// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// 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/>.
package eth
import (
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/bitutil"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/bloombits"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/params"
)
const (
// bloomServiceThreads is the number of goroutines used globally by an Ethereum
// 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 (eth *Ethereum) startBloomHandlers() {
for i := 0; i < bloomServiceThreads; i++ {
go func() {
for {
select {
case <-eth.shutdownChan:
return
case request := <-eth.bloomRequests:
task := <-request
task.Bitsets = make([][]byte, len(task.Sections))
for i, section := range task.Sections {
head := core.GetCanonicalHash(eth.chainDb, (section+1)*params.BloomBitsBlocks-1)
if compVector, err := core.GetBloomBits(eth.chainDb, 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 core.ChainIndexer, building up a rotated bloom bits index
// for the Ethereum header bloom filters, permitting blazing fast filtering.
type BloomIndexer struct {
size uint64 // section size to generate bloombits for
db ethdb.Database // 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 ethdb.Database, size uint64) *core.ChainIndexer {
backend := &BloomIndexer{
db: db,
size: size,
}
table := ethdb.NewTable(db, string(core.BloomBitsIndexPrefix))
return core.NewChainIndexer(db, table, backend, size, bloomConfirms, bloomThrottling, "bloombits")
}
// Reset implements core.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 core.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 core.ChainIndexerBackend, finalizing the bloom section and
// writing it out into the database.
func (b *BloomIndexer) Commit() error {
batch := b.db.NewBatch()
for i := 0; i < types.BloomBitLength; i++ {
bits, err := b.gen.Bitset(uint(i))
if err != nil {
return err
}
core.WriteBloomBits(batch, uint(i), b.section, b.head, bitutil.CompressBytes(bits))
}
return batch.Write()
}
