ipld-eth-statedb/trie_by_cid/trie/proof.go

113 lines
3.7 KiB
Go
Raw Normal View History

// 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 trie
import (
"bytes"
"fmt"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/trie"
log "github.com/sirupsen/logrus"
)
var VerifyProof = trie.VerifyProof
var VerifyRangeProof = trie.VerifyRangeProof
// Prove constructs a merkle proof for key. The result contains all encoded nodes
// on the path to the value at key. The value itself is also included in the last
// node and can be retrieved by verifying the proof.
//
// If the trie does not contain a value for key, the returned proof contains all
// nodes of the longest existing prefix of the key (at least the root node), ending
// with the node that proves the absence of the key.
func (t *Trie) Prove(key []byte, fromLevel uint, proofDb ethdb.KeyValueWriter) error {
// Collect all nodes on the path to key.
var (
prefix []byte
nodes []node
tn = t.root
)
key = keybytesToHex(key)
for len(key) > 0 && tn != nil {
switch n := tn.(type) {
case *shortNode:
if len(key) < len(n.Key) || !bytes.Equal(n.Key, key[:len(n.Key)]) {
// The trie doesn't contain the key.
tn = nil
} else {
tn = n.Val
prefix = append(prefix, n.Key...)
key = key[len(n.Key):]
}
nodes = append(nodes, n)
case *fullNode:
tn = n.Children[key[0]]
prefix = append(prefix, key[0])
key = key[1:]
nodes = append(nodes, n)
case hashNode:
// Retrieve the specified node from the underlying node reader.
// trie.resolveAndTrack is not used since in that function the
// loaded blob will be tracked, while it's not required here since
// all loaded nodes won't be linked to trie at all and track nodes
// may lead to out-of-memory issue.
var err error
tn, err = t.reader.node(prefix, common.BytesToHash(n))
if err != nil {
log.Error("Unhandled trie error in Trie.Prove", "err", err)
return err
}
default:
panic(fmt.Sprintf("%T: invalid node: %v", tn, tn))
}
}
hasher := newHasher(false)
defer returnHasherToPool(hasher)
for i, n := range nodes {
if fromLevel > 0 {
fromLevel--
continue
}
var hn node
n, hn = hasher.proofHash(n)
if hash, ok := hn.(hashNode); ok || i == 0 {
// If the node's database encoding is a hash (or is the
// root node), it becomes a proof element.
enc := nodeToBytes(n)
if !ok {
hash = hasher.hashData(enc)
}
proofDb.Put(hash, enc)
}
}
return nil
}
// Prove constructs a merkle proof for key. The result contains all encoded nodes
// on the path to the value at key. The value itself is also included in the last
// node and can be retrieved by verifying the proof.
//
// If the trie does not contain a value for key, the returned proof contains all
// nodes of the longest existing prefix of the key (at least the root node), ending
// with the node that proves the absence of the key.
func (t *StateTrie) Prove(key []byte, fromLevel uint, proofDb ethdb.KeyValueWriter) error {
return t.trie.Prove(key, fromLevel, proofDb)
}