// This is the method that the underlying, free-threaded
// asynchronous behavior will invoke. This will happen on
// an arbitrary thread.
private void OnAsyncCompletionMethod(object operationState)
{
AsyncData data = operationState as AsyncData;
AsyncOperation asyncOp = data.Operation;
AsyncOperationCompletedEventArgs args = new AsyncOperationCompletedEventArgs(data);
// In this case, don't allow cancellation, as the method
// is about to raise the completed event.
lock (_userStateToLifetime.SyncRoot)
{
if (!_userStateToLifetime.Contains(data.UserData))
{
asyncOp = null;
}
else
{
_userStateToLifetime.Remove(asyncOp.UserSuppliedState);
}
}
// The asyncOp object is responsible for marshaling
// the call.
if (asyncOp != null)
{
asyncOp.PostOperationCompleted(_onCompletedDelegate, args);
}
// Note that after the call to OperationCompleted,
// asyncOp is no longer usable, and any attempt to use it
// will cause an exception to be thrown.
}
private MemoryStream CopyResponseToMemory(AsyncData data, Stream responseStream, long contentLength)
{
if (responseStream == null)
{
return(null);
}
// read the stream into memory. That's the only way to satisfy the "main work
// on the other thread requirement
MemoryStream memStream = new MemoryStream();
const int size = 4096;
var bytes = new byte[size];
int numBytes;
double current = 0;
long bytesWritten = 0;
while ((numBytes = responseStream.Read(bytes, 0, size)) > 0)
{
memStream.Write(bytes, 0, numBytes);
if (data == null || data.Delegate == null)
{
continue;
}
bytesWritten += numBytes;
if (contentLength > size)
{
current = bytesWritten * 100d / contentLength;
}
// see if we are still in the list...
// Multiple threads will access the task dictionary,
// so it must be locked to serialize access.
if (CheckIfOperationIsCancelled(data.UserData))
{
throw new ArgumentException("Operation was cancelled");
}
var args = new AsyncOperationProgressEventArgs(
contentLength,
bytesWritten,
(int)current,
data.UriToUse,
data.HttpVerb,
data.UserData);
data.Operation.Post(data.Delegate, args);
}
memStream.Seek(0, SeekOrigin.Begin);
return(memStream);
}
/// <summary>
/// handles the response stream
/// copies it into the memory stream, or parses it into a feed.
/// </summary>
/// <param name="data"></param>
/// <param name="responseStream"></param>
/// <param name="contentLength"></param>
/// <returns></returns>
protected override void HandleResponseStream(AsyncData data, Stream responseStream, long contentLength)
{
if (data.ParseFeed)
{
data.Feed = CreateAndParseFeed(responseStream, data.UriToUse);
data.DataStream = null;
}
else
{
base.HandleResponseStream(data, responseStream, contentLength);
}
}
/// <summary>
/// handles the response stream
/// copies it into the memory stream, or parses it into a feed.
/// </summary>
/// <param name="data"></param>
/// <param name="responseStream"></param>
/// <param name="contentLength"></param>
/// <returns></returns>
protected virtual void HandleResponseStream(AsyncData data, Stream responseStream, long contentLength, IService service)
{
data.DataStream = CopyResponseToMemory(data, responseStream, contentLength);
IAsyncEntryData entryData = data as IAsyncEntryData;
Service serviceImpl = service as Service;
if (entryData != null && service != null)
{
entryData.Entry = serviceImpl.CreateAndParseEntry(data.DataStream, data.UriToUse);
}
}
internal bool SendProgressData(AsyncData data, AsyncOperationProgressEventArgs args)
{
// In this case, don't allow cancellation, as the method
// is about to raise the completed event.
bool ret = !CheckIfOperationIsCancelled(data.UserData);
if (ret)
{
data.Operation.Post(data.Delegate, args);
}
return(ret);
}
/// <summary>
/// constructor. takes the async data blob
/// </summary>
/// <param name="data">async data to constructor</param>
internal AsyncOperationCompletedEventArgs(AsyncData data)
: base(data.Exception, false, data.UserData)
{
_feedObject = data.Feed;
_stream = data.DataStream;
IAsyncEntryData entryData = data as IAsyncEntryData;
if (entryData != null)
{
_entryObject = entryData.Entry;
}
}
/// <summary>
/// this method cancels the corresponding async operation.
/// It sends still a completed event, but that event will then
/// have the cancel property set to true
/// </summary>
/// <param name="userData">your identifier for the operation to be cancelled</param>
public void CancelAsync(object userData)
{
lock (_userStateToLifetime.SyncRoot)
{
object obj = _userStateToLifetime[userData];
if (obj != null)
{
_userStateToLifetime.Remove(userData);
AsyncOperation asyncOp = obj as AsyncOperation;
// The asyncOp object is responsible for
// marshaling the call to the proper
// thread or context.
AsyncData data = new AsyncData(null, userData, _onProgressReportDelegate);
AsyncOperationCompletedEventArgs args = new AsyncOperationCompletedEventArgs(data, true);
asyncOp.PostOperationCompleted(_onCompletedDelegate, args);
}
}
}
internal AsyncOperationCompletedEventArgs(AsyncData data, bool cancelled)
: base(data.Exception, cancelled, data.UserData)
{
}
/// <summary>
/// handles the response stream
/// copies it into the memory stream, or parses it into a feed.
/// </summary>
/// <param name="data"></param>
/// <param name="responseStream"></param>
/// <param name="contentLength"></param>
/// <returns></returns>
protected virtual void HandleResponseStream(AsyncData data, Stream responseStream, long contentLength)
{
HandleResponseStream(data, responseStream, contentLength, null);
}
