sdk/samples/all in on code/Visual Studio 2008/CppInteractiveWindowsService/ThreadPool.h

   1 /****************************** Module Header ******************************\
   2 * Module Name:  ThreadPool.h
   3 * Project:      CppInteractiveWindowsService
   4 * Copyright (c) Microsoft Corporation.
   5 *
   6 * The class was designed by Kenny Kerr. It provides the ability to queue
   7 * simple member functions of a class to the Windows thread pool.
   8 *
   9 * Using the thread pool is simple and feels natural in C++.
  10 *
  11 * class CSampleService
  12 * {
  13 * public:
  14 *
  15 *     void AsyncRun()
  16 *     {
  17 *         CThreadPool::QueueUserWorkItem(&Service::Run, this);
  18 *     }
  19 *
  20 *     void Run()
  21 *     {
  22 *         // Some lengthy operation
  23 *     }
  24 * };
  25 *
  26 * Kenny Kerr spends most of his time designing and building distributed
  27 * applications for the Microsoft Windows platform. He also has a particular
  28 * passion for C++ and security programming. Reach Kenny at
  29 * http://weblogs.asp.net/kennykerr/ or visit his Web site:
  30 * http://www.kennyandkarin.com/Kenny/.
  31 *
  32 * This source is subject to the Microsoft Public License.
  33 * See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
  34 * All other rights reserved.
  35 *
  36 * THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
  37 * EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
  38 * WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
  39 \***************************************************************************/
  40
  41 #pragma once
  42
  43 #include <memory>
  44
  45
  46 class CThreadPool
  47 {
  48 public:
  49
  50     template <typename T>
  51     static void QueueUserWorkItem(void (T::*function)(void),
  52         T *object, ULONG flags = WT_EXECUTELONGFUNCTION)
  53     {
  54         typedef std::pair<void (T::*)(), T *> CallbackType;
  55         std::auto_ptr<CallbackType> p(new CallbackType(function, object));
  56
  57         if (::QueueUserWorkItem(ThreadProc<T>, p.get(), flags))
  58         {
  59             // The ThreadProc now has the responsibility of deleting the pair.
  60             p.release();
  61         }
  62         else
  63         {
  64             throw GetLastError();
  65         }
  66     }
  67
  68 private:
  69
  70     template <typename T>
  71     static DWORD WINAPI ThreadProc(PVOID context)
  72     {
  73         typedef std::pair<void (T::*)(), T *> CallbackType;
  74
  75         std::auto_ptr<CallbackType> p(static_cast<CallbackType *>(context));
  76
  77         (p->second->*p->first)();
  78         return 0;
  79     }
  80 };