1/*
2Copyright 2014 The Kubernetes Authors.
3
4Licensed under the Apache License, Version 2.0 (the "License");
5you may not use this file except in compliance with the License.
6You may obtain a copy of the License at
7
8    http://www.apache.org/licenses/LICENSE-2.0
9
10Unless required by applicable law or agreed to in writing, software
11distributed under the License is distributed on an "AS IS" BASIS,
12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13See the License for the specific language governing permissions and
14limitations under the License.
15*/
16
17package clock
18
19import "time"
20
21// PassiveClock allows for injecting fake or real clocks into code
22// that needs to read the current time but does not support scheduling
23// activity in the future.
24type PassiveClock interface {
25	Now() time.Time
26	Since(time.Time) time.Duration
27}
28
29// Clock allows for injecting fake or real clocks into code that
30// needs to do arbitrary things based on time.
31type Clock interface {
32	PassiveClock
33	After(d time.Duration) <-chan time.Time
34	NewTimer(d time.Duration) Timer
35	Sleep(d time.Duration)
36	Tick(d time.Duration) <-chan time.Time
37}
38
39var _ = Clock(RealClock{})
40
41// RealClock really calls time.Now()
42type RealClock struct{}
43
44// Now returns the current time.
45func (RealClock) Now() time.Time {
46	return time.Now()
47}
48
49// Since returns time since the specified timestamp.
50func (RealClock) Since(ts time.Time) time.Duration {
51	return time.Since(ts)
52}
53
54// After is the same as time.After(d).
55func (RealClock) After(d time.Duration) <-chan time.Time {
56	return time.After(d)
57}
58
59// NewTimer is the same as time.NewTimer(d)
60func (RealClock) NewTimer(d time.Duration) Timer {
61	return &realTimer{
62		timer: time.NewTimer(d),
63	}
64}
65
66// Tick is the same as time.Tick(d)
67func (RealClock) Tick(d time.Duration) <-chan time.Time {
68	return time.Tick(d)
69}
70
71// Sleep is the same as time.Sleep(d)
72func (RealClock) Sleep(d time.Duration) {
73	time.Sleep(d)
74}
75
76// Timer allows for injecting fake or real timers into code that
77// needs to do arbitrary things based on time.
78type Timer interface {
79	C() <-chan time.Time
80	Stop() bool
81	Reset(d time.Duration) bool
82}
83
84var _ = Timer(&realTimer{})
85
86// realTimer is backed by an actual time.Timer.
87type realTimer struct {
88	timer *time.Timer
89}
90
91// C returns the underlying timer's channel.
92func (r *realTimer) C() <-chan time.Time {
93	return r.timer.C
94}
95
96// Stop calls Stop() on the underlying timer.
97func (r *realTimer) Stop() bool {
98	return r.timer.Stop()
99}
100
101// Reset calls Reset() on the underlying timer.
102func (r *realTimer) Reset(d time.Duration) bool {
103	return r.timer.Reset(d)
104}
105