Loki/include/loki/ScopeGuard.h

////////////////////////////////////////////////////////////////////////////////
// The Loki Library
// Copyright (c) 2000 Andrei Alexandrescu
// Copyright (c) 2000 Petru Marginean
// Copyright (c) 2005 Joshua Lehrer
//
// Permission to use, copy, modify, distribute and sell this software for any 
//     purpose is hereby granted without fee, provided that the above copyright 
//     notice appear in all copies and that both that copyright notice and this 
//     permission notice appear in supporting documentation.
// The author makes no representations about the 
//     suitability of this software for any purpose. It is provided "as is" 
//     without express or implied warranty.
////////////////////////////////////////////////////////////////////////////////
#ifndef LOKI_SCOPEGUARD_H_
#define LOKI_SCOPEGUARD_H_

// $Header$

#include <loki/RefToValue.h>

/// \defgroup ExceptionGroup Exception-safe code

namespace Loki
{

    class ScopeGuardImplBase
    {
        ScopeGuardImplBase& operator =(const ScopeGuardImplBase&);

    protected:

        ~ScopeGuardImplBase()
        {}

        ScopeGuardImplBase(const ScopeGuardImplBase& other) throw() 
            : dismissed_(other.dismissed_)
        {
            other.Dismiss();
        }

        template <typename J>
        static void SafeExecute(J& j) throw() 
        {
            if (!j.dismissed_)
                try
                {
                    j.Execute();
                }
                catch(...)
                {}
        }
        
        mutable bool dismissed_;

    public:
        ScopeGuardImplBase() throw() : dismissed_(false) 
        {}

        void Dismiss() const throw() 
        {
            dismissed_ = true;
        }
    };
    
    ////////////////////////////////////////////////////////////////
    ///
    /// \typedef typedef const ScopeGuardImplBase& ScopeGuard
    /// \ingroup ExceptionGroup
    ///
    /// See Andrei's and Petru Marginean's CUJ article
    /// http://www.cuj.com/documents/s=8000/cujcexp1812alexandr/alexandr.htm
    ///
    /// Changes to the original code by Joshua Lehrer:
    /// http://www.lehrerfamily.com/scopeguard.html
    ////////////////////////////////////////////////////////////////
    
    typedef const ScopeGuardImplBase& ScopeGuard;

    template <typename F>
    class ScopeGuardImpl0 : public ScopeGuardImplBase
    {
    public:
        static ScopeGuardImpl0<F> MakeGuard(F fun)
        {
            return ScopeGuardImpl0<F>(fun);
        }

        ~ScopeGuardImpl0() throw() 
        {
            SafeExecute(*this);
        }

        void Execute() 
        {
            fun_();
        }

    protected:
        ScopeGuardImpl0(F fun) : fun_(fun) 
        {}

        F fun_;
    };

    template <typename F> 
    inline ScopeGuardImpl0<F> MakeGuard(F fun)
    {
        return ScopeGuardImpl0<F>::MakeGuard(fun);
    }

    template <typename F, typename P1>
    class ScopeGuardImpl1 : public ScopeGuardImplBase
    {
    public:
        static ScopeGuardImpl1<F, P1> MakeGuard(F fun, P1 p1)
        {
            return ScopeGuardImpl1<F, P1>(fun, p1);
        }

        ~ScopeGuardImpl1() throw() 
        {
            SafeExecute(*this);
        }

        void Execute()
        {
            fun_(p1_);
        }

    protected:
        ScopeGuardImpl1(F fun, P1 p1) : fun_(fun), p1_(p1) 
        {}

        F fun_;
        const P1 p1_;
    };

    template <typename F, typename P1> 
    inline ScopeGuardImpl1<F, P1> MakeGuard(F fun, P1 p1)
    {
        return ScopeGuardImpl1<F, P1>::MakeGuard(fun, p1);
    }

    template <typename F, typename P1, typename P2>
    class ScopeGuardImpl2: public ScopeGuardImplBase
    {
    public:
        static ScopeGuardImpl2<F, P1, P2> MakeGuard(F fun, P1 p1, P2 p2)
        {
            return ScopeGuardImpl2<F, P1, P2>(fun, p1, p2);
        }

        ~ScopeGuardImpl2() throw() 
        {
            SafeExecute(*this);
        }

        void Execute()
        {
            fun_(p1_, p2_);
        }

    protected:
        ScopeGuardImpl2(F fun, P1 p1, P2 p2) : fun_(fun), p1_(p1), p2_(p2) 
        {}

