/// <summary>
/// Tries to add the specified event to the storage.
/// The storage may refuse to store certain events
/// (e.g. multiple <see cref="ShuttingDownEvent"/>s).
/// </summary>
/// <param name="evnt">The event to enqueue.</param>
/// <returns><c>true</c> if the event was added to the storage; otherwise, <c>false</c>.</returns>
public bool TryPush(EventBase evnt)
{
if (evnt.NullReference())
{
throw Exc.Null(nameof(evnt));
}
lock (this.syncLock)
{
this.events.Add(evnt);
return(true);
}
}
/// <summary>
/// Finds applicable subscribers, and has them handle the specified event, on the current thread.
/// </summary>
/// <param name="evnt">The event to handle.</param>
/// <param name="exceptions">Stores exceptions throws by event handlers.</param>
protected internal void Handle(EventBase evnt, List <Exception> exceptions)
{
if (evnt.NullReference())
{
throw Exc.Null(nameof(evnt));
}
if (exceptions.NullReference())
{
throw Exc.Null(nameof(exceptions));
}
lock (this.syncLock)
{
var eventTypeInfo = evnt.GetType().GetTypeInfo();
for (int i = 0; i < this.subscribers.Count;)
{
var wrapper = this.subscribers[i];
if (EventBase.CanHandle(wrapper.EventHandlerEventTypeInfo, eventTypeInfo))
{
bool referenceFound = true;
try
{
wrapper.Handle(evnt, out referenceFound);
}
catch (Exception ex)
{
exceptions.Add(ex);
}
if (referenceFound)
{
// event handled: continue
++i;
}
else
{
// GC already collected the event handler: remove wrapper and continue
this.subscribers.RemoveAt(i);
}
}
else
{
// event handler not compatible with event: continue
++i;
}
}
}
}
/// <summary>
/// Determines whether the specified event reference is stored.
/// </summary>
/// <param name="evnt">The event to search for within the storage.</param>
/// <returns><c>true</c> if the specified event reference was found; otherwise, <c>false</c>.</returns>
public bool Contains(EventBase evnt)
{
if (evnt.NullReference())
{
return(false);
}
lock (this.syncLock)
{
bool found = false;
foreach (var e in this.events)
{
if (ReferenceEquals(e, evnt))
{
found = true;
break;
}
}
return(found);
}
}