public static SafeWaitHandle?CreateNamedMutex(bool initiallyOwned, string name, out bool createdNew)
{
// For initially owned, newly created named mutexes, there is a potential race
// between adding the mutex to the named object table and initially acquiring it.
// To avoid the possibility of another thread retrieving the mutex via its name
// before we managed to acquire it, we perform both steps while holding s_lock.
LockHolder lockHolder = new LockHolder(s_lock);
try
{
WaitableObject?waitableObject = WaitableObject.CreateNamedMutex_Locked(name, out createdNew);
if (waitableObject == null)
{
return(null);
}
SafeWaitHandle safeWaitHandle = NewHandle(waitableObject);
if (!initiallyOwned || !createdNew)
{
return(safeWaitHandle);
}
// Acquire the mutex. A thread's <see cref="ThreadWaitInfo"/> has a reference to all <see cref="Mutex"/>es locked
// by the thread. See <see cref="ThreadWaitInfo.LockedMutexesHead"/>. So, acquire the lock only after all
// possibilities for exceptions have been exhausted.
ThreadWaitInfo waitInfo = Thread.CurrentThread.WaitInfo;
int status = waitableObject.Wait_Locked(waitInfo, timeoutMilliseconds: 0, interruptible: false, prioritize: false, ref lockHolder);
Debug.Assert(status == 0);
return(safeWaitHandle);
}
finally
{
lockHolder.Dispose();
}
}
public int SignalSemaphore(int count, ref LockHolder lockHolder)
{
s_lock.VerifyIsLocked();
Debug.Assert(count > 0);
if (!IsSemaphore)
{
lockHolder.Dispose();
WaitHandle.ThrowInvalidHandleException();
}
int oldSignalCount = _signalCount;
Debug.Assert(oldSignalCount <= _maximumSignalCount);
if (count > _maximumSignalCount - oldSignalCount)
{
lockHolder.Dispose();
throw new SemaphoreFullException();
}
if (oldSignalCount != 0)
{
_signalCount = oldSignalCount + count;
return(oldSignalCount);
}
for (ThreadWaitInfo.WaitedListNode?waiterNode = _waitersHead, nextWaiterNode;
waiterNode != null;
waiterNode = nextWaiterNode)
{
// Signaling the waiter will unregister the waiter node, so keep the next node before trying
nextWaiterNode = waiterNode.NextThread;
if (waiterNode.WaitInfo.TrySignalToSatisfyWait(waiterNode, isAbandonedMutex: false) && --count == 0)
{
return(oldSignalCount);
}
}
_signalCount = count;
return(oldSignalCount);
}
public void SignalMutex(ref LockHolder lockHolder)
{
s_lock.VerifyIsLocked();
if (!IsMutex)
{
lockHolder.Dispose();
WaitHandle.ThrowInvalidHandleException();
}
if (IsSignaled || _ownershipInfo !.Thread != Thread.CurrentThread)
{
lockHolder.Dispose();
throw new ApplicationException(SR.Arg_SynchronizationLockException);
}
if (!_ownershipInfo !.TryDecrementReacquireCount())
{
SignalMutex(isAbandoned: false);
}
}
public static int SignalAndWait(
WaitableObject waitableObjectToSignal,
WaitableObject waitableObjectToWaitOn,
int timeoutMilliseconds,
bool interruptible = true,
bool prioritize = false)
{
Debug.Assert(waitableObjectToSignal != null);
Debug.Assert(waitableObjectToWaitOn != null);
Debug.Assert(timeoutMilliseconds >= -1);
ThreadWaitInfo waitInfo = Thread.CurrentThread.WaitInfo;
LockHolder lockHolder = new LockHolder(s_lock);
try
{
// A pending interrupt does not signal the specified handle
if (interruptible && waitInfo.CheckAndResetPendingInterrupt)
{
lockHolder.Dispose();
throw new ThreadInterruptedException();
}
try
{
waitableObjectToSignal.Signal(1, ref lockHolder);
}
catch (SemaphoreFullException ex)
{
s_lock.VerifyIsNotLocked();
throw new InvalidOperationException(SR.Threading_WaitHandleTooManyPosts, ex);
}
return(waitableObjectToWaitOn.Wait_Locked(waitInfo, timeoutMilliseconds, interruptible, prioritize, ref lockHolder));
}
finally
{
lockHolder.Dispose();
}
}
public static void ReleaseMutex(WaitableObject waitableObject)
{
Debug.Assert(waitableObject != null);
LockHolder lockHolder = new LockHolder(s_lock);
try
{
waitableObject.SignalMutex(ref lockHolder);
}
finally
{
lockHolder.Dispose();
}
}
public static void ResetEvent(WaitableObject waitableObject)
{
Debug.Assert(waitableObject != null);
LockHolder lockHolder = new LockHolder(s_lock);
try
{
waitableObject.UnsignalEvent(ref lockHolder);
}
finally
{
lockHolder.Dispose();
}
}
public void UnsignalEvent(ref LockHolder lockHolder)
{
s_lock.VerifyIsLocked();
if (!IsEvent)
{
lockHolder.Dispose();
WaitHandle.ThrowInvalidHandleException();
}
if (IsSignaled)
{
--_signalCount;
}
}
public int Wait(ThreadWaitInfo waitInfo, int timeoutMilliseconds, bool interruptible, bool prioritize)
{
Debug.Assert(waitInfo != null);
Debug.Assert(waitInfo.Thread == Thread.CurrentThread);
Debug.Assert(timeoutMilliseconds >= -1);
var lockHolder = new LockHolder(s_lock);
try
{
if (interruptible && waitInfo.CheckAndResetPendingInterrupt)
{
lockHolder.Dispose();
throw new ThreadInterruptedException();
}
return(Wait_Locked(waitInfo, timeoutMilliseconds, interruptible, prioritize, ref lockHolder));
}
finally
{
lockHolder.Dispose();
}
}
public static int ReleaseSemaphore(WaitableObject waitableObject, int count)
{
Debug.Assert(waitableObject != null);
Debug.Assert(count > 0);
LockHolder lockHolder = new LockHolder(s_lock);
try
{
return(waitableObject.SignalSemaphore(count, ref lockHolder));
}
finally
{
lockHolder.Dispose();
}
}
/// <summary>
/// This function does not check for a pending thread interrupt. Callers are expected to do that soon after
/// acquiring <see cref="s_lock"/>.
