robocar-road/vendor/github.com/eclipse/paho.mqtt.golang/packets/unsubscribe.go

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2020-01-04 13:10:36 +00:00
package packets
import (
"bytes"
"fmt"
"io"
)
//UnsubscribePacket is an internal representation of the fields of the
//Unsubscribe MQTT packet
type UnsubscribePacket struct {
FixedHeader
MessageID uint16
Topics []string
}
func (u *UnsubscribePacket) String() string {
str := fmt.Sprintf("%s", u.FixedHeader)
str += " "
str += fmt.Sprintf("MessageID: %d", u.MessageID)
return str
}
func (u *UnsubscribePacket) Write(w io.Writer) error {
var body bytes.Buffer
var err error
body.Write(encodeUint16(u.MessageID))
for _, topic := range u.Topics {
body.Write(encodeString(topic))
}
u.FixedHeader.RemainingLength = body.Len()
packet := u.FixedHeader.pack()
packet.Write(body.Bytes())
_, err = packet.WriteTo(w)
return err
}
//Unpack decodes the details of a ControlPacket after the fixed
//header has been read
func (u *UnsubscribePacket) Unpack(b io.Reader) error {
var err error
u.MessageID, err = decodeUint16(b)
if err != nil {
return err
}
for topic, err := decodeString(b); err == nil && topic != ""; topic, err = decodeString(b) {
u.Topics = append(u.Topics, topic)
}
return err
}
//Details returns a Details struct containing the Qos and
//MessageID of this ControlPacket
func (u *UnsubscribePacket) Details() Details {
return Details{Qos: 1, MessageID: u.MessageID}
}