Show spinner when fetching contents

The spinner should be shown when fetching the contents as we don't know
at that point whether there are some messages or not.

lib/msgstore.go

@@ -10,9 +10,10 @@ import (
 
 // Accesses to fields must be guarded by MessageStore.Lock/Unlock
 type MessageStore struct {
-	Deleted  map[uint32]interface{}
-	DirInfo  models.DirectoryInfo
-	Messages map[uint32]*models.MessageInfo
+	Deleted          map[uint32]interface{}
+	DirInfo          models.DirectoryInfo
+	Messages         map[uint32]*models.MessageInfo
+	FetchingContents bool
 	// Ordered list of known UIDs
 	uids []uint32
 
@@ -159,6 +160,7 @@ func (store *MessageStore) Update(msg types.WorkerMessage) {
 		store.worker.PostAction(&types.FetchDirectoryContents{
 			SortCriteria: store.defaultSortCriteria,
 		}, nil)
+		store.FetchingContents = true
 		update = true
 	case *types.DirectoryContents:
 		newMap := make(map[uint32]*models.MessageInfo)
@@ -172,6 +174,7 @@ func (store *MessageStore) Update(msg types.WorkerMessage) {
 		}
 		store.Messages = newMap
 		store.uids = msg.Uids
+		store.FetchingContents = false
 		update = true
 	case *types.MessageInfo:
 		if existing, ok := store.Messages[msg.Info.Uid]; ok && existing != nil {

widgets/msglist.go

@@ -61,6 +61,9 @@ func (ml *MessageList) Draw(ctx *ui.Context) {
 			ml.drawEmptyMessage(ctx)
 			return
 		}
+	} else if store.FetchingContents {
+		ml.spinner.Draw(ctx)
+		return
 	}
 
 	var (