Source: indexer/filterindexer.js

  1. /*!
  2.  * filterindexer.js - filter indexer
  3.  * Copyright (c) 2018, the bcoin developers (MIT License).
  4.  * https://github.com/bcoin-org/bcoin
  5.  */
  7. 'use strict';
  9. const bdb = require('bdb');
  10. const assert = require('bsert');
  11. const Indexer = require('./indexer');
  12. const consensus = require('../protocol/consensus');
  13. const Filter = require('../primitives/filter');
  15. /**
  16.  * FilterIndexer
  17.  * @alias module:indexer.FilterIndexer
  18.  * @extends Indexer
  19.  */
  21. class FilterIndexer extends Indexer {
  22.   /**
  23.    * Create a indexer
  24.    * @constructor
  25.    * @param {Object} options
  26.    */
  28.   constructor(options) {
  29.     super('filter', options);
  31.     this.db = bdb.create(this.options);
  32.   }
  34.   /**
  35.    * Store genesis previous filter header.
  36.    * @private
  37.    * @returns {Promise}
  38.    */
  40.   async saveGenesis() {
  41.     const prevHash = this.network.genesis.prevBlock;
  43.     // Genesis prev filter headers are defined to be zero hashes
  44.     const filter = new Filter();
  45.     filter.header = consensus.ZERO_HASH;
  46.     await this.blocks.writeFilter(prevHash, filter.toRaw());
  48.     await super.saveGenesis();
  49.   }
  51.   /**
  52.    * Index compact filters.
  53.    * @private
  54.    * @param {BlockMeta} meta
  55.    * @param {Block} block
  56.    * @param {CoinView} view
  57.    */
  59.   async indexBlock(meta, block, view) {
  60.     const hash = block.hash();
  61.     const prev = await this.getFilterHeader(block.prevBlock);
  62.     const basic = block.toFilter(view);
  64.     const filter = new Filter();
  65.     filter.header = basic.header(prev);
  66.     filter.filter = basic.toRaw();
  67.     await this.blocks.writeFilter(hash, filter.toRaw());
  68.   }
  70.   /**
  71.    * Prune compact filters.
  72.    * @private
  73.    * @param {BlockMeta} meta
  74.    */
  76.   async pruneBlock(meta) {
  77.     await this.blocks.pruneFilter(meta.hash);
  78.   }
  80.   /**
  81.    * Retrieve compact filter by hash.
  82.    * @param {Hash} hash
  83.    * @param {Number} type
  84.    * @returns {Promise} - Returns {@link Filter}.
  85.    */
  87.   async getFilter(hash) {
  88.     assert(hash);
  90.     const filter = await this.blocks.readFilter(hash);
  91.     if (!filter)
  92.       return null;
  94.     return Filter.fromRaw(filter);
  95.   }
  97.   /**
  98.    * Retrieve compact filter header by hash.
  99.    * @param {Hash} hash
  100.    * @returns {Promise} - Returns {@link Hash}.
  101.    */
  103.   async getFilterHeader(hash) {
  104.     assert(hash);
  106.     return this.blocks.readFilterHeader(hash);
  107.   }
  108. }
  110. module.exports = FilterIndexer;