1 /*
2  * Copyright (c) 2021 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef I_KV_DB_RESULT_SET_H
17 #define I_KV_DB_RESULT_SET_H
18 
19 #include "macro_utils.h"
20 #include "db_types.h"
21 
22 namespace DistributedDB {
23 
24 enum class ResultSetType : int {
25     KEYPREFIX = 0,
26     QUERY = 1,
27 };
28 
29 constexpr int INIT_POSITION = -1;
30 
31 class IKvDBResultSet {
32 public:
33     IKvDBResultSet() = default;
~IKvDBResultSet()34     virtual ~IKvDBResultSet() {}
35 
36     DISABLE_COPY_ASSIGN_MOVE(IKvDBResultSet);
37 
38     // Initialize logic
39     virtual int Open(bool isMemDb) = 0;
40 
41     // Get total entries count.
42     // >= 0: count, < 0: errCode.
43     virtual int GetCount() const = 0;
44 
45     // Get current read position.
46     // >= 0: position, < 0: errCode
47     virtual int GetPosition() const = 0;
48 
49     virtual int Move(int offset) const = 0;
50 
51     // Move the read position to an absolute position value.
52     virtual int MoveTo(int position) const = 0;
53 
54     virtual int MoveToFirst() = 0;
55 
56     virtual int MoveToLast() = 0;
57 
58     virtual bool IsFirst() const = 0;
59 
60     virtual bool IsLast() const = 0;
61 
62     virtual bool IsBeforeFirst() const = 0;
63 
64     virtual bool IsAfterLast() const = 0;
65 
66     // Get the entry of current position.
67     virtual int GetEntry(Entry &entry) const = 0;
68 
69     // Finalize logic
70     virtual int Close() = 0;
71 };
72 } // namespace DistributedDB
73 
74 #endif // I_KV_DB_RESULT_SET_H
75