58 lines
2.0 KiB
Go
58 lines
2.0 KiB
Go
// Copyright 2020 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package trie
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import (
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"github.com/ethereum/go-ethereum/ethdb"
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"github.com/ethereum/go-ethereum/ethdb/memorydb"
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)
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// KeyValueNotary tracks which keys have been accessed through a key-value reader
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// with te scope of verifying if certain proof datasets are maliciously bloated.
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type KeyValueNotary struct {
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ethdb.KeyValueReader
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reads map[string]struct{}
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}
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// NewKeyValueNotary wraps a key-value database with an access notary to track
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// which items have bene accessed.
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func NewKeyValueNotary(db ethdb.KeyValueReader) *KeyValueNotary {
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return &KeyValueNotary{
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KeyValueReader: db,
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reads: make(map[string]struct{}),
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}
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}
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// Get retrieves an item from the underlying database, but also tracks it as an
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// accessed slot for bloat checks.
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func (k *KeyValueNotary) Get(key []byte) ([]byte, error) {
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k.reads[string(key)] = struct{}{}
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return k.KeyValueReader.Get(key)
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}
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// Accessed returns s snapshot of the original key-value store containing only the
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// data accessed through the notary.
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func (k *KeyValueNotary) Accessed() ethdb.KeyValueStore {
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db := memorydb.New()
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for keystr := range k.reads {
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key := []byte(keystr)
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val, _ := k.KeyValueReader.Get(key)
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db.Put(key, val)
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}
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return db
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}
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