aboutsummaryrefslogtreecommitdiffstats
path: root/core/state/iterator.go
blob: 9d8a69b7cd2c87277d6052d051e32da81bc7675e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package state

import (
    "bytes"
    "fmt"
    "math/big"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/rlp"
    "github.com/ethereum/go-ethereum/trie"
)

// NodeIterator is an iterator to traverse the entire state trie post-order,
// including all of the contract code and contract state tries.
type NodeIterator struct {
    state *StateDB // State being iterated

    stateIt *trie.NodeIterator // Primary iterator for the global state trie
    dataIt  *trie.NodeIterator // Secondary iterator for the data trie of a contract

    accountHash common.Hash // Hash of the node containing the account
    codeHash    common.Hash // Hash of the contract source code
    code        []byte      // Source code associated with a contract

    Hash   common.Hash // Hash of the current entry being iterated (nil if not standalone)
    Entry  interface{} // Current state entry being iterated (internal representation)
    Parent common.Hash // Hash of the first full ancestor node (nil if current is the root)

    Error error // Failure set in case of an internal error in the iterator
}

// NewNodeIterator creates an post-order state node iterator.
func NewNodeIterator(state *StateDB) *NodeIterator {
    return &NodeIterator{
        state: state,
    }
}

// Next moves the iterator to the next node, returning whether there are any
// further nodes. In case of an internal error this method returns false and
// sets the Error field to the encountered failure.
func (it *NodeIterator) Next() bool {
    // If the iterator failed previously, don't do anything
    if it.Error != nil {
        return false
    }
    // Otherwise step forward with the iterator and report any errors
    if err := it.step(); err != nil {
        it.Error = err
        return false
    }
    return it.retrieve()
}

// step moves the iterator to the next entry of the state trie.
func (it *NodeIterator) step() error {
    // Abort if we reached the end of the iteration
    if it.state == nil {
        return nil
    }
    // Initialize the iterator if we've just started
    if it.stateIt == nil {
        it.stateIt = trie.NewNodeIterator(it.state.trie.Trie)
    }
    // If we had data nodes previously, we surely have at least state nodes
    if it.dataIt != nil {
        if cont := it.dataIt.Next(); !cont {
            if it.dataIt.Error != nil {
                return it.dataIt.Error
            }
            it.dataIt = nil
        }
        return nil
    }
    // If we had source code previously, discard that
    if it.code != nil {
        it.code = nil
        return nil
    }
    // Step to the next state trie node, terminating if we're out of nodes
    if cont := it.stateIt.Next(); !cont {
        if it.stateIt.Error != nil {
            return it.stateIt.Error
        }
        it.state, it.stateIt = nil, nil
        return nil
    }
    // If the state trie node is an internal entry, leave as is
    if !it.stateIt.Leaf {
        return nil
    }
    // Otherwise we've reached an account node, initiate data iteration
    var account struct {
        Nonce    uint64
        Balance  *big.Int
        Root     common.Hash
        CodeHash []byte
    }
    if err := rlp.Decode(bytes.NewReader(it.stateIt.LeafBlob), &account); err != nil {
        return err
    }
    dataTrie, err := trie.New(account.Root, it.state.db)
    if err != nil {
        return err
    }
    it.dataIt = trie.NewNodeIterator(dataTrie)
    if !it.dataIt.Next() {
        it.dataIt = nil
    }
    if bytes.Compare(account.CodeHash, emptyCodeHash) != 0 {
        it.codeHash = common.BytesToHash(account.CodeHash)
        it.code, err = it.state.db.Get(account.CodeHash)
        if err != nil {
            return fmt.Errorf("code %x: %v", account.CodeHash, err)
        }
    }
    it.accountHash = it.stateIt.Parent
    return nil
}

// retrieve pulls and caches the current state entry the iterator is traversing.
// The method returns whether there are any more data left for inspection.
func (it *NodeIterator) retrieve() bool {
    // Clear out any previously set values
    it.Hash, it.Entry = common.Hash{}, nil

    // If the iteration's done, return no available data
    if it.state == nil {
        return false
    }
    // Otherwise retrieve the current entry
    switch {
    case it.dataIt != nil:
        it.Hash, it.Entry, it.Parent = it.dataIt.Hash, it.dataIt.Node, it.dataIt.Parent
        if it.Parent == (common.Hash{}) {
            it.Parent = it.accountHash
        }
    case it.code != nil:
        it.Hash, it.Entry, it.Parent = it.codeHash, it.code, it.accountHash
    case it.stateIt != nil:
        it.Hash, it.Entry, it.Parent = it.stateIt.Hash, it.stateIt.Node, it.stateIt.Parent
    }
    return true
}