1 files changed, 58 insertions, 0 deletions
diff --git a/go/topology/volume_location.go b/go/topology/volume_location.go
new file mode 100644
index 000000000..507a240b5
--- /dev/null
+++ b/go/topology/volume_location.go
@@ -0,0 +1,58 @@
+package topology
+
+import ()
+
+type VolumeLocationList struct {
+	list []*DataNode
+}
+
+func NewVolumeLocationList() *VolumeLocationList {
+	return &VolumeLocationList{}
+}
+
+func (dnll *VolumeLocationList) Head() *DataNode {
+	return dnll.list[0]
+}
+
+func (dnll *VolumeLocationList) Length() int {
+	return len(dnll.list)
+}
+
+func (dnll *VolumeLocationList) Add(loc *DataNode) bool {
+	for _, dnl := range dnll.list {
+		if loc.Ip == dnl.Ip && loc.Port == dnl.Port {
+			return false
+		}
+	}
+	dnll.list = append(dnll.list, loc)
+	return true
+}
+
+func (dnll *VolumeLocationList) Remove(loc *DataNode) bool {
+	for i, dnl := range dnll.list {
+		if loc.Ip == dnl.Ip && loc.Port == dnl.Port {
+			dnll.list = append(dnll.list[:i], dnll.list[i+1:]...)
+			return true
+		}
+	}
+	return false
+}
+
+func (dnll *VolumeLocationList) Refresh(freshThreshHold int64) {
+	var changed bool
+	for _, dnl := range dnll.list {
+		if dnl.LastSeen < freshThreshHold {
+			changed = true
+			break
+		}
+	}
+	if changed {
+		var l []*DataNode
+		for _, dnl := range dnll.list {
+			if dnl.LastSeen >= freshThreshHold {
+				l = append(l, dnl)
+			}
+		}
+		dnll.list = l
+	}
+}