ThreadOnce.cpp

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00001 /*******************************************************************************
00002 * Copyright (C) 2004 Vintela, Inc. All rights reserved.
00003 * Copyright (C) 2005 Novell, Inc. All rights reserved.
00004 *
00005 * Redistribution and use in source and binary forms, with or without
00006 * modification, are permitted provided that the following conditions are met:
00007 *
00008 *  - Redistributions of source code must retain the above copyright notice,
00009 *    this list of conditions and the following disclaimer.
00010 *
00011 *  - Redistributions in binary form must reproduce the above copyright notice,
00012 *    this list of conditions and the following disclaimer in the documentation
00013 *    and/or other materials provided with the distribution.
00014 *
00015 *  - Neither the name of Vintela, Inc., Novell, Inc., nor the names of its
00016 *    contributors may be used to endorse or promote products derived from this
00017 *    software without specific prior written permission.
00018 *
00019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
00020 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00021 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00022 * ARE DISCLAIMED. IN NO EVENT SHALL Vintela, Inc., Novell, Inc., OR THE 
00023 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
00024 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
00025 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
00026 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
00027 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 
00028 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
00029 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00030 *******************************************************************************/
00031 
00036 #include "blocxx/BLOCXX_config.h"
00037 #include "blocxx/ThreadOnce.hpp"
00038 #include "blocxx/Assertion.hpp"
00039 
00040 #if defined(BLOCXX_WIN32)
00041 
00042 #include <stdio.h>
00043 
00044 namespace BLOCXX_NAMESPACE
00045 {
00046 
00047 void callOnce(OnceFlag& flag, void (*func)())
00048 {
00049    // this is the double-checked locking pattern, but with a bit more strength than normally implemented :-)
00050     if (InterlockedCompareExchange(&flag, 1, 1) == 0)
00051     {
00052       wchar_t mutexName[MAX_PATH];
00053       _snwprintf(mutexName, MAX_PATH, L"%X-%p-587ccea9-c95a-4e81-ac51-ab0ddc6cef63", GetCurrentProcessId(), &flag);
00054       mutexName[MAX_PATH - 1] = 0;
00055 
00056         HANDLE mutex = CreateMutexW(NULL, FALSE, mutexName);
00057         BLOCXX_ASSERT(mutex != NULL);
00058 
00059         int res = 0;
00060         res = WaitForSingleObject(mutex, INFINITE);
00061         BLOCXX_ASSERT(res == WAIT_OBJECT_0);
00062 
00063         if (InterlockedCompareExchange(&flag, 1, 1) == 0)
00064         {
00065             try
00066             {
00067                 func();
00068             }
00069             catch (...)
00070             {
00071                 res = ReleaseMutex(mutex);
00072                 BLOCXX_ASSERT(res);
00073                 res = CloseHandle(mutex);
00074                 BLOCXX_ASSERT(res);
00075                 throw;
00076             }
00077             InterlockedExchange(&flag, 1);
00078         }
00079 
00080         res = ReleaseMutex(mutex);
00081         BLOCXX_ASSERT(res);
00082         res = CloseHandle(mutex);
00083         BLOCXX_ASSERT(res);
00084     }
00085 }
00086 
00087 
00088 } // end namespace BLOCXX_NAMESPACE
00089 
00090 #endif
00091 
00092 

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