go-ethereum/core/stateless/witness.go

123 lines
4.0 KiB
Go

// Copyright 2024 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 stateless
import (
"errors"
"maps"
"slices"
"sync"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
)
// HeaderReader is an interface to pull in headers in place of block hashes for
// the witness.
type HeaderReader interface {
// GetHeader retrieves a block header from the database by hash and number,
GetHeader(hash common.Hash, number uint64) *types.Header
}
// Witness encompasses the state required to apply a set of transactions and
// derive a post state/receipt root.
type Witness struct {
context *types.Header // Header to which this witness belongs to, with rootHash and receiptHash zeroed out
Headers []*types.Header // Past headers in reverse order (0=parent, 1=parent's-parent, etc). First *must* be set.
Codes map[string]struct{} // Set of bytecodes ran or accessed
State map[string]struct{} // Set of MPT state trie nodes (account and storage together)
chain HeaderReader // Chain reader to convert block hash ops to header proofs
lock sync.Mutex // Lock to allow concurrent state insertions
}
// NewWitness creates an empty witness ready for population.
func NewWitness(context *types.Header, chain HeaderReader) (*Witness, error) {
// When building witnesses, retrieve the parent header, which will *always*
// be included to act as a trustless pre-root hash container
var headers []*types.Header
if chain != nil {
parent := chain.GetHeader(context.ParentHash, context.Number.Uint64()-1)
if parent == nil {
return nil, errors.New("failed to retrieve parent header")
}
headers = append(headers, parent)
}
// Create the wtness with a reconstructed gutted out block
return &Witness{
context: context,
Headers: headers,
Codes: make(map[string]struct{}),
State: make(map[string]struct{}),
chain: chain,
}, nil
}
// AddBlockHash adds a "blockhash" to the witness with the designated offset from
// chain head. Under the hood, this method actually pulls in enough headers from
// the chain to cover the block being added.
func (w *Witness) AddBlockHash(number uint64) {
// Keep pulling in headers until this hash is populated
for int(w.context.Number.Uint64()-number) > len(w.Headers) {
tail := w.Headers[len(w.Headers)-1]
w.Headers = append(w.Headers, w.chain.GetHeader(tail.ParentHash, tail.Number.Uint64()-1))
}
}
// AddCode adds a bytecode blob to the witness.
func (w *Witness) AddCode(code []byte) {
if len(code) == 0 {
return
}
w.Codes[string(code)] = struct{}{}
}
// AddState inserts a batch of MPT trie nodes into the witness.
func (w *Witness) AddState(nodes map[string]struct{}) {
if len(nodes) == 0 {
return
}
w.lock.Lock()
defer w.lock.Unlock()
maps.Copy(w.State, nodes)
}
// Copy deep-copies the witness object. Witness.Block isn't deep-copied as it
// is never mutated by Witness
func (w *Witness) Copy() *Witness {
cpy := &Witness{
Headers: slices.Clone(w.Headers),
Codes: maps.Clone(w.Codes),
State: maps.Clone(w.State),
chain: w.chain,
}
if w.context != nil {
cpy.context = types.CopyHeader(w.context)
}
return cpy
}
// Root returns the pre-state root from the first header.
//
// Note, this method will panic in case of a bad witness (but RLP decoding will
// sanitize it and fail before that).
func (w *Witness) Root() common.Hash {
return w.Headers[0].Root
}