forked from cerc-io/plugeth
82 lines
3.0 KiB
Go
82 lines
3.0 KiB
Go
// Copyright 2022 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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"fmt"
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"github.com/ethereum/go-ethereum/common"
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)
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// Reader wraps the Node method of a backing trie store.
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type Reader interface {
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// Node retrieves the RLP-encoded trie node blob with the provided trie
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// identifier, node path and the corresponding node hash. No error will
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// be returned if the node is not found.
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Node(owner common.Hash, path []byte, hash common.Hash) ([]byte, error)
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}
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// NodeReader wraps all the necessary functions for accessing trie node.
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type NodeReader interface {
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// GetReader returns a reader for accessing all trie nodes with provided
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// state root. Nil is returned in case the state is not available.
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GetReader(root common.Hash) Reader
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}
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// trieReader is a wrapper of the underlying node reader. It's not safe
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// for concurrent usage.
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type trieReader struct {
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owner common.Hash
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reader Reader
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banned map[string]struct{} // Marker to prevent node from being accessed, for tests
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}
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// newTrieReader initializes the trie reader with the given node reader.
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func newTrieReader(stateRoot, owner common.Hash, db NodeReader) (*trieReader, error) {
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reader := db.GetReader(stateRoot)
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if reader == nil {
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return nil, fmt.Errorf("state not found #%x", stateRoot)
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}
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return &trieReader{owner: owner, reader: reader}, nil
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}
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// newEmptyReader initializes the pure in-memory reader. All read operations
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// should be forbidden and returns the MissingNodeError.
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func newEmptyReader() *trieReader {
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return &trieReader{}
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}
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// node retrieves the rlp-encoded trie node with the provided trie node
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// information. An MissingNodeError will be returned in case the node is
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// not found or any error is encountered.
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func (r *trieReader) node(path []byte, hash common.Hash) ([]byte, error) {
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// Perform the logics in tests for preventing trie node access.
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if r.banned != nil {
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if _, ok := r.banned[string(path)]; ok {
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return nil, &MissingNodeError{Owner: r.owner, NodeHash: hash, Path: path}
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}
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}
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if r.reader == nil {
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return nil, &MissingNodeError{Owner: r.owner, NodeHash: hash, Path: path}
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}
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blob, err := r.reader.Node(r.owner, path, hash)
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if err != nil || len(blob) == 0 {
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return nil, &MissingNodeError{Owner: r.owner, NodeHash: hash, Path: path, err: err}
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}
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return blob, nil
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}
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