public override bool AddEvent(string eventKey, Topic topic)
{
base.AddEvent(eventKey, topic);
lock (_cursors)
{
// O(n), but small n and it's not common
var index = FindCursorIndex(eventKey);
if (index == -1)
{
_cursors.Add(new Cursor(eventKey, GetMessageId(topic), _stringMinifier.Minify(eventKey)));
_cursorTopics.Add(topic);
return true;
}
return false;
}
}
public virtual void SetEventTopic(string key, Topic topic)
{
// Don't call AddEvent since that's virtual
AddEventCore(key);
}
public virtual bool AddEvent(string key, Topic topic)
{
return AddEventCore(key);
}
private static ulong GetMessageId(Topic topic)
{
if (topic == null)
{
return 0;
}
return topic.Store.GetMessageCount();
}
public override void SetEventTopic(string eventKey, Topic topic)
{
base.SetEventTopic(eventKey, topic);
lock (_cursors)
{
// O(n), but small n and it's not common
var index = FindCursorIndex(eventKey);
if (index != -1)
{
_cursorTopics[index] = topic;
}
}
}
private void DestroyTopicCore(string key, Topic topic)
{
Topics.TryRemove(key);
_stringMinifier.RemoveUnminified(key);
Counters.MessageBusTopicsCurrent.Decrement();
_logger.LogInformation("RemoveTopic(" + key + ")");
if (AfterTopicGarbageCollected != null)
{
AfterTopicGarbageCollected(key, topic);
}
}
private void DestroyTopic(string key, Topic topic)
{
// The goal of this function is to destroy topics after 2 garbage collect cycles
// This first if statement will transition a topic into the dying state on the first GC cycle
// but it will prevent the code path from hitting the second if statement
if (Interlocked.CompareExchange(ref topic.State, TopicState.Dying, TopicState.NoSubscriptions) == TopicState.Dying)
{
// If we've hit this if statement we're on the second GC cycle with this soon to be
// destroyed topic. At this point we move the Topic State into the Dead state as
// long as it has not been revived from the dying state. We check if the state is
// still dying again to ensure that the topic has not been transitioned into a new
// state since we've decided to destroy it.
if (Interlocked.CompareExchange(ref topic.State, TopicState.Dead, TopicState.Dying) == TopicState.Dying)
{
DestroyTopicCore(key, topic);
}
}
}
private void ScheduleTopic(Topic topic)
{
try
{
topic.SubscriptionLock.EnterReadLock();
for (int i = 0; i < topic.Subscriptions.Count; i++)
{
ISubscription subscription = topic.Subscriptions[i];
_broker.Schedule(subscription);
}
}
finally
{
topic.SubscriptionLock.ExitReadLock();
}
}
