worker/types: fix Worker.Callbacks race condition

Worker.Process* functions were called in different goroutines than
Worker.Post*. Protect the map with a mutex. Also make the map unexported to
prevent external unprotected accesses.

Worker.Process* functions used to delete items from the map. However they
didn't delete the element they retrieved: callbacks[msg.InResponseTo()] was
read while callbacks[msg] was deleted. I'm not sure I understand why. I tried
to delete the element that was accessed - but this broke everything (UI froze
at "Connecting..."). I don't believe any elements were actually removed from
the map, so the new code just doesn't remove anything.

1 files changed, 1 insertions, 6 deletions

diff --git a/worker/worker.go b/worker/worker.go
index 959c7df..29bb560 100644
--- a/worker/worker.go
+++ b/worker/worker.go
@@ -15,12 +15,7 @@ func NewWorker(source string, logger *log.Logger) (*types.Worker, error) {
 	if err != nil {
 		return nil, err
 	}
-	worker := &types.Worker{
-		Actions:   make(chan types.WorkerMessage, 50),
-		Callbacks: make(map[types.WorkerMessage]func(msg types.WorkerMessage)),
-		Messages:  make(chan types.WorkerMessage, 50),
-		Logger:    logger,
-	}
+	worker := types.NewWorker(logger)
 	switch u.Scheme {
 	case "imap":
 		fallthrough