73 lines
1.6 KiB
Go
73 lines
1.6 KiB
Go
//
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// Copyright (c) 2018
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// Mainflux
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//
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// SPDX-License-Identifier: Apache-2.0
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//
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package coap
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import (
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"sync"
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"github.com/mainflux/mainflux"
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)
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// Observer is used to handle CoAP subscription.
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type Observer struct {
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// Expired flag is used to mark that ticker sent a
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// CON message, but response is not received yet.
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// The flag changes its value once ACK message is
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// received from the client. If Expired is true
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// when ticker is triggered, Observer should be canceled
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// and removed from the Service map.
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expired bool
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// Message ID for notification messages.
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msgID uint16
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expiredLock, msgIDLock sync.Mutex
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// Messages is used to receive messages from NATS.
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Messages chan mainflux.RawMessage
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// Cancel channel is used to cancel observing resource.
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// Cancel channel should not be used to send or receive any
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// data, it's purpose is to be closed once Observer canceled.
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Cancel chan bool
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}
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// NewObserver instantiates a new Observer.
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func NewObserver() *Observer {
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return &Observer{
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Messages: make(chan mainflux.RawMessage),
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Cancel: make(chan bool),
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}
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}
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// LoadExpired reads Expired flag in thread-safe way.
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func (o *Observer) LoadExpired() bool {
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o.expiredLock.Lock()
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defer o.expiredLock.Unlock()
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return o.expired
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}
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// StoreExpired stores Expired flag in thread-safe way.
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func (o *Observer) StoreExpired(val bool) {
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o.expiredLock.Lock()
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defer o.expiredLock.Unlock()
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o.expired = val
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}
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// LoadMessageID reads MessageID and increments
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// its value in thread-safe way.
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func (o *Observer) LoadMessageID() uint16 {
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o.msgIDLock.Lock()
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defer o.msgIDLock.Unlock()
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o.msgID++
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return o.msgID
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}
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