github.com/klaytn/klaytn@v1.12.1/node/cn/bloombits.go

// Modifications Copyright 2018 The klaytn Authors
// Copyright 2017 The go-ethereum Authors
// This file is part of go-ethereum.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
//
// This file is derived from eth/bloombits.go (2018/06/04).
// Modified and improved for the klaytn development.

package cn

import (
	"time"

	"github.com/klaytn/klaytn/blockchain"
	"github.com/klaytn/klaytn/blockchain/bloombits"
	"github.com/klaytn/klaytn/blockchain/types"
	"github.com/klaytn/klaytn/common"
	"github.com/klaytn/klaytn/common/bitutil"
	"github.com/klaytn/klaytn/params"
	"github.com/klaytn/klaytn/storage/database"
)

const (
	// bloomServiceThreads is the number of goroutines used globally by a CN
	// instance to service bloombits lookups for all running filters.
	bloomServiceThreads = 16

	// bloomFilterThreads is the number of goroutines used locally per filter to
	// multiplex requests onto the global servicing goroutines.
	bloomFilterThreads = 3

	// bloomRetrievalBatch is the maximum number of bloom bit retrievals to service
	// in a single batch.
	bloomRetrievalBatch = 16

	// bloomRetrievalWait is the maximum time to wait for enough bloom bit requests
	// to accumulate request an entire batch (avoiding hysteresis).
	bloomRetrievalWait = time.Duration(0)
)

// startBloomHandlers starts a batch of goroutines to accept bloom bit database
// retrievals from possibly a range of filters and serving the data to satisfy.
func (cn *CN) startBloomHandlers() {
	for i := 0; i < bloomServiceThreads; i++ {
		go func() {
			for {
				select {
				case <-cn.closeBloomHandler:
					return

				case request := <-cn.bloomRequests:
					task := <-request
					task.Bitsets = make([][]byte, len(task.Sections))
					for i, section := range task.Sections {
						head := cn.chainDB.ReadCanonicalHash((section+1)*params.BloomBitsBlocks - 1)
						if compVector, err := cn.chainDB.ReadBloomBits(database.BloomBitsKey(task.Bit, section, head)); err == nil {
							if blob, err := bitutil.DecompressBytes(compVector, int(params.BloomBitsBlocks)/8); err == nil {
								task.Bitsets[i] = blob
							} else {
								task.Error = err
							}
						} else {
							task.Error = err
						}
					}
					request <- task
				}
			}
		}()
	}
}

const (
	// bloomConfirms is the number of confirmation blocks before a bloom section is
	// considered probably final and its rotated bits are calculated.
	bloomConfirms = 256

	// bloomThrottling is the time to wait between processing two consecutive index
	// sections. It's useful during chain upgrades to prevent disk overload.
	bloomThrottling = 100 * time.Millisecond
)

// BloomIndexer implements a blockchain.ChainIndexer, building up a rotated bloom bits index
// for the Klaytn header bloom filters, permitting blazing fast filtering.
type BloomIndexer struct {
	size uint64 // section size to generate bloombits for

	db  database.DBManager   // database instance to write index data and metadata into
	gen *bloombits.Generator // generator to rotate the bloom bits crating the bloom index

	section uint64      // Section is the section number being processed currently
	head    common.Hash // Head is the hash of the last header processed
}

// NewBloomIndexer returns a chain indexer that generates bloom bits data for the
// canonical chain for fast logs filtering.
func NewBloomIndexer(db database.DBManager, size uint64) *blockchain.ChainIndexer {
	backend := &BloomIndexer{
		db:   db,
		size: size,
	}

	return blockchain.NewChainIndexer(db, db, backend, size, bloomConfirms, bloomThrottling, "bloombits")
}

// Reset implements blockchain.ChainIndexerBackend, starting a new bloombits index
// section.
func (b *BloomIndexer) Reset(section uint64, lastSectionHead common.Hash) error {
	gen, err := bloombits.NewGenerator(uint(b.size))
	b.gen, b.section, b.head = gen, section, common.Hash{}
	return err
}

// Process implements blockchain.ChainIndexerBackend, adding a new header's bloom into
// the index.
func (b *BloomIndexer) Process(header *types.Header) {
	b.gen.AddBloom(uint(header.Number.Uint64()-b.section*b.size), header.Bloom)
	b.head = header.Hash()
}

// Commit implements blockchain.ChainIndexerBackend, finalizing the bloom section and
// writing it out into the database.
func (b *BloomIndexer) Commit() error {
	batch := b.db.NewBatch(database.MiscDB)
	defer batch.Release()

	for i := 0; i < types.BloomBitLength; i++ {
		bits, err := b.gen.Bitset(uint(i))
		if err != nil {
			return err
		}
		err = batch.Put(database.BloomBitsKey(uint(i), b.section, b.head), bitutil.CompressBytes(bits))
		if err != nil {
			logger.Crit("Failed to store bloom bits", "err", err)
		}
	}
	return batch.Write()
}