maildir: replace ListFolder method with FolderMap

Replace ListFolder with a new method that returns a map indexed by
folder names instead of a list of folder names. A map is simpler to use
and more efficient in case we only want to check the presence of a
specific folder in the Maildir store.

Signed-off-by: Julian Pidancet <julian.pidancet@oracle.com>
Acked-by: Robin Jarry <robin@jarry.cc>
Acked-by: Tim Culverhouse <tim@timculverhouse.com>

worker/lib/maildir.go

@@ -34,12 +34,11 @@ func NewMaildirStore(root string, maildirpp bool) (*MaildirStore, error) {
 	}, nil
 }
 
-// ListFolders returns a list of maildir folders in the container
-func (s *MaildirStore) ListFolders() ([]string, error) {
-	folders := []string{}
+func (s *MaildirStore) FolderMap() (map[string]maildir.Dir, error) {
+	folders := make(map[string]maildir.Dir)
 	if s.maildirpp {
 		// In Maildir++ layout, INBOX is the root folder
-		folders = append(folders, "INBOX")
+		folders["INBOX"] = maildir.Dir(s.root)
 	}
 	err := filepath.Walk(s.root, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
@@ -81,14 +80,14 @@ func (s *MaildirStore) ListFolders() ([]string, error) {
 			}
 			dirPath = strings.TrimPrefix(dirPath, ".")
 			dirPath = strings.ReplaceAll(dirPath, ".", "/")
-			folders = append(folders, dirPath)
+			folders[dirPath] = maildir.Dir(path)
 
 			// Since all mailboxes are stored in a single directory, don't
 			// recurse into subdirectories
 			return filepath.SkipDir
 		}
 
-		folders = append(folders, dirPath)
+		folders[dirPath] = maildir.Dir(path)
 		return nil
 	})
 	return folders, err

worker/maildir/worker.go

@@ -329,12 +329,12 @@ func (w *Worker) handleListDirectories(msg *types.ListDirectories) error {
 	if w.c == nil {
 		return errors.New("Incorrect maildir directory")
 	}
-	dirs, err := w.c.Store.ListFolders()
+	dirs, err := w.c.Store.FolderMap()
 	if err != nil {
 		logging.Errorf("failed listing directories: %v", err)
 		return err
 	}
-	for _, name := range dirs {
+	for name := range dirs {
 		w.worker.PostMessage(&types.Directory{
 			Message: types.RespondTo(msg),
 			Dir: &models.Directory{
@@ -733,12 +733,12 @@ func (w *Worker) handleCheckMail(msg *types.CheckMail) {
 		if err != nil {
 			w.err(msg, fmt.Errorf("checkmail: error running command: %w", err))
 		} else {
-			dirs, err := w.c.Store.ListFolders()
+			dirs, err := w.c.Store.FolderMap()
 			if err != nil {
 				w.err(msg, fmt.Errorf("failed listing directories: %w", err))
 			}
-			for _, name := range dirs {
-				err := w.c.SyncNewMail(w.c.Store.Dir(name))
+			for name, dir := range dirs {
+				err := w.c.SyncNewMail(dir)
 				if err != nil {
 					w.err(msg, fmt.Errorf("could not sync new mail: %w", err))
 				}