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suback.go
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suback.go
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// Copyright (c) 2014 The VolantMQ Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package mqttp
// SubAck A SUBACK Packet is sent by the Server to the Client to confirm receipt and processing
// of a SUBSCRIBE Packet.
//
// A SUBACK Packet contains a list of return codes, that specify the maximum QoS level
// that was granted in each Subscription that was requested by the SUBSCRIBE.
type SubAck struct {
header
returnCodes []ReasonCode
}
var _ IFace = (*SubAck)(nil)
func newSubAck() *SubAck {
return &SubAck{}
}
// NewSubAck creates a new SUBACK packet
func NewSubAck(v ProtocolVersion) *SubAck {
p := newSubAck()
p.init(SUBACK, v, p.size, p.encodeMessage, p.decodeMessage)
return p
}
// ReturnCodes returns the list of QoS returns from the subscriptions sent in the SUBSCRIBE message.
func (msg *SubAck) ReturnCodes() []ReasonCode {
return msg.returnCodes
}
// AddReturnCodes sets the list of QoS returns from the subscriptions sent in the SUBSCRIBE message.
// An error is returned if any of the QoS values are not valid.
func (msg *SubAck) AddReturnCodes(ret []ReasonCode) error {
for _, c := range ret {
if msg.version == ProtocolV50 && !c.IsValidForType(msg.mType) {
return ErrInvalidReturnCode
} else if !QosType(c).IsValidFull() {
return ErrInvalidReturnCode
}
msg.returnCodes = append(msg.returnCodes, c)
}
return nil
}
// AddReturnCode adds a single QoS return value.
func (msg *SubAck) AddReturnCode(ret ReasonCode) error {
return msg.AddReturnCodes([]ReasonCode{ret})
}
// SetPacketID sets the ID of the packet.
func (msg *SubAck) SetPacketID(v IDType) {
msg.setPacketID(v)
}
// decode message
func (msg *SubAck) decodeMessage(from []byte) (int, error) {
offset := msg.decodePacketID(from)
if msg.version == ProtocolV50 {
n, err := msg.properties.decode(msg.Type(), from[offset:])
offset += n
if err != nil {
return offset, err
}
}
numCodes := int(msg.remLen) - offset
for i, q := range from[offset : offset+numCodes] {
code := ReasonCode(q)
if msg.version == ProtocolV50 && !code.IsValidForType(msg.mType) {
return offset + i, CodeProtocolError
} else if !QosType(code).IsValidFull() {
return offset + i, CodeRefusedServerUnavailable
}
msg.returnCodes = append(msg.returnCodes, ReasonCode(q))
}
offset += numCodes
return offset, nil
}
func (msg *SubAck) encodeMessage(to []byte) (int, error) {
// [MQTT-2.3.1]
if len(msg.packetID) == 0 {
return 0, ErrPackedIDZero
}
offset := msg.encodePacketID(to)
if msg.version == ProtocolV50 {
n, err := msg.properties.encode(to[offset:])
offset += n
if err != nil {
return offset, err
}
}
for _, q := range msg.returnCodes {
to[offset] = byte(q)
offset++
}
return offset, nil
}
func (msg *SubAck) size() int {
total := 2 + len(msg.returnCodes)
// v5.0 [MQTT-3.1.2.11]
if msg.version == ProtocolV50 {
total += msg.properties.FullLen()
}
return total
}