swarm/storage, swarm/shed: add support for persisting push tags

swarm/shed/index.go

@@ -41,6 +41,7 @@ type Item struct {
 	AccessTimestamp int64
 	StoreTimestamp  int64
 	BinID           uint64
+	Tags            []uint64
 }
 
 // Merge is a helper method to construct a new

swarm/storage/localstore/localstore.go

@@ -284,9 +284,28 @@ func New(path string, baseKey []byte, o *Options) (db *DB, err error) {
 			return e, nil
 		},
 		EncodeValue: func(fields shed.Item) (value []byte, err error) {
-			return nil, nil
+			valueBuffer := []byte{}
+			buf := make([]byte, binary.MaxVarintLen64)
+
+			for _, v := range fields.Tags {
+				n := binary.PutUvarint(buf, v)
+				if n > 0 {
+					valueBuffer = append(valueBuffer, buf[:n]...)
+				}
+			}
+
+			return valueBuffer, nil
 		},
 		DecodeValue: func(keyItem shed.Item, value []byte) (e shed.Item, err error) {
+			for {
+				v, n := binary.Uvarint(value)
+				if n > 0 {
+					e.Tags = append(e.Tags, v)
+				} else {
+					break
+				}
+				value = value[n:]
+			}
 			return e, nil
 		},
 	})