goemitter/main.go

// Package goemitter
package goemitter

import (
	"sync"
)

type EventEmitter struct {
	callbacks     map[string]map[int]func(args ...interface{})
	onceCallbacks map[string][]func(args ...interface{})
	lock          sync.Mutex
	counter       int
}

type EventHandle struct {
	id      int
	event   string
	emitter *EventEmitter
}

func (eh *EventHandle) Remove() {
	eh.emitter.lock.Lock()
	defer eh.emitter.lock.Unlock()
	if _, ok := eh.emitter.callbacks[eh.event]; ok {
		delete(eh.emitter.callbacks[eh.event], eh.id)
	}
}

func (e *EventEmitter) On(event string, callback func(args ...interface{})) *EventHandle {
	e.lock.Lock()
	defer e.lock.Unlock()
	e.counter++
	if _, ok := e.callbacks[event]; !ok {
		e.callbacks[event] = make(map[int]func(args ...interface{}))
	}
	e.callbacks[event][e.counter] = callback
	return &EventHandle{
		id:      e.counter,
		event:   event,
		emitter: e,
	}
}

func (e *EventEmitter) Once(event string, callback func(args ...interface{})) {
	e.lock.Lock()
	defer e.lock.Unlock()

	if _, ok := e.onceCallbacks[event]; !ok {
		e.onceCallbacks[event] = []func(args ...interface{}){callback}
	} else {
		e.onceCallbacks[event] = append(e.onceCallbacks[event], callback)
	}
}

func (e *EventEmitter) Emit(event string, data ...interface{}) {
	e.lock.Lock()
	defer e.lock.Unlock()

	if callbacks, ok := e.callbacks[event]; ok {
		for _, callback := range callbacks {
			go callback(data...)
		}
	}

	if onceCallbacks, ok := e.onceCallbacks[event]; ok {
		for _, callback := range onceCallbacks {
			go callback(data...)

		}
		e.onceCallbacks[event] = []func(args ...interface{}){}
	}
}

func (e *EventEmitter) EmitSync(event string, data ...interface{}) {
	e.lock.Lock()
	defer e.lock.Unlock()

	if callbacks, ok := e.callbacks[event]; ok {
		for _, callback := range callbacks {
			callback(data...)
		}
	}

	if onceCallbacks, ok := e.onceCallbacks[event]; ok {
		for _, callback := range onceCallbacks {
			callback(data...)

		}
		e.onceCallbacks[event] = []func(args ...interface{}){}
	}
}

func NewEmitter() *EventEmitter {
	ret := &EventEmitter{}
	ret.callbacks = make(map[string]map[int]func(args ...interface{}))
	ret.onceCallbacks = make(map[string][]func(args ...interface{}))
	return ret
}