go-ethereum/eth/filters/filter.go

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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
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//
// The go-ethereum library is free software: you can redistribute it and/or modify
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// 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,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// 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/>.
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package filters
import (
"math"
"time"
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"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
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"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/ethdb"
)
type AccountChange struct {
Address, StateAddress []byte
}
// Filtering interface
type Filter struct {
created time.Time
db ethdb.Database
begin, end int64
addresses []common.Address
topics [][]common.Hash
BlockCallback func(*types.Block, vm.Logs)
TransactionCallback func(*types.Transaction)
LogCallback func(*vm.Log, bool)
}
// Create a new filter which uses a bloom filter on blocks to figure out whether a particular block
// is interesting or not.
func New(db ethdb.Database) *Filter {
return &Filter{db: db}
}
// Set the earliest and latest block for filtering.
// -1 = latest block (i.e., the current block)
// hash = particular hash from-to
func (self *Filter) SetBeginBlock(begin int64) {
self.begin = begin
}
func (self *Filter) SetEndBlock(end int64) {
self.end = end
}
func (self *Filter) SetAddresses(addr []common.Address) {
self.addresses = addr
}
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func (self *Filter) SetTopics(topics [][]common.Hash) {
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self.topics = topics
}
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// Run filters logs with the current parameters set
func (self *Filter) Find() vm.Logs {
latestHash := core.GetHeadBlockHash(self.db)
latestBlock := core.GetBlock(self.db, latestHash)
if latestBlock == nil {
return vm.Logs{}
}
var beginBlockNo uint64 = uint64(self.begin)
if self.begin == -1 {
beginBlockNo = latestBlock.NumberU64()
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}
var endBlockNo uint64 = uint64(self.end)
if self.end == -1 {
endBlockNo = latestBlock.NumberU64()
}
// if no addresses are present we can't make use of fast search which
// uses the mipmap bloom filters to check for fast inclusion and uses
// higher range probability in order to ensure at least a false positive
if len(self.addresses) == 0 {
return self.getLogs(beginBlockNo, endBlockNo)
}
return self.mipFind(beginBlockNo, endBlockNo, 0)
}
func (self *Filter) mipFind(start, end uint64, depth int) (logs vm.Logs) {
level := core.MIPMapLevels[depth]
// normalise numerator so we can work in level specific batches and
// work with the proper range checks
for num := start / level * level; num <= end; num += level {
// find addresses in bloom filters
bloom := core.GetMipmapBloom(self.db, num, level)
for _, addr := range self.addresses {
if bloom.TestBytes(addr[:]) {
// range check normalised values and make sure that
// we're resolving the correct range instead of the
// normalised values.
start := uint64(math.Max(float64(num), float64(start)))
end := uint64(math.Min(float64(num+level-1), float64(end)))
if depth+1 == len(core.MIPMapLevels) {
logs = append(logs, self.getLogs(start, end)...)
} else {
logs = append(logs, self.mipFind(start, end, depth+1)...)
}
// break so we don't check the same range for each
// possible address. Checks on multiple addresses
// are handled further down the stack.
break
}
}
}
return logs
}
func (self *Filter) getLogs(start, end uint64) (logs vm.Logs) {
for i := start; i <= end; i++ {
var block *types.Block
hash := core.GetCanonicalHash(self.db, i)
if hash != (common.Hash{}) {
block = core.GetBlock(self.db, hash)
}
if block == nil { // block not found/written
return logs
}
// Use bloom filtering to see if this block is interesting given the
// current parameters
if self.bloomFilter(block) {
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// Get the logs of the block
var (
receipts = core.GetBlockReceipts(self.db, block.Hash())
unfiltered vm.Logs
)
for _, receipt := range receipts {
unfiltered = append(unfiltered, receipt.Logs...)
}
logs = append(logs, self.FilterLogs(unfiltered)...)
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}
}
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return logs
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}
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func includes(addresses []common.Address, a common.Address) bool {
for _, addr := range addresses {
if addr == a {
return true
}
}
return false
}
func (self *Filter) FilterLogs(logs vm.Logs) vm.Logs {
var ret vm.Logs
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// Filter the logs for interesting stuff
Logs:
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for _, log := range logs {
if len(self.addresses) > 0 && !includes(self.addresses, log.Address) {
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continue
}
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logTopics := make([]common.Hash, len(self.topics))
copy(logTopics, log.Topics)
// If the to filtered topics is greater than the amount of topics in
// logs, skip.
if len(self.topics) > len(log.Topics) {
continue Logs
}
for i, topics := range self.topics {
var match bool
for _, topic := range topics {
// common.Hash{} is a match all (wildcard)
if (topic == common.Hash{}) || log.Topics[i] == topic {
match = true
break
}
}
if !match {
continue Logs
}
}
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ret = append(ret, log)
}
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return ret
}
func (self *Filter) bloomFilter(block *types.Block) bool {
if len(self.addresses) > 0 {
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var included bool
for _, addr := range self.addresses {
if types.BloomLookup(block.Bloom(), addr) {
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included = true
break
}
}
if !included {
return false
}
}
for _, sub := range self.topics {
var included bool
for _, topic := range sub {
if (topic == common.Hash{}) || types.BloomLookup(block.Bloom(), topic) {
included = true
break
}
}
if !included {
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return false
}
}
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return true
}