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44 lines
888 B
44 lines
888 B
package notifier
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import (
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"context"
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"sync"
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)
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// A Notifier is a synchronization primitive for waking upp all listeners at once.
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type Notifier struct {
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mutex sync.Mutex
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ch chan struct{}
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}
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// Broadcast wakes all listeners if there are any.
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func (notifier *Notifier) Broadcast() {
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notifier.mutex.Lock()
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if notifier.ch != nil {
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close(notifier.ch)
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notifier.ch = nil
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}
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notifier.mutex.Unlock()
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}
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// C gets the channel that'll close on the next notification.
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func (notifier *Notifier) C() <-chan struct{} {
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notifier.mutex.Lock()
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if notifier.ch == nil {
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notifier.ch = make(chan struct{})
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}
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ch := notifier.ch
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notifier.mutex.Unlock()
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return ch
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}
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// Wait waits for the next `Broadcast` call, or the context's termination.
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func (notifier *Notifier) Wait(ctx context.Context) error {
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select {
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case <-notifier.C():
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return nil
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case <-ctx.Done():
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return ctx.Err()
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}
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}
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