private DBPooledObject GetFromPool(object owningObject)
{
DBPooledObject res = null;
res = (DBPooledObject)_stackNew.Pop();
if (res == null)
{
res = (DBPooledObject)_stackOld.Pop();
}
// Shouldn't be null, we could assert here.
Debug.Assert(res != null, "GetFromPool called with nothing in the pool!");
if (null != res)
{
res.PostPop(owningObject);
#if ALLOWTRACING
ADP.TraceObjectPoolActivity("GetFromGeneralPool", res);
#endif //ALLOWTRACING
}
return(res);
}
public DBPooledObject GetObject(object owningObject, out bool isInTransaction)
{
DBPooledObject obj = null;
isInTransaction = false;
if (_state != State.Running)
{
return(null);
}
// Try to get from the context if we're context specific:
obj = TryGetResourceFromContext(out isInTransaction);
if (null != obj)
{
obj.PostPop(owningObject);
}
else
{
#if USECOUNTEROBJECT
_poolCounter.Modify(cAddWait);
#else //!USECOUNTEROBJECT
Interlocked.Increment(ref _waitCount);
#endif //!USECOUNTEROBJECT
ObjectPoolWaitHandle[] localWaitHandles = _waitHandles;
while (obj == null)
{
int r = WaitHandle.WaitAny(localWaitHandles, PoolControl.CreationTimeout, false);
// 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 (r)
{
case WAIT_TIMEOUT:
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddWait);
#else //!USECOUNTEROBJECT
Interlocked.Decrement(ref _waitCount);
#endif //!USECOUNTEROBJECT
return(null);
case ERROR_HANDLE:
// Throw the error that PoolCreateRequest stashed.
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddWait);
#else //!USECOUNTEROBJECT
Interlocked.Decrement(ref _waitCount);
#endif //!USECOUNTEROBJECT
throw _resError;
case CREATION_HANDLE:
try {
obj = UserCreateRequest();
if (null != obj)
{
obj.PostPop(owningObject);
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddWait);
#else //!USECOUNTEROBJECT
Interlocked.Decrement(ref _waitCount);
#endif //!USECOUNTEROBJECT
}
else
{
// If we were not able to create an object, check to see if
// we reached MaxPool. If so, we will no longer wait on the
// CreationHandle, but instead wait for a free object or
// the timeout.
// BUG - if we receive the CreationHandle midway into the wait
// period and re-wait, we will be waiting on the full period
#if USECOUNTEROBJECT
if (_poolCounter.TotalCount == PoolControl.MaxPool)
{
#else //!USECOUNTEROBJECT
if (Count >= PoolControl.MaxPool)
{
#endif //!USECOUNTEROBJECT
if (!ReclaimEmancipatedObjects())
{
// modify handle array not to wait on creation mutex anymore
localWaitHandles = new ObjectPoolWaitHandle[2];
localWaitHandles[0] = _waitHandles[0];
localWaitHandles[1] = _waitHandles[1];
}
}
}
}
finally {
_creationMutex.ReleaseMutex();
}
break;
default:
//
// guaranteed available inventory
//
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddWait - cAddFree);
#else //!USECOUNTEROBJECT
Interlocked.Decrement(ref _waitCount);
#endif //!USECOUNTEROBJECT
obj = GetFromPool(owningObject);
break;
}
}
}
Debug.Assert(obj != null, "Failed to create pooled object, resulted in null instance.");
if (null != obj)
{
obj.Activate();
}
return(obj);
}