1/*
2 * Copyright 2014-present Facebook, Inc.
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 <chrono>
19#include <iosfwd>
20
21#include <folly/portability/SysTypes.h>
22
23namespace folly {
24
25/**
26 * A class for tracking time durations in test code.
27 *
28 * This is primarily useful for testing timeout functionality. When comparing
29 * the differences between two TimePoints, it can exclude time spent waiting on
30 * the OS scheduler. This helps avoid spurious test failures when timeouts are
31 * exceeded by longer than expected simply because the underlying system was
32 * busy and could not schedule this thread in time.
33 */
34class TimePoint {
35 public:
36 explicit TimePoint(bool set = true) : tid_(0) {
37 if (set) {
38 reset();
39 }
40 }
41
42 void reset();
43
44 bool isUnset() const {
45 return (
46 timeStart_.time_since_epoch().count() == 0 &&
47 timeEnd_.time_since_epoch().count() == 0 && timeWaiting_.count() == 0);
48 }
49
50 std::chrono::steady_clock::time_point getTime() const {
51 return timeStart_;
52 }
53
54 std::chrono::steady_clock::time_point getTimeStart() const {
55 return timeStart_;
56 }
57
58 std::chrono::steady_clock::time_point getTimeEnd() const {
59 return timeStart_;
60 }
61
62 std::chrono::nanoseconds getTimeWaiting() const {
63 return timeWaiting_;
64 }
65
66 pid_t getTid() const {
67 return tid_;
68 }
69
70 private:
71 std::chrono::steady_clock::time_point timeStart_;
72 std::chrono::steady_clock::time_point timeEnd_;
73 std::chrono::nanoseconds timeWaiting_{0};
74 pid_t tid_;
75};
76
77std::ostream& operator<<(std::ostream& os, const TimePoint& timePoint);
78
79bool checkTimeout(
80 const TimePoint& start,
81 const TimePoint& end,
82 std::chrono::nanoseconds expected,
83 bool allowSmaller,
84 std::chrono::nanoseconds tolerance = std::chrono::milliseconds(5));
85} // namespace folly
86