// 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 light
import (
"context"
"fmt"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/trie"
)
func NewState(ctx context.Context, head *types.Header, odr OdrBackend) *state.StateDB {
state, _ := state.New(head.Root, NewStateDatabase(ctx, head, odr))
return state
}
func NewStateDatabase(ctx context.Context, head *types.Header, odr OdrBackend) state.Database {
return &odrDatabase{ctx, StateTrieID(head), odr}
}
type odrDatabase struct {
ctx context.Context
id *TrieID
backend OdrBackend
}
func (db *odrDatabase) OpenTrie(root common.Hash) (state.Trie, error) {
return &odrTrie{db: db, id: db.id}, nil
}
func (db *odrDatabase) OpenStorageTrie(addrHash, root common.Hash) (state.Trie, error) {
return &odrTrie{db: db, id: StorageTrieID(db.id, addrHash, root)}, nil
}
func (db *odrDatabase) CopyTrie(t state.Trie) state.Trie {
switch t := t.(type) {
case *odrTrie:
cpy := &odrTrie{db: t.db, id: t.id}
if t.trie != nil {
cpytrie := *t.trie
cpy.trie = &cpytrie
}
return cpy
default:
panic(fmt.Errorf("unknown trie type %T", t))
}
}
func (db *odrDatabase) ContractCode(addrHash, codeHash common.Hash) ([]byte, error) {
if codeHash == sha3_nil {
return nil, nil
}
if code, err := db.backend.Database().Get(codeHash[:]); err == nil {
return code, nil
}
id := *db.id
id.AccKey = addrHash[:]
req := &CodeRequest{Id: &id, Hash: codeHash}
err := db.backend.Retrieve(db.ctx, req)
return req.Data, err
}
func (db *odrDatabase) ContractCodeSize(addrHash, codeHash common.Hash) (int, error) {
code, err := db.ContractCode(addrHash, codeHash)
return len(code), err
}
type odrTrie struct {
db *odrDatabase
id *TrieID
trie *trie.Trie
}
func (t *odrTrie) TryGet(key []byte) ([]byte, error) {
key = crypto.Keccak256(key)
var res []byte
err := t.do(key, func() (err error) {
res, err = t.trie.TryGet(key)
return err
})
return res, err
}
func (t *odrTrie) TryUpdate(key, value []byte) error {
key = crypto.Keccak256(key)
return t.do(key, func() error {
return t.trie.TryDelete(key)
})
}
func (t *odrTrie) TryDelete(key []byte) error {
key = crypto.Keccak256(key)
return t.do(key, func() error {
return t.trie.TryDelete(key)
})
}
func (t *odrTrie) CommitTo(db trie.DatabaseWriter) (common.Hash, error) {
if t.trie == nil {
return t.id.Root, nil
}
return t.trie.CommitTo(db)
}
func (t *odrTrie) Hash() common.Hash {
if t.trie == nil {
return t.id.Root
}
return t.trie.Hash()
}
func (t *odrTrie) NodeIterator(startkey []byte) trie.NodeIterator {
return newNodeIterator(t, startkey)
}
func (t *odrTrie) GetKey(sha []byte) []byte {
return nil
}
// do tries and retries to execute a function until it returns with no error or
// an error type other than MissingNodeError
func (t *odrTrie) do(key []byte, fn func() error) error {
for {
var err error
if t.trie == nil {
t.trie, err = trie.New(t.id.Root, t.db.backend.Database())
}
if err == nil {
err = fn()
}
if _, ok := err.(*trie.MissingNodeError); !ok {
return err
}
r := &TrieRequest{Id: t.id, Key: key}
if err := t.db.backend.Retrieve(t.db.ctx, r); err != nil {
return fmt.Errorf("can't fetch trie key %x: %v", key, err)
}
}
}
type nodeIterator struct {
trie.NodeIterator
t *odrTrie
err error
}
func newNodeIterator(t *odrTrie, startkey []byte) trie.NodeIterator {
it := &nodeIterator{t: t}
// Open the actual non-ODR trie if that hasn't happened yet.
if t.trie == nil {
it.do(func() error {
t, err := trie.New(t.id.Root, t.db.backend.Database())
if err == nil {
it.t.trie = t
}
return err
})
}
it.do(func() error {
it.NodeIterator = it.t.trie.NodeIterator(startkey)
return it.NodeIterator.Error()
})
return it
}
func (it *nodeIterator) Next(descend bool) bool {
var ok bool
it.do(func() error {
ok = it.NodeIterator.Next(descend)
return it.NodeIterator.Error()
})
return ok
}
// do runs fn and attempts to fill in missing nodes by retrieving.
func (it *nodeIterator) do(fn func() error) {
var lasthash common.Hash
for {
it.err = fn()
missing, ok := it.err.(*trie.MissingNodeError)
if !ok {
return
}
if missing.NodeHash == lasthash {
it.err = fmt.Errorf("retrieve loop for trie node %x", missing.NodeHash)
return
}
lasthash = missing.NodeHash
r := &TrieRequest{Id: it.t.id, Key: nibblesToKey(missing.Path)}
if it.err = it.t.db.backend.Retrieve(it.t.db.ctx, r); it.err != nil {
return
}
}
}
func (it *nodeIterator) Error() error {
if it.err != nil {
return it.err
}
return it.NodeIterator.Error()
}
func nibblesToKey(nib []byte) []byte {
if len(nib) > 0 && nib[len(nib)-1] == 0x10 {
nib = nib[:len(nib)-1] // drop terminator
}
if len(nib)&1 == 1 {
nib = append(nib, 0) // make even
}
key := make([]byte, len(nib)/2)
for bi, ni := 0, 0; ni < len(nib); bi, ni = bi+1, ni+2 {
key[bi] = nib[ni]<<4 | nib[ni+1]
}
return key
}
