smartptr.h

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        RefCounted(const RefCounted& rhs)
        : pCount_(rhs.pCount_)
        {}

        // MWCW lacks template friends, hence the following kludge
        template <typename P1>
        RefCounted(const RefCounted<P1>& rhs)
        : pCount_(reinterpret_cast<const RefCounted&>(rhs).pCount_)
        {}

        P Clone(const P& val)
        {
            ++*pCount_;
            return val;
        }

        bool Release(const P&)
        {
            if (!--*pCount_)
            {
                SmallObject<>::operator delete(pCount_, sizeof(uintptr_t));
                pCount_ = NULL;
                return true;
            }
            return false;
        }

        void Swap(RefCounted& rhs)
        { std::swap(pCount_, rhs.pCount_); }

        enum { destructiveCopy = false };

    private:
        // Data
        uintptr_t* pCount_;
    };

////////////////////////////////////////////////////////////////////////////////
///  \struct RefCountedMT
///
///  \ingroup  SmartPointerOwnershipGroup
///  Implementation of the OwnershipPolicy used by SmartPtr
///  Implements external reference counting for multithreaded programs
///  Policy Usage: RefCountedMTAdj<ThreadingModel>::RefCountedMT
///
///  \par Warning
///  There could be a race condition, see bug "Race condition in RefCountedMTAdj::Release"
///  http://sourceforge.net/tracker/index.php?func=detail&aid=1408845&group_id=29557&atid=396644
///  As stated in bug 1408845, the Release function is not thread safe if a
///  SmartPtr copy-constructor tries to copy the last pointer to an object in
///  one thread, while the destructor is acting on the last pointer in another
///  thread.  The existence of a race between a copy-constructor and destructor
///  implies a design flaw at a higher level.  That race condition must be
///  fixed at a higher design level, and no change to this class could fix it.
////////////////////////////////////////////////////////////////////////////////

    template <template <class, class> class ThreadingModel,
              class MX = LOKI_DEFAULT_MUTEX >
    struct RefCountedMTAdj
    {
        template <class P>
        class RefCountedMT : public ThreadingModel< RefCountedMT<P>, MX >
        {
            typedef ThreadingModel< RefCountedMT<P>, MX > base_type;
            typedef typename base_type::IntType       CountType;
            typedef volatile CountType               *CountPtrType;

        public:
            RefCountedMT()
            {
                pCount_ = static_cast<CountPtrType>(
                    SmallObject<LOKI_DEFAULT_THREADING_NO_OBJ_LEVEL>::operator new(
                        sizeof(*pCount_)));
                assert(pCount_);
                //*pCount_ = 1;
                ThreadingModel<RefCountedMT, MX>::AtomicAssign(*pCount_, 1);
            }

            RefCountedMT(const RefCountedMT& rhs)
            : pCount_(rhs.pCount_)
            {}

            //MWCW lacks template friends, hence the following kludge
            template <typename P1>
            RefCountedMT(const RefCountedMT<P1>& rhs)
            : pCount_(reinterpret_cast<const RefCountedMT<P>&>(rhs).pCount_)
            {}

            P Clone(const P& val)
            {
                ThreadingModel<RefCountedMT, MX>::AtomicIncrement(*pCount_);
                return val;
            }

            bool Release(const P&)
            {
                bool isZero = false;
                ThreadingModel< RefCountedMT, MX >::AtomicDecrement( *pCount_, 0, isZero );
                if ( isZero )
                {
                    SmallObject<LOKI_DEFAULT_THREADING_NO_OBJ_LEVEL>::operator delete(
                        const_cast<CountType *>(pCount_),
                        sizeof(*pCount_));
                    return true;
                }
                return false;
            }

            void Swap(RefCountedMT& rhs)
            { std::swap(pCount_, rhs.pCount_); }

            enum { destructiveCopy = false };

        private:
            // Data
            CountPtrType pCount_;
        };
    };

