rmdir: ensure proper sequence of operations

Ensure the proper sequence of opening and removing a directory. Fix a
potential race between the OpenDirectory (issued by dirlist.Select())
and the RemoveDirectory messages when removing a directory.

Due to the delay in the current dirlist.Select() function, the
RemoveDirectory message can arrive at the backend before the directory
was changed to a different one. This can cause an error on some imap
servers and problems with the watcher on the maildir backends.

Introduce dirlist.Open() that accepts a callback function so that the
operations can be performed in proper sequence. Dirlist.Select() is now
a wrapper call to dirlist.Open().

Reported-by: inwit <inwit@sindominio.net>
Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>
Tested-by: Inwit <inwit@sindominio.net>

1 files changed, 10 insertions, 1 deletions

diff --git a/app/dirlist.go b/app/dirlist.go
index d77ace42..708eb824 100644
--- a/app/dirlist.go
+++ b/app/dirlist.go
@@ -26,6 +26,7 @@ type DirectoryLister interface {
 
 	Selected() string
 	Select(string)
+	Open(string, time.Duration, func(types.WorkerMessage))
 
 	Update(types.WorkerMessage)
 	List() []string
@@ -172,11 +173,16 @@ func (dirlist *DirectoryList) ExpandFolder() {
 }
 
 func (dirlist *DirectoryList) Select(name string) {
+	dirlist.Open(name, dirlist.UiConfig(name).DirListDelay, nil)
+}
+
+func (dirlist *DirectoryList) Open(name string, delay time.Duration,
+	cb func(types.WorkerMessage),
+) {
 	dirlist.selecting = name
 
 	dirlist.cancel()
 	dirlist.ctx, dirlist.cancel = context.WithCancel(context.Background())
-	delay := dirlist.UiConfig(name).DirListDelay
 
 	go func(ctx context.Context) {
 		defer log.PanicHandler()
@@ -198,6 +204,9 @@ func (dirlist *DirectoryList) Select(name string) {
 					case *types.Cancelled:
 						log.Debugf("OpenDirectory cancelled")
 					}
+					if cb != nil {
+						cb(msg)
+					}
 				})
 		case <-ctx.Done():
 			log.Tracef("dirlist: skip %s", name)