add memory kv store

weed/util/bptree/tree_store/memory_store.go

@@ -0,0 +1,29 @@
+package tree_store
+
+import "errors"
+
+var (
+	NotFound = errors.New("not found")
+)
+
+type MemoryTreeStore struct {
+	m map[int64][]byte
+}
+
+func NewMemoryTreeStore() *MemoryTreeStore{
+	return &MemoryTreeStore{
+		m: make(map[int64][]byte),
+	}
+}
+
+func (m *MemoryTreeStore) Put(k int64, v []byte) error {
+	m.m[k] = v
+	return nil
+}
+
+func (m *MemoryTreeStore) Get(k int64) ([]byte, error) {
+	if v, found := m.m[k]; found {
+		return v, nil
+	}
+	return nil, NotFound
+}

weed/util/bptree/tree_store/tree_store.go.go

@@ -0,0 +1,6 @@
+package tree_store
+
+type TreeStore interface {
+	Put(k int64, v []byte) error
+	Get(k int64) ([]byte, error)
+}