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disconnect.go
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disconnect.go
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package packets
import (
"bytes"
"fmt"
"io"
"github.com/winc-link/hummingbird/internal/pkg/codes"
)
// Disconnect represents the MQTT Disconnect packet
type Disconnect struct {
Version Version
FixHeader *FixHeader
// V5
Code codes.Code
Properties *Properties
}
func (d *Disconnect) String() string {
return fmt.Sprintf("Disconnect, Version: %v, Code: %v, Properties: %s", d.Version, d.Code, d.Properties)
}
// Pack encodes the packet struct into bytes and writes it into io.Writer.
func (d *Disconnect) Pack(w io.Writer) error {
var err error
d.FixHeader = &FixHeader{PacketType: DISCONNECT, Flags: FlagReserved}
if IsVersion3X(d.Version) {
d.FixHeader.RemainLength = 0
return d.FixHeader.Pack(w)
}
bufw := &bytes.Buffer{}
if d.Code != codes.Success || d.Properties != nil {
bufw.WriteByte(d.Code)
d.Properties.Pack(bufw, DISCONNECT)
}
d.FixHeader.RemainLength = bufw.Len()
err = d.FixHeader.Pack(w)
if err != nil {
return err
}
_, err = bufw.WriteTo(w)
return err
}
// Unpack read the packet bytes from io.Reader and decodes it into the packet struct.
func (d *Disconnect) Unpack(r io.Reader) error {
restBuffer := make([]byte, d.FixHeader.RemainLength)
_, err := io.ReadFull(r, restBuffer)
if err != nil {
return codes.ErrMalformed
}
if d.Version == Version5 {
d.Properties = &Properties{}
bufr := bytes.NewBuffer(restBuffer)
if d.FixHeader.RemainLength == 0 {
d.Code = codes.Success
return nil
}
d.Code, err = bufr.ReadByte()
if err != nil {
return codes.ErrMalformed
}
if !ValidateCode(DISCONNECT, d.Code) {
return codes.ErrProtocol
}
return d.Properties.Unpack(bufr, DISCONNECT)
}
return nil
}
// NewDisConnectPackets returns a Disconnect instance by the given FixHeader and io.Reader
func NewDisConnectPackets(fh *FixHeader, version Version, r io.Reader) (*Disconnect, error) {
if fh.Flags != 0 {
return nil, codes.ErrMalformed
}
p := &Disconnect{FixHeader: fh, Version: version}
err := p.Unpack(r)
if err != nil {
return nil, err
}
return p, nil
}