87 lines
2.6 KiB
Go
87 lines
2.6 KiB
Go
// Copyright 2018 Vulcanize
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package retriever
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import (
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"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
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)
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// Block retriever is used to retrieve the first block for a given contract and the most recent block
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// It requires a vDB synced database with blocks, transactions, receipts, and logs
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type BlockRetriever interface {
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RetrieveFirstBlock(contractAddr string) (int64, error)
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RetrieveMostRecentBlock() (int64, error)
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}
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type blockRetriever struct {
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*postgres.DB
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}
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func NewBlockRetriever(db *postgres.DB) (r *blockRetriever) {
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return &blockRetriever{
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DB: db,
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}
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}
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// Try both methods of finding the first block, with the receipt method taking precedence
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func (r *blockRetriever) RetrieveFirstBlock(contractAddr string) (int64, error) {
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i, err := r.retrieveFirstBlockFromReceipts(contractAddr)
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if err != nil {
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i, err = r.retrieveFirstBlockFromLogs(contractAddr)
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}
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return i, err
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}
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// For some contracts the contract creation transaction receipt doesn't have the contract address so this doesn't work (e.g. Sai)
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func (r *blockRetriever) retrieveFirstBlockFromReceipts(contractAddr string) (int64, error) {
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var firstBlock int
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err := r.DB.Get(
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&firstBlock,
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`SELECT number FROM blocks
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WHERE id = (SELECT block_id FROM receipts
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WHERE contract_address = $1
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ORDER BY block_id ASC
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LIMIT 1)`,
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contractAddr,
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)
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return int64(firstBlock), err
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}
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// In which case this servers as a heuristic to find the first block by finding the first contract event log
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func (r *blockRetriever) retrieveFirstBlockFromLogs(contractAddr string) (int64, error) {
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var firstBlock int
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err := r.DB.Get(
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&firstBlock,
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"SELECT block_number FROM logs WHERE address = $1 ORDER BY block_number ASC LIMIT 1",
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contractAddr,
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)
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return int64(firstBlock), err
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}
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// Method to retrieve the most recent block in vDB
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func (r *blockRetriever) RetrieveMostRecentBlock() (int64, error) {
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var lastBlock int64
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err := r.DB.Get(
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&lastBlock,
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"SELECT number FROM blocks ORDER BY number DESC LIMIT 1",
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)
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return lastBlock, err
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}
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