github.com/vescale/zgraph@v0.0.0-20230410094002-959c02d50f95/internal/structure/structure.go (about) 1 // Copyright 2022 zGraph Authors. All rights reserved. 2 // 3 // Copyright 2015 PingCAP, Inc. 4 // 5 // Licensed under the Apache License, Version 2.0 (the "License"); 6 // you may not use this file except in compliance with the License. 7 // You may obtain a copy of the License at 8 // 9 // http://www.apache.org/licenses/LICENSE-2.0 10 // 11 // Unless required by applicable law or agreed to in writing, software 12 // distributed under the License is distributed on an "AS IS" BASIS, 13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 // See the License for the specific language governing permissions and 15 // limitations under the License. 16 17 package structure 18 19 import ( 20 "github.com/pingcap/errors" 21 "github.com/vescale/zgraph/storage/kv" 22 ) 23 24 var ( 25 ErrWriteOnSnapshot = errors.New("write on snapshot") 26 ErrInvalidListIndex = errors.New("invalid list index") 27 ErrInvalidListMetaData = errors.New("invalid list metadata") 28 ErrInvalidHashKeyFlag = errors.New("invalid hash key flash") 29 ) 30 31 // NewStructure creates a TxStructure with Retriever, RetrieverMutator and key prefix. 32 func NewStructure(reader kv.Retriever, readWriter kv.RetrieverMutator, prefix []byte) *TxStructure { 33 return &TxStructure{ 34 reader: reader, 35 readWriter: readWriter, 36 prefix: prefix, 37 } 38 } 39 40 // TxStructure supports some simple data structures like string, hash, list, etc... and 41 // you can use these in a transaction. 42 type TxStructure struct { 43 reader kv.Retriever 44 readWriter kv.RetrieverMutator 45 prefix []byte 46 }