github.1485827954.workers.dev/ethereum/go-ethereum@v1.14.3/trie/trie_reader.go (about)

     1  // Copyright 2022 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/common"
    21  	"github.com/ethereum/go-ethereum/core/types"
    22  	"github.com/ethereum/go-ethereum/log"
    23  	"github.com/ethereum/go-ethereum/trie/triestate"
    24  	"github.com/ethereum/go-ethereum/triedb/database"
    25  )
    26  
    27  // trieReader is a wrapper of the underlying node reader. It's not safe
    28  // for concurrent usage.
    29  type trieReader struct {
    30  	owner  common.Hash
    31  	reader database.Reader
    32  	banned map[string]struct{} // Marker to prevent node from being accessed, for tests
    33  }
    34  
    35  // newTrieReader initializes the trie reader with the given node reader.
    36  func newTrieReader(stateRoot, owner common.Hash, db database.Database) (*trieReader, error) {
    37  	if stateRoot == (common.Hash{}) || stateRoot == types.EmptyRootHash {
    38  		if stateRoot == (common.Hash{}) {
    39  			log.Error("Zero state root hash!")
    40  		}
    41  		return &trieReader{owner: owner}, nil
    42  	}
    43  	reader, err := db.Reader(stateRoot)
    44  	if err != nil {
    45  		return nil, &MissingNodeError{Owner: owner, NodeHash: stateRoot, err: err}
    46  	}
    47  	return &trieReader{owner: owner, reader: reader}, nil
    48  }
    49  
    50  // newEmptyReader initializes the pure in-memory reader. All read operations
    51  // should be forbidden and returns the MissingNodeError.
    52  func newEmptyReader() *trieReader {
    53  	return &trieReader{}
    54  }
    55  
    56  // node retrieves the rlp-encoded trie node with the provided trie node
    57  // information. An MissingNodeError will be returned in case the node is
    58  // not found or any error is encountered.
    59  func (r *trieReader) node(path []byte, hash common.Hash) ([]byte, error) {
    60  	// Perform the logics in tests for preventing trie node access.
    61  	if r.banned != nil {
    62  		if _, ok := r.banned[string(path)]; ok {
    63  			return nil, &MissingNodeError{Owner: r.owner, NodeHash: hash, Path: path}
    64  		}
    65  	}
    66  	if r.reader == nil {
    67  		return nil, &MissingNodeError{Owner: r.owner, NodeHash: hash, Path: path}
    68  	}
    69  	blob, err := r.reader.Node(r.owner, path, hash)
    70  	if err != nil || len(blob) == 0 {
    71  		return nil, &MissingNodeError{Owner: r.owner, NodeHash: hash, Path: path, err: err}
    72  	}
    73  	return blob, nil
    74  }
    75  
    76  // MerkleLoader implements triestate.TrieLoader for constructing tries.
    77  type MerkleLoader struct {
    78  	db database.Database
    79  }
    80  
    81  // NewMerkleLoader creates the merkle trie loader.
    82  func NewMerkleLoader(db database.Database) *MerkleLoader {
    83  	return &MerkleLoader{db: db}
    84  }
    85  
    86  // OpenTrie opens the main account trie.
    87  func (l *MerkleLoader) OpenTrie(root common.Hash) (triestate.Trie, error) {
    88  	return New(TrieID(root), l.db)
    89  }
    90  
    91  // OpenStorageTrie opens the storage trie of an account.
    92  func (l *MerkleLoader) OpenStorageTrie(stateRoot common.Hash, addrHash, root common.Hash) (triestate.Trie, error) {
    93  	return New(StorageTrieID(stateRoot, addrHash, root), l.db)
    94  }