Improve event emitter/subscription abilities

server/events.go

@@ -1,14 +1,9 @@
 package server
 
 import (
-	"fmt"
-	"github.com/mitchellh/colorstring"
+	"sync"
 )
 
-type EventListeners map[string][]EventListenerFunction
-
-type EventListenerFunction *func(string)
-
 // Defines all of the possible output events for a server.
 // noinspection GoNameStartsWithPackageName
 const (
@@ -19,47 +14,63 @@ const (
 	StatsEvent         = "stats"
 )
 
-// Adds an event listener for the server instance.
-func (s *Server) AddListener(event string, f EventListenerFunction) {
-	if s.listeners == nil {
-		s.listeners = make(map[string][]EventListenerFunction)
+type Event struct {
+	Data  string
+	Topic string
+}
+
+type EventBus struct {
+	subscribers map[string][]chan Event
+	mu          sync.Mutex
+}
+
+// Returns the server's emitter instance.
+func (s *Server) Events() *EventBus {
+	if s.emitter == nil {
+		s.emitter = &EventBus{
+			subscribers: map[string][]chan Event{},
+		}
 	}
 
-	if _, ok := s.listeners[event]; ok {
-		s.listeners[event] = append(s.listeners[event], f)
-	} else {
-		s.listeners[event] = []EventListenerFunction{f}
+	return s.emitter
+}
+
+// Publish data to a given topic.
+func (e *EventBus) Publish(topic string, data string) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	if ch, ok := e.subscribers[topic]; ok {
+		go func(data Event, cs []chan Event) {
+			for _, channel := range cs {
+				channel <- data
+			}
+		}(Event{Data: data, Topic: topic}, ch)
 	}
 }
 
-// Removes the event listener for the server instance.
-func (s *Server) RemoveListener(event string, f EventListenerFunction) {
-	if _, ok := s.listeners[event]; ok {
-		for i := range s.listeners[event] {
-			if s.listeners[event][i] == f {
-				s.listeners[event] = append(s.listeners[event][:i], s.listeners[event][i+1:]...)
-				break
+// Subscribe to an emitter topic using a channel.
+func (e *EventBus) Subscribe(topic string, ch chan Event) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	if p, ok := e.subscribers[topic]; ok {
+		e.subscribers[topic] = append(p, ch)
+	} else {
+		e.subscribers[topic] = append([]chan Event{}, ch)
+	}
+}
+
+// Unsubscribe a channel from a topic.
+func (e *EventBus) Unsubscribe(topic string, ch chan Event) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	if _, ok := e.subscribers[topic]; ok {
+		for i := range e.subscribers[topic] {
+			if ch == e.subscribers[topic][i] {
+				e.subscribers[topic] = append(e.subscribers[topic][:i], e.subscribers[topic][i+1:]...)
 			}
 		}
 	}
-}
-
-// Emits an event to all of the active listeners for a server.
-func (s *Server) Emit(event string, data string) {
-	if _, ok := s.listeners[event]; ok {
-		for _, handler := range s.listeners[event] {
-			go func(f EventListenerFunction, d string) {
-				(*f)(d)
-			}(handler, data)
-		}
-	}
-}
-
-// Sends output to the server console formatted to appear correctly as being sent
-// from Wings.
-func (s *Server) SendConsoleOutputFromDaemon(data string) {
-	s.Emit(
-		ConsoleOutputEvent,
-		colorstring.Color(fmt.Sprintf("[yellow][bold][Pterodactyl Daemon]:[default] %s", data)),
-	)
-}
+}