/
registry.go
163 lines (141 loc) · 3.16 KB
/
registry.go
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package event
import (
"container/list"
"strings"
"sync"
"sync/atomic"
)
type HandlerID uint32
var hidCounter uint32 = 0
func NewHandlerID() HandlerID {
return HandlerID(atomic.AddUint32(&hidCounter, 1))
}
type Handler interface {
Run(...interface{})
Id() HandlerID
}
type basicHandler struct {
fn func(...interface{})
id HandlerID
}
func (h *basicHandler) Run(ev ...interface{}) {
h.fn(ev...)
}
func (h *basicHandler) Id() HandlerID {
return h.id
}
func NewHandler(h func(...interface{})) Handler {
return &basicHandler{h, NewHandlerID()}
}
type EventDispatcher interface {
Dispatch(name string, ev ...interface{})
}
type EventRegistry interface {
AddHandler(h Handler, names ...string)
DelHandler(h Handler, names ...string)
Dispatch(name string, ev ...interface{})
ClearEvents(name string)
}
type registry struct {
// Event registry as a lockable map of linked-lists
sync.RWMutex
events map[string]*list.List
dispatcher func(r *registry, name string, ev ...interface{})
}
func NewRegistry() *registry {
r := ®istry{events: make(map[string]*list.List)}
r.Parallel()
return r
}
func (r *registry) AddHandler(h Handler, names ...string) {
if len(names) == 0 {
return
}
r.Lock()
defer r.Unlock()
N:
for _, name := range names {
name = strings.ToLower(name)
if _, ok := r.events[name]; !ok {
r.events[name] = list.New()
}
for e := r.events[name].Front(); e != nil; e = e.Next() {
// Check we're not adding a duplicate handler to this event
if e.Value.(Handler).Id() == h.Id() {
continue N
}
}
r.events[name].PushBack(h)
}
}
func _del(l *list.List, id HandlerID) bool {
for e := l.Front(); e != nil; e = e.Next() {
if e.Value.(Handler).Id() == id {
l.Remove(e)
}
}
return l.Len() == 0
}
func (r *registry) DelHandler(h Handler, names ...string) {
r.Lock()
defer r.Unlock()
if len(names) == 0 {
for name, l := range r.events {
if _del(l, h.Id()) {
delete(r.events, name)
}
}
} else {
for _, name := range names {
name = strings.ToLower(name)
if l, ok := r.events[name]; ok {
if _del(l, h.Id()) {
delete(r.events, name)
}
}
}
}
}
func (r *registry) Dispatch(name string, ev ...interface{}) {
r.dispatcher(r, strings.ToLower(name), ev...)
}
func (r *registry) ClearEvents(name string) {
name = strings.ToLower(name)
r.Lock()
defer r.Unlock()
if l, ok := r.events[name]; ok {
l.Init() // I hope this is enough to GC all list elements.
delete(r.events, name)
}
}
func (r *registry) Parallel() {
r.dispatcher = (*registry).parallelDispatch
}
func (r *registry) Serial() {
r.dispatcher = (*registry).serialDispatch
}
func (r *registry) parallelDispatch(name string, ev ...interface{}) {
r.RLock()
defer r.RUnlock()
if l, ok := r.events[name]; ok {
for e := l.Front(); e != nil; e = e.Next() {
h := e.Value.(Handler)
go h.Run(ev...)
}
}
}
func (r *registry) serialDispatch(name string, ev ...interface{}) {
r.RLock()
defer r.RUnlock()
if l, ok := r.events[name]; ok {
hlist := make([]Handler, l.Len())
for e, i := l.Front(), 0; e != nil; e, i = e.Next(), i+1 {
hlist[i] = e.Value.(Handler)
}
go func() {
for _, h := range hlist {
h.Run(ev...)
}
}()
}
}