        F fun_;
        const P1 p1_;
        const P2 p2_;
    };

    template <typename F, typename P1, typename P2>
    inline ScopeGuardImpl2<F, P1, P2> MakeGuard(F fun, P1 p1, P2 p2)
    {
        return ScopeGuardImpl2<F, P1, P2>::MakeGuard(fun, p1, p2);
    }

    template <typename F, typename P1, typename P2, typename P3>
    class ScopeGuardImpl3 : public ScopeGuardImplBase
    {
    public:
        static ScopeGuardImpl3<F, P1, P2, P3> MakeGuard(F fun, P1 p1, P2 p2, P3 p3)
        {
            return ScopeGuardImpl3<F, P1, P2, P3>(fun, p1, p2, p3);
        }

        ~ScopeGuardImpl3() throw() 
        {
            SafeExecute(*this);
        }

        void Execute()
        {
            fun_(p1_, p2_, p3_);
        }

    protected:
        ScopeGuardImpl3(F fun, P1 p1, P2 p2, P3 p3) : fun_(fun), p1_(p1), p2_(p2), p3_(p3) 
        {}

        F fun_;
        const P1 p1_;
        const P2 p2_;
        const P3 p3_;
    };

    template <typename F, typename P1, typename P2, typename P3>
    inline ScopeGuardImpl3<F, P1, P2, P3> MakeGuard(F fun, P1 p1, P2 p2, P3 p3)
    {
        return ScopeGuardImpl3<F, P1, P2, P3>::MakeGuard(fun, p1, p2, p3);
    }

    //************************************************************

    template <class Obj, typename MemFun>
    class ObjScopeGuardImpl0 : public ScopeGuardImplBase
    {
    public:
        static ObjScopeGuardImpl0<Obj, MemFun> MakeObjGuard(Obj& obj, MemFun memFun)
        {
            return ObjScopeGuardImpl0<Obj, MemFun>(obj, memFun);
        }

        ~ObjScopeGuardImpl0() throw() 
        {
            SafeExecute(*this);
        }

        void Execute() 
        {
            (obj_.*memFun_)();
        }

    protected:
        ObjScopeGuardImpl0(Obj& obj, MemFun memFun) : obj_(obj), memFun_(memFun) 
        {}

        Obj& obj_;
        MemFun memFun_;
    };

    template <class Obj, typename MemFun>
    inline ObjScopeGuardImpl0<Obj, MemFun> MakeObjGuard(Obj& obj, MemFun memFun)
    {
        return ObjScopeGuardImpl0<Obj, MemFun>::MakeObjGuard(obj, memFun);
    }

    template <typename Ret, class Obj1, class Obj2>
    inline ObjScopeGuardImpl0<Obj1,Ret(Obj2::*)()> MakeGuard(Ret(Obj2::*memFun)(), Obj1 &obj) 
    {
      return ObjScopeGuardImpl0<Obj1,Ret(Obj2::*)()>::MakeObjGuard(obj,memFun);
    }

    template <typename Ret, class Obj1, class Obj2>
    inline ObjScopeGuardImpl0<Obj1,Ret(Obj2::*)()> MakeGuard(Ret(Obj2::*memFun)(), Obj1 *obj) 
    {
      return ObjScopeGuardImpl0<Obj1,Ret(Obj2::*)()>::MakeObjGuard(*obj,memFun);
    }

    template <class Obj, typename MemFun, typename P1>
    class ObjScopeGuardImpl1 : public ScopeGuardImplBase
    {
    public:
        static ObjScopeGuardImpl1<Obj, MemFun, P1> MakeObjGuard(Obj& obj, MemFun memFun, P1 p1)
        {
            return ObjScopeGuardImpl1<Obj, MemFun, P1>(obj, memFun, p1);
        }

        ~ObjScopeGuardImpl1() throw() 
        {
            SafeExecute(*this);
        }

        void Execute() 
        {
            (obj_.*memFun_)(p1_);
        }

    protected:
        ObjScopeGuardImpl1(Obj& obj, MemFun memFun, P1 p1) : obj_(obj), memFun_(memFun), p1_(p1) 
        {}
        
