/// <summary>
///
/// </summary>
/// <param name="subscriber"></param>
/// <param name="cursor"></param>
/// <param name="callback"></param>
/// <returns></returns>
public virtual IDisposable Subscribe(ISubscriber subscriber, string cursor, Func <MessageResult, Task <bool> > callback, int messageBufferSize)
{
Subscription subscription = CreateSubscription(subscriber, cursor, callback, messageBufferSize);
var topics = new HashSet <Topic>();
foreach (var key in subscriber.EventKeys)
{
Topic topic = GetTopic(key);
// Set the subscription for this topic
subscription.SetEventTopic(key, topic);
topics.Add(topic);
}
Action <string> eventAdded = eventKey =>
{
Topic topic = GetTopic(eventKey);
// Add or update the cursor (in case it already exists)
subscription.AddEvent(eventKey, topic);
// Add it to the list of subs
topic.AddSubscription(subscription);
};
Action <string> eventRemoved = eventKey => RemoveEvent(subscription, eventKey);
subscriber.EventAdded += eventAdded;
subscriber.EventRemoved += eventRemoved;
// Add the subscription when it's all set and can be scheduled
// for work
foreach (var topic in topics)
{
topic.AddSubscription(subscription);
}
// If there's a cursor then schedule work for this subscription
if (!String.IsNullOrEmpty(cursor))
{
_broker.Schedule(subscription);
}
return(new DisposableAction(() =>
{
// This will stop work from continuting to happen
subscription.Dispose();
subscriber.EventAdded -= eventAdded;
subscriber.EventRemoved -= eventRemoved;
string currentCursor = subscription.GetCursor();
foreach (var eventKey in subscriber.EventKeys)
{
RemoveEvent(subscription, eventKey);
}
subscription.Invoke(new MessageResult(currentCursor));
}));
}
