USe RWMutex to optimize read speed

agenda/print.go

@@ -19,8 +19,8 @@ func (h *Agenda) PrettyPrint(output io.Writer) {
 	w := tabwriter.NewWriter(output, 0, 0, 1, ' ', 0)
 
 	// Ensure our queue is not modified
-	h.mu.Lock()
-	defer h.mu.Unlock()
+	h.mu.RLock()
+	defer h.mu.RUnlock()
 
 	for _, event := range h.queue {
 		// Establish formats

agenda/sort.go

@@ -15,18 +15,18 @@ type EventEntry struct {
 // Agenda is a minheap of calendar events.
 type Agenda struct {
 	queue []EventEntry
-	mu    sync.Mutex
+	mu    sync.RWMutex
 }
 
 func (el *Agenda) Len() int {
-	el.mu.Lock()
-	defer el.mu.Unlock()
+	el.mu.RLock()
+	defer el.mu.RUnlock()
 	return len(el.queue)
 }
 
 func (el *Agenda) Less(i, j int) bool {
-	el.mu.Lock()
-	defer el.mu.Unlock()
+	el.mu.RLock()
+	defer el.mu.RUnlock()
 	return el.queue[i].Start.Before(*el.queue[j].Start)
 }