Move code around and drop not needed pieces (#297)

alloc/state.go

@@ -102,7 +102,7 @@ func (s *State) VolatileSize() uint64 {
 
 // Node returns node bytes.
 func (s *State) Node(nodeAddress types.VolatileAddress) unsafe.Pointer {
-	return unsafe.Add(s.dataP, nodeAddress*types.NodeLength)
+	return unsafe.Add(s.dataP, nodeAddress.Naked()*types.NodeLength)
 }
 
 // Bytes returns byte slice of a node.

db.go

@@ -253,16 +253,13 @@ func (db *DB) deleteSnapshot(
 		},
 	)
 
-	//nolint:nestif
 	if nextSnapshotInfo.DeallocationRoot.VolatileAddress != types.FreeAddress {
-		var err error
 		for nextDeallocSnapshot := range space.IteratorAndDeallocator(
 			nextSnapshotInfo.DeallocationRoot,
 			db.config.State,
 			deallocationNodeAssistant,
 			volatileDeallocator,
 			persistentDeallocator,
-			&err,
 		) {
 			if nextDeallocSnapshot.Key.SnapshotID > snapshotInfo.PreviousSnapshotID &&
 				nextDeallocSnapshot.Key.SnapshotID <= snapshotID {
@@ -287,9 +284,6 @@ func (db *DB) deleteSnapshot(
 				return err
 			}
 		}
-		if err != nil {
-			return err
-		}
 	}
 
 	nextSnapshotInfo.DeallocationRoot = snapshotInfo.DeallocationRoot

space/address.go

@@ -0,0 +1,25 @@
+package space
+
+import (
+	"github.com/outofforest/quantum/types"
+)
+
+const (
+	// flagPointerNode says that this is pointer node.
+	flagPointerNode = types.FlagNaked + 1
+
+	// flagHashMod says that key hash must be recalculated.
+	flagHashMod = flagPointerNode << 1
+)
+
+func isFree(address types.VolatileAddress) bool {
+	return address == types.FreeAddress
+}
+
+func isPointer(address types.VolatileAddress) bool {
+	return address.IsSet(flagPointerNode)
+}
+
+func isData(address types.VolatileAddress) bool {
+	return !isFree(address) && !isPointer(address)
+}

space/data.go

@@ -8,9 +8,15 @@ import (
 	"github.com/outofforest/quantum/types"
 )
 
+// DataItem stores single key-value pair.
+type DataItem[K, V comparable] struct {
+	Key   K
+	Value V
+}
+
 // NewDataNodeAssistant creates new space data node assistant.
 func NewDataNodeAssistant[K, V comparable]() (*DataNodeAssistant[K, V], error) {
-	itemSize := uint64(unsafe.Sizeof(types.DataItem[K, V]{})+types.UInt64Length-1) /
+	itemSize := uint64(unsafe.Sizeof(DataItem[K, V]{})+types.UInt64Length-1) /
 		types.UInt64Length * types.UInt64Length
 
 	numOfItems := types.NodeLength / (itemSize + types.UInt64Length) // Uint64Length is for key hash.
@@ -45,8 +51,8 @@ func (na *DataNodeAssistant[K, V]) ItemOffset(index uint64) uint64 {
 }
 
 // Item maps the memory address given by the node address and offset to an item.
-func (na *DataNodeAssistant[K, V]) Item(n unsafe.Pointer, offset uint64) *types.DataItem[K, V] {
-	return (*types.DataItem[K, V])(unsafe.Add(n, offset))
+func (na *DataNodeAssistant[K, V]) Item(n unsafe.Pointer, offset uint64) *DataItem[K, V] {
+	return (*DataItem[K, V])(unsafe.Add(n, offset))
 }
 
 // KeyHashes returns slice of key hashes stored in the node.
@@ -55,18 +61,3 @@ func (na *DataNodeAssistant[K, V]) KeyHashes(n unsafe.Pointer) []types.KeyHash {
 	// alignment to compare them.
 	return unsafe.Slice((*types.KeyHash)(n), na.numOfItems)
 }
-
-// Iterator iterates over items.
-func (na *DataNodeAssistant[K, V]) Iterator(n unsafe.Pointer) func(func(uint64, *types.DataItem[K, V]) bool) {
-	return func(yield func(uint64, *types.DataItem[K, V]) bool) {
-		keyHashP := n
-		itemP := unsafe.Add(n, na.itemOffset)
-		for i := range na.numOfItems {
-			if *(*types.KeyHash)(keyHashP) != 0 && !yield(i, (*types.DataItem[K, V])(itemP)) {
-				return
-			}
-			keyHashP = unsafe.Add(keyHashP, types.UInt64Length)
-			itemP = unsafe.Add(itemP, na.itemSize)
-		}
-	}
-}