public bool CanExecute(PatternState state)
{
TraceItem trace = state.Trace.OnCanExecute(this);
bool result = OnCanExecute(state);
trace.Update(result);
return(result);
}
private TraceItem StartTrace(TraceKind kind, PatternElement source)
{
TraceItem traceElement = new TraceItem
{
Kind = kind,
PatternElement = source,
State = TraceState.InProgress
};
Items.Add(traceElement);
if (!Tally.TryGetValue(source, out TallyEntry entry))
{
entry = new TallyEntry
{
LastPosition = 0,
Count = 0
};
Tally.Add(source, entry);
}
if (entry.LastPosition != State.Enumerator.Index)
{
entry.Count = 0;
entry.LastPosition = State.Enumerator.Index;
}
entry.Count++;
if (entry.Count > CycleThreshold)
{
throw new Exception("Possible cycle detected!");
}
return(traceElement);
}
