteInt(const std::string& name, int nValue);
      bool ReadInt(const std::string& name, int& nValue);
      bool LoadBlockIndexGuts(boost::function<CBlockIndex*(const uint256&)> insertBlockIndex);
      bool ReadLegacyBlockIndex(const uint256& blockHash, CLegacyBlockIndex& biRet);
      bool WriteMoneySupply(const int64_t& nSupply);
      bool ReadMoneySupply(int64_t& nSupply) const;
  };
  
  /** Zerocoin database (zerocoin/) */
  class CZerocoinDB : public CDBWrapper
  {
  public:
      CZerocoinDB(size_t nCacheSize, bool fMemory = false, bool fWipe = false);
  
  private:
      CZerocoinDB(const CZerocoinDB&);
      void operator=(const CZerocoinDB&);
  
  public:
      /** Write zSAGA mints to the zerocoinDB in a batch */
      bool WriteCoinMintBatch(const std::vector<std::pair<libzerocoin::PublicCoin, uint256> >& mintInfo);
      bool ReadCoinMint(const CBigNum& bnPubcoin, uint256& txHash);
      bool ReadCoinMint(const uint256& hashPubcoin, uint256& hashTx);
      /** Write zSAGA spends to the zerocoinDB in a batch */
      bool WriteCoinSpendBatch(const std::vector<std::pair<libzerocoin::CoinSpend, uint256> >& spendInfo);
      bool ReadCoinSpend(const CBigNum& bnSerial, uint256& txHash);
      bool ReadCoinSpend(const uint256& hashSerial, uint256 &txHash);
      bool EraseCoinMint(const CBigNum& bnPubcoin);
      bool EraseCoinSpend(const CBigNum& bnSerial);
      bool WipeCoins(std::string strType);
  
      /** Map supply [denom] --> supply     */
      bool WriteZCSupply(const std::map<libzerocoin::CoinDenomination, int64_t>& mapZCS);
      bool ReadZCSupply(std::map<libzerocoin::CoinDenomination, int64_t>& mapZCS) const;
      /** Accumulators (only for zPoS IBD): [checksum, denom] --> block height **/
      bool WriteAccChecksum(const uint32_t& nChecksum, const libzerocoin::CoinDenomination denom, const int nHeight);
      bool ReadAccChecksum(const uint32_t& nChecksum, const libzerocoin::CoinDenomination denom, int& nHeightRet);
      bool EraseAccChecksum(const uint32_t& nChecksum, const libzerocoin::CoinDenomination denom);
      bool WipeAccChecksums();
  };
  
  #endif // BITCOIN_TXDB_H
  