////////////////////////////////////////////////////////////////////////////////
///  \class COMRefCounted
///
///  \ingroup  SmartPointerOwnershipGroup
///  Implementation of the OwnershipPolicy used by SmartPtr
///  Adapts COM intrusive reference counting to OwnershipPolicy-specific syntax
////////////////////////////////////////////////////////////////////////////////

    template <class P>
    class COMRefCounted
    {
    public:
        COMRefCounted()
        {}

        template <class U>
        COMRefCounted(const COMRefCounted<U>&)
        {}

        static P Clone(const P& val)
        {
            if(val!=0)
               val->AddRef();
            return val;
        }

        static bool Release(const P& val)
        {
            if(val!=0)
                val->Release();
            return false;
        }

        enum { destructiveCopy = false };

        static void Swap(COMRefCounted&)
        {}
    };

////////////////////////////////////////////////////////////////////////////////
///  \struct DeepCopy
///
///  \ingroup  SmartPointerOwnershipGroup
///  Implementation of the OwnershipPolicy used by SmartPtr
///  Implements deep copy semantics, assumes existence of a Clone() member
///  function of the pointee type
////////////////////////////////////////////////////////////////////////////////

    template <class P>
    struct DeepCopy
    {
        DeepCopy()
        {}

        template <class P1>
        DeepCopy(const DeepCopy<P1>&)
        {}

        static P Clone(const P& val)
        { return val->Clone(); }

        static bool Release(const P&)
        { return true; }

        static void Swap(DeepCopy&)
        {}

        enum { destructiveCopy = false };
    };

////////////////////////////////////////////////////////////////////////////////
///  \class RefLinked
///
///  \ingroup  SmartPointerOwnershipGroup
///  Implementation of the OwnershipPolicy used by SmartPtr
///  Implements reference linking
////////////////////////////////////////////////////////////////////////////////

    namespace Private
    {
        class LOKI_EXPORT RefLinkedBase
        {
        public:
            RefLinkedBase()
            { prev_ = next_ = this; }

            RefLinkedBase(const RefLinkedBase& rhs);

            bool Release();

            void Swap(RefLinkedBase& rhs);

            bool Merge( RefLinkedBase & rhs );

            enum { destructiveCopy = false };

        private:
            static unsigned int CountPrevCycle( const RefLinkedBase * pThis );
            static unsigned int CountNextCycle( const RefLinkedBase * pThis );
            bool HasPrevNode( const RefLinkedBase * p ) const;
            bool HasNextNode( const RefLinkedBase * p ) const;

            mutable const RefLinkedBase* prev_;
            mutable const RefLinkedBase* next_;
        };
    }

    template <class P>
    class RefLinked : public Private::RefLinkedBase
    {
    public:
        RefLinked()
        {}

        template <class P1>
        RefLinked(const RefLinked<P1>& rhs)
        : Private::RefLinkedBase(rhs)
        {}

        static P Clone(const P& val)
        { return val; }

        bool Release(const P&)
        { return Private::RefLinkedBase::Release(); }

        template < class P1 >
        bool Merge( RefLinked< P1 > & rhs )
        {
            return Private::RefLinkedBase::Merge( rhs );
        }
    };

////////////////////////////////////////////////////////////////////////////////
///  \class DestructiveCopy
///
///  \ingroup  SmartPointerOwnershipGroup
///  Implementation of the OwnershipPolicy used by SmartPtr
///  Implements destructive copy semantics (a la std::auto_ptr)
////////////////////////////////////////////////////////////////////////////////

    template <class P>
    class DestructiveCopy
    {
    public:
        DestructiveCopy()
        {}

        template <class P1>
        DestructiveCopy(const DestructiveCopy<P1>&)
        {}

        template <class P1>
        static P Clone(P1& val)
        {
            P result(val);
            val = P1();
            return result;
        }

        static bool Release(const P&)
        { return true; }

        static void Swap(DestructiveCopy&)
        {}

        enum { destructiveCopy = true };
    };

