// Caller may invoke this repeatedly until EndRead returns zero, at which point the entire entity has been read.
public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, Object state)
{
HttpWorkerRequest wr = _context.WorkerRequest;
// Only perform an async read if the worker request supports it and we're not in a cancellable period.
// If we were to allow async read in a cancellable period, the timeout manager could raise a ThreadAbortEx and
// corrupt the state of the request.
if (wr != null && wr.SupportsAsyncRead && !_context.IsInCancellablePeriod)
{
if (!_preloadedContentRead)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (offset < 0)
{
throw new ArgumentOutOfRangeException("offset");
}
if (count < 0)
{
throw new ArgumentOutOfRangeException("count");
}
if (buffer.Length - offset < count)
{
throw new ArgumentException(SR.GetString(SR.InvalidOffsetOrCount, "offset", "count"));
}
_preloadedBytesRead = GetPreloadedContent(buffer, ref offset, ref count);
}
if (_remainingBytes == 0)
{
// set count to zero and invoke BeginRead to return an async result
count = 0;
}
if (_persistEntityBody)
{
// hold a reference so we can add bytes to _rawContent when EndRead is called
_buffer = buffer;
_offset = offset;
_count = count;
}
try {
return(wr.BeginRead(buffer, offset, count, callback, state));
}
catch (HttpException) {
if (_persistEntityBody)
{
SetRawContentOnce();
}
throw;
}
}
else
{
// perform a sync read
return(base.BeginRead(buffer, offset, count, callback, state));
}
}
