134 lines
3.8 KiB
Go
134 lines
3.8 KiB
Go
// Copyright 2015 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 state
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import (
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"bytes"
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"fmt"
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"math/big"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/rlp"
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"github.com/ethereum/go-ethereum/trie"
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)
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// NodeIterator is an iterator to traverse the entire state trie post-order,
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// including all of the contract code and contract state tries.
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type NodeIterator struct {
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state *StateDB // State being iterated
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stateIt *trie.NodeIterator // Primary iterator for the global state trie
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dataIt *trie.NodeIterator // Secondary iterator for the data trie of a contract
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code []byte // Source code associated with a contract
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Entry interface{} // Current state entry being iterated (internal representation)
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}
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// NewNodeIterator creates an post-order state node iterator.
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func NewNodeIterator(state *StateDB) *NodeIterator {
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return &NodeIterator{
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state: state,
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}
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}
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// Next moves the iterator to the next node, returning whether there are any
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// further nodes.
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func (it *NodeIterator) Next() bool {
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it.step()
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return it.retrieve()
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}
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// step moves the iterator to the next entry of the state trie.
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func (it *NodeIterator) step() {
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// Abort if we reached the end of the iteration
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if it.state == nil {
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return
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}
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// Initialize the iterator if we've just started
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if it.stateIt == nil {
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it.stateIt = trie.NewNodeIterator(it.state.trie.Trie)
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}
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// If we had data nodes previously, we surely have at least state nodes
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if it.dataIt != nil {
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if cont := it.dataIt.Next(); !cont {
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it.dataIt = nil
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}
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return
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}
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// If we had source code previously, discard that
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if it.code != nil {
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it.code = nil
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return
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}
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// Step to the next state trie node, terminating if we're out of nodes
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if cont := it.stateIt.Next(); !cont {
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it.state, it.stateIt = nil, nil
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return
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}
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// If the state trie node is an internal entry, leave as is
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if !it.stateIt.Leaf {
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return
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}
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// Otherwise we've reached an account node, initiate data iteration
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var account struct {
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Nonce uint64
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Balance *big.Int
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Root common.Hash
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CodeHash []byte
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}
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err := rlp.Decode(bytes.NewReader(it.stateIt.LeafBlob), &account)
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if err != nil {
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panic(err)
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}
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dataTrie, err := trie.New(account.Root, it.state.db)
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if err != nil {
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panic(err)
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}
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it.dataIt = trie.NewNodeIterator(dataTrie)
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if !it.dataIt.Next() {
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it.dataIt = nil
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}
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if bytes.Compare(account.CodeHash, emptyCodeHash) != 0 {
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it.code, err = it.state.db.Get(account.CodeHash)
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if err != nil {
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panic(fmt.Sprintf("code %x: %v", account.CodeHash, err))
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}
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}
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}
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// retrieve pulls and caches the current state entry the iterator is traversing.
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// The method returns whether there are any more data left for inspection.
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func (it *NodeIterator) retrieve() bool {
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// Clear out any previously set values
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it.Entry = nil
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// If the iteration's done, return no available data
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if it.state == nil {
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return false
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}
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// Otherwise retrieve the current entry
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switch {
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case it.dataIt != nil:
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it.Entry = it.dataIt.Node
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case it.code != nil:
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it.Entry = it.code
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case it.stateIt != nil:
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it.Entry = it.stateIt.Node
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}
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return true
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}
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