private bool TryGetConnection(DbConnection owningObject, uint waitForMultipleObjectsTimeout, bool allowCreate, bool onlyOneCheckConnection, DbConnectionOptions userOptions, out DbConnectionInternal connection)
{
DbConnectionInternal obj = null;
if (null == obj)
{
Interlocked.Increment(ref _waitCount);
do
{
int waitResult = BOGUS_HANDLE;
try
{
try
{
}
finally
{
waitResult = WaitHandle.WaitAny(_waitHandles.GetHandles(allowCreate), unchecked ((int)waitForMultipleObjectsTimeout));
}
// From the WaitAny docs: "If more than one object became signaled during
// the call, this is the array index of the signaled object with the
// smallest index value of all the signaled objects." This is important
// so that the free object signal will be returned before a creation
// signal.
switch (waitResult)
{
case WaitHandle.WaitTimeout:
Interlocked.Decrement(ref _waitCount);
connection = null;
return(false);
case ERROR_HANDLE:
// Throw the error that PoolCreateRequest stashed.
Interlocked.Decrement(ref _waitCount);
throw TryCloneCachedException();
case CREATION_HANDLE:
try
{
obj = UserCreateRequest(owningObject, userOptions);
}
catch
{
if (null == obj)
{
Interlocked.Decrement(ref _waitCount);
}
throw;
}
finally
{
// Ensure that we release this waiter, regardless
// of any exceptions that may be thrown.
if (null != obj)
{
Interlocked.Decrement(ref _waitCount);
}
}
if (null == obj)
{
// If we were not able to create an object, check to see if
// we reached MaxPoolSize. If so, we will no longer wait on
// the CreationHandle, but instead wait for a free object or
// the timeout.
if (Count >= MaxPoolSize && 0 != MaxPoolSize)
{
if (!ReclaimEmancipatedObjects())
{
// modify handle array not to wait on creation mutex anymore
Debug.Assert(2 == CREATION_HANDLE, "creation handle changed value");
allowCreate = false;
}
}
}
break;
case SEMAPHORE_HANDLE:
//
// guaranteed available inventory
//
Interlocked.Decrement(ref _waitCount);
obj = GetFromGeneralPool();
if ((obj != null) && (!obj.IsConnectionAlive()))
{
DestroyObject(obj);
obj = null; // Setting to null in case creating a new object fails
if (onlyOneCheckConnection)
{
if (_waitHandles.CreationSemaphore.WaitOne(unchecked ((int)waitForMultipleObjectsTimeout)))
{
try
{
obj = UserCreateRequest(owningObject, userOptions);
}
finally
{
_waitHandles.CreationSemaphore.Release(1);
}
}
else
{
// Timeout waiting for creation semaphore - return null
connection = null;
return(false);
}
}
}
break;
default:
Interlocked.Decrement(ref _waitCount);
throw ADP.InternalError(ADP.InternalErrorCode.UnexpectedWaitAnyResult);
}
}
finally
{
if (CREATION_HANDLE == waitResult)
{
_waitHandles.CreationSemaphore.Release(1);
}
}
} while (null == obj);
}
if (null != obj)
{
PrepareConnection(owningObject, obj);
}
connection = obj;
return(true);
}
private bool TryGetConnection(DbConnection owningObject, int waitForMultipleObjectsTimeout, bool allowCreate, bool onlyOneCheckConnection, DbConnectionOptions userOptions, out DbConnectionInternal connection)
{
DbConnectionInternal obj = null;
if (null == obj)
{
Interlocked.Increment(ref _waitCount);
do
{
int waitResult = WaitHandle.WaitTimeout;
try
{
if (!allowCreate)
{
if (_waitHandles.PoolSemaphore.Wait(waitForMultipleObjectsTimeout))
{
waitResult = SEMAPHORE_HANDLE;
}
else
{
waitResult = WaitHandle.WaitTimeout;
}
}
else
{
bool obtainedPoolSemaphore = false;
DateTime start = DateTime.UtcNow;
do
{
waitResult = WaitHandle.WaitAny(_waitHandles.Handles, waitForMultipleObjectsTimeout);
// Obtaining the WaitHandle for a SemaphoreSlim doesn't actually take one from the count
// So we need to wait on the SemaphoreSlim seperately
if (waitResult == SEMAPHORE_HANDLE)
{
if (_waitHandles.PoolSemaphore.Wait(TimeSpan.Zero))
{
obtainedPoolSemaphore = true;
}
else
{
DateTime currentTime = DateTime.UtcNow;
waitForMultipleObjectsTimeout -= (currentTime - start).Milliseconds;
}
}
} while ((waitResult == SEMAPHORE_HANDLE) && !obtainedPoolSemaphore);
}
// From the WaitAny docs: "If more than one object became signaled during
// the call, this is the array index of the signaled object with the
// smallest index value of all the signaled objects." This is important
// so that the free object signal will be returned before a creation
// signal.
switch (waitResult)
{
case WaitHandle.WaitTimeout:
Interlocked.Decrement(ref _waitCount);
connection = null;
return(false);
case CREATION_HANDLE:
try
{
obj = UserCreateRequest(owningObject, userOptions);
}
catch
{
if (null == obj)
{
Interlocked.Decrement(ref _waitCount);
}
throw;
}
finally
{
// Ensure that we release this waiter, regardless
// of any exceptions that may be thrown.
if (null != obj)
{
Interlocked.Decrement(ref _waitCount);
}
}
if (null == obj)
{
// If we were not able to create an object, check to see if
// we reached MaxPoolSize. If so, we will no longer wait on
// the CreationHandle, but instead wait for a free object or
// the timeout.
if (Count >= MaxPoolSize && 0 != MaxPoolSize)
{
if (!ReclaimEmancipatedObjects())
{
// modify handle array not to wait on creation mutex anymore
allowCreate = false;
}
}
}
break;
case SEMAPHORE_HANDLE:
//
// guaranteed available inventory
//
Interlocked.Decrement(ref _waitCount);
obj = GetFromGeneralPool();
if ((obj != null) && (!obj.IsConnectionAlive()))
{
DestroyObject(obj);
obj = null; // Setting to null in case creating a new object fails
if (onlyOneCheckConnection)
{
if (_waitHandles.CreationSemaphore.WaitOne(unchecked ((int)waitForMultipleObjectsTimeout)))
{
try
{
obj = UserCreateRequest(owningObject, userOptions);
}
finally
{
_waitHandles.CreationSemaphore.Release(1);
}
}
else
{
// Timeout waiting for creation semaphore - return null
connection = null;
return(false);
}
}
}
break;
default:
Interlocked.Decrement(ref _waitCount);
throw ADP.InternalError(ADP.InternalErrorCode.UnexpectedWaitAnyResult);
}
}
finally
{
if (CREATION_HANDLE == waitResult)
{
_waitHandles.CreationSemaphore.Release();
}
}
} while (null == obj);
}
if (null != obj)
{
PrepareConnection(owningObject, obj);
}
connection = obj;
return(true);
}
