monitor a good

Former-commit-id: 5a37bfdfe208d3d1a71e6b4924209d0c8e6f53a0

monitor/monitor.go

@@ -0,0 +1,67 @@
+package monitor
+
+import (
+	"local/rssmon3/config"
+	"time"
+)
+
+type Monitor struct {
+	queue    *Queue
+	Incoming chan *Item
+	Outgoing chan *Item
+}
+
+func New() *Monitor {
+	return &Monitor{
+		queue:    newQueue(),
+		Incoming: make(chan *Item),
+		Outgoing: make(chan *Item),
+	}
+}
+
+func (m *Monitor) Run() error {
+	for {
+		select {
+		case <-m.stopped():
+			return nil
+		case i := <-m.enqueued():
+			m.enqueue(i)
+			continue
+		case <-m.triggered():
+			m.trigger()
+		}
+	}
+}
+
+func (m *Monitor) stopped() <-chan struct{} {
+	return config.Values().Ctx.Done()
+}
+
+func (m *Monitor) enqueued() chan *Item {
+	return m.Incoming
+}
+
+func (m *Monitor) enqueue(i *Item) {
+	m.queue.Push(i)
+}
+
+func (m *Monitor) triggered() <-chan time.Time {
+	if m.queue.Len() < 1 {
+		return nil
+	}
+	top := m.queue.Peek()
+	if top == nil {
+		return nil
+	}
+	return time.After(time.Until(top.Last().Add(top.Interval())))
+}
+
+func (m *Monitor) trigger() {
+	i := m.queue.Pop()
+	if i == nil {
+		return
+	}
+	m.Outgoing <- i
+	i.Mark()
+	m.queue.Push(i)
+}