76 lines
1.7 KiB
Go
76 lines
1.7 KiB
Go
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package delay
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import (
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"math/rand"
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"sync"
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"time"
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)
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// D (Delay) makes it easy to add (threadsafe) configurable delays to other
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// objects.
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type D interface {
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Set(time.Duration) time.Duration
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Wait()
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NextWaitTime() time.Duration
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Get() time.Duration
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}
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type delay struct {
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l sync.RWMutex
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t time.Duration
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generator Generator
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}
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func (d *delay) Set(t time.Duration) time.Duration {
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d.l.Lock()
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defer d.l.Unlock()
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prev := d.t
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d.t = t
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return prev
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}
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func (d *delay) Wait() {
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d.l.RLock()
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defer d.l.RUnlock()
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time.Sleep(d.generator.NextWaitTime(d.t))
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}
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func (d *delay) NextWaitTime() time.Duration {
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d.l.Lock()
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defer d.l.Unlock()
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return d.generator.NextWaitTime(d.t)
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}
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func (d *delay) Get() time.Duration {
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d.l.Lock()
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defer d.l.Unlock()
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return d.t
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}
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// Delay generates a generic delay form a t, a sleeper, and a generator
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func Delay(t time.Duration, generator Generator) D {
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return &delay{
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t: t,
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generator: generator,
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}
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}
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// Fixed returns a delay with fixed latency
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func Fixed(t time.Duration) D {
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return Delay(t, FixedGenerator())
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}
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// VariableUniform is a delay following a uniform distribution
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// Notice that to implement the D interface Set can only change the minimum delay
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// the delta is set only at initialization
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func VariableUniform(t, d time.Duration, rng *rand.Rand) D {
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return Delay(t, VariableUniformGenerator(d, rng))
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}
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// VariableNormal is a delay following a normal distribution
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// Notice that to implement the D interface Set can only change the mean delay
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// the standard deviation is set only at initialization
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func VariableNormal(t, std time.Duration, rng *rand.Rand) D {
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return Delay(t, VariableNormalGenerator(std, rng))
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}
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