/
clock.go
53 lines (43 loc) · 1.77 KB
/
clock.go
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// Copyright 2015 Canonical Ltd.
// Licensed under the LGPLv3, see LICENCE file for details.
package clock
import "time"
// Clock provides an interface for dealing with clocks.
type Clock interface {
// Now returns the current clock time.
Now() time.Time
// After waits for the duration to elapse and then sends the
// current time on the returned channel.
After(time.Duration) <-chan time.Time
// AfterFunc waits for the duration to elapse and then calls f in its own goroutine.
// It returns a Timer that can be used to cancel the call using its Stop method.
AfterFunc(d time.Duration, f func()) Timer
// NewTimer creates a new Timer that will send the current time
// on its channel after at least duration d.
NewTimer(d time.Duration) Timer
}
// Alarm returns a channel that will have the time sent on it at some point
// after the supplied time occurs.
//
// This is short for c.After(t.Sub(c.Now())).
func Alarm(c Clock, t time.Time) <-chan time.Time {
return c.After(t.Sub(c.Now()))
}
// The Timer type represents a single event.
// A Timer must be created with AfterFunc.
// This interface follows time.Timer's methods but provides easier mocking.
type Timer interface {
// When the Timer expires, the current time will be sent on the
// channel returned from Chan, unless the Timer was created by
// AfterFunc.
Chan() <-chan time.Time
// Reset changes the timer to expire after duration d.
// It returns true if the timer had been active, false if
// the timer had expired or been stopped.
Reset(time.Duration) bool
// Stop prevents the Timer from firing. It returns true if
// the call stops the timer, false if the timer has already expired or been stopped.
// Stop does not close the channel, to prevent a read
// from the channel succeeding incorrectly.
Stop() bool
}