1 /*
2 * Copyright (c) 2022 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 CORE_THREADING_TASK_QUEUE_H
17 #define CORE_THREADING_TASK_QUEUE_H
18
19 #include <cstdint>
20 #include <functional>
21
22 #include <base/containers/vector.h>
23 #include <core/namespace.h>
24 #include <core/threading/intf_thread_pool.h>
25
CORE_BEGIN_NAMESPACE()26 CORE_BEGIN_NAMESPACE()
27
28 // Helper class for running std::function as a ThreadPool task.
29 class FunctionTask final : public IThreadPool::ITask {
30 public:
31 static Ptr Create(std::function<void()>&& func)
32 {
33 return Ptr { new FunctionTask(std::move(func)) };
34 }
35
36 explicit FunctionTask(std::function<void()>&& func) : func_(std::move(func)) {};
37
38 void operator()() override
39 {
40 func_();
41 }
42
43 protected:
44 void Destroy() override
45 {
46 delete this;
47 }
48
49 private:
50 std::function<void()> func_;
51 };
52
53 // Abstract base class for task queues.
54 /* Usage examples:
55 * 1. SequentialTaskQueue queue(threadManager.GetThreadPool());
56 * 2. queue.Submit("identifier A", FunctionTask::Create(function));
57 * 3. queue.Submit("identifier B", FunctionTask::Create(std::bind(&Classname::function, this)));
58 * 4. queue.Submit("identifier C", FunctionTask::Create([]() { <code> }));
59 */
60 class TaskQueue {
61 public:
62 /** Constructor for the task queue.
63 @param aThreadPool Optional thread pool, if support for threading is desired.
64 */
65 explicit TaskQueue(const IThreadPool::Ptr& threadPool);
66 TaskQueue(const TaskQueue& other) = delete;
67 TaskQueue& operator=(const TaskQueue& other) = delete;
68
69 virtual ~TaskQueue();
70
71 /** Submit task to end of execution queue.
72 @param taskIdentifier Identifier of the task, must be unique.
73 @param task Task to execute.
74 */
75 virtual void Submit(uint64_t taskIdentifier, IThreadPool::ITask::Ptr&& task) = 0;
76
77 /** Remove task from execution queue.
78 @param taskIdentifier Identifier of the task.
79 */
80 virtual void Remove(uint64_t taskIdentifier) = 0;
81
82 /** Remove all tasks from execution queue. */
83 virtual void Clear() = 0;
84
85 /** Execute task queue in this thread. */
86 virtual void Execute() = 0;
87
88 /** Execute task queue asynchronously in new thread. */
89 virtual void ExecuteAsync();
90
91 /** Checks if task queue is running asynchronously.
92 @return True if task queue is currently running and can't be re-executed.
93 */
94 bool IsRunningAsync() const;
95
96 /** Waits until task queue has completed asynchronous execution */
97 void Wait();
98
99 protected:
100 class ExecuteAsyncTask final : public IThreadPool::ITask {
101 public:
102 explicit ExecuteAsyncTask(TaskQueue& queue);
103 void operator()() override;
104
105 protected:
106 void Destroy() override;
107
108 private:
109 TaskQueue& queue_;
110 };
111
112 struct Entry {
113 Entry() = default;
114 Entry(uint64_t identifier, IThreadPool::ITask::Ptr task);
115 bool operator==(uint64_t identifier) const;
116 bool operator==(const Entry& other) const;
117
118 IThreadPool::ITask::Ptr task;
119 uint64_t identifier {};
120 BASE_NS::vector<uint64_t> dependencies;
121 };
122
123 IThreadPool::Ptr threadPool_;
124 IThreadPool::IResult::Ptr asyncOperation_;
125 int32_t isRunningAsync_;
126 };
127 CORE_END_NAMESPACE()
128
129 #endif // CORE_THREADING_TASK_QUEUE_H
130