core: move storage-related interop code into the storage package

pkg/core/interop/storage/basic.go

@@ -0,0 +1,139 @@
+package storage
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/interop"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+)
+
+var (
+	// ErrGasLimitExceeded is returned from interops when there is not enough
+	// GAS left in the execution context to complete the action.
+	ErrGasLimitExceeded   = errors.New("gas limit exceeded")
+	errFindInvalidOptions = errors.New("invalid Find options")
+)
+
+// Context contains contract ID and read/write flag, it's used as
+// a context for storage manipulation functions.
+type Context struct {
+	ID       int32
+	ReadOnly bool
+}
+
+// storageDelete deletes stored key-value pair.
+func Delete(ic *interop.Context) error {
+	stcInterface := ic.VM.Estack().Pop().Value()
+	stc, ok := stcInterface.(*Context)
+	if !ok {
+		return fmt.Errorf("%T is not a storage.Context", stcInterface)
+	}
+	if stc.ReadOnly {
+		return errors.New("storage.Context is read only")
+	}
+	key := ic.VM.Estack().Pop().Bytes()
+	ic.DAO.DeleteStorageItem(stc.ID, key)
+	return nil
+}
+
+// Get returns stored key-value pair.
+func Get(ic *interop.Context) error {
+	stcInterface := ic.VM.Estack().Pop().Value()
+	stc, ok := stcInterface.(*Context)
+	if !ok {
+		return fmt.Errorf("%T is not a storage.Context", stcInterface)
+	}
+	key := ic.VM.Estack().Pop().Bytes()
+	si := ic.DAO.GetStorageItem(stc.ID, key)
+	if si != nil {
+		ic.VM.Estack().PushItem(stackitem.NewByteArray([]byte(si)))
+	} else {
+		ic.VM.Estack().PushItem(stackitem.Null{})
+	}
+	return nil
+}
+
+// GetContext returns storage context for the currently executing contract.
+func GetContext(ic *interop.Context) error {
+	return getContextInternal(ic, false)
+}
+
+// GetReadOnlyContext returns read-only storage context for the currently executing contract.
+func GetReadOnlyContext(ic *interop.Context) error {
+	return getContextInternal(ic, true)
+}
+
+// getContextInternal is internal version of storageGetContext and
+// storageGetReadOnlyContext which allows to specify ReadOnly context flag.
+func getContextInternal(ic *interop.Context, isReadOnly bool) error {
+	contract, err := ic.GetContract(ic.VM.GetCurrentScriptHash())
+	if err != nil {
+		return err
+	}
+	sc := &Context{
+		ID:       contract.ID,
+		ReadOnly: isReadOnly,
+	}
+	ic.VM.Estack().PushItem(stackitem.NewInterop(sc))
+	return nil
+}
+
+func putWithContext(ic *interop.Context, stc *Context, key []byte, value []byte) error {
+	if len(key) > storage.MaxStorageKeyLen {
+		return errors.New("key is too big")
+	}
+	if len(value) > storage.MaxStorageValueLen {
+		return errors.New("value is too big")
+	}
+	if stc.ReadOnly {
+		return errors.New("storage.Context is read only")
+	}
+	si := ic.DAO.GetStorageItem(stc.ID, key)
+	sizeInc := len(value)
+	if si == nil {
+		sizeInc = len(key) + len(value)
+	} else if len(value) != 0 {
+		if len(value) <= len(si) {
+			sizeInc = (len(value)-1)/4 + 1
+		} else if len(si) != 0 {
+			sizeInc = (len(si)-1)/4 + 1 + len(value) - len(si)
+		}
+	}
+	if !ic.VM.AddGas(int64(sizeInc) * ic.BaseStorageFee()) {
+		return ErrGasLimitExceeded
+	}
+	ic.DAO.PutStorageItem(stc.ID, key, value)
+	return nil
+}
+
+// Put puts key-value pair into the storage.
+func Put(ic *interop.Context) error {
+	stcInterface := ic.VM.Estack().Pop().Value()
+	stc, ok := stcInterface.(*Context)
+	if !ok {
+		return fmt.Errorf("%T is not a storage.Context", stcInterface)
+	}
+	key := ic.VM.Estack().Pop().Bytes()
+	value := ic.VM.Estack().Pop().Bytes()
+	return putWithContext(ic, stc, key, value)
+}
+
+// ContextAsReadOnly sets given context to read-only mode.
+func ContextAsReadOnly(ic *interop.Context) error {
+	stcInterface := ic.VM.Estack().Pop().Value()
+	stc, ok := stcInterface.(*Context)
+	if !ok {
+		return fmt.Errorf("%T is not a storage.Context", stcInterface)
+	}
+	if !stc.ReadOnly {
+		stx := &Context{
+			ID:       stc.ID,
+			ReadOnly: true,
+		}
+		stc = stx
+	}
+	ic.VM.Estack().PushItem(stackitem.NewInterop(stc))
+	return nil
+}