First implementation

vendor/github.com/eclipse/paho.mqtt.golang/token.go

@@ -0,0 +1,184 @@
+/*
+ * Copyright (c) 2014 IBM Corp.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * 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() bool
+	WaitTimeout(time.Duration) bool
+	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 will wait indefinitely for the Token to complete, ie the Publish
+// to be sent and confirmed receipt from the broker
+func (b *baseToken) Wait() bool {
+	<-b.complete
+	return true
+}
+
+// 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
+func (b *baseToken) WaitTimeout(d time.Duration) bool {
+	b.m.Lock()
+	defer b.m.Unlock()
+
+	timer := time.NewTimer(d)
+	select {
+	case <-b.complete:
+		if !timer.Stop() {
+			<-timer.C
+		}
+		return true
+	case <-timer.C:
+	}
+
+	return false
+}
+
+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 acknowlegement 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
+}
+
+// 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
+}
+
+// DisconnectToken is an extension of Token containing the extra fields
+// required to provide information about calls to Disconnect()
+type DisconnectToken struct {
+	baseToken
+}