ipld-eth-server/pkg/contract_watcher/header/retriever/block_retriever.go
2019-05-01 12:12:55 -05:00

61 lines
1.8 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 retriever
import (
"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
)
// Block retriever is used to retrieve the first block for a given contract and the most recent block
// It requires a vDB synced database with blocks, transactions, receipts, and logs
type BlockRetriever interface {
RetrieveFirstBlock() (int64, error)
RetrieveMostRecentBlock() (int64, error)
}
type blockRetriever struct {
db *postgres.DB
}
func NewBlockRetriever(db *postgres.DB) (r *blockRetriever) {
return &blockRetriever{
db: db,
}
}
// Retrieve block number of earliest header in repo
func (r *blockRetriever) RetrieveFirstBlock() (int64, error) {
var firstBlock int
err := r.db.Get(
&firstBlock,
"SELECT block_number FROM headers ORDER BY block_number LIMIT 1",
)
return int64(firstBlock), err
}
// Retrieve block number of latest header in repo
func (r *blockRetriever) RetrieveMostRecentBlock() (int64, error) {
var lastBlock int
err := r.db.Get(
&lastBlock,
"SELECT block_number FROM headers ORDER BY block_number DESC LIMIT 1",
)
return int64(lastBlock), err
}