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mirror of https://github.com/FirebirdSQL/firebird.git synced 2025-01-31 06:43:02 +01:00
firebird-mirror/src/common/classes/locks.cpp
2008-01-23 19:27:36 +00:00

117 lines
2.6 KiB
C++

/*
* PROGRAM: Client/Server Common Code
* MODULE: locks.cpp
* DESCRIPTION: Win32 Mutex support compatible with
* old OS versions (like Windows 95)
*
* The contents of this file are subject to the Initial
* Developer's Public License Version 1.0 (the "License");
* you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
* http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
*
* Software distributed under the License is distributed AS IS,
* WITHOUT WARRANTY OF ANY KIND, either express or implied.
* See the License for the specific language governing rights
* and limitations under the License.
*
* The Original Code was created by Alexander Peshkoff
* for the Firebird Open Source RDBMS project.
*
* Copyright (c) 2003 Alexander Peshkoff <peshkoff@mail.ru>
* and all contributors signed below.
*
* All Rights Reserved.
* Contributor(s): ______________________________________.
*/
#include "../../include/firebird.h"
#include "../../common/classes/locks.h"
#include "../../common/thd.h"
#include "../../jrd/common.h"
namespace Firebird {
#ifdef WIN_NT
#define MISS_SPIN_COUNT ((tSetCriticalSectionSpinCount *)(-1))
#define INIT_SPIN_COUNT ((tSetCriticalSectionSpinCount *)(0))
tSetCriticalSectionSpinCount*
Spinlock::SetCriticalSectionSpinCount = INIT_SPIN_COUNT;
void Spinlock::init()
{
if (SetCriticalSectionSpinCount == MISS_SPIN_COUNT)
return;
if (SetCriticalSectionSpinCount == INIT_SPIN_COUNT) {
HMODULE kernel32 = LoadLibrary("kernel32.dll");
if (!kernel32) {
SetCriticalSectionSpinCount = MISS_SPIN_COUNT;
return;
}
SetCriticalSectionSpinCount =
(tSetCriticalSectionSpinCount *) GetProcAddress(
kernel32, "SetCriticalSectionSpinCount");
if (!SetCriticalSectionSpinCount) {
SetCriticalSectionSpinCount = MISS_SPIN_COUNT;
return;
}
}
SetCriticalSectionSpinCount(&spinlock, 4000);
}
#endif // WIN_NT
// In some cases recursive mutex's are not protected by try/catch
// therefore keep old (return value) logic
int RecursiveMutex::enter()
{
if (threadId == getThreadId())
{
++count;
}
else
{
try
{
mutex.enter();
}
catch (const Firebird::system_call_failed& e)
{
return e.getErrorCode();
}
threadId = getThreadId();
count = 1;
}
return 0;
}
int RecursiveMutex::leave()
{
if (threadId != getThreadId())
{
return FB_FAILURE;
}
if (--count == 0)
{
threadId = 0;
try
{
mutex.leave();
}
catch (const Firebird::system_call_failed& e)
{
return e.getErrorCode();
}
}
return 0;
}
} // namespace Firebird