/// <summary>
/// Handle pending and active data requests. Call this function regularly from the background worker thread.
/// </summary>
static public void Update()
{
#if VERBOSE
if (PendingRequestCount > 0 || ActiveRequestCount > 0)
{
Log.Write(Log.Levels.Verbose, "DataStore: Update() : " + PendingRequestCount + " requests pending, " + ActiveRequestCount + " active.");
}
#endif
// clean out finished requests.
for (int i = 0; i < m_activeRequests.Count; i++)
{
DataRequestHTTP dr = m_activeRequests[i] as DataRequestHTTP;
if (dr.State != DataRequestState.InProcess)
{
#if VERBOSE
Log.Write(Log.Levels.Verbose, "DataStore: removing request " + dr.Source + " in state " + dr.State.ToString());
#endif
if (dr.State == DataRequestState.Finished && dr.RequestDescriptor.CompletionCallback != null)
{
#if VERBOSE
Log.Write(Log.Levels.Verbose, "DataStore: calling completion callback...");
#endif
dr.RequestDescriptor.CompletionCallback(dr);
}
else if (dr.State == DataRequestState.Error)
{
dr.State = DataRequestState.Delayed;
dr.NextTry = DateTime.Now + TimeSpan.FromSeconds(120);
Log.Write(Log.Levels.Warning, "DataStore: request " + dr.Source + " has error, delaying until " + dr.NextTry.ToLongTimeString());
m_pendingRequests.Add(dr);
}
m_activeRequests.Remove(dr);
}
}
lock (m_lock)
{
// if we're ready to activate new requests, first sort them according to current priority
if (ActiveRequestCount < m_maxActiveRequests)
{
foreach (DataRequest dr in m_pendingRequests)
{
dr.UpdatePriority();
//if (dr.Priority < 0)
// dr.Cancel();
if (dr.State == DataRequestState.Delayed && dr.NextTry < DateTime.Now)
{
dr.State = DataRequestState.NoCache;
}
}
// also clean up cancelled requests
for (int i = 0; i < PendingRequestCount; i++)
{
DataRequest dr = m_pendingRequests[i] as DataRequest;
if (dr.State == DataRequestState.Queued)
{
if (dr.TryCache())
{
dr.RequestDescriptor.CompletionCallback(dr);
m_pendingRequests.Remove(dr);
}
else
{
dr.State = DataRequestState.NoCache;
}
}
if (dr.State == DataRequestState.Cancelled)
{
m_pendingRequests.Remove(dr);
}
}
m_pendingRequests.Sort();
}
}
// see if we can start any more requests
while ((PendingRequestCount > 0) && (ActiveRequestCount < m_maxActiveRequests))
{
// look for first pending request
DataRequest drd = null;
lock (m_lock)
{
drd = m_pendingRequests[0] as DataRequest;
// if the top priority request is delayed, we won't find anything better.
// so we can break out immediately.
if (drd.State != DataRequestState.NoCache || drd.NextTry > DateTime.Now)
{
break;
}
m_pendingRequests.RemoveAt(0);
}
#if VERBOSE
Log.Write(Log.Levels.Verbose, "DataStore: Activating request for " + drd.Source);
#endif
// if (!drd.TryCache())
{
drd.Start();
m_activeRequests.Add(drd);
}
}
}