        Obj& obj_;
        MemFun memFun_;
        const P1 p1_;
    };

    template <class Obj, typename MemFun, typename P1>
    inline ObjScopeGuardImpl1<Obj, MemFun, P1> MakeObjGuard(Obj& obj, MemFun memFun, P1 p1)
    {
        return ObjScopeGuardImpl1<Obj, MemFun, P1>::MakeObjGuard(obj, memFun, p1);
    }

    template <typename Ret, class Obj1, class Obj2, typename P1a, typename P1b>
    inline ObjScopeGuardImpl1<Obj1,Ret(Obj2::*)(P1a),P1b> MakeGuard(Ret(Obj2::*memFun)(P1a), Obj1 &obj, P1b p1) 
    {
      return ObjScopeGuardImpl1<Obj1,Ret(Obj2::*)(P1a),P1b>::MakeObjGuard(obj,memFun,p1);
    }

    template <typename Ret, class Obj1, class Obj2, typename P1a, typename P1b>
    inline ObjScopeGuardImpl1<Obj1,Ret(Obj2::*)(P1a),P1b> MakeGuard(Ret(Obj2::*memFun)(P1a), Obj1 *obj, P1b p1) 
    {
      return ObjScopeGuardImpl1<Obj1,Ret(Obj2::*)(P1a),P1b>::MakeObjGuard(*obj,memFun,p1);
    }

    template <class Obj, typename MemFun, typename P1, typename P2>
    class ObjScopeGuardImpl2 : public ScopeGuardImplBase
    {
    public:
        static ObjScopeGuardImpl2<Obj, MemFun, P1, P2> MakeObjGuard(Obj& obj, MemFun memFun, P1 p1, P2 p2)
        {
            return ObjScopeGuardImpl2<Obj, MemFun, P1, P2>(obj, memFun, p1, p2);
        }

        ~ObjScopeGuardImpl2() throw() 
        {
            SafeExecute(*this);
        }

        void Execute() 
        {
            (obj_.*memFun_)(p1_, p2_);
        }

    protected:
        ObjScopeGuardImpl2(Obj& obj, MemFun memFun, P1 p1, P2 p2) : obj_(obj), memFun_(memFun), p1_(p1), p2_(p2) 
        {}

        Obj& obj_;
        MemFun memFun_;
        const P1 p1_;
        const P2 p2_;
    };

    template <class Obj, typename MemFun, typename P1, typename P2>
    inline ObjScopeGuardImpl2<Obj, MemFun, P1, P2> MakeObjGuard(Obj& obj, MemFun memFun, P1 p1, P2 p2)
    {
        return ObjScopeGuardImpl2<Obj, MemFun, P1, P2>::MakeObjGuard(obj, memFun, p1, p2);
    }

    template <typename Ret, class Obj1, class Obj2, typename P1a, typename P1b, typename P2a, typename P2b>
    inline ObjScopeGuardImpl2<Obj1,Ret(Obj2::*)(P1a,P2a),P1b,P2b> MakeGuard(Ret(Obj2::*memFun)(P1a,P2a), Obj1 &obj, P1b p1, P2b p2) 
    {
      return ObjScopeGuardImpl2<Obj1,Ret(Obj2::*)(P1a,P2a),P1b,P2b>::MakeObjGuard(obj,memFun,p1,p2);
    }

    template <typename Ret, class Obj1, class Obj2, typename P1a, typename P1b, typename P2a, typename P2b>
    inline ObjScopeGuardImpl2<Obj1,Ret(Obj2::*)(P1a,P2a),P1b,P2b> MakeGuard(Ret(Obj2::*memFun)(P1a,P2a), Obj1 *obj, P1b p1, P2b p2) 
    {
      return ObjScopeGuardImpl2<Obj1,Ret(Obj2::*)(P1a,P2a),P1b,P2b>::MakeObjGuard(*obj,memFun,p1,p2);
    }

} // namespace Loki

#define LOKI_CONCATENATE_DIRECT(s1, s2)  s1##s2
#define LOKI_CONCATENATE(s1, s2)         LOKI_CONCATENATE_DIRECT(s1, s2)
#define LOKI_ANONYMOUS_VARIABLE(str)     LOKI_CONCATENATE(str, __LINE__)

#define LOKI_ON_BLOCK_EXIT      ScopeGuard LOKI_ANONYMOUS_VARIABLE(scopeGuard) = MakeGuard
#define LOKI_ON_BLOCK_EXIT_OBJ  ScopeGuard LOKI_ANONYMOUS_VARIABLE(scopeGuard) = MakeObjGuard

#endif // end file guardian