/// </summary>
public int Wait_Locked(ThreadWaitInfo waitInfo, int timeoutMilliseconds, bool interruptible, bool prioritize, ref LockHolder lockHolder)
{
s_lock.VerifyIsLocked();
Debug.Assert(waitInfo != null);
Debug.Assert(waitInfo.Thread == Thread.CurrentThread);
Debug.Assert(timeoutMilliseconds >= -1);
Debug.Assert(!interruptible || !waitInfo.CheckAndResetPendingInterrupt);
if (IsSignaled)
{
bool isAbandoned = IsAbandonedMutex;
AcceptSignal(waitInfo);
return(isAbandoned ? WaitHandle.WaitAbandoned : WaitHandle.WaitSuccess);
}
if (IsMutex && _ownershipInfo != null && _ownershipInfo.Thread == waitInfo.Thread)
{
if (!_ownershipInfo.CanIncrementReacquireCount)
{
lockHolder.Dispose();
throw new OverflowException(SR.Overflow_MutexReacquireCount);
}
_ownershipInfo.IncrementReacquireCount();
return(WaitHandle.WaitSuccess);
}
if (timeoutMilliseconds == 0)
{
return(WaitHandle.WaitTimeout);
}
WaitableObject?[] waitableObjects = waitInfo.GetWaitedObjectArray(1);
waitableObjects[0] = this;
waitInfo.RegisterWait(1, prioritize, isWaitForAll: false);
return
(waitInfo.Wait(
timeoutMilliseconds,
interruptible,
isSleep: false,
ref lockHolder));
}
public void SignalEvent(ref LockHolder lockHolder)
{
s_lock.VerifyIsLocked();
switch (_type)
{
case WaitableObjectType.ManualResetEvent:
SignalManualResetEvent();
break;
case WaitableObjectType.AutoResetEvent:
SignalAutoResetEvent();
break;
default:
lockHolder.Dispose();
WaitHandle.ThrowInvalidHandleException();
break;
}
}
public static int Wait(
WaitableObject?[]?waitableObjects,
int count,
bool waitForAll,
ThreadWaitInfo waitInfo,
int timeoutMilliseconds,
bool interruptible,
bool prioritize)
{
s_lock.VerifyIsNotLocked();
Debug.Assert(waitInfo != null);
Debug.Assert(waitInfo.Thread == Thread.CurrentThread);
Debug.Assert(waitableObjects != null);
Debug.Assert(waitableObjects.Length >= count);
Debug.Assert(count > 1);
Debug.Assert(timeoutMilliseconds >= -1);
var lockHolder = new LockHolder(s_lock);
try
{
if (interruptible && waitInfo.CheckAndResetPendingInterrupt)
{
lockHolder.Dispose();
throw new ThreadInterruptedException();
}
if (!waitForAll)
{
// Check if any is already signaled
for (int i = 0; i < count; ++i)
{
WaitableObject waitableObject = waitableObjects[i] !;
Debug.Assert(waitableObject != null);
if (waitableObject.IsSignaled)
{
bool isAbandoned = waitableObject.IsAbandonedMutex;
waitableObject.AcceptSignal(waitInfo);
if (isAbandoned)
{
return(WaitHandle.WaitAbandoned + i);
}
return(WaitHandle.WaitSuccess + i);
}
if (waitableObject.IsMutex)
{
OwnershipInfo ownershipInfo = waitableObject._ownershipInfo !;
if (ownershipInfo.Thread == waitInfo.Thread)
{
if (!ownershipInfo.CanIncrementReacquireCount)
{
lockHolder.Dispose();
throw new OverflowException(SR.Overflow_MutexReacquireCount);
}
ownershipInfo.IncrementReacquireCount();
return(WaitHandle.WaitSuccess + i);
}
}
}
}
else
{
// Check if all are already signaled
bool areAllSignaled = true;
bool isAnyAbandonedMutex = false;
for (int i = 0; i < count; ++i)
{
WaitableObject waitableObject = waitableObjects[i] !;
Debug.Assert(waitableObject != null);
if (waitableObject.IsSignaled)
{
if (!isAnyAbandonedMutex && waitableObject.IsAbandonedMutex)
{
isAnyAbandonedMutex = true;
}
continue;
}
if (waitableObject.IsMutex)
{
OwnershipInfo ownershipInfo = waitableObject._ownershipInfo !;
if (ownershipInfo.Thread == waitInfo.Thread)
{
if (!ownershipInfo.CanIncrementReacquireCount)
{
lockHolder.Dispose();
throw new OverflowException(SR.Overflow_MutexReacquireCount);
}
continue;
}
}
areAllSignaled = false;
break;
}
if (areAllSignaled)
{
