/// <summary>
/// Допустимый ли переход состояний
/// </summary>
/// <param name="newState">Новое состояние</param>
/// <param name="oldState">Старое состояние</param>
/// <returns>Допустим переход</returns>
private static bool IsValidStateTransition(ThreadPoolWorkItemState newState, ThreadPoolWorkItemState oldState)
{
switch (oldState)
{
case ThreadPoolWorkItemState.Created:
return(newState == ThreadPoolWorkItemState.Started || newState == ThreadPoolWorkItemState.Cancelled);
case ThreadPoolWorkItemState.Started:
return(newState == ThreadPoolWorkItemState.Completed);
case ThreadPoolWorkItemState.Completed:
return(false);
case ThreadPoolWorkItemState.Cancelled:
return(false);
}
return(false);
}
private void UpdateState(ThreadPoolWorkItemState newState)
{
#if DEBUG
SpinWait sw = new SpinWait();
int curState = Volatile.Read(ref _state);
while (IsValidStateTransition(newState, (ThreadPoolWorkItemState)curState))
{
if (Interlocked.CompareExchange(ref _state, (int)newState, curState) == curState)
{
return;
}
sw.SpinOnce();
curState = Volatile.Read(ref _state);
}
throw new WrongStateException("Not allowed ThreadPoolWorkItem state change from '" + ((ThreadPoolWorkItemState)curState).ToString() + "' to '" + newState.ToString() + "'");
#endif
}
