lib/msgstore: debounce directoryUpdateRequests

Apparently sending an event for every incoming messageInfo slows down
the application significantly.

Therefore this slows down the emmision rate, on the cost of being out of date
in some cases.

lib/msgstore.go

@@ -42,6 +42,9 @@ type MessageStore struct {
 
 	triggerNewEmail        func(*models.MessageInfo)
 	triggerDirectoryChange func()
+
+	dirInfoUpdateDebounce *time.Timer
+	dirInfoUpdateDelay    time.Duration
 }
 
 func NewMessageStore(worker *types.Worker,
@@ -50,6 +53,8 @@ func NewMessageStore(worker *types.Worker,
 	triggerNewEmail func(*models.MessageInfo),
 	triggerDirectoryChange func()) *MessageStore {
 
+	dirInfoUpdateDelay := 5 * time.Second
+
 	return &MessageStore{
 		Deleted:  make(map[uint32]interface{}),
 		DirInfo:  *dirInfo,
@@ -68,6 +73,9 @@ func NewMessageStore(worker *types.Worker,
 
 		triggerNewEmail:        triggerNewEmail,
 		triggerDirectoryChange: triggerDirectoryChange,
+
+		dirInfoUpdateDelay:    dirInfoUpdateDelay,
+		dirInfoUpdateDebounce: time.NewTimer(dirInfoUpdateDelay),
 	}
 }
 
@@ -267,9 +275,15 @@ func (store *MessageStore) Update(msg types.WorkerMessage) {
 	}
 
 	if requestDirInfo {
-		store.worker.PostAction(&types.DirectoryInfoUpdateRequest{
-			Name: store.DirInfo.Name,
-		}, nil)
+		select {
+		case <-store.dirInfoUpdateDebounce.C:
+			store.worker.PostAction(&types.DirectoryInfoUpdateRequest{
+				Name: store.DirInfo.Name,
+			}, nil)
+			store.dirInfoUpdateDebounce.Reset(store.dirInfoUpdateDelay)
+		default:
+			// do nothing
+		}
 	}
 }
 

worker/imap/worker.go

@@ -181,6 +181,8 @@ func (w *IMAPWorker) handleMessage(msg types.WorkerMessage) error {
 		w.handleAppendMessage(msg)
 	case *types.SearchDirectory:
 		w.handleSearchDirectory(msg)
+	case *types.DirectoryInfoUpdateRequest:
+		// not implemented
 	default:
 		reterr = errUnsupported
 	}