public void Schedule(Subscription subscription)
{
if (subscription.SetQueued())
{
lock (_queue)
{
_queue.Enqueue(subscription);
Monitor.Pulse(_queue);
AddWorker();
}
}
}
public void RemoveSubscription(Subscription subscription)
{
lock (Subscriptions)
{
if (_subs.Remove(subscription.Identity))
{
Subscriptions.Remove(subscription);
}
}
}
public void AddSubscription(Subscription subscription)
{
lock (Subscriptions)
{
if (_subs.Add(subscription.Identity))
{
Subscriptions.Add(subscription);
}
}
}
private void RemoveEvent(Subscription subscription, string eventKey)
{
Topic topic;
if (_topics.TryGetValue(eventKey, out topic))
{
topic.RemoveSubscription(subscription);
subscription.RemoveCursor(eventKey);
}
}
/// <summary>
///
/// </summary>
/// <param name="subscriber"></param>
/// <param name="cursor"></param>
/// <param name="callback"></param>
/// <returns></returns>
public IDisposable Subscribe(ISubscriber subscriber, string cursor, Func<MessageResult, Task<bool>> callback, int messageBufferSize)
{
IEnumerable<Cursor> cursors = null;
if (cursor == null)
{
cursors = from key in subscriber.EventKeys
select new Cursor
{
Key = key,
Id = GetMessageId(key)
};
}
else
{
cursors = Cursor.GetCursors(cursor);
}
var subscription = new Subscription(subscriber.Identity, cursors, callback, messageBufferSize, _counters);
var topics = new HashSet<Topic>();
foreach (var key in subscriber.EventKeys)
{
Topic topic = _topics.GetOrAdd(key, _ => new Topic());
// Set the subscription for this topic
subscription.SetCursorTopic(key, topic);
// Add it to the list of topics
topics.Add(topic);
}
foreach (var topic in topics)
{
topic.AddSubscription(subscription);
}
if (!String.IsNullOrEmpty(cursor))
{
// Update all of the cursors so we're within the range
foreach (var pair in subscription.Cursors)
{
Topic topic;
if (_topics.TryGetValue(pair.Key, out topic) && pair.Id > topic.Store.GetMessageCount())
{
subscription.UpdateCursor(pair.Key, 0);
}
}
}
Action<string, string> eventAdded = (eventKey, eventCursor) =>
{
Topic topic = _topics.GetOrAdd(eventKey, _ => new Topic());
// Get the cursor for this event key
ulong id = eventCursor == null ? 0 : UInt64.Parse(eventCursor);
// Add or update the cursor (in case it already exists)
subscription.AddOrUpdateCursor(eventKey, id, topic);
// Add it to the list of subs
topic.AddSubscription(subscription);
};
Action<string> eventRemoved = eventKey => RemoveEvent(subscription, eventKey);
subscriber.EventAdded += eventAdded;
subscriber.EventRemoved += eventRemoved;
// If there's a cursor then schedule work for this subscription
if (!String.IsNullOrEmpty(cursor))
{
_engine.Schedule(subscription);
}
return new DisposableAction(() =>
{
// This will stop work from continuting to happen
subscription.Dispose();
subscriber.EventAdded -= eventAdded;
subscriber.EventRemoved -= eventRemoved;
string currentCursor = Cursor.MakeCursor(subscription.Cursors);
foreach (var eventKey in subscriber.EventKeys)
{
RemoveEvent(subscription, eventKey);
}
subscription.Invoke(new MessageResult(currentCursor));
});
}
private void PumpImplAsync(Task workTask, Subscription subscription, TaskCompletionSource<object> taskCompletionSource)
{
// Async path
workTask.ContinueWith(task =>
{
subscription.UnsetQueued();
_busyWorkersCounter.SafeSetRaw(Interlocked.Decrement(ref _busyWorkers));
Debug.Assert(_busyWorkers >= 0, "The number of busy workers has somehow gone negative");
if (task.IsFaulted)
{
taskCompletionSource.TrySetException(task.Exception);
}
else
{
PumpImpl(taskCompletionSource);
}
});
}
