internal unsafe Task SendFileAsyncCore(string fileName, long offset, long?count, CancellationToken cancellationToken)
{
if (_skipWrites)
{
return(Task.CompletedTask);
}
var started = _requestContext.Response.HasStarted;
if (count == 0 && started)
{
// No data to send and we've already sent the headers
return(Task.CompletedTask);
}
if (cancellationToken.IsCancellationRequested)
{
Abort(ThrowWriteExceptions);
return(Task.FromCanceled <int>(cancellationToken));
}
// We are setting buffer size to 1 to prevent FileStream from allocating it's internal buffer
// It's too expensive to validate anything before opening the file. Open the file and then check the lengths.
var fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite, bufferSize: 1,
options: FileOptions.Asynchronous | FileOptions.SequentialScan); // Extremely expensive.
try
{
var length = fileStream.Length; // Expensive, only do it once
if (!count.HasValue)
{
count = length - offset;
}
if (offset < 0 || offset > length)
{
throw new ArgumentOutOfRangeException(nameof(offset), offset, string.Empty);
}
if (count < 0 || count > length - offset)
{
throw new ArgumentOutOfRangeException(nameof(count), count, string.Empty);
}
CheckWriteCount(count);
}
catch
{
fileStream.Dispose();
throw;
}
// Make sure all validation is performed before this computes the headers
var flags = ComputeLeftToWrite(count.Value);
uint statusCode;
uint bytesSent = 0;
var chunked = _requestContext.Response.BoundaryType == BoundaryType.Chunked;
var asyncResult = new ResponseStreamAsyncResult(this, fileStream, offset, count.Value, chunked, cancellationToken);
try
{
if (!started)
{
statusCode = _requestContext.Response.SendHeaders(null, asyncResult, flags, false);
bytesSent = asyncResult.BytesSent;
}
else
{
// TODO: If opaque then include the buffer data flag.
statusCode = HttpApi.HttpSendResponseEntityBody(
RequestQueueHandle,
RequestId,
(uint)flags,
asyncResult.DataChunkCount,
asyncResult.DataChunks,
&bytesSent,
IntPtr.Zero,
0,
asyncResult.NativeOverlapped !,
IntPtr.Zero);
}
}
catch (Exception e)
{
Log.FileSendAsyncError(Logger, e);
asyncResult.Dispose();
Abort();
throw;
}
if (statusCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_SUCCESS && statusCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_IO_PENDING)
{
if (cancellationToken.IsCancellationRequested)
{
Log.FileSendAsyncCancelled(Logger, statusCode);
asyncResult.Cancel(ThrowWriteExceptions);
}
else if (ThrowWriteExceptions)
{
asyncResult.Dispose();
var exception = new IOException(string.Empty, new HttpSysException((int)statusCode));
Log.FileSendAsyncError(Logger, exception);
Abort();
throw exception;
}
else
{
// Abort the request but do not close the stream, let future writes complete
Log.FileSendAsyncErrorIgnored(Logger, statusCode);
asyncResult.FailSilently();
}
}
if (statusCode == ErrorCodes.ERROR_SUCCESS && HttpSysListener.SkipIOCPCallbackOnSuccess)
{
// IO operation completed synchronously - callback won't be called to signal completion.
asyncResult.IOCompleted(statusCode, bytesSent);
}
// Last write, cache it for special cancellation handling.
if ((flags & HttpApiTypes.HTTP_FLAGS.HTTP_SEND_RESPONSE_FLAG_MORE_DATA) == 0)
{
_lastWrite = asyncResult;
}
return(asyncResult.Task);
}
// Simpler than Flush because it will never be called at the end of the request from Dispose.
private unsafe Task FlushInternalAsync(ArraySegment <byte> data, CancellationToken cancellationToken)
{
if (_skipWrites)
{
return(Task.CompletedTask);
}
var started = _requestContext.Response.HasStarted;
if (data.Count == 0 && started)
{
// No data to send and we've already sent the headers
return(Task.CompletedTask);
}
if (cancellationToken.IsCancellationRequested)
{
Abort(ThrowWriteExceptions);
return(Task.FromCanceled <int>(cancellationToken));
}
// Make sure all validation is performed before this computes the headers
var flags = ComputeLeftToWrite(data.Count);
uint statusCode;
var chunked = _requestContext.Response.BoundaryType == BoundaryType.Chunked;
var asyncResult = new ResponseStreamAsyncResult(this, data, chunked, cancellationToken);
uint bytesSent = 0;
try
{
if (!started)
{
statusCode = _requestContext.Response.SendHeaders(null, asyncResult, flags, false);
bytesSent = asyncResult.BytesSent;
}
else
{
statusCode = HttpApi.HttpSendResponseEntityBody(
RequestQueueHandle,
RequestId,
(uint)flags,
asyncResult.DataChunkCount,
asyncResult.DataChunks,
&bytesSent,
IntPtr.Zero,
0,
asyncResult.NativeOverlapped !,
IntPtr.Zero);
}
}
catch (Exception e)
{
Log.ErrorWhenFlushAsync(Logger, e);
asyncResult.Dispose();
Abort();
throw;
}
if (statusCode != ErrorCodes.ERROR_SUCCESS && statusCode != ErrorCodes.ERROR_IO_PENDING)
{
if (cancellationToken.IsCancellationRequested)
{
Log.WriteFlushCancelled(Logger, statusCode);
asyncResult.Cancel(ThrowWriteExceptions);
}
else if (ThrowWriteExceptions)
{
asyncResult.Dispose();
Exception exception = new IOException(string.Empty, new HttpSysException((int)statusCode));
Log.ErrorWhenFlushAsync(Logger, exception);
Abort();
throw exception;
}
else
{
// Abort the request but do not close the stream, let future writes complete silently
Log.WriteErrorIgnored(Logger, statusCode);
asyncResult.FailSilently();
}
}
if (statusCode == ErrorCodes.ERROR_SUCCESS && HttpSysListener.SkipIOCPCallbackOnSuccess)
{
// IO operation completed synchronously - callback won't be called to signal completion.
asyncResult.IOCompleted(statusCode, bytesSent);
}
// Last write, cache it for special cancellation handling.
if ((flags & HttpApiTypes.HTTP_FLAGS.HTTP_SEND_RESPONSE_FLAG_MORE_DATA) == 0)
{
_lastWrite = asyncResult;
}
return(asyncResult.Task);
}