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filters.go
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filters.go
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package filters
import (
"context"
"encoding/binary"
"fmt"
"math/big"
"github.com/pkg/errors"
tmrpctypes "github.com/cometbft/cometbft/rpc/core/types"
"github.com/ethereum/go-ethereum/common"
ethtypes "github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/eth/filters"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/rpc"
"github.com/artela-network/artela/ethereum/rpc/utils"
)
// BloomIV represents the bit indexes and value inside the bloom filter that belong
// to some key.
type BloomIV struct {
I [3]uint
V [3]byte
}
// Filter can be used to retrieve and filter logs.
type Filter struct {
logger log.Logger
backend Backend
criteria filters.FilterCriteria
bloomFilters [][]BloomIV // Filter the system is matching for
}
// NewBlockFilter creates a new filter which directly inspects the contents of
// a block to figure out whether it is interesting or not.
func NewBlockFilter(logger log.Logger, backend Backend, criteria filters.FilterCriteria) *Filter {
// Create a generic filter and convert it into a block filter
return newFilter(logger, backend, criteria, nil)
}
// NewRangeFilter creates a new filter which uses a bloom filter on blocks to
// figure out whether a particular block is interesting or not.
func NewRangeFilter(logger log.Logger, backend Backend, begin, end int64, addresses []common.Address, topics [][]common.Hash) *Filter {
// Flatten the address and topic filter clauses into a single bloombits filter
// system. Since the bloombits are not positional, nil topics are permitted,
// which get flattened into a nil byte slice.
var filtersBz [][][]byte //nolint: prealloc
if len(addresses) > 0 {
filter := make([][]byte, len(addresses))
for i, address := range addresses {
filter[i] = address.Bytes()
}
filtersBz = append(filtersBz, filter)
}
for _, topicList := range topics {
filter := make([][]byte, len(topicList))
for i, topic := range topicList {
filter[i] = topic.Bytes()
}
filtersBz = append(filtersBz, filter)
}
// Create a generic filter and convert it into a range filter
criteria := filters.FilterCriteria{
FromBlock: big.NewInt(begin),
ToBlock: big.NewInt(end),
Addresses: addresses,
Topics: topics,
}
return newFilter(logger, backend, criteria, createBloomFilters(filtersBz, logger))
}
// newFilter returns a new Filter
func newFilter(logger log.Logger, backend Backend, criteria filters.FilterCriteria, bloomFilters [][]BloomIV) *Filter {
return &Filter{
logger: logger,
backend: backend,
criteria: criteria,
bloomFilters: bloomFilters,
}
}
const (
maxToOverhang = 600
)
// Logs searches the blockchain for matching log entries, returning all from the
// first block that contains matches, updating the start of the filter accordingly.
func (f *Filter) Logs(_ context.Context, logLimit int, blockLimit int64) ([]*ethtypes.Log, error) {
logs := []*ethtypes.Log{}
var err error
// If we're doing singleton block filtering, execute and return
if f.criteria.BlockHash != nil && *f.criteria.BlockHash != (common.Hash{}) {
resBlock, err := f.backend.CosmosBlockByHash(*f.criteria.BlockHash)
if err != nil {
return nil, fmt.Errorf("failed to fetch header by hash %s: %w", f.criteria.BlockHash, err)
}
blockRes, err := f.backend.CosmosBlockResultByNumber(&resBlock.Block.Height)
if err != nil {
f.logger.Debug("failed to fetch block result from cometbft", "height", resBlock.Block.Height, "error", err.Error())
return nil, nil
}
bloom, err := f.backend.BlockBloom(blockRes)
if err != nil {
return nil, err
}
return f.blockLogs(blockRes, bloom)
}
// Figure out the limits of the filter range
header, err := f.backend.HeaderByNumber(context.Background(), rpc.LatestBlockNumber)
if err != nil {
return nil, fmt.Errorf("failed to fetch header by number (latest): %w", err)
}
if header == nil || header.Number == nil {
f.logger.Debug("header not found or has no number")
return nil, nil
}
head := header.Number.Int64()
if f.criteria.FromBlock.Int64() < 0 {
f.criteria.FromBlock = big.NewInt(head)
} else if f.criteria.FromBlock.Int64() == 0 {
f.criteria.FromBlock = big.NewInt(1)
}
if f.criteria.ToBlock.Int64() < 0 {
f.criteria.ToBlock = big.NewInt(head)
} else if f.criteria.ToBlock.Int64() == 0 {
f.criteria.ToBlock = big.NewInt(1)
}
if f.criteria.ToBlock.Int64()-f.criteria.FromBlock.Int64() > blockLimit {
return nil, fmt.Errorf("maximum [from, to] blocks distance: %d", blockLimit)
}
// check bounds
if f.criteria.FromBlock.Int64() > head {
return []*ethtypes.Log{}, nil
} else if f.criteria.ToBlock.Int64() > head+maxToOverhang {
f.criteria.ToBlock = big.NewInt(head + maxToOverhang)
}
from := f.criteria.FromBlock.Int64()
to := f.criteria.ToBlock.Int64()
for height := from; height <= to; height++ {
blockRes, err := f.backend.CosmosBlockResultByNumber(&height)
if err != nil {
f.logger.Debug("failed to fetch block result from cometbft", "height", height, "error", err.Error())
return nil, nil
}
bloom, err := f.backend.BlockBloom(blockRes)
if err != nil {
return nil, err
}
filtered, err := f.blockLogs(blockRes, bloom)
if err != nil {
return nil, errors.Wrapf(err, "failed to fetch block by number %d", height)
}
// check logs limit
if len(logs)+len(filtered) > logLimit {
return nil, fmt.Errorf("query returned more than %d results", logLimit)
}
logs = append(logs, filtered...)
