packet

lib/message/suback.go

@@ -0,0 +1,160 @@
+// Copyright (c) 2014 The SurgeMQ 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 message
+
+import "fmt"
+
+// 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 SubackMessage struct {
+	header
+
+	returnCodes []byte
+}
+
+var _ Message = (*SubackMessage)(nil)
+
+// NewSubackMessage creates a new SUBACK message.
+func NewSubackMessage() *SubackMessage {
+	msg := &SubackMessage{}
+	msg.SetType(SUBACK)
+
+	return msg
+}
+
+// String returns a string representation of the message.
+func (this SubackMessage) String() string {
+	return fmt.Sprintf("%s, Packet ID=%d, Return Codes=%v", this.header, this.PacketId(), this.returnCodes)
+}
+
+// ReturnCodes returns the list of QoS returns from the subscriptions sent in the SUBSCRIBE message.
+func (this *SubackMessage) ReturnCodes() []byte {
+	return this.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 (this *SubackMessage) AddReturnCodes(ret []byte) error {
+	for _, c := range ret {
+		if c != QosAtMostOnce && c != QosAtLeastOnce && c != QosExactlyOnce && c != QosFailure {
+			return fmt.Errorf("suback/AddReturnCode: Invalid return code %d. Must be 0, 1, 2, 0x80.", c)
+		}
+
+		this.returnCodes = append(this.returnCodes, c)
+	}
+
+	this.dirty = true
+
+	return nil
+}
+
+// AddReturnCode adds a single QoS return value.
+func (this *SubackMessage) AddReturnCode(ret byte) error {
+	return this.AddReturnCodes([]byte{ret})
+}
+
+func (this *SubackMessage) Len() int {
+	if !this.dirty {
+		return len(this.dbuf)
+	}
+
+	ml := this.msglen()
+
+	if err := this.SetRemainingLength(int32(ml)); err != nil {
+		return 0
+	}
+
+	return this.header.msglen() + ml
+}
+
+func (this *SubackMessage) Decode(src []byte) (int, error) {
+	total := 0
+
+	hn, err := this.header.decode(src[total:])
+	total += hn
+	if err != nil {
+		return total, err
+	}
+
+	//this.packetId = binary.BigEndian.Uint16(src[total:])
+	this.packetId = src[total : total+2]
+	total += 2
+
+	l := int(this.remlen) - (total - hn)
+	this.returnCodes = src[total : total+l]
+	total += len(this.returnCodes)
+
+	for i, code := range this.returnCodes {
+		if code != 0x00 && code != 0x01 && code != 0x02 && code != 0x80 {
+			return total, fmt.Errorf("suback/Decode: Invalid return code %d for topic %d", code, i)
+		}
+	}
+
+	this.dirty = false
+
+	return total, nil
+}
+
+func (this *SubackMessage) Encode(dst []byte) (int, error) {
+	if !this.dirty {
+		if len(dst) < len(this.dbuf) {
+			return 0, fmt.Errorf("suback/Encode: Insufficient buffer size. Expecting %d, got %d.", len(this.dbuf), len(dst))
+		}
+
+		return copy(dst, this.dbuf), nil
+	}
+
+	for i, code := range this.returnCodes {
+		if code != 0x00 && code != 0x01 && code != 0x02 && code != 0x80 {
+			return 0, fmt.Errorf("suback/Encode: Invalid return code %d for topic %d", code, i)
+		}
+	}
+
+	hl := this.header.msglen()
+	ml := this.msglen()
+
+	if len(dst) < hl+ml {
+		return 0, fmt.Errorf("suback/Encode: Insufficient buffer size. Expecting %d, got %d.", hl+ml, len(dst))
+	}
+
+	if err := this.SetRemainingLength(int32(ml)); err != nil {
+		return 0, err
+	}
+
+	total := 0
+
+	n, err := this.header.encode(dst[total:])
+	total += n
+	if err != nil {
+		return total, err
+	}
+
+	if copy(dst[total:total+2], this.packetId) != 2 {
+		dst[total], dst[total+1] = 0, 0
+	}
+	total += 2
+
+	copy(dst[total:], this.returnCodes)
+	total += len(this.returnCodes)
+
+	return total, nil
+}
+
+func (this *SubackMessage) msglen() int {
+	return 2 + len(this.returnCodes)
+}