75 lines
1.5 KiB
Go
75 lines
1.5 KiB
Go
package core
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import (
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"errors"
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"github.com/sirupsen/logrus"
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"golang.org/x/sync/semaphore"
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)
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type dispatcher struct {
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listeners map[int16]chan string
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counter int16
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sem *semaphore.Weighted
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}
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func NewDispatcher() *dispatcher {
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return &dispatcher{
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listeners: make(map[int16]chan string),
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counter: 0,
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sem: semaphore.NewWeighted(1),
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}
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}
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func (d *dispatcher) SetStreaming(s bool) bool {
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if ok := d.sem.TryAcquire(1); s && ok {
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// if i want to turn on and can get semaphore then return success
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return true
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} else if !s && !ok {
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// if i want to turn off and cant get semaphore, i can safely turn off by releasing semaphore and return success
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d.sem.Release(1)
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return true
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}
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return false
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}
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func (d *dispatcher) IsClosed() bool {
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if d.sem.TryAcquire(1) {
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d.sem.Release(1)
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return true
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}
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return false
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}
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func (d *dispatcher) Publish(message string) {
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if d.IsClosed() {
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return
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}
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logrus.Tracef("publishing to %v listeners\n", len(d.listeners))
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logrus.Trace(message)
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for _, ch := range d.listeners {
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select {
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case ch <- message:
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default:
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logrus.Traceln("dispatcher: skip closed channel")
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}
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}
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}
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func (d *dispatcher) Subscribe() (id int16, receiver <-chan string) {
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key := d.counter
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d.counter++
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rec := make(chan string)
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d.listeners[key] = rec
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return key, rec
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}
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func (d *dispatcher) Unsubscribe(id int16) error {
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receiver, ok := d.listeners[id]
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if !ok {
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return errors.New("no subscription with id")
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}
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delete(d.listeners, id)
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close(receiver)
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return nil
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}
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