1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef SIMPLE_PERF_IOEVENT_LOOP_H_
18#define SIMPLE_PERF_IOEVENT_LOOP_H_
19
20#include <time.h>
21
22#include <functional>
23#include <memory>
24#include <vector>
25
26struct IOEvent;
27typedef IOEvent* IOEventRef;
28struct event_base;
29
30// IOEventLoop is a class wrapper of libevent, it monitors events happened,
31// and calls the corresponding callbacks. Possible events are: file ready to
32// read, file ready to write, signal happens, periodic timer timeout.
33class IOEventLoop {
34 public:
35  IOEventLoop();
36  ~IOEventLoop();
37
38  // Register a read Event, so [callback] is called when [fd] can be read
39  // without blocking. If registered successfully, return the reference
40  // to control the Event, otherwise return nullptr.
41  IOEventRef AddReadEvent(int fd, const std::function<bool()>& callback);
42
43  // Register a write Event, so [callback] is called when [fd] can be written
44  // without blocking.
45  IOEventRef AddWriteEvent(int fd, const std::function<bool()>& callback);
46
47  // Register a signal Event, so [callback] is called each time signal [sig]
48  // happens.
49  bool AddSignalEvent(int sig, const std::function<bool()>& callback);
50
51  // Register a vector of signal Events.
52  bool AddSignalEvents(std::vector<int> sigs,
53                       const std::function<bool()>& callback);
54
55  // Register a periodic Event, so [callback] is called periodically every
56  // [duration].
57  bool AddPeriodicEvent(timeval duration,
58                        const std::function<bool()>& callback);
59
60  // Run a loop polling for Events. It only exits when ExitLoop() is called
61  // in a callback function of registered Events.
62  bool RunLoop();
63
64  // Exit the loop started by RunLoop().
65  bool ExitLoop();
66
67  // Disable an Event, which can be enabled later.
68  static bool DisableEvent(IOEventRef ref);
69  // Enable a disabled Event.
70  static bool EnableEvent(IOEventRef ref);
71
72  // Unregister an Event.
73  static bool DelEvent(IOEventRef ref);
74
75 private:
76  bool EnsureInit();
77  IOEventRef AddEvent(int fd_or_sig, short events, timeval* timeout,
78                      const std::function<bool()>& callback);
79  static void EventCallbackFn(int, short, void*);
80
81  event_base* ebase_;
82  std::vector<std::unique_ptr<IOEvent>> events_;
83  bool has_error_;
84};
85
86#endif  // SIMPLE_PERF_IOEVENT_LOOP_H_
87