lbcd/wire/msgcftypes.go

102 lines
3.2 KiB
Go

// Copyright (c) 2017 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package wire
import "io"
// FilterType is used to represent a filter type.
type FilterType uint8
const (
// GCSFilterRegular is the regular filter type.
GCSFilterRegular FilterType = iota
// GCSFilterExtended is the extended filter type.
GCSFilterExtended
)
// MsgCFTypes is the cftypes message.
type MsgCFTypes struct {
SupportedFilters []FilterType
}
// BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
// This is part of the Message interface implementation.
func (msg *MsgCFTypes) BtcDecode(r io.Reader, pver uint32, _ MessageEncoding) error {
// Read the number of filter types supported.
count, err := ReadVarInt(r, pver)
if err != nil {
return err
}
// Read each filter type.
msg.SupportedFilters = make([]FilterType, count)
for i := uint64(0); i < count; i++ {
var filterType uint8
err = readElement(r, &filterType)
if err != nil {
return err
}
msg.SupportedFilters[i] = FilterType(filterType)
}
return nil
}
// BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
// This is part of the Message interface implementation.
func (msg *MsgCFTypes) BtcEncode(w io.Writer, pver uint32, _ MessageEncoding) error {
// Write length of supported filters slice. We assume it's deduplicated.
err := WriteVarInt(w, pver, uint64(len(msg.SupportedFilters)))
if err != nil {
return err
}
for i := range msg.SupportedFilters {
err = writeElement(w, msg.SupportedFilters[i])
if err != nil {
return err
}
}
return nil
}
// Deserialize decodes a filter from r into the receiver using a format that is
// suitable for long-term storage such as a database. This function differs
// from BtcDecode in that BtcDecode decodes from the bitcoin wire protocol as
// it was sent across the network. The wire encoding can technically differ
// depending on the protocol version and doesn't even really need to match the
// format of a stored filter at all. As of the time this comment was written,
// the encoded filter is the same in both instances, but there is a distinct
// difference and separating the two allows the API to be flexible enough to
// deal with changes.
func (msg *MsgCFTypes) Deserialize(r io.Reader) error {
// At the current time, there is no difference between the wire encoding
// and the stable long-term storage format. As a result, make use of
// BtcDecode.
return msg.BtcDecode(r, 0, BaseEncoding)
}
// Command returns the protocol command string for the message. This is part
// of the Message interface implementation.
func (msg *MsgCFTypes) Command() string {
return CmdCFTypes
}
// MaxPayloadLength returns the maximum length the payload can be for the
// receiver. This is part of the Message interface implementation.
func (msg *MsgCFTypes) MaxPayloadLength(pver uint32) uint32 {
// 2 bytes for filter count, and 1 byte for up to 256 filter types.
return 258
}
// NewMsgCFTypes returns a new bitcoin cftypes message that conforms to the
// Message interface. See MsgCFTypes for details.
func NewMsgCFTypes(filterTypes []FilterType) *MsgCFTypes {
return &MsgCFTypes{
SupportedFilters: filterTypes,
}
}