/// <summary>
/// Unregisters this wait handle registration from the wait threads.
/// </summary>
/// <param name="waitObject">The event to signal when the handle is unregistered.</param>
/// <returns>If the handle was successfully marked to be removed and the provided wait handle was set as the user provided event.</returns>
/// <remarks>
/// This method will only return true on the first call.
/// Passing in a wait handle with a value of -1 will result in a blocking wait, where Unregister will not return until the full unregistration is completed.
/// </remarks>
public bool Unregister(WaitHandle?waitObject)
{
GC.SuppressFinalize(this);
_callbackLock.Acquire();
bool needToRollBackRefCountOnException = false;
try
{
if (_unregisterCalled)
{
return(false);
}
UserUnregisterWaitHandle = waitObject?.SafeWaitHandle;
UserUnregisterWaitHandle?.DangerousAddRef(ref needToRollBackRefCountOnException);
UserUnregisterWaitHandleValue = UserUnregisterWaitHandle?.DangerousGetHandle() ?? IntPtr.Zero;
if (_unregistered)
{
SignalUserWaitHandle();
return(true);
}
if (IsBlocking)
{
_callbacksComplete = RentEvent();
}
else
{
_removed = RentEvent();
}
_unregisterCalled = true;
}
catch (Exception) // Rollback state on exception
{
if (_removed != null)
{
ReturnEvent(_removed);
_removed = null;
}
else if (_callbacksComplete != null)
{
ReturnEvent(_callbacksComplete);
_callbacksComplete = null;
}
UserUnregisterWaitHandleValue = IntPtr.Zero;
if (needToRollBackRefCountOnException)
{
UserUnregisterWaitHandle?.DangerousRelease();
}
UserUnregisterWaitHandle = null;
throw;
}
finally
{
_callbackLock.Release();
}
WaitThread !.UnregisterWait(this);
return(true);
}
public bool Unregister(WaitHandle waitObject)
{
// The registered wait handle must have been registered by this time, otherwise the instance is not handed out to
// the caller of the public variants of RegisterWaitForSingleObject
Debug.Assert(WaitThread != null);
s_callbackLock.Acquire();
bool needToRollBackRefCountOnException = false;
try
{
if (_unregisterCalled)
{
return(false);
}
UserUnregisterWaitHandle = waitObject?.SafeWaitHandle;
UserUnregisterWaitHandle?.DangerousAddRef(ref needToRollBackRefCountOnException);
UserUnregisterWaitHandleValue = UserUnregisterWaitHandle?.DangerousGetHandle() ?? IntPtr.Zero;
if (_unregistered)
{
SignalUserWaitHandle();
return(true);
}
if (IsBlocking)
{
_callbacksComplete = RentEvent();
}
else
{
_removed = RentEvent();
}
}
catch (Exception) // Rollback state on exception
{
if (_removed != null)
{
ReturnEvent(_removed);
_removed = null;
}
else if (_callbacksComplete != null)
{
ReturnEvent(_callbacksComplete);
_callbacksComplete = null;
}
UserUnregisterWaitHandleValue = IntPtr.Zero;
if (needToRollBackRefCountOnException)
{
UserUnregisterWaitHandle?.DangerousRelease();
}
UserUnregisterWaitHandle = null;
throw;
}
finally
{
_unregisterCalled = true;
s_callbackLock.Release();
}
WaitThread !.UnregisterWait(this);
return(true);
}
