1 /*
2  * Copyright (c) 2021-2023 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 BASE_EVENTHANDLER_FRAMEWORKS_EVENTHANDLER_INCLUDE_DEAMON_IO_WAITER_H
17 #define BASE_EVENTHANDLER_FRAMEWORKS_EVENTHANDLER_INCLUDE_DEAMON_IO_WAITER_H
18 
19 #include <atomic>
20 #include <map>
21 #include <mutex>
22 
23 #include <sys/epoll.h>
24 #include "io_waiter.h"
25 #include "nocopyable.h"
26 #include "event_queue.h"
27 #include "file_descriptor_listener.h"
28 
29 #define LOCAL_API __attribute__((visibility ("hidden")))
30 namespace OHOS {
31 namespace AppExecFwk {
32 class EventHandler;
33 
34 // Use epoll to listen file descriptor.
35 class DeamonIoWaiter {
36 public:
37     DeamonIoWaiter() = default;
38     ~DeamonIoWaiter();
39     static DeamonIoWaiter& GetInstance();
40     DISALLOW_COPY_AND_MOVE(DeamonIoWaiter);
41 
42     /**
43      * Initialize epoll.
44      *
45      * @return True if succeeded.
46      */
47     bool Init();
48 
49     void NotifyOne();
50     void NotifyAll();
51     void StopEpollIoWaiter();
52     void StartEpollIoWaiter();
53     bool SupportListeningFileDescriptor() const;
54 
55     LOCAL_API bool AddFileDescriptor(int32_t fileDescriptor, uint32_t events, const std::string &taskName,
56         const std::shared_ptr<FileDescriptorListener>& listener, EventQueue::Priority priority);
57     LOCAL_API void RemoveFileDescriptor(int32_t fileDescriptor);
58 
59     LOCAL_API void InsertFileDescriptorMap(int32_t fileDescriptor, const std::string& taskName,
60         EventQueue::Priority priority, const std::shared_ptr<FileDescriptorListener>& listener);
61     LOCAL_API void EraseFileDescriptorMap(int32_t fileDescriptor);
62     LOCAL_API std::shared_ptr<FileDescriptorInfo> GetFileDescriptorMap(int32_t fileDescriptor);
63     LOCAL_API void HandleFileDescriptorEvent(int32_t fileDescriptor, uint32_t events);
64 private:
65     LOCAL_API void EpollWaitFor();
66     LOCAL_API void DrainAwakenPipe() const;
67     LOCAL_API void HandleEpollEvents(struct epoll_event *epollEvents, int32_t eventsCount);
68 
69     // File descriptor for epoll.
70     int32_t epollFd_{-1};
71     // File descriptor used to wake up epoll.
72     int32_t awakenFd_{-1};
73     std::mutex fileDescriptorMapLock;
74     std::atomic<int32_t> waitingCount_{0};
75     std::atomic<bool> running_ = false;
76     std::atomic<bool> isFinished_ = false;
77     std::unique_ptr<std::thread> epollThread_;
78     std::map<int32_t, std::shared_ptr<FileDescriptorInfo>> fileDescriptorMap_;
79 };
80 }  // namespace AppExecFwk
81 }  // namespace OHOS
82 
83 #endif  // #ifndef BASE_EVENTHANDLER_FRAMEWORKS_EVENTHANDLER_INCLUDE_DEAMON_IO_WAITER_H
84