maildir: fix handling of FSEvents

Maildir uses a filesystem watcher to watch the currently selected
directory for changes, updating the UI as necessary. Not all changes get
updated based on the current logic. Send a MessageInfo if the event was
a Rename. Send a MessagesDeleted if the event was a Remove. Tell the UI
to refetch the list if the event was a Create.

Note: This leads to some unnecessary fetching in the UI, as renames also
come with a Create event in most cases. Koni suggested sending the
MessageInfo and having the UI perform a binary search and inserting the
message in the proper position. This is optimization is left out of this
series, with a TODO left in the code.

Fixes: https://todo.sr.ht/~rjarry/aerc/171
Fixes: 91ac21ac6155 ("msgstore: fetch message list based on OpenDirectory msg")
Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>

2 files changed, 44 insertions, 8 deletions

diff --git a/worker/maildir/container.go b/worker/maildir/container.go
index f9fb507b..946de74d 100644
--- a/worker/maildir/container.go
+++ b/worker/maildir/container.go
@@ -93,6 +93,15 @@ func (c *Container) Message(d maildir.Dir, uid uint32) (*Message, error) {
 		uid, d)
 }
 
+func (c *Container) MessageFromKey(d maildir.Dir, key string) *Message {
+	uid := c.uids.GetOrInsert(key)
+	return &Message{
+		dir: d,
+		uid: uid,
+		key: key,
+	}
+}
+
 // DeleteAll deletes a set of messages by UID and returns the subset of UIDs
 // which were successfully deleted, stopping upon the first error.
 func (c *Container) DeleteAll(d maildir.Dir, uids []uint32) ([]uint32, error) {
diff --git a/worker/maildir/worker.go b/worker/maildir/worker.go
index 69d39fa8..ded0faac 100644
--- a/worker/maildir/worker.go
+++ b/worker/maildir/worker.go
@@ -132,15 +132,42 @@ func (w *Worker) handleFSEvent(ev *types.FSEvent) {
 		return
 	}
 
-	dirInfo := w.getDirectoryInfo(w.selectedName)
-	var refetch bool
-	if dirInfo.Exists > w.selectedInfo.Exists {
-		refetch = true
+	w.selectedInfo = w.getDirectoryInfo(w.selectedName)
+	dirInfoMsg := &types.DirectoryInfo{
+		Info: w.selectedInfo,
 	}
-	w.worker.PostMessage(&types.DirectoryInfo{
-		Info:    dirInfo,
-		Refetch: refetch,
-	}, nil)
+
+	base := filepath.Base(ev.Path)
+	parts := strings.SplitN(base, ":", 2)
+	if len(parts) != 2 {
+		log.Errorf("Couldn't parse key from file: %s", ev.Path)
+		return
+	}
+	msg := w.c.MessageFromKey(*w.selected, parts[0])
+
+	switch ev.Operation {
+	case types.FSCreate:
+		// TODO for FSCreate we should send a new message type that
+		// creates the message in the UI, does a binary search based on
+		// current sort criteria and inserts message at proper index
+		// For now, we just refetch the list.
+		dirInfoMsg.Refetch = true
+	case types.FSRename:
+		msgInfo, err := msg.MessageInfo()
+		if err != nil {
+			log.Errorf(err.Error())
+			return
+		}
+		w.worker.PostMessage(&types.MessageInfo{
+			Info: msgInfo,
+		}, nil)
+	case types.FSRemove:
+		w.worker.PostMessage(&types.MessagesDeleted{
+			Uids: []uint32{msg.uid},
+		}, nil)
+	}
+
+	w.worker.PostMessage(dirInfoMsg, nil)
 }
 
 func (w *Worker) done(msg types.WorkerMessage) {