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metastate.go
64 lines (53 loc) · 1.61 KB
/
metastate.go
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/*
Copyright IBM Corp. All Rights Reserved.
SPDX-License-Identifier: Apache-2.0
*/
package common
import (
"bytes"
"encoding/binary"
"github.com/pkg/errors"
)
// NodeMetastate information to store the information about current
// height of the ledger (last accepted block sequence number).
type NodeMetastate struct {
// Actual ledger height
LedgerHeight uint64
}
// NewNodeMetastate creates new meta data with given ledger height
func NewNodeMetastate(height uint64) *NodeMetastate {
return &NodeMetastate{height}
}
// Bytes decodes meta state into byte array for serialization
func (n *NodeMetastate) Bytes() ([]byte, error) {
buffer := new(bytes.Buffer)
// Explicitly specify byte order for write into the buffer
// to provide cross platform support, note the it consistent
// with FromBytes function
err := binary.Write(buffer, binary.BigEndian, *n)
if err != nil {
return nil, errors.WithStack(err)
}
return buffer.Bytes(), nil
}
// Height returns ledger height from the state
func (n *NodeMetastate) Height() uint64 {
return n.LedgerHeight
}
// Update state with new ledger height
func (n *NodeMetastate) Update(height uint64) {
n.LedgerHeight = height
}
// FromBytes - encode from byte array into meta data structure
func FromBytes(buf []byte) (*NodeMetastate, error) {
state := NodeMetastate{}
reader := bytes.NewReader(buf)
// As bytes are written in the big endian to keep supporting
// cross platforming and for consistency reasons read also
// done using same order
err := binary.Read(reader, binary.BigEndian, &state)
if err != nil {
return nil, errors.WithStack(err)
}
return &state, nil
}