Source code of Windows XP (NT5)
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/*****************************************************************************
*
* (C) COPYRIGHT MICROSOFT CORPORATION, 2000
*
* TITLE: w32utils.h
*
* VERSION: 1.0
*
* AUTHOR: LazarI
*
* DATE: 23-Dec-2000
*
* DESCRIPTION: Win32 templates & utilities (ported from printscan\ui\printui)
*
*****************************************************************************/
#ifndef _W32UTILS_H
#define _W32UTILS_H
////////////////////////////////////////////////
//
// template class CScopeLocker<TLOCK>
//
template <class TLOCK>
class CScopeLocker
{
public:
CScopeLocker(TLOCK &lock):
m_Lock(lock), m_bLocked(false)
{ m_bLocked = (m_Lock && m_Lock.Lock()); }
~CScopeLocker()
{ if (m_bLocked) m_Lock.Unlock(); }
operator bool () const
{ return m_bLocked; }
private:
bool m_bLocked;
TLOCK &m_Lock;
};
////////////////////////////////////////////////
//
// class CCSLock - win32 critical section lock.
//
class CCSLock
{
public:
// CCSLock::Locker should be used as locker class.
typedef CScopeLocker<CCSLock> Locker;
CCSLock(): m_bInitialized(false)
{
__try
{
// InitializeCriticalSection may rise STATUS_NO_MEMORY exception
// in low memory conditions (according the SDK)
InitializeCriticalSection(&m_CS);
m_bInitialized = true;
return;
}
__except(EXCEPTION_EXECUTE_HANDLER) {}
// if we end up here m_bInitialized will remain false
// (i.e. out of memory exception was thrown)
}
~CCSLock()
{
if (m_bInitialized)
{
// delete the critical section only if initialized successfully
DeleteCriticalSection(&m_CS);
}
}
operator bool () const
{
return m_bInitialized;
}
bool Lock()
{
__try
{
// EnterCriticalSection may rise STATUS_NO_MEMORY exception
// in low memory conditions (this may happen if there is contention
// and ntdll can't allocate the wait semaphore)
EnterCriticalSection(&m_CS);
return true;
}
__except(EXCEPTION_EXECUTE_HANDLER) {}
// out of memory or invalid handle exception was thrown.
return false;
}
void Unlock()
{
// Unlock() should be called *ONLY* if the corresponding
// Lock() call has succeeded.
LeaveCriticalSection(&m_CS);
}
private:
bool m_bInitialized;
CRITICAL_SECTION m_CS;
};
#endif // endif _W32UTILS_H