Clear Queue bug

[cwinsnes]

If you are in a queue that gets cleared by a queue owner, trying to queue in another queue before refreshing the page results in a warning that you are already in a queue.

[cwinsnes]

https://github.com/mvk13ogb/qwait/tree/clearqueuebugfix seems to solve the problem but I think the solution is kind of ugly.

@dflemstr, is there any better way of doing this that you can think of?

[dflemstr]

@cwinsnes try to reuse the existing methods on the ApiProviderImpl for removing queue positions, instead of re-implementing the functionality in this method. E.g. call deleteQueuePosition(...)

[cwinsnes]

I changed the code so that it removes every queue position using deleteQueuePosition. Does that look better?

I also removed the message on the message bus that said QueueCleared since everyone already is removed when having iterated through the list, but that could of course be readded if there is another reason to do this.

There is a race condition in this code though, since someone could join the queue while the queue is getting cleared. Could that me remedied by locking the queue before the loop and unlocking after or should something else be done about that?

[dflemstr]

The SQL transaction ensures that nobody can join the queue while it is being cleared.

The idea was that the QueueCleared message should replace the mass queue position removal messages... That is still a possible solution of course but you seem to prefer sending multiple messages which should be fine too...