private void PushLevel(bool permitIntraLevel)
{
Stack <LeveledLock> currentLevelStack;
try
{
currentLevelStack = Thread.GetData(LockLevelTlsSlot) as Stack <LeveledLock>;
}
catch (Exception)
{
return;
}
if (currentLevelStack is null)
{
// We've never accessed the TLS data yet; construct a new Stack for our levels
// and stash it away in TLS.
currentLevelStack = new Stack <LeveledLock>();
Thread.SetData(LockLevelTlsSlot, currentLevelStack);
}
else if (currentLevelStack.Count > 0)
{
// If the stack in TLS already recorded a lock, validate that we are not violating
// the locking protocol. A violation occurs when our lock is higher level than the
// current lock, or equal to the level (when the reentrant bit has not been set on
// at least one of the locks involved).
LeveledLock currentLock = currentLevelStack.Peek();
int currentLevel = currentLock._level;
if (_level > currentLevel ||
(ReferenceEquals(currentLock, this) && !_reentrant) ||
(!ReferenceEquals(currentLock, this) && _level == currentLevel && !permitIntraLevel))
{
throw new LockLevelException(currentLock, this);
}
}
// If we reached here, we are OK to proceed with locking. Stash the current level in TLS.
currentLevelStack.Push(this);
}
public LockLevelException(LeveledLock currentLock, LeveledLock newLock) :
base(string.Format("You attempted to violate the locking protocol by acquiring lock {0} " +
"while the thread already owns lock {1}.", newLock, currentLock))
{
}
internal LeveledLockCookie(LeveledLock lck)
{
_lck = lck;
}