Line data    Source code

       1             : // Copyright (c) 2018-2021 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             : static const char* const DEFAULT_BLOCKFILTERINDEX = "0";
      16             : 
      17             : /** Interval between compact filter checkpoints. See BIP 157. */
      18             : static constexpr int CFCHECKPT_INTERVAL = 1000;
      19             : 
      20             : /**
      21             :  * BlockFilterIndex is used to store and retrieve block filters, hashes, and headers for a range of
      22             :  * blocks by height. An index is constructed for each supported filter type with its own database
      23             :  * (ie. filter data for different types are stored in separate databases).
      24             :  *
      25             :  * This index is used to serve BIP 157 net requests.
      26             :  */
      27             : class BlockFilterIndex final : public BaseIndex
      28             : {
      29             : private:
      30             :     /** Version of the blockfilter index format. Increment this when breaking changes are made. */
      31             :     static constexpr int CURRENT_VERSION = 2;
      32             : 
      33             :     BlockFilterType m_filter_type;
      34             :     std::string m_name;
      35             :     std::unique_ptr<BaseIndex::DB> m_db;
      36             : 
      37             :     FlatFilePos m_next_filter_pos;
      38             :     std::unique_ptr<FlatFileSeq> m_filter_fileseq;
      39             : 
      40             :     bool ReadFilterFromDisk(const FlatFilePos& pos, const uint256& hash, BlockFilter& filter) const;
      41             :     size_t WriteFilterToDisk(FlatFilePos& pos, const BlockFilter& filter);
      42             : 
      43             :     Mutex m_cs_headers_cache;
      44             :     /** cache of block hash to filter header, to avoid disk access when responding to getcfcheckpt. */
      45             :     std::unordered_map<uint256, uint256, FilterHeaderHasher> m_headers_cache GUARDED_BY(m_cs_headers_cache);
      46             : 
      47          17 :     bool AllowPrune() const override { return true; }
      48             : 
      49             : protected:
      50             :     bool Init() override;
      51             : 
      52             :     bool CommitInternal(CDBBatch& batch) override;
      53             : 
      54             :     bool WriteBlock(const CBlock& block, const CBlockIndex* pindex) override;
      55             : 
      56             :     bool Rewind(const CBlockIndex* current_tip, const CBlockIndex* new_tip) override;
      57             : 
      58          22 :     BaseIndex::DB& GetDB() const LIFETIMEBOUND override { return *m_db; }
      59             : 
      60          23 :     const char* GetName() const LIFETIMEBOUND override { return m_name.c_str(); }
      61             : 
      62             : public:
      63             :     /** Constructs the index, which becomes available to be queried. */
      64             :     explicit BlockFilterIndex(BlockFilterType filter_type,
      65             :                               size_t n_cache_size, bool f_memory = false, bool f_wipe = false);
      66             : 
      67         558 :     BlockFilterType GetFilterType() const { return m_filter_type; }
      68             : 
      69             :     /** Get a single filter by block. */
      70             :     bool LookupFilter(const CBlockIndex* block_index, BlockFilter& filter_out) const;
      71             : 
      72             :     /** Get a single filter header by block. */
      73             :     bool LookupFilterHeader(const CBlockIndex* block_index, uint256& header_out) EXCLUSIVE_LOCKS_REQUIRED(!m_cs_headers_cache);
      74             : 
      75             :     /** Get a range of filters between two heights on a chain. */
      76             :     bool LookupFilterRange(int start_height, const CBlockIndex* stop_index,
      77             :                            std::vector<BlockFilter>& filters_out) const;
      78             : 
      79             :     /** Get a range of filter hashes between two heights on a chain. */
      80             :     bool LookupFilterHashRange(int start_height, const CBlockIndex* stop_index,
      81             :                                std::vector<uint256>& hashes_out) const;
      82             : };
      83             : 
      84             : /**
      85             :  * Get a block filter index by type. Returns nullptr if index has not been initialized or was
      86             :  * already destroyed.
      87             :  */
      88             : BlockFilterIndex* GetBlockFilterIndex(BlockFilterType filter_type);
      89             : 
      90             : /** Iterate over all running block filter indexes, invoking fn on each. */
      91             : void ForEachBlockFilterIndex(std::function<void (BlockFilterIndex&)> fn);
      92             : 
      93             : /**
      94             :  * Initialize a block filter index for the given type if one does not already exist. Returns true if
      95             :  * a new index is created and false if one has already been initialized.
      96             :  */
      97             : bool InitBlockFilterIndex(BlockFilterType filter_type,
      98             :                           size_t n_cache_size, bool f_memory = false, bool f_wipe = false);
      99             : 
     100             : /**
     101             :  * Destroy the block filter index with the given type. Returns false if no such index exists. This
     102             :  * just releases the allocated memory and closes the database connection, it does not delete the
     103             :  * index data.
     104             :  */
     105             : bool DestroyBlockFilterIndex(BlockFilterType filter_type);
     106             : 
     107             : /** Destroy all open block filter indexes. */
     108             : void DestroyAllBlockFilterIndexes();
     109             : 
     110             : #endif // BITCOIN_INDEX_BLOCKFILTERINDEX_H