public AsyncTileRequest CreateRequest(Uri uri, TileInfo tileInfo, NetworkPriority networkPriority, AsyncTileRequestCompletedHandler callback)
{
AsyncTileRequest tempTileRequest = new AsyncTileRequest(uri, tileInfo, callback)
{
NetworkPriority = networkPriority
};
lock (this.pendingRequests)
{
this.pendingRequests.Add(tempTileRequest);
}
this.thereMayBeWorkToDo.Set();
return(tempTileRequest);
}
private void DownloadThreadStart()
{
while (true)
{
WaitHandle[] waitHandleArray = new WaitHandle[] { this.thereMayBeWorkToDo };
WaitHandle.WaitAll(waitHandleArray);
AsyncTileRequest tempTileREQUEST = null;
lock (this.executingRequests)
{
lock (this.pendingRequests)
{
(from pendingRequest in this.pendingRequests
where pendingRequest.IsAborted
select pendingRequest).ToList <AsyncTileRequest>().ForEach((AsyncTileRequest tr) => this.pendingRequests.Remove(tr));
foreach (AsyncTileRequest pendingRequest in this.pendingRequests)
{
pendingRequest.NetworkPrioritySnapshot = pendingRequest.NetworkPriority;
}
this.pendingRequests.Sort((AsyncTileRequest left, AsyncTileRequest right) => Comparer <int> .Default.Compare((int)left.NetworkPrioritySnapshot, (int)right.NetworkPrioritySnapshot));
if (this.executingRequests.Count >= AsyncTileRequestQueue.MaxSimultaneousRequests || this.pendingRequests.Count <= 0)
{
this.thereMayBeWorkToDo.Reset();
}
else
{
tempTileREQUEST = this.pendingRequests[this.pendingRequests.Count - 1];
this.pendingRequests.RemoveAt(this.pendingRequests.Count - 1);
}
}
if (tempTileREQUEST != null)
{
WebClient webClient = new WebClient()
{
CachePolicy = new RequestCachePolicy(RequestCacheLevel.CacheIfAvailable),
Proxy = WebProxy,
Credentials = Credentials
};
webClient.DownloadDataCompleted += new DownloadDataCompletedEventHandler(this.DownloadDataCompleted);
this.executingRequests.Add(tempTileREQUEST, webClient);
webClient.DownloadDataAsync(tempTileREQUEST.Uri, null);
}
}
}
}
private void DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
{
AsyncTileRequest key = null;
lock (this.executingRequests)
{
KeyValuePair <AsyncTileRequest, WebClient> keyValuePair = this.executingRequests.First <KeyValuePair <AsyncTileRequest, WebClient> >((KeyValuePair <AsyncTileRequest, WebClient> item) => item.Value == sender);
key = keyValuePair.Key;
this.executingRequests.Remove(key);
this.thereMayBeWorkToDo.Set();
}
byte[] requestedTileInBytes = null;
Exception error = e.Error;
if (error == null)
{
try
{
if ((int)e.Result.Length <= 0)
{
error = new Exception("empty result");
}
else
{
requestedTileInBytes = e.Result;
}
}
catch (Exception exception)
{
error = exception;
requestedTileInBytes = null;
}
}
// Save the requested tile into cache.
if (requestedTileInBytes != null && key.TileInfo != null && TileCache != null)
{
TileCache.Save(key.TileInfo, requestedTileInBytes);
}
key.Callback(requestedTileInBytes, error);
((WebClient)sender).Dispose();
}
