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 TASK_POOL_H
17 #define TASK_POOL_H
18 
19 #include <functional>
20 #include <string>
21 
22 #include "macro_utils.h"
23 
24 namespace DistributedDB {
25 using Task = std::function<void(void)>;
26 
27 class TaskPool {
28 public:
29     // Start the task pool.
30     virtual int Start() = 0;
31 
32     // Stop the task pool.
33     virtual void Stop() = 0;
34 
35     // Schedule a task, the task can be ran in any thread.
36     virtual int Schedule(const Task &task) = 0;
37 
38     // Schedule tasks using FIFO policy(tasks with the same 'tag').
39     virtual int Schedule(const std::string &tag, const Task &task) = 0;
40 
41     // Shrink memory associated with the given tag if possible.
42     virtual void ShrinkMemory(const std::string &tag) = 0;
43 
44     // Create/Destroy a task pool.
45     static TaskPool *Create(int maxThreads, int minThreads, int &errCode);
46     static void Release(TaskPool *&taskPool);
47 
48 protected:
49     TaskPool() = default;
~TaskPool()50     virtual ~TaskPool() {}
51     DISABLE_COPY_ASSIGN_MOVE(TaskPool);
52 };
53 } // namespace DistributedDB
54 
55 #endif // TASK_POOL_H