blockfilterindex.h raw

   1  // Copyright (c) 2018-2022 The Limenka 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 LIMENKA_INDEX_BLOCKFILTERINDEX_H
   6  #define LIMENKA_INDEX_BLOCKFILTERINDEX_H
   7  
   8  #include <attributes.h>
   9  #include <blockfilter.h>
  10  #include <chain.h>
  11  #include <flatfile.h>
  12  #include <index/base.h>
  13  #include <util/hasher.h>
  14  
  15  #include <unordered_map>
  16  
  17  static const char* const DEFAULT_BLOCKFILTERINDEX = "0";
  18  
  19  /** Interval between compact filter checkpoints. See BIP 157. */
  20  static constexpr int CFCHECKPT_INTERVAL = 1000;
  21  
  22  /**
  23   * BlockFilterIndex is used to store and retrieve block filters, hashes, and headers for a range of
  24   * blocks by height. An index is constructed for each supported filter type with its own database
  25   * (ie. filter data for different types are stored in separate databases).
  26   *
  27   * This index is used to serve BIP 157 net requests.
  28   */
  29  class BlockFilterIndex final : public BaseIndex
  30  {
  31  private:
  32      BlockFilterType m_filter_type;
  33      std::unique_ptr<BaseIndex::DB> m_db;
  34  
  35      FlatFilePos m_next_filter_pos;
  36      std::unique_ptr<FlatFileSeq> m_filter_fileseq;
  37  
  38      bool ReadFilterFromDisk(const FlatFilePos& pos, const uint256& hash, BlockFilter& filter) const;
  39      size_t WriteFilterToDisk(FlatFilePos& pos, const BlockFilter& filter);
  40  
  41      Mutex m_cs_headers_cache;
  42      /** cache of block hash to filter header, to avoid disk access when responding to getcfcheckpt. */
  43      std::unordered_map<uint256, uint256, FilterHeaderHasher> m_headers_cache GUARDED_BY(m_cs_headers_cache);
  44  
  45      // Last computed header to avoid disk reads on every new block.
  46      uint256 m_last_header{};
  47  
  48      bool AllowPrune() const override { return true; }
  49      bilingual_str GetDisableAction() const override;
  50  
  51      bool Write(const BlockFilter& filter, uint32_t block_height, const uint256& filter_header);
  52  
  53      std::optional<uint256> ReadFilterHeader(int height, const uint256& expected_block_hash);
  54  
  55  protected:
  56      bool CustomInit(const std::optional<interfaces::BlockRef>& block) override;
  57  
  58      bool CustomCommit(CDBBatch& batch) override;
  59  
  60      bool CustomAppend(const interfaces::BlockInfo& block) override;
  61  
  62      bool CustomRewind(const interfaces::BlockRef& current_tip, const interfaces::BlockRef& new_tip) override;
  63  
  64      BaseIndex::DB& GetDB() const LIFETIMEBOUND override { return *m_db; }
  65  
  66  public:
  67      /** Constructs the index, which becomes available to be queried. */
  68      explicit BlockFilterIndex(std::unique_ptr<interfaces::Chain> chain, BlockFilterType filter_type,
  69                                size_t n_cache_size, bool f_memory = false, bool f_wipe = false);
  70  
  71      BlockFilterType GetFilterType() const { return m_filter_type; }
  72  
  73      /** Get a single filter by block. */
  74      bool LookupFilter(const CBlockIndex* block_index, BlockFilter& filter_out) const;
  75  
  76      /** Get a single filter header by block. */
  77      bool LookupFilterHeader(const CBlockIndex* block_index, uint256& header_out) EXCLUSIVE_LOCKS_REQUIRED(!m_cs_headers_cache);
  78  
  79      /** Get a range of filters between two heights on a chain. */
  80      bool LookupFilterRange(int start_height, const CBlockIndex* stop_index,
  81                             std::vector<BlockFilter>& filters_out) const;
  82  
  83      /** Get a range of filter hashes between two heights on a chain. */
  84      bool LookupFilterHashRange(int start_height, const CBlockIndex* stop_index,
  85                                 std::vector<uint256>& hashes_out) const;
  86  };
  87  
  88  /**
  89   * Get a block filter index by type. Returns nullptr if index has not been initialized or was
  90   * already destroyed.
  91   */
  92  BlockFilterIndex* GetBlockFilterIndex(BlockFilterType filter_type);
  93  
  94  /** Iterate over all running block filter indexes, invoking fn on each. */
  95  void ForEachBlockFilterIndex(std::function<void (BlockFilterIndex&)> fn);
  96  
  97  /**
  98   * Initialize a block filter index for the given type if one does not already exist. Returns true if
  99   * a new index is created and false if one has already been initialized.
 100   */
 101  bool InitBlockFilterIndex(std::function<std::unique_ptr<interfaces::Chain>()> make_chain, BlockFilterType filter_type,
 102                            size_t n_cache_size, bool f_memory = false, bool f_wipe = false);
 103  
 104  /**
 105   * Destroy the block filter index with the given type. Returns false if no such index exists. This
 106   * just releases the allocated memory and closes the database connection, it does not delete the
 107   * index data.
 108   */
 109  bool DestroyBlockFilterIndex(BlockFilterType filter_type);
 110  
 111  /** Destroy all open block filter indexes. */
 112  void DestroyAllBlockFilterIndexes();
 113  
 114  #endif // LIMENKA_INDEX_BLOCKFILTERINDEX_H
 115