private void ExtractValuesFromGetItemResult(GetItemResult result, out SessionStateStoreData rqItem,
out bool locked, out TimeSpan lockAge, out object rqLockId, out SessionStateActions rqActionFlags)
{
rqItem = result.Item;
locked = result.Locked;
lockAge = result.LockAge;
rqLockId = result.LockId;
rqActionFlags = result.Actions;
}
private Task <GetItemResult> DoGetAsync(HttpContextBase context, string id, bool exclusive)
{
bool locked;
TimeSpan lockAge;
object lockId;
SessionStateActions actionFlags;
var item = DoGet(context, id, exclusive, out locked, out lockAge, out lockId, out actionFlags);
GetItemResult result = new GetItemResult(item, locked, lockAge, lockId, actionFlags);
return(Task.FromResult <GetItemResult>(result));
}
private async Task LockSessionStateItemAsync()
{
Debug.Assert(_rqId != null, "_rqId != null");
if (!_rqReadonly)
{
GetItemResult result = await _store.GetItemExclusiveAsync(_rqContext, _rqId, GetCancellationToken());
SessionStateStoreData storedItem;
bool locked;
TimeSpan lockAge;
Debug.Assert(result != null, "Must succeed in retrieving item from the store through _rqId");
ExtractValuesFromGetItemResult(result, out storedItem, out locked, out lockAge, out _rqLockId,
out _rqActionFlags);
Debug.Assert(storedItem != null, "Must succeed in locking session state item.");
}
}
private async Task GetSessionStateItemAsync()
{
bool isCompleted = false;
bool isQueued = false;
try
{
while (!isCompleted)
{
isCompleted = true;
bool locked = false;
TimeSpan lockAge = default(TimeSpan);
Debug.Assert(_rqId != null, "_rqId != null");
if (_rqReadonly || AppSettings.AllowConcurrentRequestsPerSession)
{
GetItemResult result = await _store.GetItemAsync(_rqContext, _rqId, GetCancellationToken());
if (result != null)
{
ExtractValuesFromGetItemResult(result, out _rqItem, out locked, out lockAge, out _rqLockId,
out _rqActionFlags);
}
}
else
{
GetItemResult result = await _store.GetItemExclusiveAsync(_rqContext, _rqId, GetCancellationToken());
if (result != null)
{
ExtractValuesFromGetItemResult(result, out _rqItem, out locked, out lockAge, out _rqLockId,
out _rqActionFlags);
}
// WebForm and WebService Session Access Concurrency Issue
// If we have an expired session, we need to insert the state in the store here to
// ensure serialized access in case more than one entity requests it simultaneously.
// If the state has already been created before, CreateUninitializedSessionState is a no-op.
if (_rqItem == null && locked == false && _rqId != null)
{
if (!(ConfigCookieless == HttpCookieMode.UseUri && s_configRegenerateExpiredSessionId))
{
await _store.CreateUninitializedItemAsync(_rqContext, _rqId, s_timeout, GetCancellationToken());
GetItemResult getItemResult =
await _store.GetItemExclusiveAsync(_rqContext, _rqId, GetCancellationToken());
if (getItemResult != null)
{
ExtractValuesFromGetItemResult(getItemResult, out _rqItem, out locked, out lockAge,
out _rqLockId, out _rqActionFlags);
}
}
}
}
// We didn't get it because it's locked....
if (_rqItem == null && locked)
{
if (!isQueued)
{
QueueRef();
isQueued = true;
}
if (lockAge >= _rqExecutionTimeout)
{
/* Release the lock on the item, which is held by another thread*/
await _store.ReleaseItemExclusiveAsync(_rqContext, _rqId, _rqLockId, GetCancellationToken());
}
isCompleted = false;
}
if (!isCompleted)
{
await Task.Delay(s_pollingTimespan);
}
}
}
finally
{
if (isQueued)
{
DequeRef();
}
}
}