mirror of
https://github.com/ethereum/go-ethereum.git
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288 lines
8.6 KiB
Go
288 lines
8.6 KiB
Go
// Copyright 2025 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 bintrie
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import (
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"errors"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/trie"
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)
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var errIteratorEnd = errors.New("end of iteration")
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type binaryNodeIteratorState struct {
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Node BinaryNode
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Index int
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}
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type binaryNodeIterator struct {
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trie *BinaryTrie
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current BinaryNode
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lastErr error
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stack []binaryNodeIteratorState
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}
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func newBinaryNodeIterator(t *BinaryTrie, _ []byte) (trie.NodeIterator, error) {
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if t.Hash() == zero {
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return &binaryNodeIterator{trie: t, lastErr: errIteratorEnd}, nil
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}
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it := &binaryNodeIterator{trie: t, current: t.root}
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// it.err = it.seek(start)
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return it, nil
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}
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// Next moves the iterator to the next node. If the parameter is false, any child
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// nodes will be skipped.
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func (it *binaryNodeIterator) Next(descend bool) bool {
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if it.lastErr == errIteratorEnd {
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it.lastErr = errIteratorEnd
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return false
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}
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if len(it.stack) == 0 {
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it.stack = append(it.stack, binaryNodeIteratorState{Node: it.trie.root})
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it.current = it.trie.root
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return true
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}
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switch node := it.current.(type) {
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case *InternalNode:
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// index: 0 = nothing visited, 1=left visited, 2=right visited
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context := &it.stack[len(it.stack)-1]
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// recurse into both children
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if context.Index == 0 {
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if _, isempty := node.left.(Empty); node.left != nil && !isempty {
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it.stack = append(it.stack, binaryNodeIteratorState{Node: node.left})
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it.current = node.left
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return it.Next(descend)
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}
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context.Index++
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}
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if context.Index == 1 {
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if _, isempty := node.right.(Empty); node.right != nil && !isempty {
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it.stack = append(it.stack, binaryNodeIteratorState{Node: node.right})
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it.current = node.right
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return it.Next(descend)
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}
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context.Index++
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}
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// Reached the end of this node, go back to the parent, if
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// this isn't root.
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if len(it.stack) == 1 {
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it.lastErr = errIteratorEnd
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return false
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}
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it.stack = it.stack[:len(it.stack)-1]
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it.current = it.stack[len(it.stack)-1].Node
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it.stack[len(it.stack)-1].Index++
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return it.Next(descend)
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case *StemNode:
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// Look for the next non-empty value
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for i := it.stack[len(it.stack)-1].Index; i < 256; i++ {
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if node.Values[i] != nil {
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it.stack[len(it.stack)-1].Index = i + 1
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return true
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}
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}
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// go back to parent to get the next leaf
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// Check if we're at the root before popping
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if len(it.stack) == 1 {
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it.lastErr = errIteratorEnd
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return false
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}
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it.stack = it.stack[:len(it.stack)-1]
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it.current = it.stack[len(it.stack)-1].Node
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it.stack[len(it.stack)-1].Index++
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return it.Next(descend)
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case HashedNode:
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// resolve the node
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data, err := it.trie.nodeResolver(it.Path(), common.Hash(node))
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if err != nil {
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panic(err)
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}
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it.current, err = DeserializeNode(data, len(it.stack)-1)
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if err != nil {
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panic(err)
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}
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// update the stack and parent with the resolved node
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it.stack[len(it.stack)-1].Node = it.current
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parent := &it.stack[len(it.stack)-2]
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if parent.Index == 0 {
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parent.Node.(*InternalNode).left = it.current
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} else {
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parent.Node.(*InternalNode).right = it.current
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}
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return it.Next(descend)
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case Empty:
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// do nothing
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return false
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default:
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panic("invalid node type")
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}
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}
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// Error returns the error status of the iterator.
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func (it *binaryNodeIterator) Error() error {
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if it.lastErr == errIteratorEnd {
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return nil
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}
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return it.lastErr
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}
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// Hash returns the hash of the current node.
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func (it *binaryNodeIterator) Hash() common.Hash {
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return it.current.Hash()
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}
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// Parent returns the hash of the parent of the current node. The hash may be the one
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// grandparent if the immediate parent is an internal node with no hash.
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func (it *binaryNodeIterator) Parent() common.Hash {
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return it.stack[len(it.stack)-1].Node.Hash()
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}
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// Path returns the hex-encoded path to the current node.
