Line data    Source code

       1             : // Copyright (c) 2018-2022 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_INDEX_BLOCKFILTERINDEX_H
       6             : #define BITCOIN_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           0 :     bool AllowPrune() const override { return true; }
      46             : 
      47             : protected:
      48             :     bool CustomInit(const std::optional<interfaces::BlockKey>& block) override;
      49             : 
      50             :     bool CustomCommit(CDBBatch& batch) override;
      51             : 
      52             :     bool CustomAppend(const interfaces::BlockInfo& block) override;
      53             : 
      54             :     bool CustomRewind(const interfaces::BlockKey& current_tip, const interfaces::BlockKey& new_tip) override;
      55             : 
      56           0 :     BaseIndex::DB& GetDB() const LIFETIMEBOUND override { return *m_db; }
      57             : 
      58             : public:
      59             :     /** Constructs the index, which becomes available to be queried. */
      60             :     explicit BlockFilterIndex(std::unique_ptr<interfaces::Chain> chain, BlockFilterType filter_type,
      61             :                               size_t n_cache_size, bool f_memory = false, bool f_wipe = false);
      62             : 
      63           0 :     BlockFilterType GetFilterType() const { return m_filter_type; }
      64             : 
      65             :     /** Get a single filter by block. */
      66             :     bool LookupFilter(const CBlockIndex* block_index, BlockFilter& filter_out) const;
      67             : 
      68             :     /** Get a single filter header by block. */
      69             :     bool LookupFilterHeader(const CBlockIndex* block_index, uint256& header_out) EXCLUSIVE_LOCKS_REQUIRED(!m_cs_headers_cache);
      70             : 
      71             :     /** Get a range of filters between two heights on a chain. */
      72             :     bool LookupFilterRange(int start_height, const CBlockIndex* stop_index,
      73             :                            std::vector<BlockFilter>& filters_out) const;
      74             : 
      75             :     /** Get a range of filter hashes between two heights on a chain. */
      76             :     bool LookupFilterHashRange(int start_height, const CBlockIndex* stop_index,
      77             :                                std::vector<uint256>& hashes_out) const;
      78             : };
      79             : 
      80             : /**
      81             :  * Get a block filter index by type. Returns nullptr if index has not been initialized or was
      82             :  * already destroyed.
      83             :  */
      84             : BlockFilterIndex* GetBlockFilterIndex(BlockFilterType filter_type);
      85             : 
      86             : /** Iterate over all running block filter indexes, invoking fn on each. */
      87             : void ForEachBlockFilterIndex(std::function<void (BlockFilterIndex&)> fn);
      88             : 
      89             : /**
      90             :  * Initialize a block filter index for the given type if one does not already exist. Returns true if
      91             :  * a new index is created and false if one has already been initialized.
      92             :  */
      93             : bool InitBlockFilterIndex(std::function<std::unique_ptr<interfaces::Chain>()> make_chain, BlockFilterType filter_type,
      94             :                           size_t n_cache_size, bool f_memory = false, bool f_wipe = false);
      95             : 
      96             : /**
      97             :  * Destroy the block filter index with the given type. Returns false if no such index exists. This
      98             :  * just releases the allocated memory and closes the database connection, it does not delete the
      99             :  * index data.
     100             :  */
     101             : bool DestroyBlockFilterIndex(BlockFilterType filter_type);
     102             : 
     103             : /** Destroy all open block filter indexes. */
     104             : void DestroyAllBlockFilterIndexes();
     105             : 
     106             : #endif // BITCOIN_INDEX_BLOCKFILTERINDEX_H