ipld-eth-server/pkg/transformers/shared/log_fetcher.go
2018-12-10 21:12:55 +01:00

57 lines
1.7 KiB
Go

// Copyright 2018 Vulcanize
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package shared
import (
"github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/vulcanize/vulcanizedb/pkg/core"
)
type LogFetcher interface {
FetchLogs(contractAddresses []common.Address, topics []common.Hash, missingHeader core.Header) ([]types.Log, error)
}
type Fetcher struct {
blockChain core.BlockChain
}
func NewFetcher(blockchain core.BlockChain) Fetcher {
return Fetcher{
blockChain: blockchain,
}
}
// Checks all topic0s, on all addresses, fetching matching logs for the given header
func (fetcher Fetcher) FetchLogs(addresses []common.Address, topic0s []common.Hash, header core.Header) ([]types.Log, error) {
blockHash := common.HexToHash(header.Hash)
query := ethereum.FilterQuery{
BlockHash: &blockHash,
Addresses: addresses,
// Search for _any_ of the topics in topic0 position; see docs on `FilterQuery`
Topics: [][]common.Hash{topic0s},
}
logs, err := fetcher.blockChain.GetEthLogsWithCustomQuery(query)
if err != nil {
// TODO review aggregate fetching error handling
return []types.Log{}, err
}
return logs, nil
}