////////////////////////////////////////////////////////////////////////////////
///  \class NoCopy
///
///  \ingroup  SmartPointerOwnershipGroup
///  Implementation of the OwnershipPolicy used by SmartPtr
///  Implements a policy that doesn't allow copying objects
////////////////////////////////////////////////////////////////////////////////

    template <class P>
    class NoCopy
    {
    public:
        NoCopy()
        {}

        template <class P1>
        NoCopy(const NoCopy<P1>&)
        {}

        static P Clone(const P&)
        {
            // Make it depended on template parameter
            static const bool DependedFalse = sizeof(P*) == 0;

            LOKI_STATIC_CHECK(DependedFalse, This_Policy_Disallows_Value_Copying);
        }

        static bool Release(const P&)
        { return true; }

        static void Swap(NoCopy&)
        {}

        enum { destructiveCopy = false };
    };

////////////////////////////////////////////////////////////////////////////////
///  \struct AllowConversion
///
///  \ingroup  SmartPointerConversionGroup
///  Implementation of the ConversionPolicy used by SmartPtr
///  Allows implicit conversion from SmartPtr to the pointee type
////////////////////////////////////////////////////////////////////////////////

    struct AllowConversion
    {
        enum { allow = true };

        void Swap(AllowConversion&)
        {}
    };

////////////////////////////////////////////////////////////////////////////////
///  \struct DisallowConversion
///
///  \ingroup  SmartPointerConversionGroup
///  Implementation of the ConversionPolicy used by SmartPtr
///  Does not allow implicit conversion from SmartPtr to the pointee type
///  You can initialize a DisallowConversion with an AllowConversion
////////////////////////////////////////////////////////////////////////////////

    struct DisallowConversion
    {
        DisallowConversion()
        {}

        DisallowConversion(const AllowConversion&)
        {}

        enum { allow = false };

        void Swap(DisallowConversion&)
        {}
    };

////////////////////////////////////////////////////////////////////////////////
///  \struct NoCheck
///
///  \ingroup  SmartPointerCheckingGroup
///  Implementation of the CheckingPolicy used by SmartPtr
///  Well, it's clear what it does :o)
////////////////////////////////////////////////////////////////////////////////

    template <class P>
    struct NoCheck
    {
        NoCheck()
        {}

        template <class P1>
        NoCheck(const NoCheck<P1>&)
        {}

        static void OnDefault(const P&)
        {}

        static void OnInit(const P&)
        {}

        static void OnDereference(const P&)
        {}

        static void Swap(NoCheck&)
        {}
    };


////////////////////////////////////////////////////////////////////////////////
///  \struct AssertCheck
///
///  \ingroup  SmartPointerCheckingGroup
///  Implementation of the CheckingPolicy used by SmartPtr
///  Checks the pointer before dereference
////////////////////////////////////////////////////////////////////////////////

    template <class P>
    struct AssertCheck
    {
        AssertCheck()
        {}

        template <class P1>
        AssertCheck(const AssertCheck<P1>&)
        {}

        template <class P1>
        AssertCheck(const NoCheck<P1>&)
        {}

        static void OnDefault(const P&)
        {}

        static void OnInit(const P&)
        {}

        static void OnDereference(P val)
        { assert(val); (void)val; }

        static void Swap(AssertCheck&)
        {}
    };

////////////////////////////////////////////////////////////////////////////////
///  \struct AssertCheckStrict
///
///  \ingroup  SmartPointerCheckingGroup
///  Implementation of the CheckingPolicy used by SmartPtr
///  Checks the pointer against zero upon initialization and before dereference
///  You can initialize an AssertCheckStrict with an AssertCheck
////////////////////////////////////////////////////////////////////////////////

    template <class P>
    struct AssertCheckStrict
    {
        AssertCheckStrict()
        {}