116 lines
3.1 KiB
Go
116 lines
3.1 KiB
Go
//
|
|
// Copyright © 2020 Vulcanize, Inc
|
|
//
|
|
// This program is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Affero General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// This program 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 Affero General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Affero General Public License
|
|
// along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
package iterator
|
|
|
|
import (
|
|
// "fmt"
|
|
"bytes"
|
|
|
|
// "github.com/ethereum/go-ethereum/common"
|
|
"github.com/ethereum/go-ethereum/common"
|
|
"github.com/ethereum/go-ethereum/core/state"
|
|
"github.com/ethereum/go-ethereum/trie"
|
|
)
|
|
|
|
// Simplified trie node iterator
|
|
type NodeIterator interface {
|
|
Next(bool) bool
|
|
Error() error
|
|
Hash() common.Hash
|
|
Path() []byte
|
|
Leaf() bool
|
|
}
|
|
|
|
type prefixBoundIterator struct {
|
|
current trie.NodeIterator
|
|
endKey []byte
|
|
}
|
|
|
|
func (it *prefixBoundIterator) Next(descend bool) bool {
|
|
if it.endKey == nil {
|
|
return it.current.Next(descend)
|
|
}
|
|
cmp := bytes.Compare(it.current.Path(), it.endKey) // stop before endKey
|
|
if cmp >= 0 {
|
|
return false
|
|
}
|
|
return it.current.Next(descend)
|
|
}
|
|
|
|
func (it *prefixBoundIterator) Error() error {
|
|
return it.current.Error()
|
|
}
|
|
func (it *prefixBoundIterator) Hash() common.Hash {
|
|
return it.current.Hash()
|
|
}
|
|
func (it *prefixBoundIterator) Path() []byte {
|
|
return it.current.Path()
|
|
}
|
|
func (it *prefixBoundIterator) Leaf() bool {
|
|
return it.current.Leaf()
|
|
}
|
|
|
|
// Iterator with an upper bound value (hex path prefix)
|
|
func NewPrefixBoundIterator(it trie.NodeIterator, to []byte) NodeIterator {
|
|
return &prefixBoundIterator{current: it, endKey: to}
|
|
}
|
|
|
|
// array of 0..f with prefix
|
|
func prefixedNibbles(prefix []byte) [][]byte {
|
|
var ret [][]byte
|
|
for i := byte(0); i < 16; i++ {
|
|
elem := make([]byte, len(prefix))
|
|
copy(elem, prefix)
|
|
elem = append(elem, i)
|
|
ret = append(ret, elem)
|
|
}
|
|
return ret
|
|
}
|
|
|
|
// Generates ordered cartesian product of all nibbles of given length, w/ optional prefix
|
|
// eg. MakePaths([4], 2) => [[4 0 0] [4 0 1] ... [4 f f]]
|
|
func MakePaths(prefix []byte, length int) [][]byte {
|
|
paths := [][]byte{prefix}
|
|
for depth := 0; depth < length; depth++ {
|
|
var newPaths [][]byte
|
|
for _, path := range paths {
|
|
for _, newPath := range prefixedNibbles(path) {
|
|
newPaths = append(newPaths, newPath)
|
|
}
|
|
}
|
|
paths = newPaths
|
|
}
|
|
return paths
|
|
}
|
|
|
|
// Apply a function to 16^cutdepth subtries divided by path prefix
|
|
func VisitSubtries(tree state.Trie, cutDepth int, callback func(NodeIterator)) {
|
|
prefixes := MakePaths(nil, cutDepth)
|
|
// pre- and postpend nil to include root & tail
|
|
prefixes = append(prefixes, nil)
|
|
prefixes = append([][]byte{nil}, prefixes...)
|
|
|
|
for i := 0; i < len(prefixes)-1; i++ {
|
|
key := prefixes[i]
|
|
if len(key)%2 != 0 { // zero-pad for odd-length keys
|
|
key = append(key, 0)
|
|
}
|
|
it := tree.NodeIterator(HexToKeyBytes(key))
|
|
callback(NewPrefixBoundIterator(it, prefixes[i+1]))
|
|
}
|
|
}
|