github.com/baptiste-b-pegasys/quorum/v22@v22.4.2/trie/notary.go (about) 1 // Copyright 2020 The go-ethereum Authors 2 // This file is part of the go-ethereum library. 3 // 4 // The go-ethereum library is free software: you can redistribute it and/or modify 5 // it under the terms of the GNU Lesser General Public License as published by 6 // the Free Software Foundation, either version 3 of the License, or 7 // (at your option) any later version. 8 // 9 // The go-ethereum library is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU Lesser General Public License for more details. 13 // 14 // You should have received a copy of the GNU Lesser General Public License 15 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. 16 17 package trie 18 19 import ( 20 "github.com/ethereum/go-ethereum/ethdb" 21 "github.com/ethereum/go-ethereum/ethdb/memorydb" 22 ) 23 24 // KeyValueNotary tracks which keys have been accessed through a key-value reader 25 // with te scope of verifying if certain proof datasets are maliciously bloated. 26 type KeyValueNotary struct { 27 ethdb.KeyValueReader 28 reads map[string]struct{} 29 } 30 31 // NewKeyValueNotary wraps a key-value database with an access notary to track 32 // which items have bene accessed. 33 func NewKeyValueNotary(db ethdb.KeyValueReader) *KeyValueNotary { 34 return &KeyValueNotary{ 35 KeyValueReader: db, 36 reads: make(map[string]struct{}), 37 } 38 } 39 40 // Get retrieves an item from the underlying database, but also tracks it as an 41 // accessed slot for bloat checks. 42 func (k *KeyValueNotary) Get(key []byte) ([]byte, error) { 43 k.reads[string(key)] = struct{}{} 44 return k.KeyValueReader.Get(key) 45 } 46 47 // Accessed returns s snapshot of the original key-value store containing only the 48 // data accessed through the notary. 49 func (k *KeyValueNotary) Accessed() ethdb.KeyValueStore { 50 db := memorydb.New() 51 for keystr := range k.reads { 52 key := []byte(keystr) 53 val, _ := k.KeyValueReader.Get(key) 54 db.Put(key, val) 55 } 56 return db 57 }