}
return logs, nil
}
// blockLogs returns the logs matching the filter criteria within a single block.
func (f *Filter) blockLogs(blockRes *tmrpctypes.ResultBlockResults, bloom ethtypes.Bloom) ([]*ethtypes.Log, error) {
if !bloomFilter(bloom, f.criteria.Addresses, f.criteria.Topics) {
return []*ethtypes.Log{}, nil
}
logsList, err := utils.GetLogsFromBlockResults(blockRes)
if err != nil {
return []*ethtypes.Log{}, errors.Wrapf(err, "failed to fetch logs block number %d", blockRes.Height)
}
unfiltered := make([]*ethtypes.Log, 0)
for _, logs := range logsList {
unfiltered = append(unfiltered, logs...)
}
logs := FilterLogs(unfiltered, nil, nil, f.criteria.Addresses, f.criteria.Topics)
if len(logs) == 0 {
return []*ethtypes.Log{}, nil
}
return logs, nil
}
func createBloomFilters(filters [][][]byte, logger log.Logger) [][]BloomIV {
bloomFilters := make([][]BloomIV, 0)
for _, filter := range filters {
// Gather the bit indexes of the filter rule, special casing the nil filter
if len(filter) == 0 {
continue
}
bloomIVs := make([]BloomIV, len(filter))
// Transform the filter rules (the addresses and topics) to the bloom index and value arrays
// So it can be used to compare with the bloom of the block header. If the rule has any nil
// clauses. The rule will be ignored.
for i, clause := range filter {
if clause == nil {
bloomIVs = nil
break
}
iv, err := calcBloomIVs(clause)
if err != nil {
bloomIVs = nil
logger.Error("calcBloomIVs error: %v", err)
break
}
bloomIVs[i] = iv
}
// Accumulate the filter rules if no nil rule was within
if bloomIVs != nil {
bloomFilters = append(bloomFilters, bloomIVs)
}
}
return bloomFilters
}
// calcBloomIVs returns BloomIV for the given data,
// revised from https://github.com/ethereum/go-ethereum/blob/401354976bb44f0ad4455ca1e0b5c0dc31d9a5f5/core/types/bloom9.go#L139
func calcBloomIVs(data []byte) (BloomIV, error) {
hashbuf := make([]byte, 6)
biv := BloomIV{}
sha := crypto.NewKeccakState()
sha.Reset()
if _, err := sha.Write(data); err != nil {
return BloomIV{}, err
}
if _, err := sha.Read(hashbuf); err != nil {
return BloomIV{}, err
}
// The actual bits to flip
biv.V[0] = byte(1 << (hashbuf[1] & 0x7))
biv.V[1] = byte(1 << (hashbuf[3] & 0x7))
biv.V[2] = byte(1 << (hashbuf[5] & 0x7))
// The indices for the bytes to OR in
biv.I[0] = ethtypes.BloomByteLength - uint((binary.BigEndian.Uint16(hashbuf)&0x7ff)>>3) - 1
biv.I[1] = ethtypes.BloomByteLength - uint((binary.BigEndian.Uint16(hashbuf[2:])&0x7ff)>>3) - 1
biv.I[2] = ethtypes.BloomByteLength - uint((binary.BigEndian.Uint16(hashbuf[4:])&0x7ff)>>3) - 1
return biv, nil
}