BeginGetRequest(
AsyncCallback requestCallback,
Object stateObject)
{
//
// Validation
//
if (m_AppPoolHandle == NativeMethods.INVALID_HANDLE_VALUE)
{
throw new InvalidOperationException("The AppPool handle is invalid");
}
//
// prepare the ListenerAsyncResult object ( this will have it's own
// event that the user can wait on for IO completion - which means we
// need to signal it when IO completes )
//
GlobalLog.Print("BeginGetRequest() creating ListenerAsyncResult");
ListenerAsyncResult AResult = new ListenerAsyncResult(
stateObject,
requestCallback);
AutoResetEvent m_Event = new AutoResetEvent(false);
Marshal.WriteIntPtr(
AResult.m_Overlapped,
Win32.OverlappedhEventOffset,
m_Event.Handle);
//
// issue unmanaged call until we read enough data:
// usually starting with a InitialBufferSize==4096 bytes we should be
// able to get all the headers ( and part of the entity body, if any
// is present ), if we don't, if the call didn't fail for othe reasons,
// we get indication in BytesReturned, on how big the buffer should be
// to receive the data available, so usually the second call will
// succeed, but we have to consider the case of two competing calls
// for the same RequestId, and that's why we need a loop and not just
// a try/retry-expecting-success fashion
//
int result;
for (;;)
{
//
// check if we're in a healthy state
//
if (AResult.m_Retries++ > m_MaxRetries)
{
throw new InvalidOperationException("UlReceiveHttpRequest() Too many retries");
}
result =
ComNetOS.IsWinNt ?
UlSysApi.UlReceiveHttpRequest(
m_AppPoolHandle,
AResult.m_RequestId,
UlConstants.UL_RECEIVE_REQUEST_FLAG_COPY_BODY,
AResult.m_Buffer,
AResult.m_BufferSize,
ref AResult.m_BytesReturned,
AResult.m_Overlapped)
:
UlVxdApi.UlReceiveHttpRequestHeaders(
m_AppPoolHandle,
AResult.m_RequestId,
0,
AResult.m_Buffer,
AResult.m_BufferSize,
ref AResult.m_BytesReturned,
AResult.m_Overlapped);
GlobalLog.Print("UlReceiveHttpRequest() returns:"
+ Convert.ToString(result));
if (result == NativeMethods.ERROR_SUCCESS || result == NativeMethods.ERROR_IO_PENDING)
{
//
// synchronous success or successfull pending: we are done
//
break;
}
if (result == NativeMethods.ERROR_INVALID_PARAMETER)
{
//
// we might get this if somebody stole our RequestId,
// set RequestId to null
//
AResult.m_RequestId = 0;
//
// and start all over again with the buffer we
// just allocated
//
continue;
}
if (result == NativeMethods.ERROR_MORE_DATA)
{
//
// the buffer was not big enough to fit the headers, we need
// to read the RequestId returned, grow the buffer, keeping
// the data already transferred
//
AResult.m_RequestId = Marshal.ReadInt64(IntPtrHelper.Add(AResult.m_Buffer, m_RequestIdOffset));
//
// allocate a new buffer of the required size
//
IntPtr NewBuffer = Marshal.AllocHGlobal(AResult.m_BytesReturned);
//
// copy the data already read from the old buffer into the
// new one
//
NativeMethods.CopyMemory(NewBuffer, AResult.m_Buffer, AResult.m_BufferSize);
//
// free the old buffer
//
Marshal.FreeHGlobal(AResult.m_Buffer);
//
// update buffer pointer and size
//
AResult.m_Buffer = NewBuffer;
AResult.m_BufferSize = AResult.m_BytesReturned;
AResult.m_BytesReturned = 0;
//
// and start all over again with the new buffer
//
continue;
}
//
// someother bad error, possible( ? ) return values are:
//
// ERROR_INVALID_HANDLE
// ERROR_INSUFFICIENT_BUFFER
// ERROR_OPERATION_ABORTED
// ERROR_IO_PENDING
//
throw new InvalidOperationException("UlReceiveHttpRequest() failed, err#" + Convert.ToString(result));
}
//
// we get here only if a break happens, i.e.
