1 //
2 // Copyright (C) 2020 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 #pragma once
17
18 #include <atomic>
19 #include <chrono>
20 #include <condition_variable>
21 #include <deque>
22 #include <functional>
23 #include <mutex>
24 #include <thread>
25
26 namespace cuttlefish {
27
28 template <typename T>
makeSafeCallback(T * me,std::function<void (T *)> f)29 std::function<void()> makeSafeCallback(T *me, std::function<void(T *)> f) {
30 return [f, me] {
31 if (me) {
32 f(me);
33 }
34 };
35 }
36
37 template<typename T, typename... Params>
makeSafeCallback(T * obj,void (T::* f)(const Params &...),const Params &...params)38 std::function<void()> makeSafeCallback(
39 T *obj, void (T::*f)(const Params&...), const Params&... params) {
40 return makeSafeCallback<T>(obj,
41 [f, params...](T *me) { (me->*f)(params...); });
42 }
43
44 template<typename T, typename... Params>
makeSafeCallback(T * obj,void (T::* f)(Params...),const Params &...params)45 std::function<void()> makeSafeCallback(
46 T *obj, void (T::*f)(Params...), const Params&... params) {
47 return makeSafeCallback<T>(obj,
48 [f, params...](T *me) { (me->*f)(params...); });
49 }
50
51 class ThreadLooper {
52 public:
53 ThreadLooper();
54 ~ThreadLooper();
55
56 ThreadLooper(const ThreadLooper &) = delete;
57 ThreadLooper &operator=(const ThreadLooper &) = delete;
58
59 typedef std::function<void()> Callback;
60 typedef int32_t Serial;
61
62 Serial Post(Callback cb);
63 Serial PostWithDelay(std::chrono::steady_clock::duration delay, Callback cb);
64
65 void Stop();
66
67 // Returns true if matching event was canceled.
68 bool CancelSerial(Serial serial);
69
70 private:
71 struct Event {
72 std::chrono::steady_clock::time_point when;
73 Callback cb;
74 Serial serial;
75
76 bool operator<=(const Event &other) const;
77 };
78
79 bool stopped_;
80 std::thread looper_thread_;
81
82 std::mutex lock_;
83 std::condition_variable cond_;
84 std::deque<Event> queue_;
85 std::atomic<Serial> next_serial_;
86
87 void ThreadLoop();
88
89 void Insert(const Event &event);
90 };
91
92 }; // namespace cuttlefish
93