// Copyright 2017 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 state
import (
"fmt"
"sync"
"github.com/dexon-foundation/dexon/common"
"github.com/dexon-foundation/dexon/ethdb"
"github.com/dexon-foundation/dexon/trie"
lru "github.com/hashicorp/golang-lru"
)
// Trie cache generation limit after which to evict trie nodes from memory.
var MaxTrieCacheGen = uint16(120)
const (
// Number of past tries to keep. This value is chosen such that
// reasonable chain reorg depths will hit an existing trie.
maxPastTries = 12
// Number of codehash->size associations to keep.
codeSizeCacheSize = 100000
)
// Database wraps access to tries and contract code.
type Database interface {
// OpenTrie opens the main account trie.
OpenTrie(root common.Hash) (Trie, error)
// OpenStorageTrie opens the storage trie of an account.
OpenStorageTrie(addrHash, root common.Hash) (Trie, error)
// CopyTrie returns an independent copy of the given trie.
CopyTrie(Trie) Trie
// ContractCode retrieves a particular contract's code.
ContractCode(addrHash, codeHash common.Hash) ([]byte, error)
// ContractCodeSize retrieves a particular contracts code's size.
ContractCodeSize(addrHash, codeHash common.Hash) (int, error)
// TrieDB retrieves the low level trie database used for data storage.
TrieDB() *trie.Database
}
// Trie is a Ethereum Merkle Trie.
type Trie interface {
TryGet(key []byte) ([]byte, error)
TryUpdate(key, value []byte) error
TryDelete(key []byte) error
Commit(onleaf trie.LeafCallback) (common.Hash, error)
Hash() common.Hash
NodeIterator(startKey []byte) trie.NodeIterator
GetKey([]byte) []byte // TODO(fjl): remove this when SecureTrie is removed
Prove(key []byte, fromLevel uint, proofDb ethdb.Putter) error
}
// NewDatabase creates a backing store for state. The returned database is safe for
// concurrent use and retains a few recent expanded trie nodes in memory. To keep
// more historical state in memory, use the NewDatabaseWithCache constructor.
func NewDatabase(db ethdb.Database) Database {
return NewDatabaseWithCache(db, 0)
}
// NewDatabase creates a backing store for state. The returned database is safe for
// concurrent use and retains both a few recent expanded trie nodes in memory, as
// well as a lot of collapsed RLP trie nodes in a large memory cache.
func NewDatabaseWithCache(db ethdb.Database, cache int) Database {
csc, _ := lru.New(codeSizeCacheSize)
return &cachingDB{
db: trie.NewDatabaseWithCache(db, cache),
codeSizeCache: csc,
}
}
type cachingDB struct {
db *trie.Database
mu sync.Mutex
pastTries []*trie.SecureTrie
codeSizeCache *lru.Cache
}
// OpenTrie opens the main account trie.
func (db *cachingDB) OpenTrie(root common.Hash) (Trie, error) {
db.mu.Lock()
defer db.mu.Unlock()
for i := len(db.pastTries) - 1; i >= 0; i-- {
if db.pastTries[i].Hash() == root {
return cachedTrie{db.pastTries[i].Copy(), db}, nil
}
}
tr, err := trie.NewSecure(root, db.db, MaxTrieCacheGen)
if err != nil {
return nil, err
}
return cachedTrie{tr, db}, nil
}
func (db *cachingDB) pushTrie(t *trie.SecureTrie) {
db.mu.Lock()
defer db.mu.Unlock()
if len(db.pastTries) >= maxPastTries {
copy(db.pastTries, db.pastTries[1:])
db.pastTries[len(db.pastTries)-1] = t
} else {
db.pastTries = append(db.pastTries, t)
}
}
// OpenStorageTrie opens the storage trie of an account.
func (db *cachingDB) OpenStorageTrie(addrHash, root common.Hash) (Trie, error) {
return trie.NewSecure(root, db.db, 0)
}
// CopyTrie returns an independent copy of the given trie.
func (db *cachingDB) CopyTrie(t Trie) Trie {
switch t := t.(type) {
case cachedTrie:
return cachedTrie{t.SecureTrie.Copy(), db}
case *trie.SecureTrie:
return t.Copy()
default:
panic(fmt.Errorf("unknown trie type %T", t))
}
}
// ContractCode retrieves a particular contract's code.
func (db *cachingDB) ContractCode(addrHash, codeHash common.Hash) ([]byte, error) {
code, err := db.db.Node(codeHash)
if err == nil {
db.codeSizeCache.Add(codeHash, len(code))
}
return code, err
}
// ContractCodeSize retrieves a particular contracts code's size.
func (db *cachingDB) ContractCodeSize(addrHash, codeHash common.Hash) (int, error) {
if cached, ok := db.codeSizeCache.Get(codeHash); ok {
return cached.(int), nil
}
code, err := db.ContractCode(addrHash, codeHash)
return len(code), err
}
// TrieDB retrieves any intermediate trie-node caching layer.
func (db *cachingDB) TrieDB() *trie.Database {
return db.db
}
// cachedTrie inserts its trie into a cachingDB on commit.
type cachedTrie struct {
*trie.SecureTrie
db *cachingDB
}
func (m cachedTrie) Commit(onleaf trie.LeafCallback) (common.Hash, error) {
root, err := m.SecureTrie.Commit(onleaf)
if err == nil {
m.db.pushTrie(m.SecureTrie)
}
return root, err
}
func (m cachedTrie) Prove(key []byte, fromLevel uint, proofDb ethdb.Putter) error {
return m.SecureTrie.Prove(key, fromLevel, proofDb)
}