|
public static CompareExchange ( |
||
| location | ||
| value | ||
| comparand | ||
| return | ||
public void EnterWriteLock()
{
ClientSpinWait sw = new ClientSpinWait();
do
{
int state = rwlock;
if (state < RwWrite)
{
if (ClientInterlocked.CompareExchange(ref rwlock, RwWrite, state) == state)
{
return;
}
state = rwlock;
}
// We register our interest in taking the Write lock (if upgradeable it's already done)
while ((state & RwWait) == 0 && ClientInterlocked.CompareExchange(ref rwlock, state | RwWait, state) != state)
{
state = rwlock;
}
// Before falling to sleep
while (rwlock > RwWait)
{
sw.SpinOnce();
}
} while (true);
}
public void Enter(ref bool lockTaken)
{
if (lockTaken)
{
throw new ArgumentException("lockTaken", "lockTaken must be initialized to false");
}
if (isThreadOwnerTrackingEnabled && IsHeldByCurrentThread)
{
throw new LockRecursionException();
}
int slot = -1;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
slot = ClientInterlocked.Increment(ref ticket.Users) - 1;
ClientSpinWait wait = new ClientSpinWait();
while (slot != ticket.Value)
{
wait.SpinOnce();
while (stallTickets != null && ((ClientConcurrentOrderedList <int>)stallTickets).TryRemove(ticket.Value))
{
++ticket.Value;
}
}
}
finally
{
if (slot == ticket.Value)
{
lockTaken = true;
threadWhoTookLock = Thread.CurrentThread.ManagedThreadId;
}
else if (slot != -1)
{
// We have been interrupted, initialize stallTickets
if (stallTickets == null)
{
ClientInterlocked.CompareExchange(ref stallTickets, new ClientConcurrentOrderedList <int>(), null);
}
((ClientConcurrentOrderedList <int>)stallTickets).TryAdd(slot);
}
}
}
public void TryEnter(int millisecondsTimeout, ref bool lockTaken)
{
if (millisecondsTimeout < -1)
{
throw new ArgumentOutOfRangeException("milliSeconds", "millisecondsTimeout is a negative number other than -1");
}
if (lockTaken)
{
throw new ArgumentException("lockTaken", "lockTaken must be initialized to false");
}
if (isThreadOwnerTrackingEnabled && IsHeldByCurrentThread)
{
throw new LockRecursionException();
}
long start = millisecondsTimeout == -1 ? 0 : sw.ElapsedMilliseconds;
bool stop = false;
do
{
while (stallTickets != null && ((ClientConcurrentOrderedList <int>)stallTickets).TryRemove(ticket.Value))
{
++ticket.Value;
}
long u = ticket.Users;
long totalValue = (u << 32) | u;
long newTotalValue
= BitConverter.IsLittleEndian ? (u << 32) | (u + 1) : ((u + 1) << 32) | u;
RuntimeHelpers.PrepareConstrainedRegions();
try { }
finally
{
lockTaken = ClientInterlocked.CompareExchange(ref ticket.TotalValue, newTotalValue, totalValue) == totalValue;
if (lockTaken)
{
threadWhoTookLock = Thread.CurrentThread.ManagedThreadId;
stop = true;
}
}
} while (!stop && (millisecondsTimeout == -1 || (sw.ElapsedMilliseconds - start) < millisecondsTimeout));
}
