internal void OnAsyncCompletion(int bytesCompleted, int hresult, IntPtr pAsyncCompletionContext) {
// clear _asyncResultBase because when we call Complete the user's callback
// may begin another async operation
AsyncResultBase ar = _asyncResultBase;
_asyncResultBase = null;
ar.Complete(bytesCompleted, hresult, pAsyncCompletionContext, synchronous: false);
}
// Begin an asynchronous read of the request entity body. To read the entire entity, invoke
// repeatedly until total bytes read is equal to Request.ContentLength or EndRead indicates
// that zero bytes were read. If Request.ContentLength is zero and the request is chunked,
// then invoke repeatedly until EndRead indicates that zero bytes were read.
//
// If an error occurs and the client is no longer connected, an HttpException will be thrown.
//
// This implements Stream.BeginRead, and as such, should throw
// exceptions as described on MSDN when errors occur.
public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, Object state) {
// Do as Stream does.
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"));
ReadAsyncResult ar = new ReadAsyncResult(callback, state, buffer, offset, count, updatePerfCounter: true);
if (count == 0) {
ar.Complete(0, HResults.S_OK, IntPtr.Zero, synchronous: true);
return ar;
}
// we only allow one async operation at a time
if (Interlocked.CompareExchange(ref _asyncResultBase, ar, null) != null)
throw new InvalidOperationException(SR.GetString(SR.Async_operation_pending));
// initiate async operation here
bool fAsync = true;
int bytesRead = 0;
IntPtr ppAsyncReceiveBuffer;
int hresult = IIS.MgdReadEntityBody(_context,
null, // for async the data is copied from a native buffer to avoid pinning
0, // for async, offset is ignored
count, // number of bytes to read
fAsync,
out bytesRead,
out ppAsyncReceiveBuffer);
if (hresult < 0) {
_asyncResultBase = null;
// treat every error as if the client disconnected
IncrementRequestsDisconnected();
throw new HttpException(SR.GetString(SR.ClientDisconnected), hresult);
}
// if we completed synchronously, then ppAsyncReceiveBuffer will be non-null
else if (ppAsyncReceiveBuffer != IntPtr.Zero) {
_asyncResultBase = null;
ar.Complete(bytesRead, HResults.S_OK, ppAsyncReceiveBuffer, synchronous: true);
return ar;
}
else {
return ar;
}
}
// Begin an asynchronous flush of the response. To support this, the worker request buffers
// the status, headers, and resonse body until an asynchronous flush operation is initiated.
public override IAsyncResult BeginFlush(AsyncCallback callback, Object state) {
if (_context == IntPtr.Zero) {
throw new InvalidOperationException();
}
FlushAsyncResult ar = new FlushAsyncResult(callback, state);
// we only allow one async operation at a time
if (Interlocked.CompareExchange(ref _asyncResultBase, ar, null) != null)
throw new InvalidOperationException(SR.GetString(SR.Async_operation_pending));
// initiate async operation here
bool async = true;
bool completedSynchronously;
int hresult = IIS.MgdExplicitFlush(_context, async, out completedSynchronously);
if (hresult < 0) {
_asyncResultBase = null;
// treat every error as if the client disconnected
IncrementRequestsDisconnected();
throw new HttpException(SR.GetString(SR.ClientDisconnected), hresult);
}
else if (completedSynchronously) {
_asyncResultBase = null;
ar.Complete(0, HResults.S_OK, IntPtr.Zero, synchronous: true);
return ar;
}
else {
return ar;
}
}
