1 files changed, 33 insertions, 60 deletions
diff --git a/core/state/sync.go b/core/state/sync.go
index e9bebe8ee..5a388886c 100644
--- a/core/state/sync.go
+++ b/core/state/sync.go
@@ -21,78 +21,51 @@ import (
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/crypto/sha3"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/trie"
 )
 
-type StateSync struct {
-	db          ethdb.Database
-	sync        *trie.TrieSync
-	codeReqs    map[common.Hash]struct{} // requested but not yet written to database
-	codeReqList []common.Hash            // requested since last Missing
-}
+// StateSync is the main state  synchronisation scheduler, which provides yet the
+// unknown state hashes to retrieve, accepts node data associated with said hashes
+// and reconstructs the state database step by step until all is done.
+type StateSync trie.TrieSync
 
-var sha3_nil = common.BytesToHash(sha3.NewKeccak256().Sum(nil))
+// NewStateSync create a new state trie download scheduler.
+func NewStateSync(root common.Hash, database ethdb.Database) *StateSync {
+	// Pre-declare the result syncer t
+	var syncer *trie.TrieSync
 
-func NewStateSync(root common.Hash, db ethdb.Database) *StateSync {
-	ss := &StateSync{
-		db:       db,
-		codeReqs: make(map[common.Hash]struct{}),
-	}
-	ss.codeReqs[sha3_nil] = struct{}{} // never request the nil hash
-	ss.sync = trie.NewTrieSync(root, db, ss.leafFound)
-	return ss
-}
+	callback := func(leaf []byte, parent common.Hash) error {
+		var obj struct {
+			Nonce    uint64
+			Balance  *big.Int
+			Root     common.Hash
+			CodeHash []byte
+		}
+		if err := rlp.Decode(bytes.NewReader(leaf), &obj); err != nil {
+			return err
+		}
+		syncer.AddSubTrie(obj.Root, 64, parent, nil)
+		syncer.AddRawEntry(common.BytesToHash(obj.CodeHash), 64, parent)
 
-func (self *StateSync) leafFound(leaf []byte, parent common.Hash) error {
-	var obj struct {
-		Nonce    uint64
-		Balance  *big.Int
-		Root     common.Hash
-		CodeHash []byte
-	}
-	if err := rlp.Decode(bytes.NewReader(leaf), &obj); err != nil {
-		return err
+		return nil
 	}
-	self.sync.AddSubTrie(obj.Root, 64, parent, nil)
+	syncer = trie.NewTrieSync(root, database, callback)
+	return (*StateSync)(syncer)
+}
 
-	codehash := common.BytesToHash(obj.CodeHash)
-	if _, ok := self.codeReqs[codehash]; !ok {
-		code, _ := self.db.Get(obj.CodeHash)
-		if code == nil {
-			self.codeReqs[codehash] = struct{}{}
-			self.codeReqList = append(self.codeReqList, codehash)
-		}
-	}
-	return nil
+// Missing retrieves the known missing nodes from the state trie for retrieval.
+func (s *StateSync) Missing(max int) []common.Hash {
+	return (*trie.TrieSync)(s).Missing(max)
 }
 
-func (self *StateSync) Missing(max int) []common.Hash {
-	cr := len(self.codeReqList)
-	gh := 0
-	if max != 0 {
-		if cr > max {
-			cr = max
-		}
-		gh = max - cr
-	}
-	list := append(self.sync.Missing(gh), self.codeReqList[:cr]...)
-	self.codeReqList = self.codeReqList[cr:]
-	return list
+// Process injects a batch of retrieved trie nodes data.
+func (s *StateSync) Process(list []trie.SyncResult) (int, error) {
+	return (*trie.TrieSync)(s).Process(list)
 }
 
-func (self *StateSync) Process(list []trie.SyncResult) error {
-	for i := 0; i < len(list); i++ {
-		if _, ok := self.codeReqs[list[i].Hash]; ok { // code data, not a node
-			self.db.Put(list[i].Hash[:], list[i].Data)
-			delete(self.codeReqs, list[i].Hash)
-			list[i] = list[len(list)-1]
-			list = list[:len(list)-1]
-			i--
-		}
-	}
-	_, err := self.sync.Process(list)
-	return err
+// Pending returns the number of state entries currently pending for download.
+func (s *StateSync) Pending() int {
+	return (*trie.TrieSync)(s).Pending()
 }