neoneo-go/pkg/core/mpt/empty.go
Evgeniy Stratonikov bd2b1a0521 mpt: add Size method to trie nodes
Knowing serialized size of the node is useful for
preallocating byte-slice in advance.

Signed-off-by: Evgeniy Stratonikov <evgeniy@nspcc.ru>
2021-08-06 12:01:16 +03:00

56 lines
1.1 KiB
Go

package mpt
import (
"encoding/json"
"errors"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/util"
)
// EmptyNode represents empty node.
type EmptyNode struct{}
// DecodeBinary implements io.Serializable interface.
func (e EmptyNode) DecodeBinary(*io.BinReader) {
}
// EncodeBinary implements io.Serializable interface.
func (e EmptyNode) EncodeBinary(*io.BinWriter) {
}
// Size implements Node interface.
func (EmptyNode) Size() int { return 0 }
// MarshalJSON implements Node interface.
func (e EmptyNode) MarshalJSON() ([]byte, error) {
return []byte(`{}`), nil
}
// UnmarshalJSON implements Node interface.
func (e EmptyNode) UnmarshalJSON(bytes []byte) error {
var m map[string]interface{}
err := json.Unmarshal(bytes, &m)
if err != nil {
return err
}
if len(m) != 0 {
return errors.New("expected empty node")
}
return nil
}
// Hash implements Node interface.
func (e EmptyNode) Hash() util.Uint256 {
panic("can't get hash of an EmptyNode")
}
// Type implements Node interface.
func (e EmptyNode) Type() NodeType {
return EmptyT
}
// Bytes implements Node interface.
func (e EmptyNode) Bytes() []byte {
return nil
}