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 returns the channel of a new Timer.
34	// This method does not allow to free/GC the backing timer before it fires. Use
35	// NewTimer instead.
36	After(d time.Duration) <-chan time.Time
37	// NewTimer returns a new Timer.
38	NewTimer(d time.Duration) Timer
39	// Sleep sleeps for the provided duration d.
40	// Consider making the sleep interruptible by using 'select' on a context channel and a timer channel.
41	Sleep(d time.Duration)
42	// Tick returns the channel of a new Ticker.
43	// This method does not allow to free/GC the backing ticker. Use
44	// NewTicker from WithTicker instead.
45	Tick(d time.Duration) <-chan time.Time
46}
47
48// WithTicker allows for injecting fake or real clocks into code that
49// needs to do arbitrary things based on time.
50type WithTicker interface {
51	Clock
52	// NewTicker returns a new Ticker.
53	NewTicker(time.Duration) Ticker
54}
55
56// Ticker defines the Ticker interface.
57type Ticker interface {
58	C() <-chan time.Time
59	Stop()
60}
61
62var _ = WithTicker(RealClock{})
63
64// RealClock really calls time.Now()
65type RealClock struct{}
66
67// Now returns the current time.
68func (RealClock) Now() time.Time {
69	return time.Now()
70}
71
72// Since returns time since the specified timestamp.
73func (RealClock) Since(ts time.Time) time.Duration {
74	return time.Since(ts)
75}
76
77// After is the same as time.After(d).
78// This method does not allow to free/GC the backing timer before it fires. Use
79// NewTimer instead.
80func (RealClock) After(d time.Duration) <-chan time.Time {
81	return time.After(d)
82}
83
84// NewTimer is the same as time.NewTimer(d)
85func (RealClock) NewTimer(d time.Duration) Timer {
86	return &realTimer{
87		timer: time.NewTimer(d),
88	}
89}
90
91// Tick is the same as time.Tick(d)
92// This method does not allow to free/GC the backing ticker. Use
93// NewTicker instead.
94func (RealClock) Tick(d time.Duration) <-chan time.Time {
95	return time.Tick(d)
96}
97
98// NewTicker returns a new Ticker.
99func (RealClock) NewTicker(d time.Duration) Ticker {
100	return &realTicker{
101		ticker: time.NewTicker(d),
102	}
103}
104
105// Sleep is the same as time.Sleep(d)
106// Consider making the sleep interruptible by using 'select' on a context channel and a timer channel.
107func (RealClock) Sleep(d time.Duration) {
108	time.Sleep(d)
109}
110
111// Timer allows for injecting fake or real timers into code that
112// needs to do arbitrary things based on time.
113type Timer interface {
114	C() <-chan time.Time
115	Stop() bool
116	Reset(d time.Duration) bool
117}
118
119var _ = Timer(&realTimer{})
120
121// realTimer is backed by an actual time.Timer.
122type realTimer struct {
123	timer *time.Timer
124}
125
126// C returns the underlying timer's channel.
127func (r *realTimer) C() <-chan time.Time {
128	return r.timer.C
129}
130
131// Stop calls Stop() on the underlying timer.
132func (r *realTimer) Stop() bool {
133	return r.timer.Stop()
134}
135
136// Reset calls Reset() on the underlying timer.
137func (r *realTimer) Reset(d time.Duration) bool {
138	return r.timer.Reset(d)
139}
140
141type realTicker struct {
142	ticker *time.Ticker
143}
144
145func (r *realTicker) C() <-chan time.Time {
146	return r.ticker.C
147}
148
149func (r *realTicker) Stop() {
150	r.ticker.Stop()
151}
152