structure: Rename Length to FieldCount

structure/hash.go

@@ -30,17 +30,17 @@ type HashPair struct {
 }
 
 type hashMeta struct {
-	Length int64
+	FieldCount int64
 }
 
 func (meta hashMeta) Value() []byte {
 	buf := make([]byte, 8)
-	binary.BigEndian.PutUint64(buf[0:8], uint64(meta.Length))
+	binary.BigEndian.PutUint64(buf[0:8], uint64(meta.FieldCount))
 	return buf
 }
 
 func (meta hashMeta) IsEmpty() bool {
-	return meta.Length <= 0
+	return meta.FieldCount <= 0
 }
 
 // HSet sets the string value of a hash field.
@@ -119,7 +119,7 @@ func (t *TxStructure) updateHash(key []byte, field []byte, fn func(oldValue []by
 	}
 
 	if oldValue == nil {
-		meta.Length++
+		meta.FieldCount++
 		if err = t.txn.Set(metaKey, meta.Value()); err != nil {
 			return errors.Trace(err)
 		}
@@ -135,7 +135,7 @@ func (t *TxStructure) HLen(key []byte) (int64, error) {
 	if err != nil {
 		return 0, errors.Trace(err)
 	}
-	return meta.Length, nil
+	return meta.FieldCount, nil
 }
 
 // HDel deletes one or more hash fields.
@@ -160,7 +160,7 @@ func (t *TxStructure) HDel(key []byte, fields ...[]byte) error {
 				return errors.Trace(err)
 			}
 
-			meta.Length--
+			meta.FieldCount--
 		}
 	}
 
@@ -260,7 +260,7 @@ func (t *TxStructure) loadHashMeta(metaKey []byte) (hashMeta, error) {
 		return hashMeta{}, errors.Trace(err)
 	}
 
-	meta := hashMeta{Length: 0}
+	meta := hashMeta{FieldCount: 0}
 	if v == nil {
 		return meta, nil
 	}
@@ -269,7 +269,7 @@ func (t *TxStructure) loadHashMeta(metaKey []byte) (hashMeta, error) {
 		return meta, errors.New("invalid list meta data")
 	}
 
-	meta.Length = int64(binary.BigEndian.Uint64(v[0:8]))
+	meta.FieldCount = int64(binary.BigEndian.Uint64(v[0:8]))
 	return meta, nil
 }