monitor a good

Former-commit-id: 5a37bfdfe208d3d1a71e6b4924209d0c8e6f53a0

monitor/item.go

@@ -0,0 +1,124 @@
+package monitor
+
+import (
+	"bytes"
+	"encoding/gob"
+	"local/rssmon3/config"
+	"log"
+	"time"
+
+	"github.com/golang-collections/go-datastructures/queue"
+)
+
+type Item struct {
+	Key string
+}
+
+const nsLast = "nsLast"
+const nsInterval = "nsInterval"
+
+var never = time.Date(2999, time.January, 1, 1, 1, 1, 1, time.UTC)
+var forever = time.Duration(time.Hour * 99999)
+
+func NewItem(key string, interval time.Duration) (*Item, error) {
+	i := &Item{
+		Key: key,
+	}
+
+	if err := i.setInterval(interval); err != nil {
+		return nil, err
+	}
+	if err := i.setLast(time.Now().Add(-2 * interval)); err != nil {
+		return nil, err
+	}
+
+	return &Item{
+		Key: key,
+	}, nil
+}
+
+func (i *Item) Compare(other queue.Item) int {
+	j := other.(*Item)
+	iNext := i.Last().Add(i.Interval())
+	jNext := j.Last().Add(j.Interval())
+	if iNext.Before(jNext) {
+		return 1
+	} else if jNext.Before(iNext) {
+		return -1
+	} else {
+		return 0
+	}
+}
+
+func (i *Item) Interval() time.Duration {
+	t, err := i.getInterval()
+	if err != nil {
+		log.Println(err)
+		return forever
+	}
+	return t
+}
+
+func (i *Item) getInterval() (time.Duration, error) {
+	t := time.Duration(0)
+	b, err := config.Values().DB.Get(i.Key, nsInterval)
+	if err != nil {
+		return forever, err
+	}
+	buff := bytes.NewBuffer(b)
+	dec := gob.NewDecoder(buff)
+	err = dec.Decode(&t)
+	return t, err
+}
+
+func (i *Item) setInterval(t time.Duration) error {
+	buff := bytes.NewBuffer(nil)
+	enc := gob.NewEncoder(buff)
+	if err := enc.Encode(t); err != nil {
+		return err
+	}
+	if err := config.Values().DB.Set(i.Key, buff.Bytes(), nsInterval); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (i *Item) Last() time.Time {
+	t, err := i.getLast()
+	if err != nil {
+		log.Println(err)
+	}
+	return t
+}
+
+func (i *Item) Mark() {
+	if err := i.setLast(time.Now()); err != nil {
+		log.Println(err)
+	}
+}
+
+func (i *Item) setLast(t time.Time) error {
+	buff := bytes.NewBuffer(nil)
+	enc := gob.NewEncoder(buff)
+	if err := enc.Encode(t); err != nil {
+		return err
+	}
+	if err := config.Values().DB.Set(i.Key, buff.Bytes(), nsLast); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (i *Item) getLast() (time.Time, error) {
+	t := time.Now()
+	b, err := config.Values().DB.Get(i.Key, nsLast)
+	if err != nil {
+		return never, err
+	}
+	buff := bytes.NewBuffer(b)
+	dec := gob.NewDecoder(buff)
+	if err := dec.Decode(&t); err != nil {
+		return never, err
+	}
+	return t, nil
+}