1// Copyright (c) 2018 The btcsuite developers
2// Use of this source code is governed by an ISC
3// license that can be found in the LICENSE file.
4
5package wire
6
7import (
8	"io"
9
10	"github.com/btcsuite/btcd/chaincfg/chainhash"
11)
12
13// MsgGetCFCheckpt is a request for filter headers at evenly spaced intervals
14// throughout the blockchain history. It allows to set the FilterType field to
15// get headers in the chain of basic (0x00) or extended (0x01) headers.
16type MsgGetCFCheckpt struct {
17	FilterType FilterType
18	StopHash   chainhash.Hash
19}
20
21// BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
22// This is part of the Message interface implementation.
23func (msg *MsgGetCFCheckpt) BtcDecode(r io.Reader, pver uint32, _ MessageEncoding) error {
24	err := readElement(r, &msg.FilterType)
25	if err != nil {
26		return err
27	}
28
29	return readElement(r, &msg.StopHash)
30}
31
32// BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
33// This is part of the Message interface implementation.
34func (msg *MsgGetCFCheckpt) BtcEncode(w io.Writer, pver uint32, _ MessageEncoding) error {
35	err := writeElement(w, msg.FilterType)
36	if err != nil {
37		return err
38	}
39
40	return writeElement(w, &msg.StopHash)
41}
42
43// Command returns the protocol command string for the message.  This is part
44// of the Message interface implementation.
45func (msg *MsgGetCFCheckpt) Command() string {
46	return CmdGetCFCheckpt
47}
48
49// MaxPayloadLength returns the maximum length the payload can be for the
50// receiver.  This is part of the Message interface implementation.
51func (msg *MsgGetCFCheckpt) MaxPayloadLength(pver uint32) uint32 {
52	// Filter type + uint32 + block hash
53	return 1 + chainhash.HashSize
54}
55
56// NewMsgGetCFCheckpt returns a new bitcoin getcfcheckpt message that conforms
57// to the Message interface using the passed parameters and defaults for the
58// remaining fields.
59func NewMsgGetCFCheckpt(filterType FilterType, stopHash *chainhash.Hash) *MsgGetCFCheckpt {
60	return &MsgGetCFCheckpt{
61		FilterType: filterType,
62		StopHash:   *stopHash,
63	}
64}
65