Restruct (#34)

* modify

* remove

* modify

* modify

* remove no use

* add online/offline notification

* modify

* format log

* add reference

lib/topics/topics.go

@@ -0,0 +1,91 @@
+package topics
+
+import (
+	"fmt"
+
+	"github.com/eclipse/paho.mqtt.golang/packets"
+)
+
+const (
+	// MWC is the multi-level wildcard
+	MWC = "#"
+
+	// SWC is the single level wildcard
+	SWC = "+"
+
+	// SEP is the topic level separator
+	SEP = "/"
+
+	// SYS is the starting character of the system level topics
+	SYS = "$"
+
+	// Both wildcards
+	_WC = "#+"
+)
+
+var (
+	providers = make(map[string]TopicsProvider)
+)
+
+// TopicsProvider
+type TopicsProvider interface {
+	Subscribe(topic []byte, qos byte, subscriber interface{}) (byte, error)
+	Unsubscribe(topic []byte, subscriber interface{}) error
+	Subscribers(topic []byte, qos byte, subs *[]interface{}, qoss *[]byte) error
+	Retain(msg *packets.PublishPacket) error
+	Retained(topic []byte, msgs *[]*packets.PublishPacket) error
+	Close() error
+}
+
+func Register(name string, provider TopicsProvider) {
+	if provider == nil {
+		panic("topics: Register provide is nil")
+	}
+
+	if _, dup := providers[name]; dup {
+		panic("topics: Register called twice for provider " + name)
+	}
+
+	providers[name] = provider
+}
+
+func Unregister(name string) {
+	delete(providers, name)
+}
+
+type Manager struct {
+	p TopicsProvider
+}
+
+func NewManager(providerName string) (*Manager, error) {
+	p, ok := providers[providerName]
+	if !ok {
+		return nil, fmt.Errorf("session: unknown provider %q", providerName)
+	}
+
+	return &Manager{p: p}, nil
+}
+
+func (this *Manager) Subscribe(topic []byte, qos byte, subscriber interface{}) (byte, error) {
+	return this.p.Subscribe(topic, qos, subscriber)
+}
+
+func (this *Manager) Unsubscribe(topic []byte, subscriber interface{}) error {
+	return this.p.Unsubscribe(topic, subscriber)
+}
+
+func (this *Manager) Subscribers(topic []byte, qos byte, subs *[]interface{}, qoss *[]byte) error {
+	return this.p.Subscribers(topic, qos, subs, qoss)
+}
+
+func (this *Manager) Retain(msg *packets.PublishPacket) error {
+	return this.p.Retain(msg)
+}
+
+func (this *Manager) Retained(topic []byte, msgs *[]*packets.PublishPacket) error {
+	return this.p.Retained(topic, msgs)
+}
+
+func (this *Manager) Close() error {
+	return this.p.Close()
+}