开源包mqtt源码_token

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• 开源包mqtt源码_token
  • 测试代码
  • token代码
  • 分析
  • 附加

开源包mqtt源码_token

github.com/eclipse/paho.mqtt.golang

测试代码

/*
 * Copyright (c) 2021 IBM Corp and others.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v2.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 *
 * The Eclipse Public License is available at
 *    https://www.eclipse.org/legal/epl-2.0/
 * and the Eclipse Distribution License is available at
 *   http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *    Allan Stockdill-Mander
 */

package mqtt

import (
	"errors"
	"testing"
	"time"
)

func TestWaitTimeout(t *testing.T) {
	b := baseToken{}

	if b.WaitTimeout(time.Second) {
		t.Fatal("Should have failed")
	}

	// Now lets confirm that WaitTimeout returns
	// setError() grabs the mutex which previously caused issues
	// when there is a result (it returns true in this case)
	b = baseToken{complete: make(chan struct{})}
	go func(bt *baseToken) {
		bt.setError(errors.New("test error"))
	}(&b)
	if !b.WaitTimeout(5 * time.Second) {
		t.Fatal("Should have succeeded")
	}
}

token代码

/*
 * Copyright (c) 2021 IBM Corp and others.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v2.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 *
 * The Eclipse Public License is available at
 *    https://www.eclipse.org/legal/epl-2.0/
 * and the Eclipse Distribution License is available at
 *   http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *    Allan Stockdill-Mander
 */

package mqtt

import (
	"sync"
	"time"

	"github.com/eclipse/paho.mqtt.golang/packets"
)

// PacketAndToken is a struct that contains both a ControlPacket and a
// Token. This struct is passed via channels between the client interface
// code and the underlying code responsible for sending and receiving
// MQTT messages.
type PacketAndToken struct {
	p packets.ControlPacket
	t tokenCompletor
}

// Token defines the interface for the tokens used to indicate when
// actions have completed.
type Token interface {
	// Wait will wait indefinitely for the Token to complete, ie the Publish
	// to be sent and confirmed receipt from the broker.
	Wait() bool

	// WaitTimeout takes a time.Duration to wait for the flow associated with the
	// Token to complete, returns true if it returned before the timeout or
	// returns false if the timeout occurred. In the case of a timeout the Token
	// does not have an error set in case the caller wishes to wait again.
	WaitTimeout(time.Duration) bool

	// Done returns a channel that is closed when the flow associated
	// with the Token completes. Clients should call Error after the
	// channel is closed to check if the flow completed successfully.
	//
	// Done is provided for use in select statements. Simple use cases may
	// use Wait or WaitTimeout.
	Done() <-chan struct{}

	Error() error
}

type TokenErrorSetter interface {
	setError(error)
}

type tokenCompletor interface {
	Token
	TokenErrorSetter
	flowComplete()
}

type baseToken struct {
	m        sync.RWMutex
	complete chan struct{}
	err      error
}

// Wait implements the Token Wait method.
func (b *baseToken) Wait() bool {
	<-b.complete
	return true
}

// WaitTimeout implements the Token WaitTimeout method.
func (b *baseToken) WaitTimeout(d time.Duration) bool {
	timer := time.NewTimer(d)
	select {
	case <-b.complete:
		if !timer.Stop() {
			<-timer.C
		}
		return true
	case <-timer.C:
	}

	return false
}

// Done implements the Token Done method.
func (b *baseToken) Done() <-chan struct{} {
	return b.complete
}

func (b *baseToken) flowComplete() {
	select {
	case <-b.complete:
	default:
		close(b.complete)
	}
}

func (b *baseToken) Error() error {
	b.m.RLock()
	defer b.m.RUnlock()
	return b.err
}

func (b *baseToken) setError(e error) {
	b.m.Lock()
	b.err = e
	b.flowComplete()
	b.m.Unlock()
}

func newToken(tType byte) tokenCompletor {
	switch tType {
	case packets.Connect:
		return &ConnectToken{baseToken: baseToken{complete: make(chan struct{})}}
	case packets.Subscribe:
		return &SubscribeToken{baseToken: baseToken{complete: make(chan struct{})}, subResult: make(map[string]byte)}
	case packets.Publish:
		return &PublishToken{baseToken: baseToken{complete: make(chan struct{})}}
	case packets.Unsubscribe:
		return &UnsubscribeToken{baseToken: baseToken{complete: make(chan struct{})}}
	case packets.Disconnect:
		return &DisconnectToken{baseToken: baseToken{complete: make(chan struct{})}}
	}
	return nil
}