// 1) syncronous completion
// 2) the IO pended
//
if (result == NativeMethods.ERROR_SUCCESS)
{
//
// set syncronous completion to true
//
AResult.Complete(true);
//
// and call the internal callback
//
WaitCallback(AResult, false);
}
else
{
//
// create a new delegate
// and spin a new thread from the thread pool to wake up when the
// event is signaled and call the delegate
//
ThreadPool.RegisterWaitForSingleObject(
m_Event,
new WaitOrTimerCallback(WaitCallback),
AResult,
-1,
true);
}
GlobalLog.Print("returning AResult");
return(AResult);
} // StartListen()
GetRequest()
{
//
// Validation
//
if (m_AppPoolHandle == NativeMethods.INVALID_HANDLE_VALUE)
{
throw new InvalidOperationException("The AppPool handle is invalid");
}
int result;
int retries = 0;
//
// defined in ulcommonapi.cs
//
int RcvHeadersBufferSize = UlConstants.InitialBufferSize;
//
// prepare ( allocate/pin ) buffers and data for the first unmanaged call
//
GCHandle PinnedBuffer;
GCHandle NewPinnedBuffer;
IntPtr AddrOfPinnedBuffer = IntPtr.Zero;
IntPtr NewAddrOfPinnedBuffer = IntPtr.Zero;
int BytesReturned = 0;
long RequestId = 0;
byte[] RcvHeadersBuffer = new byte[RcvHeadersBufferSize];
//
// pin buffers and data for the unmanaged call
//
PinnedBuffer = GCHandle.Alloc(RcvHeadersBuffer, GCHandleType.Pinned);
AddrOfPinnedBuffer = PinnedBuffer.AddrOfPinnedObject();
//
// issue unmanaged blocking call until we read enough data:
// usually starting with a InitialBufferSize==4096 bytes we should be
// able to get all the headers ( and part of the entity body, if any
// is present ), if we don't, if the call didn't fail for othe reasons,
// we get indication in BytesReturned, on how big the buffer should be
// to receive the data available, so usually the second call will
// succeed, but we have to consider the case of two competing calls
// for the same RequestId, and that's why we need a loop and not just
// a try/retry-expecting-success fashion
//
for (;;)
{
//
// check if we're in a healthy state
//
if (retries++ > m_MaxRetries)
{
throw new InvalidOperationException("UlReceiveHttpRequest() Too many retries");
}
result =
ComNetOS.IsWinNt ?
UlSysApi.UlReceiveHttpRequest(
m_AppPoolHandle,
RequestId,
UlConstants.UL_RECEIVE_REQUEST_FLAG_COPY_BODY,
AddrOfPinnedBuffer,
RcvHeadersBufferSize,
ref BytesReturned,
IntPtr.Zero)
:
UlVxdApi.UlReceiveHttpRequestHeaders(
m_AppPoolHandle,
RequestId,
0,
AddrOfPinnedBuffer,
RcvHeadersBufferSize,
ref BytesReturned,
IntPtr.Zero);
if (result == NativeMethods.ERROR_SUCCESS)
{
//
// success, we are done.
//
break;
}
if (result == NativeMethods.ERROR_INVALID_PARAMETER)
{
//
// we might get this if somebody stole our RequestId,
// set RequestId to null
//
RequestId = 0;
//
// and start all over again with the buffer we
// just allocated
//
continue;
}
//
// let's check if ul is in good shape:
//
if (BytesReturned < RcvHeadersBufferSize)
{
throw new InvalidOperationException("UlReceiveHttpRequest() sent bogus BytesReturned: " + Convert.ToString(BytesReturned));
}
if (result == NativeMethods.ERROR_MORE_DATA)
{
//
// the buffer was not big enough to fit the headers, we need
// to read the RequestId returned, grow the buffer, keeping
// the data already transferred
//
RequestId = Marshal.ReadInt64(IntPtrHelper.Add(AddrOfPinnedBuffer, m_RequestIdOffset));
//
// CODEWORK: wait for the answer from LarrySu
//
//
// if the buffer size was too small, grow the buffer
// this reallocation dereferences the old buffer, but since
// this was previously pinned, it won't be garbage collected
// until we unpin it ( which we do below )
//
RcvHeadersBuffer = new byte[BytesReturned];
//
// pin the new one
//
NewPinnedBuffer = GCHandle.Alloc(RcvHeadersBuffer, GCHandleType.Pinned);
NewAddrOfPinnedBuffer = NewPinnedBuffer.AddrOfPinnedObject();
//
// copy the valid data
//
Marshal.Copy(AddrOfPinnedBuffer, RcvHeadersBuffer, 0, RcvHeadersBufferSize);
RcvHeadersBufferSize = BytesReturned;
//
// unpin the old buffer, reset pinned/unmanaged pointers
//
PinnedBuffer.Free();
PinnedBuffer = NewPinnedBuffer;
AddrOfPinnedBuffer = NewAddrOfPinnedBuffer;
//
// and start all over again with the new buffer
//
continue;
}
//
// someother bad error, possible( ? ) return values are:
//
// ERROR_INVALID_HANDLE
// ERROR_INSUFFICIENT_BUFFER
// ERROR_OPERATION_ABORTED
// ERROR_IO_PENDING
//
throw new InvalidOperationException("UlReceiveHttpRequest() failed, err#" + Convert.ToString(result));
}
GlobalLog.Print("GetRequest RequestId:" + Convert.ToString(RequestId)); //
// translate unmanaged results into a new managed object
//
HttpListenerWebRequest
myWebRequest =
new HttpListenerWebRequest(AddrOfPinnedBuffer, RcvHeadersBufferSize, m_AppPoolHandle);
//
// free the unmanaged buffer ( deallocate/unpin ) after unmanaged call
//
PinnedBuffer.Free();
return(myWebRequest);
} // GetRequest()
