Server/service.go

package lucifer3

import (
	"fmt"
	"sync/atomic"
)

type Service interface {
	Active() bool
	ServiceID() ServiceID
	Handle(bus *EventBus, event Event, sender ServiceID)
}

type ServiceID struct {
	Kind ServiceKind
	ID   int64
	Name string
}

func (s *ServiceID) String() string {
	if s == nil {
		return "BROADCAST"
	}
	if s.Kind == SKNotService {
		return "EXTERNAL"
	}

	if s.Name != "" {
		return s.Name
	} else {
		return fmt.Sprintf("%s[%d]", s.Kind.String(), s.ID)
	}

}

type ServiceCommon struct {
	serviceID ServiceID
	inactive  uint32
}

func (s *ServiceCommon) Active() bool {
	return atomic.LoadUint32(&s.inactive) == 0
}

func (s *ServiceCommon) markInactive() {
	atomic.StoreUint32(&s.inactive, 1)
}

func (s *ServiceCommon) ServiceID() ServiceID {
	return s.serviceID
}

type ServiceKind int

func (s ServiceKind) String() string {
	switch s {
	case SKSingleton:
		return "Singleton"
	case SKStorage:
		return "Storage"
	case SKDeviceHub:
		return "DeviceHub"
	case SKEffect:
		return "Effect"
	case SKCallback:
		return "Callback"
	case SKNotService:
		return "NotService"
	default:
		return "???"
	}
}

const (
	SKNotService ServiceKind = iota
	SKSingleton
	SKStorage
	SKDeviceHub
	SKEffect
	SKCallback
)

type callbackService struct {
	ServiceCommon
	cb func(event Event, sender ServiceID) bool
}

func (c *callbackService) Handle(_ *EventBus, event Event, sender ServiceID) {
	if !c.cb(event, sender) {
		c.markInactive()
	}
}

var nextCallback int64 = 0

func newCallbackService(cb func(event Event, sender ServiceID) bool) Service {
	return &callbackService{
		ServiceCommon: ServiceCommon{
			serviceID: ServiceID{
				Kind: SKCallback,
				ID:   atomic.AddInt64(&nextCallback, 1),
			},
			inactive: 0,
		},
		cb: cb,
	}
}