for (int i = 0; i < count; ++i)
{
WaitableObject waitableObject = waitableObjects[i] !;
if (waitableObject.IsSignaled)
{
waitableObject.AcceptSignal(waitInfo);
continue;
}
Debug.Assert(waitableObject.IsMutex);
OwnershipInfo ownershipInfo = waitableObject._ownershipInfo !;
Debug.Assert(ownershipInfo.Thread == waitInfo.Thread);
ownershipInfo.IncrementReacquireCount();
}
if (isAnyAbandonedMutex)
{
lockHolder.Dispose();
throw new AbandonedMutexException();
}
return(WaitHandle.WaitSuccess);
}
}
if (timeoutMilliseconds == 0)
{
return(WaitHandle.WaitTimeout);
}
waitableObjects = null; // no need to clear this anymore, RegisterWait / Wait will take over from here
waitInfo.RegisterWait(count, prioritize, waitForAll);
return(waitInfo.Wait(timeoutMilliseconds, interruptible, isSleep: false, ref lockHolder));
}
finally
{
lockHolder.Dispose();
if (waitableObjects != null)
{
for (int i = 0; i < count; ++i)
{
waitableObjects[i] = null;
}
}
}
}
public int Wait(int timeoutMilliseconds, bool interruptible, bool isSleep, ref LockHolder lockHolder)
{
if (isSleep)
{
s_lock.VerifyIsNotLocked();
}
else
{
s_lock.VerifyIsLocked();
}
Debug.Assert(_thread == Thread.CurrentThread);
Debug.Assert(timeoutMilliseconds >= -1);
Debug.Assert(timeoutMilliseconds != 0); // caller should have taken care of it
_thread.SetWaitSleepJoinState();
// <see cref="_waitMonitor"/> must be acquired before <see cref="s_lock"/> is released, to ensure that there is
// no gap during which a waited object may be signaled to satisfy the wait but the thread may not yet be in a
// wait state to accept the signal
_waitMonitor.Acquire();
if (!isSleep)
{
lockHolder.Dispose();
}
Debug.Assert(_waitedObjectIndexThatSatisfiedWait < 0);
Debug.Assert(_waitSignalState == WaitSignalState.NotWaiting);
// A signaled state may be set only when the thread is in one of the following states
_waitSignalState = interruptible ? WaitSignalState.Waiting_Interruptible : WaitSignalState.Waiting;
try
{
if (isSleep && interruptible && CheckAndResetPendingInterrupt)
{
throw new ThreadInterruptedException();
}
if (timeoutMilliseconds < 0)
{
do
{
_waitMonitor.Wait();
} while (IsWaiting);
int waitResult = ProcessSignaledWaitState();
Debug.Assert(waitResult != WaitHandle.WaitTimeout);
return(waitResult);
}
int elapsedMilliseconds = 0;
int startTimeMilliseconds = Environment.TickCount;
while (true)
{
bool monitorWaitResult = _waitMonitor.Wait(timeoutMilliseconds - elapsedMilliseconds);
// It's possible for the wait to have timed out, but before the monitor could reacquire the lock, a
// signaler could have acquired it and signaled to satisfy the wait or interrupt the thread. Accept the
// signal and ignore the wait timeout.
int waitResult = ProcessSignaledWaitState();
if (waitResult != WaitHandle.WaitTimeout)
{
return(waitResult);
}
if (monitorWaitResult)
{
elapsedMilliseconds = Environment.TickCount - startTimeMilliseconds;
if (elapsedMilliseconds < timeoutMilliseconds)
{
continue;
}
}
// Timeout
Debug.Assert(_waitedObjectIndexThatSatisfiedWait < 0);
break;
}
}
finally
{
_waitSignalState = WaitSignalState.NotWaiting;
_waitMonitor.Release();
_thread.ClearWaitSleepJoinState();
}
// Timeout. It's ok to read <see cref="_waitedCount"/> without acquiring <see cref="s_lock"/> here, because it
// is initially set by this thread, and another thread cannot unregister this thread's wait without first
// signaling this thread, in which case this thread wouldn't be timing out.
Debug.Assert(isSleep == (_waitedCount == 0));
if (!isSleep)
{
s_lock.Acquire();
UnregisterWait();
s_lock.Release();
}
return(WaitHandle.WaitTimeout);
}
