From cce112465ff6e995e53bcc6e077e897e5823d4fe Mon Sep 17 00:00:00 2001
From: Alex Bramley <a.bramley@gmail.com>
Date: Wed, 27 Jul 2011 17:49:34 +0100
Subject: [PATCH] Make Handler an interface type; make dispatcher private;
 correctly unbox ev.

---
 event/registry.go | 57 +++++++++++++++++++++++++++++------------------
 1 file changed, 35 insertions(+), 22 deletions(-)

diff --git a/event/registry.go b/event/registry.go
index 5a2ad6b..fd86889 100644
--- a/event/registry.go
+++ b/event/registry.go
@@ -8,24 +8,37 @@ import (
 )
 
 type HandlerID uint32
-type Handler struct {
-	Run func(...interface{})
-	ID	HandlerID
-}
-
 var hidCounter uint32 = 0
 
 func NewHandlerID() HandlerID {
 	return HandlerID(atomic.AddUint32(&hidCounter, 1))
 }
 
-func NewHandler(h func(...interface{})) *Handler {
-	return &Handler{h, NewHandlerID()}
+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 EventRegistry interface {
-	AddHandler(name string, h *Handler)
-	DelHandler(h *Handler)
+	AddHandler(name string, h Handler)
+	DelHandler(h Handler)
 	Dispatch(name string, ev ...interface{})
 	ClearEvents(name string)
 }
@@ -34,7 +47,7 @@ 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{})
+	dispatcher func(r *registry, name string, ev ...interface{})
 }	
 
 func NewRegistry() *registry {
@@ -43,7 +56,7 @@ func NewRegistry() *registry {
 	return r
 }
 
-func (r *registry) AddHandler(name string, h *Handler) {
+func (r *registry) AddHandler(name string, h Handler) {
 	name = strings.ToLower(name)
 	r.Lock()
 	defer r.Unlock()
@@ -52,20 +65,20 @@ func (r *registry) AddHandler(name string, h *Handler) {
 	}
 	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 {
+		if e.Value.(Handler).Id() == h.Id() {
 			return
 		}
 	}
 	r.events[name].PushBack(h)
 }
 
-func (r *registry) DelHandler(h *Handler) {
+func (r *registry) DelHandler(h Handler) {
 	// This is a bit brute-force. Don't add too many handlers!
 	r.Lock()
 	defer r.Unlock()
 	for _, l := range r.events {
 		for e := l.Front(); e != nil; e = e.Next() {
-			if e.Value.(*Handler).ID == h.ID {
+			if e.Value.(Handler).Id() == h.Id() {
 				l.Remove(e)
 			}
 		}
@@ -73,15 +86,15 @@ func (r *registry) DelHandler(h *Handler) {
 }
 
 func (r *registry) Dispatch(name string, ev ...interface{}) {
-	r.Dispatcher(r, name, ev)
+	r.dispatcher(r, name, ev...)
 }
 
 func (r *registry) Parallel() {
-	r.Dispatcher = (*registry).parallelDispatch
+	r.dispatcher = (*registry).parallelDispatch
 }
 
 func (r *registry) Serial() {
-	r.Dispatcher = (*registry).serialDispatch
+	r.dispatcher = (*registry).serialDispatch
 }
 
 func (r *registry) parallelDispatch(name string, ev ...interface{}) {
@@ -90,8 +103,8 @@ func (r *registry) parallelDispatch(name string, ev ...interface{}) {
 	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)
+			h := e.Value.(Handler)
+			go h.Run(ev...)
 		}
 	}
 }
@@ -101,13 +114,13 @@ func (r *registry) serialDispatch(name string, ev ...interface{}) {
 	r.RLock()
 	defer r.RUnlock()
 	if l, ok := r.events[name]; ok {
-		hlist := make([]*Handler, 0, l.Len())
+		hlist := make([]Handler, 0, l.Len())
 		for e := l.Front(); e != nil; e = e.Next() {
-			hlist = append(hlist, e.Value.(*Handler))
+			hlist = append(hlist, e.Value.(Handler))
 		}
 		go func() {
 			for _, h := range hlist {
-				h.Run(ev)
+				h.Run(ev...)
 			}
 		}()
 	}