first commit

pkg/observable/observable.go

@@ -0,0 +1,67 @@
+package observable
+
+// Ref: github.com/Dreamacro/clash/common/observable
+
+import (
+	"errors"
+	"sync"
+)
+
+type Observable struct {
+	iterable Iterable
+	listener map[Subscription]*Subscriber
+	mux      sync.Mutex
+	done     bool
+}
+
+func (o *Observable) process() {
+	for item := range o.iterable {
+		o.mux.Lock()
+		for _, sub := range o.listener {
+			sub.Emit(item)
+		}
+		o.mux.Unlock()
+	}
+	o.close()
+}
+
+func (o *Observable) close() {
+	o.mux.Lock()
+	defer o.mux.Unlock()
+
+	o.done = true
+	for _, sub := range o.listener {
+		sub.Close()
+	}
+}
+
+func (o *Observable) Subscribe() (Subscription, error) {
+	o.mux.Lock()
+	defer o.mux.Unlock()
+	if o.done {
+		return nil, errors.New("observable is closed")
+	}
+	subscriber := newSubscriber()
+	o.listener[subscriber.Out()] = subscriber
+	return subscriber.Out(), nil
+}
+
+func (o *Observable) UnSubscribe(sub Subscription) {
+	o.mux.Lock()
+	defer o.mux.Unlock()
+	subscriber, exist := o.listener[sub]
+	if !exist {
+		return
+	}
+	delete(o.listener, sub)
+	subscriber.Close()
+}
+
+func NewObservable(any Iterable) *Observable {
+	observable := &Observable{
+		iterable: any,
+		listener: map[Subscription]*Subscriber{},
+	}
+	go observable.process()
+	return observable
+}