refactor slab index register reading/writing to separate file and imp…

…rove naming

runtime/account_storage_v1.go

@@ -175,7 +175,7 @@ func (s *AccountStorageV1) writeStorageDomainSlabIndex(
 	storageDomainKey interpreter.StorageDomainKey,
 	slabIndex atree.SlabIndex,
 ) error {
-	return writeSlabIndex(
+	return writeSlabIndexToRegister(
 		s.ledger,
 		storageDomainKey.Address,
 		[]byte(storageDomainKey.Domain.Identifier()),
@@ -191,7 +191,7 @@ func getDomainStorageMapFromV1DomainRegister(
 	domain common.StorageDomain,
 ) (*interpreter.DomainStorageMap, error) {
 
-	domainStorageSlabIndex, domainRegisterExists, err := getSlabIndexFromRegisterValue(
+	domainStorageSlabIndex, domainRegisterExists, err := readSlabIndexFromRegister(
 		ledger,
 		address,
 		[]byte(domain.Identifier()),

runtime/account_storage_v2.go

@@ -238,23 +238,23 @@ func (s *AccountStorageV2) writeAccountStorageSlabIndex(
 	address common.Address,
 	slabIndex atree.SlabIndex,
 ) error {
-	return writeSlabIndex(
+	return writeSlabIndexToRegister(
 		s.ledger,
 		address,
 		[]byte(AccountStorageKey),
 		slabIndex,
 	)
 }
 
-func getAccountStorageSlabIndex(
+func readAccountStorageSlabIndexFromRegister(
 	ledger atree.Ledger,
 	address common.Address,
 ) (
 	atree.SlabIndex,
 	bool,
 	error,
 ) {
-	return getSlabIndexFromRegisterValue(
+	return readSlabIndexFromRegister(
 		ledger,
 		address,
 		[]byte(AccountStorageKey),
@@ -269,7 +269,7 @@ func getAccountStorageMapFromRegister(
 	*interpreter.AccountStorageMap,
 	error,
 ) {
-	slabIndex, registerExists, err := getAccountStorageSlabIndex(
+	slabIndex, registerExists, err := readAccountStorageSlabIndexFromRegister(
 		ledger,
 		address,
 	)
@@ -293,7 +293,7 @@ func hasAccountStorageMap(
 	address common.Address,
 ) (bool, error) {
 
-	_, registerExists, err := getAccountStorageSlabIndex(
+	_, registerExists, err := readAccountStorageSlabIndexFromRegister(
 		ledger,
 		address,
 	)

runtime/slabindex.go

@@ -0,0 +1,86 @@
+/*
+ * Cadence - The resource-oriented smart contract programming language
+ *
+ * Copyright Flow Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package runtime
+
+import (
+	"github.com/onflow/atree"
+
+	"github.com/onflow/cadence/common"
+	"github.com/onflow/cadence/errors"
+	"github.com/onflow/cadence/interpreter"
+)
+
+// readSlabIndexFromRegister returns register value as atree.SlabIndex.
+// This function returns error if
+// - underlying ledger panics, or
+// - underlying ledger returns error when retrieving ledger value, or
+// - retrieved ledger value is invalid (for atree.SlabIndex).
+func readSlabIndexFromRegister(
+	ledger atree.Ledger,
+	address common.Address,
+	key []byte,
+) (atree.SlabIndex, bool, error) {
+	var data []byte
+	var err error
+	errors.WrapPanic(func() {
+		data, err = ledger.GetValue(address[:], key)
+	})
+	if err != nil {
+		return atree.SlabIndex{}, false, interpreter.WrappedExternalError(err)
+	}
+
+	dataLength := len(data)
+
+	if dataLength == 0 {
+		return atree.SlabIndex{}, false, nil
+	}
+
+	isStorageIndex := dataLength == storageIndexLength
+	if !isStorageIndex {
+		// Invalid data in register
+
+		// TODO: add dedicated error type?
+		return atree.SlabIndex{}, false, errors.NewUnexpectedError(
+			"invalid storage index for storage map of account '%x': expected length %d, got %d",
+			address[:], storageIndexLength, dataLength,
+		)
+	}
+
+	return atree.SlabIndex(data), true, nil
+}
+
+func writeSlabIndexToRegister(
+	ledger atree.Ledger,
+	address common.Address,
+	key []byte,
+	slabIndex atree.SlabIndex,
+) error {
+	var err error
+	errors.WrapPanic(func() {
+		err = ledger.SetValue(
+			address[:],
+			key,
+			slabIndex[:],
+		)
+	})
+	if err != nil {
+		return interpreter.WrappedExternalError(err)
+	}
+	return nil
+}

runtime/storage.go

@@ -213,7 +213,7 @@ func (s *Storage) IsV1Account(address common.Address) (isV1 bool) {
 	// Check if a storage map register exists for any of the domains.
 	// Check the most frequently used domains first, such as storage, public, private.
 	for _, domain := range common.AllStorageDomains {
-		_, domainExists, err := getSlabIndexFromRegisterValue(
+		_, domainExists, err := readSlabIndexFromRegister(
 			s.Ledger,
 			address,
 			[]byte(domain.Identifier()),
@@ -247,45 +247,6 @@ func (s *Storage) cacheDomainStorageMap(
 	s.cachedDomainStorageMaps[storageDomainKey] = domainStorageMap
 }
 
-// getSlabIndexFromRegisterValue returns register value as atree.SlabIndex.
-// This function returns error if
-// - underlying ledger panics, or
-// - underlying ledger returns error when retrieving ledger value, or
-// - retrieved ledger value is invalid (for atree.SlabIndex).
-func getSlabIndexFromRegisterValue(
-	ledger atree.Ledger,
-	address common.Address,
-	key []byte,
-) (atree.SlabIndex, bool, error) {
-	var data []byte
-	var err error
-	errors.WrapPanic(func() {
-		data, err = ledger.GetValue(address[:], key)
-	})
-	if err != nil {
-		return atree.SlabIndex{}, false, interpreter.WrappedExternalError(err)
-	}
-
-	dataLength := len(data)
-
-	if dataLength == 0 {
-		return atree.SlabIndex{}, false, nil
-	}
-
-	isStorageIndex := dataLength == storageIndexLength
-	if !isStorageIndex {
-		// Invalid data in register
-
-		// TODO: add dedicated error type?
-		return atree.SlabIndex{}, false, errors.NewUnexpectedError(
-			"invalid storage index for storage map of account '%x': expected length %d, got %d",
-			address[:], storageIndexLength, dataLength,
-		)
-	}
-
-	return atree.SlabIndex(data), true, nil
-}
-
 func (s *Storage) recordContractUpdate(
 	location common.AddressLocation,
 	contractValue *interpreter.CompositeValue,
@@ -606,23 +567,3 @@ func (UnreferencedRootSlabsError) IsInternalError() {}
 func (e UnreferencedRootSlabsError) Error() string {
 	return fmt.Sprintf("slabs not referenced: %s", e.UnreferencedRootSlabIDs)
 }
-
-func writeSlabIndex(
-	ledger atree.Ledger,
-	address common.Address,
-	key []byte,
-	slabIndex atree.SlabIndex,
-) error {
-	var err error
-	errors.WrapPanic(func() {
-		err = ledger.SetValue(
-			address[:],
-			key,
-			slabIndex[:],
-		)
-	})
-	if err != nil {
-		return interpreter.WrappedExternalError(err)
-	}
-	return nil
-}