ipld-eth-server/pkg/btc/filterer.go
2020-05-29 22:02:47 -05:00

160 lines
5.1 KiB
Go

// VulcanizeDB
// Copyright © 2019 Vulcanize
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program 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 Affero General Public License for more details.
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package btc
import (
"bytes"
"fmt"
"math/big"
"github.com/multiformats/go-multihash"
"github.com/vulcanize/ipfs-chain-watcher/pkg/ipfs"
"github.com/vulcanize/ipfs-chain-watcher/pkg/ipfs/ipld"
"github.com/vulcanize/ipfs-chain-watcher/pkg/shared"
)
// ResponseFilterer satisfies the ResponseFilterer interface for bitcoin
type ResponseFilterer struct{}
// NewResponseFilterer creates a new Filterer satisfying the ResponseFilterer interface
func NewResponseFilterer() *ResponseFilterer {
return &ResponseFilterer{}
}
// Filter is used to filter through btc data to extract and package requested data into a Payload
func (s *ResponseFilterer) Filter(filter shared.SubscriptionSettings, payload shared.ConvertedData) (shared.IPLDs, error) {
btcFilters, ok := filter.(*SubscriptionSettings)
if !ok {
return IPLDs{}, fmt.Errorf("btc filterer expected filter type %T got %T", &SubscriptionSettings{}, filter)
}
btcPayload, ok := payload.(ConvertedPayload)
if !ok {
return IPLDs{}, fmt.Errorf("btc filterer expected payload type %T got %T", ConvertedPayload{}, payload)
}
height := int64(btcPayload.BlockPayload.BlockHeight)
if checkRange(btcFilters.Start.Int64(), btcFilters.End.Int64(), height) {
response := new(IPLDs)
if err := s.filterHeaders(btcFilters.HeaderFilter, response, btcPayload); err != nil {
return IPLDs{}, err
}
if err := s.filterTransactions(btcFilters.TxFilter, response, btcPayload); err != nil {
return IPLDs{}, err
}
response.BlockNumber = big.NewInt(height)
return *response, nil
}
return IPLDs{}, nil
}
func (s *ResponseFilterer) filterHeaders(headerFilter HeaderFilter, response *IPLDs, payload ConvertedPayload) error {
if !headerFilter.Off {
headerBuffer := new(bytes.Buffer)
if err := payload.Header.Serialize(headerBuffer); err != nil {
return err
}
data := headerBuffer.Bytes()
cid, err := ipld.RawdataToCid(ipld.MBitcoinHeader, data, multihash.DBL_SHA2_256)
if err != nil {
return err
}
response.Header = ipfs.BlockModel{
Data: data,
CID: cid.String(),
}
}
return nil
}
func checkRange(start, end, actual int64) bool {
if (end <= 0 || end >= actual) && start <= actual {
return true
}
return false
}
func (s *ResponseFilterer) filterTransactions(trxFilter TxFilter, response *IPLDs, payload ConvertedPayload) error {
if !trxFilter.Off {
response.Transactions = make([]ipfs.BlockModel, 0, len(payload.TxMetaData))
for i, txMeta := range payload.TxMetaData {
if checkTransaction(txMeta, trxFilter) {
trxBuffer := new(bytes.Buffer)
if err := payload.Txs[i].MsgTx().Serialize(trxBuffer); err != nil {
return err
}
data := trxBuffer.Bytes()
cid, err := ipld.RawdataToCid(ipld.MBitcoinTx, data, multihash.DBL_SHA2_256)
if err != nil {
return err
}
response.Transactions = append(response.Transactions, ipfs.BlockModel{
Data: data,
CID: cid.String(),
})
}
}
}
return nil
}
// checkTransaction returns true if the provided transaction has a hit on the filter
func checkTransaction(txMeta TxModelWithInsAndOuts, txFilter TxFilter) bool {
passesSegwitFilter := false
if !txFilter.Segwit || (txFilter.Segwit && txMeta.SegWit) {
passesSegwitFilter = true
}
passesMultiSigFilter := !txFilter.MultiSig
if txFilter.MultiSig {
for _, out := range txMeta.TxOutputs {
if out.RequiredSigs > 1 {
passesMultiSigFilter = true
}
}
}
passesWitnessFilter := len(txFilter.WitnessHashes) == 0
for _, wantedWitnessHash := range txFilter.WitnessHashes {
if wantedWitnessHash == txMeta.WitnessHash {
passesWitnessFilter = true
}
}
passesAddressFilter := len(txFilter.Addresses) == 0
for _, wantedAddress := range txFilter.Addresses {
for _, out := range txMeta.TxOutputs {
for _, actualAddress := range out.Addresses {
if wantedAddress == actualAddress {
passesAddressFilter = true
}
}
}
}
passesIndexFilter := len(txFilter.Indexes) == 0
for _, wantedIndex := range txFilter.Indexes {
if wantedIndex == txMeta.Index {
passesIndexFilter = true
}
}
passesPkScriptClassFilter := len(txFilter.PkScriptClasses) == 0
for _, wantedPkScriptClass := range txFilter.PkScriptClasses {
for _, out := range txMeta.TxOutputs {
if out.ScriptClass == wantedPkScriptClass {
passesPkScriptClassFilter = true
}
}
}
return passesSegwitFilter && passesMultiSigFilter && passesWitnessFilter && passesAddressFilter && passesIndexFilter && passesPkScriptClassFilter
}