core/state: move slot RLP encoding into the MPT implementation (#27000)

Continuing with a series of PRs to make the Trie interface more generic, this PR moves
the RLP encoding of storage slots inside the StateTrie and light.Trie implementations,
as other types of tries don't use RLP.

core/state/state_object.go

@@ -185,6 +185,7 @@ func (s *stateObject) GetCommittedState(db Database, key common.Hash) common.Has
 	var (
 		enc   []byte
 		err   error
+		value common.Hash
 	)
 	if s.db.snap != nil {
 		start := time.Now()
@@ -192,6 +193,13 @@ func (s *stateObject) GetCommittedState(db Database, key common.Hash) common.Has
 		if metrics.EnabledExpensive {
 			s.db.SnapshotStorageReads += time.Since(start)
 		}
+		if len(enc) > 0 {
+			_, content, _, err := rlp.Split(enc)
+			if err != nil {
+				s.db.setError(err)
+			}
+			value.SetBytes(content)
+		}
 	}
 	// If the snapshot is unavailable or reading from it fails, load from the database.
 	if s.db.snap == nil || err != nil {
@@ -201,7 +209,7 @@ func (s *stateObject) GetCommittedState(db Database, key common.Hash) common.Has
 			s.db.setError(err)
 			return common.Hash{}
 		}
-		enc, err = tr.GetStorage(s.address, key.Bytes())
+		val, err := tr.GetStorage(s.address, key.Bytes())
 		if metrics.EnabledExpensive {
 			s.db.StorageReads += time.Since(start)
 		}
@@ -209,14 +217,7 @@ func (s *stateObject) GetCommittedState(db Database, key common.Hash) common.Has
 			s.db.setError(err)
 			return common.Hash{}
 		}
-	}
-	var value common.Hash
-	if len(enc) > 0 {
-		_, content, _, err := rlp.Split(enc)
-		if err != nil {
-			s.db.setError(err)
-		}
-		value.SetBytes(content)
+		value.SetBytes(val)
 	}
 	s.originStorage[key] = value
 	return value
@@ -292,7 +293,8 @@ func (s *stateObject) updateTrie(db Database) (Trie, error) {
 		}
 		s.originStorage[key] = value
 
-		var v []byte
+		// rlp-encoded value to be used by the snapshot
+		var snapshotVal []byte
 		if (value == common.Hash{}) {
 			if err := tr.DeleteStorage(s.address, key[:]); err != nil {
 				s.db.setError(err)
@@ -300,9 +302,10 @@ func (s *stateObject) updateTrie(db Database) (Trie, error) {
 			}
 			s.db.StorageDeleted += 1
 		} else {
+			trimmedVal := common.TrimLeftZeroes(value[:])
 			// Encoding []byte cannot fail, ok to ignore the error.
-			v, _ = rlp.EncodeToBytes(common.TrimLeftZeroes(value[:]))
-			if err := tr.UpdateStorage(s.address, key[:], v); err != nil {
+			snapshotVal, _ = rlp.EncodeToBytes(trimmedVal)
+			if err := tr.UpdateStorage(s.address, key[:], trimmedVal); err != nil {
 				s.db.setError(err)
 				return nil, err
 			}
@@ -317,7 +320,7 @@ func (s *stateObject) updateTrie(db Database) (Trie, error) {
 					s.db.snapStorage[s.addrHash] = storage
 				}
 			}
-			storage[crypto.HashData(hasher, key[:])] = v // v will be nil if it's deleted
+			storage[crypto.HashData(hasher, key[:])] = snapshotVal // will be nil if it's deleted
 		}
 		usedStorage = append(usedStorage, common.CopyBytes(key[:])) // Copy needed for closure
 	}

light/trie.go

@@ -108,12 +108,16 @@ type odrTrie struct {
 
 func (t *odrTrie) GetStorage(_ common.Address, key []byte) ([]byte, error) {
 	key = crypto.Keccak256(key)
-	var res []byte
+	var enc []byte
 	err := t.do(key, func() (err error) {
-		res, err = t.trie.Get(key)
+		enc, err = t.trie.Get(key)
 		return err
 	})
-	return res, err
+	if err != nil || len(enc) == 0 {
+		return nil, err
+	}
+	_, content, _, err := rlp.Split(enc)
+	return content, err
 }
 
 func (t *odrTrie) GetAccount(address common.Address) (*types.StateAccount, error) {
@@ -145,8 +149,9 @@ func (t *odrTrie) UpdateAccount(address common.Address, acc *types.StateAccount)
 
 func (t *odrTrie) UpdateStorage(_ common.Address, key, value []byte) error {
 	key = crypto.Keccak256(key)
+	v, _ := rlp.EncodeToBytes(value)
 	return t.do(key, func() error {
-		return t.trie.Update(key, value)
+		return t.trie.Update(key, v)
 	})
 }
 

trie/secure_trie.go

@@ -86,7 +86,12 @@ func (t *StateTrie) MustGet(key []byte) []byte {
 // If the specified storage slot is not in the trie, nil will be returned.
 // If a trie node is not found in the database, a MissingNodeError is returned.
 func (t *StateTrie) GetStorage(_ common.Address, key []byte) ([]byte, error) {
-	return t.trie.Get(t.hashKey(key))
+	enc, err := t.trie.Get(t.hashKey(key))
+	if err != nil || len(enc) == 0 {
+		return nil, err
+	}
+	_, content, _, err := rlp.Split(enc)
+	return content, err
 }
 
 // GetAccount attempts to retrieve an account with provided account address.
@@ -148,7 +153,8 @@ func (t *StateTrie) MustUpdate(key, value []byte) {
 // If a node is not found in the database, a MissingNodeError is returned.
 func (t *StateTrie) UpdateStorage(_ common.Address, key, value []byte) error {
 	hk := t.hashKey(key)
-	err := t.trie.Update(hk, value)
+	v, _ := rlp.EncodeToBytes(value)
+	err := t.trie.Update(hk, v)
 	if err != nil {
 		return err
 	}