refactor out listStore

weed/util/skiplist/list_store.go

@@ -0,0 +1,32 @@
+package skiplist
+
+type ListStore interface {
+	SaveElement(id int64, element *SkipListElement) error
+	DeleteElement(id int64) error
+	LoadElement(id int64) (*SkipListElement, error)
+}
+
+type MemStore struct {
+	m map[int64]*SkipListElement
+}
+
+func newMemStore() *MemStore {
+	return &MemStore{
+		m: make(map[int64]*SkipListElement),
+	}
+}
+
+func (m *MemStore) SaveElement(id int64, element *SkipListElement) error {
+	m.m[id] = element
+	return nil
+}
+
+func (m *MemStore) DeleteElement(id int64) error {
+	delete(m.m, id)
+	return nil
+}
+
+func (m *MemStore) LoadElement(id int64) (*SkipListElement, error) {
+	element := m.m[id]
+	return element, nil
+}