mcs/class/Facades/System.Threading.Overlapped/ClrThreadPoolBoundHandleOverlapped.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 namespace System.Threading
   6 {
   7     /// <summary>
   8     /// Overlapped subclass adding data needed by ThreadPoolBoundHandle.
   9     /// </summary>
  10     internal sealed class ThreadPoolBoundHandleOverlapped : Overlapped
  11     {
  12         private readonly IOCompletionCallback _userCallback;
  13         internal readonly object _userState;
  14         internal PreAllocatedOverlapped _preAllocated;
  15         internal unsafe NativeOverlapped* _nativeOverlapped;
  16         internal ThreadPoolBoundHandle _boundHandle;
  17         internal bool _completed;
  18
  19         public unsafe ThreadPoolBoundHandleOverlapped(IOCompletionCallback callback, object state, object pinData, PreAllocatedOverlapped preAllocated)
  20         {
  21             _userCallback = callback;
  22             _userState = state;
  23             _preAllocated = preAllocated;
  24
  25             _nativeOverlapped = Pack(CompletionCallback, pinData);
  26             _nativeOverlapped->OffsetLow = 0;        // CLR reuses NativeOverlapped instances and does not reset these
  27             _nativeOverlapped->OffsetHigh = 0;
  28         }
  29
  30         private unsafe static void CompletionCallback(uint errorCode, uint numBytes, NativeOverlapped* nativeOverlapped)
  31         {
  32             ThreadPoolBoundHandleOverlapped overlapped = (ThreadPoolBoundHandleOverlapped)Overlapped.Unpack(nativeOverlapped);
  33
  34             //
  35             // The Win32 thread pool implementation of ThreadPoolBoundHandle does not permit reuse of NativeOverlapped
  36             // pointers without freeing them and allocating new a new one.  We need to ensure that code using the CLR
  37             // ThreadPool implementation follows those rules.
  38             //
  39             if (overlapped._completed)
  40                 throw new InvalidOperationException(SR.InvalidOperation_NativeOverlappedReused);
  41
  42             overlapped._completed = true;
  43
  44             if (overlapped._boundHandle == null)
  45                 throw new InvalidOperationException(SR.Argument_NativeOverlappedAlreadyFree);
  46
  47             overlapped._userCallback(errorCode, numBytes, nativeOverlapped);
  48         }
  49     }
  50 }