102 lines
1.7 KiB
Go
102 lines
1.7 KiB
Go
package observer
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import (
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"errors"
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"sync"
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)
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type Observer interface {
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Add(id string, ch chan interface{}) error
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Remove(id string, rch chan interface{}) error
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Notify(id string, arg interface{}) error
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}
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type observer struct {
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mtx sync.Mutex
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events map[string][]chan interface{}
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}
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func (o *observer) Add(id string, ch chan interface{}) error {
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o.mtx.Lock()
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defer o.mtx.Unlock()
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_, ok := o.events[id]
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if ok {
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o.events[id] = append(o.events[id], ch)
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} else {
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arr := make([]chan interface{}, 0)
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arr = append(arr, ch)
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o.events[id] = arr
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}
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return nil
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}
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func (o *observer) Remove(id string, rch chan interface{}) error {
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o.mtx.Lock()
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defer o.mtx.Unlock()
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newArr := make([]chan interface{}, 0)
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chans, ok := o.events[id]
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if !ok {
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return errors.New("event not found")
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}
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for _, ch := range chans {
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if ch != rch {
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newArr = append(newArr, ch)
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} else {
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close(ch)
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ch = nil
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}
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}
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if len(newArr) == 0 {
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delete(o.events,id)
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} else {
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o.events[id] = newArr
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}
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return nil
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}
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func (o *observer) Notify(id string, arg interface{}) error {
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o.mtx.Lock()
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defer o.mtx.Unlock()
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chans, ok := o.events[id]
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if !ok {
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return errors.New("event not found")
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}
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for _, ch := range chans {
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ch <- arg
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}
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return nil
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}
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var _observer *observer
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var once sync.Once
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func init() {
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once.Do(func() {
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_observer = &observer{
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events: make(map[string][]chan interface{}),
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}
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})
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}
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// interface
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func GetInstance() Observer {
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return _observer
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}
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func Add(id string, ch chan interface{}) error {
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return _observer.Add(id, ch)
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}
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func Remove(id string, rch chan interface{}) error {
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return _observer.Remove(id, rch)
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}
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func Notify(id string, arg interface{}) error {
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return _observer.Notify(id, arg)
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} |