126 lines
3.2 KiB
Go
126 lines
3.2 KiB
Go
/*
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* Copyright (c) 2013 IBM Corp.
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*
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html
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*
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* Contributors:
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* Seth Hoenig
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* Allan Stockdill-Mander
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* Mike Robertson
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*/
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package mqtt
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import (
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"fmt"
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"git.eclipse.org/gitroot/paho/org.eclipse.paho.mqtt.golang.git/packets"
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"strconv"
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)
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const (
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inboundPrefix = "i."
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outboundPrefix = "o."
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)
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// Store is an interface which can be used to provide implementations
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// for message persistence.
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// Because we may have to store distinct messages with the same
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// message ID, we need a unique key for each message. This is
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// possible by prepending "i." or "o." to each message id
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type Store interface {
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Open()
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Put(string, packets.ControlPacket)
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Get(string) packets.ControlPacket
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All() []string
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Del(string)
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Close()
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Reset()
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}
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// A key MUST have the form "X.[messageid]"
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// where X is 'i' or 'o'
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func mIDFromKey(key string) uint16 {
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s := key[2:]
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i, err := strconv.Atoi(s)
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chkerr(err)
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return uint16(i)
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}
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// Return a string of the form "i.[id]"
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func inboundKeyFromMID(id uint16) string {
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return fmt.Sprintf("%s%d", inboundPrefix, id)
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}
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// Return a string of the form "o.[id]"
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func outboundKeyFromMID(id uint16) string {
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return fmt.Sprintf("%s%d", outboundPrefix, id)
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}
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// govern which outgoing messages are persisted
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func persistOutbound(s Store, m packets.ControlPacket) {
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switch m.Details().Qos {
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case 0:
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switch m.(type) {
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case *packets.PubackPacket, *packets.PubcompPacket:
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// Sending puback. delete matching publish
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// from ibound
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s.Del(inboundKeyFromMID(m.Details().MessageID))
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}
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case 1:
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switch m.(type) {
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case *packets.PublishPacket, *packets.PubrelPacket, *packets.SubscribePacket, *packets.UnsubscribePacket:
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// Sending publish. store in obound
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// until puback received
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s.Put(outboundKeyFromMID(m.Details().MessageID), m)
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default:
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chkcond(false)
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}
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case 2:
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switch m.(type) {
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case *packets.PublishPacket:
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// Sending publish. store in obound
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// until pubrel received
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s.Put(outboundKeyFromMID(m.Details().MessageID), m)
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default:
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chkcond(false)
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}
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}
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}
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// govern which incoming messages are persisted
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func persistInbound(s Store, m packets.ControlPacket) {
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switch m.Details().Qos {
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case 0:
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switch m.(type) {
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case *packets.PubackPacket, *packets.SubackPacket, *packets.UnsubackPacket, *packets.PubcompPacket:
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// Received a puback. delete matching publish
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// from obound
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s.Del(outboundKeyFromMID(m.Details().MessageID))
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case *packets.PublishPacket, *packets.PubrecPacket, *packets.PingrespPacket, *packets.ConnackPacket:
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default:
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chkcond(false)
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}
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case 1:
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switch m.(type) {
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case *packets.PublishPacket, *packets.PubrelPacket:
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// Received a publish. store it in ibound
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// until puback sent
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s.Put(inboundKeyFromMID(m.Details().MessageID), m)
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default:
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chkcond(false)
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}
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case 2:
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switch m.(type) {
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case *packets.PublishPacket:
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// Received a publish. store it in ibound
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// until pubrel received
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s.Put(inboundKeyFromMID(m.Details().MessageID), m)
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default:
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chkcond(false)
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}
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}
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}
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