63 lines
1.3 KiB
Go
63 lines
1.3 KiB
Go
package state
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import (
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"sync"
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)
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// NotifyGroup is used to allow a simple notification mechanism.
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// Channels can be marked as waiting, and when notify is invoked,
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// all the waiting channels get a message and are cleared from the
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// notify list.
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type NotifyGroup struct {
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l sync.Mutex
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notify map[chan struct{}]struct{}
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}
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// Notify will do a non-blocking send to all waiting channels, and
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// clear the notify list
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func (n *NotifyGroup) Notify() {
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n.l.Lock()
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defer n.l.Unlock()
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for ch := range n.notify {
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select {
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case ch <- struct{}{}:
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default:
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}
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}
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n.notify = nil
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}
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// Wait adds a channel to the notify group
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func (n *NotifyGroup) Wait(ch chan struct{}) {
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n.l.Lock()
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defer n.l.Unlock()
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if n.notify == nil {
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n.notify = make(map[chan struct{}]struct{})
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}
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n.notify[ch] = struct{}{}
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}
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// Clear removes a channel from the notify group
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func (n *NotifyGroup) Clear(ch chan struct{}) {
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n.l.Lock()
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defer n.l.Unlock()
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if n.notify == nil {
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return
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}
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delete(n.notify, ch)
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}
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// WaitCh allocates a channel that is subscribed to notifications
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func (n *NotifyGroup) WaitCh() chan struct{} {
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ch := make(chan struct{}, 1)
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n.Wait(ch)
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return ch
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}
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// Empty checks if there are no channels to notify
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func (n *NotifyGroup) Empty() bool {
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n.l.Lock()
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defer n.l.Unlock()
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return len(n.notify) == 0
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}
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