feat(store/v2): gaskv store

store/gas.go

@@ -0,0 +1,82 @@
+package store
+
+import "fmt"
+
+// Gas defines type alias of uint64 for gas consumption. Gas is measured by the
+// SDK for store operations such as Get and Set calls. In addition, callers have
+// the ability to explicitly charge gas for costly operations such as signature
+// verification.
+type Gas uint64
+
+// Gas consumption descriptors.
+const (
+	GasIterNextCostFlatDesc = "IterNextFlat"
+	GasValuePerByteDesc     = "ValuePerByte"
+	GasWritePerByteDesc     = "WritePerByte"
+	GasReadPerByteDesc      = "ReadPerByte"
+	GasWriteCostFlatDesc    = "WriteFlat"
+	GasReadCostFlatDesc     = "ReadFlat"
+	GasHasDesc              = "Has"
+	GasDeleteDesc           = "Delete"
+)
+
+type (
+	// ErrorNegativeGasConsumed defines an error thrown when the amount of gas refunded
+	// results in a negative gas consumed amount.
+	ErrorNegativeGasConsumed struct {
+		Descriptor string
+	}
+
+	// ErrorOutOfGas defines an error thrown when an action results in out of gas.
+	ErrorOutOfGas struct {
+		Descriptor string
+	}
+
+	// ErrorGasOverflow defines an error thrown when an action results gas consumption
+	// unsigned integer overflow.
+	ErrorGasOverflow struct {
+		Descriptor string
+	}
+)
+
+// GasMeter defines an interface for gas consumption tracking.
+type GasMeter interface {
+	GasConsumed() Gas
+	GasConsumedToLimit() Gas
+	GasRemaining() Gas
+	Limit() Gas
+	ConsumeGas(amount Gas, descriptor string)
+	RefundGas(amount Gas, descriptor string)
+	IsPastLimit() bool
+	IsOutOfGas() bool
+
+	fmt.Stringer
+}
+
+// GasConfig defines gas cost for each operation on a KVStore.
+type GasConfig struct {
+	HasCost          Gas
+	DeleteCost       Gas
+	ReadCostFlat     Gas
+	ReadCostPerByte  Gas
+	WriteCostFlat    Gas
+	WriteCostPerByte Gas
+	IterNextCostFlat Gas
+}
+
+// DefaultGasConfig returns a default GasConfig for gas metering.
+//
+// Note, these values are essentially arbitrary. They are not based on any specific
+// computation or measurements, but mainly reflect relative costs, i.e. writes
+// should be more expensive than reads.
+func DefaultGasConfig() GasConfig {
+	return GasConfig{
+		HasCost:          1000,
+		DeleteCost:       1000,
+		ReadCostFlat:     1000,
+		ReadCostPerByte:  3,
+		WriteCostFlat:    2000,
+		WriteCostPerByte: 30,
+		IterNextCostFlat: 30,
+	}
+}

store/gaskv/store.go

@@ -0,0 +1,49 @@
+package gaskv
+
+import "cosmossdk.io/store/v2"
+
+var _ store.BranchedKVStore = (*Store)(nil)
+
+type Store struct {
+	parent store.KVStore
+}
+
+func (s *Store) GetStoreKey() string {
+	return s.parent.GetStoreKey()
+}
+
+func (s *Store) GetStoreType() store.StoreType {
+	return store.StoreTypeGas
+}
+
+func (s *Store) Get(key []byte) []byte {
+	panic("not implemented!")
+}
+
+func (s *Store) Has(key []byte) bool {
+	panic("not implemented!")
+}
+
+func (s *Store) Set(key, value []byte) {
+	panic("not implemented!")
+}
+
+func (s *Store) Delete(key []byte) {
+	panic("not implemented!")
+}
+
+func (s *Store) GetChangeset() *store.Changeset {
+	panic("not implemented!")
+}
+
+func (s *Store) Reset() error {
+	panic("not implemented!")
+}
+
+func (s *Store) Iterator(start, end []byte) store.Iterator {
+	panic("not implemented!")
+}
+
+func (s *Store) ReverseIterator(start, end []byte) store.Iterator {
+	panic("not implemented!")
+}

store/memkv/store.go

@@ -8,10 +8,8 @@ import (
 	"cosmossdk.io/store/v2"
 )
 
-const (
-	// degree defines the approximate number of items and children per B-tree node.
-	degree = 32
-)
+// degree defines the approximate number of items and children per B-tree node.
+const degree = 32
 
 var _ store.KVStore = (*Store)(nil)
 

store/store.go

@@ -14,6 +14,7 @@ const (
 	StoreTypeBranch StoreType = iota
 	StoreTypeTrace
 	StoreTypeMem
+	StoreTypeGas
 )
 
 // RootStore defines an abstraction layer containing a State Storage (SS) engine