// ConnectToken is an extension of Token containing the extra fields
// required to provide information about calls to Connect()
type ConnectToken struct {
	baseToken
	returnCode     byte
	sessionPresent bool
}

// ReturnCode returns the acknowledgement code in the connack sent
// in response to a Connect()
func (c *ConnectToken) ReturnCode() byte {
	c.m.RLock()
	defer c.m.RUnlock()
	return c.returnCode
}

// SessionPresent returns a bool representing the value of the
// session present field in the connack sent in response to a Connect()
func (c *ConnectToken) SessionPresent() bool {
	c.m.RLock()
	defer c.m.RUnlock()
	return c.sessionPresent
}

// PublishToken is an extension of Token containing the extra fields
// required to provide information about calls to Publish()
type PublishToken struct {
	baseToken
	messageID uint16
}

// MessageID returns the MQTT message ID that was assigned to the
// Publish packet when it was sent to the broker
func (p *PublishToken) MessageID() uint16 {
	return p.messageID
}

// SubscribeToken is an extension of Token containing the extra fields
// required to provide information about calls to Subscribe()
type SubscribeToken struct {
	baseToken
	subs      []string
	subResult map[string]byte
	messageID uint16
}

// Result returns a map of topics that were subscribed to along with
// the matching return code from the broker. This is either the Qos
// value of the subscription or an error code.
func (s *SubscribeToken) Result() map[string]byte {
	s.m.RLock()
	defer s.m.RUnlock()
	return s.subResult
}

// UnsubscribeToken is an extension of Token containing the extra fields
// required to provide information about calls to Unsubscribe()
type UnsubscribeToken struct {
	baseToken
	messageID uint16
}

// DisconnectToken is an extension of Token containing the extra fields
// required to provide information about calls to Disconnect()
type DisconnectToken struct {
	baseToken
}

分析

去除业务，这个token包主要是为了表示动作完成的操作

附加

可以综合mqtt文档看一下mqtt包控制报文类型

// mqtt 控制包类型
// Below are the constants assigned to each of the MQTT packet type
// 下面来自mqtt 中文文档
//Table 2.1 - Control packet types
//
//|Name           |Value          |Direction of flow                   |Description
//|Reserved       |0              |Forbidden                   |Reserved
//|CONNECT        |1              |Client to Server                       |
//|CONNACK        |2              |Server to Client                       |Connect acknowledgment
//|PUBLISH        |3              |Client to Server or Server to Client   |Publish message
//|PUBACK         |4              |Client to Server or Server to Client   |Publish acknowledgment
//|PUBREC         |5              |Client to Server or Server to Client   |Publish received (assured delivery part 1)
//|PUBREL         |6              |Client to Server or Server to Client   |Publish release (assured delivery part 2)
//|PUBCOMP        |7              |Client to Server or Server to Client   |Publish complete (assured delivery part 3)
//|SUBSCRIBE      |8              |Client to Server                       |Client subscribe request
//|SUBACK         |9              |Server to Client                       |Subscribe acknowledgment
//|UNSUBSCRIBE    |10             |Client to Server                       |Unsubscribe request
//|UNSUBACK       |11             |Server to Client                       |Unsubscribe acknowledgment
//|PINGREQ        |12             |Client to Server                       |PING request
//|PINGRESP       |13             |Server to Client                       |PING response
//|DISCONNECT     |14             |Client to Server                       |Client is disconnecting
//|Reserved       |15             |Forbidden                              |Reserved
const (
	Connect     = 1
	Connack     = 2
	Publish     = 3
	Puback      = 4
	Pubrec      = 5
	Pubrel      = 6
	Pubcomp     = 7
	Subscribe   = 8
	Suback      = 9
	Unsubscribe = 10
	Unsuback    = 11
	Pingreq     = 12
	Pingresp    = 13
	Disconnect  = 14
)

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