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 SQLITE_SINGLE_VER_FORWARD_CURSOR_H
17 #define SQLITE_SINGLE_VER_FORWARD_CURSOR_H
18 
19 #include <mutex>
20 
21 #include "macro_utils.h"
22 #include "ikvdb_raw_cursor.h"
23 #include "sqlite_single_ver_storage_executor.h"
24 #include "sqlite_single_ver_natural_store.h"
25 
26 namespace DistributedDB {
27 class SQLiteSingleVerForwardCursor : public IKvDBRawCursor {
28 public:
29     SQLiteSingleVerForwardCursor(SQLiteSingleVerNaturalStore *kvDB, const Key &keyPrefix);
30     SQLiteSingleVerForwardCursor(SQLiteSingleVerNaturalStore *kvDB, const QueryObject &queryObj);
31     ~SQLiteSingleVerForwardCursor() override;
32 
33     // Delete the copy and assign constructors
34     DISABLE_COPY_ASSIGN_MOVE(SQLiteSingleVerForwardCursor);
35 
36     // Open the raw cursor.
37     int Open() override;
38 
39     // Close the raw cursor before invoking operator delete.
40     void Close() override;
41 
42     // Reload all data.
43     int Reload() override;
44 
45     // Get total entries count.
46     int GetCount() const override;
47 
48     // Get next entry, return errCode if it fails.
49     int GetNext(Entry &entry, bool isCopy) const override;
50 
51 private:
52     SQLiteSingleVerNaturalStore *kvDB_;
53     Key keyPrefix_;
54     QueryObject queryObj_;
55     mutable SQLiteSingleVerStorageExecutor *handle_;
56     int count_;
57     mutable bool isOpen_;
58     bool isQueryMode_;
59     mutable std::mutex isOpenMutex_;
60 };
61 } // namespace DistributedDB
62 
63 #endif // SQLITE_SINGLE_VER_FORWARD_CURSOR_H
64