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// Callers must not retain references to the return value after calling Next.
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// For leaf nodes, the last element of the path is the 'terminator symbol' 0x10.
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func (it *binaryNodeIterator) Path() []byte {
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if it.Leaf() {
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return it.LeafKey()
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}
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var path []byte
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for i, state := range it.stack {
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// skip the last byte
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if i >= len(it.stack)-1 {
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break
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}
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path = append(path, byte(state.Index))
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}
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return path
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}
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// NodeBlob returns the serialized bytes of the current node.
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func (it *binaryNodeIterator) NodeBlob() []byte {
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return SerializeNode(it.current, it.trie.groupDepth)
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}
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// Leaf returns true iff the current node is a leaf node.
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// In a Binary Trie, a StemNode contains up to 256 leaf values.
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// The iterator is only considered to be "at a leaf" when it's positioned
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// at a specific non-nil value within the StemNode, not just at the StemNode itself.
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func (it *binaryNodeIterator) Leaf() bool {
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sn, ok := it.current.(*StemNode)
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if !ok {
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return false
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}
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// Check if we have a valid stack position
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if len(it.stack) == 0 {
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return false
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}
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// The Index in the stack state points to the NEXT position after the current value.
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// So if Index is 0, we haven't started iterating through the values yet.
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// If Index is 5, we're currently at value[4] (the 5th value, 0-indexed).
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idx := it.stack[len(it.stack)-1].Index
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if idx == 0 || idx > 256 {
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return false
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}
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// Check if there's actually a value at the current position
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currentValueIndex := idx - 1
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return sn.Values[currentValueIndex] != nil
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}
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// LeafKey returns the key of the leaf. The method panics if the iterator is not
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// positioned at a leaf. Callers must not retain references to the value after
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// calling Next.
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func (it *binaryNodeIterator) LeafKey() []byte {
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leaf, ok := it.current.(*StemNode)
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if !ok {
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panic("Leaf() called on an binary node iterator not at a leaf location")
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}
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return leaf.Key(it.stack[len(it.stack)-1].Index - 1)
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}
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// LeafBlob returns the content of the leaf. The method panics if the iterator
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// is not positioned at a leaf. Callers must not retain references to the value
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// after calling Next.
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func (it *binaryNodeIterator) LeafBlob() []byte {
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leaf, ok := it.current.(*StemNode)
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if !ok {
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panic("LeafBlob() called on an binary node iterator not at a leaf location")
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}
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return leaf.Values[it.stack[len(it.stack)-1].Index-1]
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}
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// LeafProof returns the Merkle proof of the leaf. The method panics if the
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// iterator is not positioned at a leaf. Callers must not retain references
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// to the value after calling Next.
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func (it *binaryNodeIterator) LeafProof() [][]byte {
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sn, ok := it.current.(*StemNode)
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if !ok {
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panic("LeafProof() called on an binary node iterator not at a leaf location")
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}
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proof := make([][]byte, 0, len(it.stack)+StemNodeWidth)
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// Build proof by walking up the stack and collecting sibling hashes
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for i := range it.stack[:len(it.stack)-2] {
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state := it.stack[i]
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internalNode := state.Node.(*InternalNode) // should panic if the node isn't an InternalNode
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// Add the sibling hash to the proof
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if state.Index == 0 {
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// We came from left, so include right sibling
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proof = append(proof, internalNode.right.Hash().Bytes())
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} else {
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// We came from right, so include left sibling
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proof = append(proof, internalNode.left.Hash().Bytes())
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}
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}
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// Add the stem and siblings
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proof = append(proof, sn.Stem)
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for _, v := range sn.Values {
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proof = append(proof, v)
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}
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return proof
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}
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// AddResolver sets an intermediate database to use for looking up trie nodes
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// before reaching into the real persistent layer.
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//
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// This is not required for normal operation, rather is an optimization for
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// cases where trie nodes can be recovered from some external mechanism without
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// reading from disk. In those cases, this resolver allows short circuiting
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// accesses and returning them from memory.
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//
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// Before adding a similar mechanism to any other place in Geth, consider
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// making trie.Database an interface and wrapping at that level. It's a huge
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// refactor, but it could be worth it if another occurrence arises.
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func (it *binaryNodeIterator) AddResolver(trie.NodeResolver) {
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// Not implemented, but should not panic
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}
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