CriticalSection.h

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//==============================================================================================
//  FILENAME    :   CriticalSection.h
//  AUTHOR      :   Jing Ning
//  CREATION    :   9/26/01
//  Copyright (C) MicroStrategy Incorporated 2001
//==============================================================================================
#ifndef MSynch_CriticialSection_h
#define MSynch_CriticialSection_h

#include "Base/Defines/StrongPtr.h"
#include "Base/Defines/NoCopy.h"

#include "Synch.h"
#include "LockCategories.h"

namespace MSynch
{

    class CriticalSection
    {
    public:

        typedef MBase::StrongPtr<CriticalSection, MBase::DeleteOperatorGeneric<CriticalSection> > Ptr;
        typedef MBase::ReturnPtr<CriticalSection, MBase::DeleteOperatorGeneric<CriticalSection> > ReturnPtr;


        class DLL_SYNCH_EXIM SmartLock:
            public MBase::NoCopy
        {
        public:
            // OPTIMIZATION WARNING! The methods on SmartLock are inlined
            // on purpose for performance reasons.
            SmartLock(CriticalSection& irCriticalSection):
                mrCriticalSection(irCriticalSection),
                mbLocked(true)
            {
                mrCriticalSection.Lock();
            }

            ~SmartLock() throw()
            {
                if (mbLocked)
                {
                    this->Unlock();
                }
            }

            void Lock()
            {
                _ASSERTE(!mbLocked);
                mrCriticalSection.Lock();
                mbLocked = true;
            }

            void Unlock() throw()
            {
                _ASSERTE(mbLocked);
                mrCriticalSection.Unlock();
                mbLocked = false;
            }

        private:
            //These members may never be changed or added to.
            CriticalSection& mrCriticalSection;
            bool mbLocked;
        };


        virtual void SetLockCategory(EnumDSSLockStackCategory iLockStackCategory) = 0;

        virtual void Delete() throw() = 0;

    protected:
        friend class SmartLock;     

        virtual void Lock() = 0;

        virtual void Unlock() throw() = 0;  

    public:
        // Pretend these two methods don't exist.
        // They are only for supporting obsolete
        // interfaces that have explicit lock/unlock
        virtual void Exception_unsafe_Lock__which_should_NOT_be_used_because_of_imminent_deadlocks__Use_SmartLock_instead() = 0;
        virtual void Exception_unsafe_Unlock__which_should_NOT_be_used_because_of_imminent_deadlocks__Use_SmartLock_instead() = 0;
    };

    // this typedef is obsolete
    typedef CriticalSection::Ptr CriticalSectionPtr;

    DLL_SYNCH_EXIM CriticalSection* CreateCriticalSection(
        EnumDSSLockStackCategory iLockStackCategory = DssLkStkCatNotNestingLock);

    DLL_SYNCH_EXIM CriticalSection* GetBootstrapCriticalSection();
}

#endif // MSynch_CriticialSection_h