Added eventsMutex and wrap all events calls with it.

Due to some "golangish" code this library have possibility to
run into data race when application is working with callbacks.
This commit adds eventsMutex (which is a sync.Mutex), removed
all "golangish" ifs-map reads, and wrap events map read with
sync.Mutex to avoid data races.

irc_callback.go

@@ -13,13 +13,17 @@ import (
 func (irc *Connection) AddCallback(eventcode string, callback func(*Event)) int {
 	eventcode = strings.ToUpper(eventcode)
 	id := 0
-	if _, ok := irc.events[eventcode]; !ok {
+
+	irc.eventsMutex.Lock()
+	_, ok := irc.events[eventcode]
+	if !ok {
 		irc.events[eventcode] = make(map[int]func(*Event))
 		id = 0
 	} else {
 		id = len(irc.events[eventcode])
 	}
 	irc.events[eventcode][id] = callback
+	irc.eventsMutex.Unlock()
 	return id
 }
 
@@ -28,15 +32,20 @@ func (irc *Connection) AddCallback(eventcode string, callback func(*Event)) int
 func (irc *Connection) RemoveCallback(eventcode string, i int) bool {
 	eventcode = strings.ToUpper(eventcode)
 
-	if event, ok := irc.events[eventcode]; ok {
+	irc.eventsMutex.Lock()
+	event, ok := irc.events[eventcode]
+	if ok {
 		if _, ok := event[i]; ok {
 			delete(irc.events[eventcode], i)
+			irc.eventsMutex.Unlock()
 			return true
 		}
 		irc.Log.Printf("Event found, but no callback found at id %d\n", i)
+		irc.eventsMutex.Unlock()
 		return false
 	}
 
+	irc.eventsMutex.Unlock()
 	irc.Log.Println("Event not found")
 	return false
 }
@@ -46,10 +55,14 @@ func (irc *Connection) RemoveCallback(eventcode string, i int) bool {
 func (irc *Connection) ClearCallback(eventcode string) bool {
 	eventcode = strings.ToUpper(eventcode)
 
-	if _, ok := irc.events[eventcode]; ok {
+	irc.eventsMutex.Lock()
+	_, ok := irc.events[eventcode]
+	if ok {
 		irc.events[eventcode] = make(map[int]func(*Event))
+		irc.eventsMutex.Unlock()
 		return true
 	}
+	irc.eventsMutex.Unlock()
 
 	irc.Log.Println("Event not found")
 	return false
@@ -59,7 +72,10 @@ func (irc *Connection) ClearCallback(eventcode string) bool {
 func (irc *Connection) ReplaceCallback(eventcode string, i int, callback func(*Event)) {
 	eventcode = strings.ToUpper(eventcode)
 
-	if event, ok := irc.events[eventcode]; ok {
+	irc.eventsMutex.Lock()
+	event, ok := irc.events[eventcode]
+	irc.eventsMutex.Unlock()
+	if ok {
 		if _, ok := event[i]; ok {
 			event[i] = callback
 			return
@@ -109,7 +125,10 @@ func (irc *Connection) RunCallbacks(event *Event) {
 		event.Arguments[len(event.Arguments)-1] = msg
 	}
 
-	if callbacks, ok := irc.events[event.Code]; ok {
+	irc.eventsMutex.Lock()
+	callbacks, ok := irc.events[event.Code]
+	irc.eventsMutex.Unlock()
+	if ok {
 		if irc.VerboseCallbackHandler {
 			irc.Log.Printf("%v (%v) >> %#v\n", event.Code, len(callbacks), event)
 		}
@@ -121,12 +140,15 @@ func (irc *Connection) RunCallbacks(event *Event) {
 		irc.Log.Printf("%v (0) >> %#v\n", event.Code, event)
 	}
 
-	if callbacks, ok := irc.events["*"]; ok {
+	irc.eventsMutex.Lock()
+	allcallbacks, ok := irc.events["*"]
+	irc.eventsMutex.Unlock()
+	if ok {
 		if irc.VerboseCallbackHandler {
 			irc.Log.Printf("%v (0) >> %#v\n", event.Code, event)
 		}
 
-		for _, callback := range callbacks {
+		for _, callback := range allcallbacks {
 			callback(event)
 		}
 	}

irc_struct.go

@@ -39,6 +39,7 @@ type Connection struct {
 	user        string
 	registered  bool
 	events      map[string]map[int]func(*Event)
+	eventsMutex sync.Mutex
 
 	QuitMessage string
 	lastMessage time.Time