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package utils
import (
"sync"
"github.com/NeowayLabs/wabbit"
)
const listenerSlots = 128
// ErrBroadcast enables broadcast an error channel to various listener channels
type ErrBroadcast struct {
sync.Mutex // Protects listeners
listeners []chan<- wabbit.Error
c chan wabbit.Error
}
// NewErrBroadcast creates a broadcast object for push errors to subscribed channels
func NewErrBroadcast() *ErrBroadcast {
b := &ErrBroadcast{
c: make(chan wabbit.Error),
listeners: make([]chan<- wabbit.Error, 0, listenerSlots),
}
go func() {
for {
select {
case e := <-b.c:
b.spread(e)
}
}
}()
return b
}
// Add a new listener
func (b *ErrBroadcast) Add(c chan<- wabbit.Error) {
b.Lock()
b.listeners = append(b.listeners, c)
b.Unlock()
}
// Delete the listener
func (b *ErrBroadcast) Delete(c chan<- wabbit.Error) {
i, ok := b.findIndex(c)
if !ok {
return
}
b.Lock()
b.listeners[i] = b.listeners[len(b.listeners)-1]
b.listeners[len(b.listeners)-1] = nil
b.listeners = b.listeners[:len(b.listeners)-1]
b.Unlock()
}
// Write to subscribed channels
func (b *ErrBroadcast) Write(err wabbit.Error) {
b.c <- err
}
func (b *ErrBroadcast) spread(err wabbit.Error) {
b.Lock()
for _, l := range b.listeners {
l <- err
}
b.Unlock()
}
func (b *ErrBroadcast) findIndex(c chan<- wabbit.Error) (int, bool) {
b.Lock()
defer b.Unlock()
for i := range b.listeners {
if b.listeners[i] == c {
return i, true
}
}
return -1, false
}
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