ScopeGuard11.h

#pragma once

template <class Fun>
class ScopeGuard
{
private:
    Fun f;
    bool active;

public:
    ScopeGuard(Fun f)
        : f(std::move(f))
        , active(true)
    {
    }

    ~ScopeGuard()
    {
        if (active)
        {
            f();
        }
    }

    void dismiss()
    {
        active = false;
    }
    
    ScopeGuard() = delete;
    ScopeGuard(const ScopeGuard&) = delete;
    ScopeGuard& operator = (const ScopeGuard&) = delete;

    ScopeGuard(ScopeGuard&& rhs)
        :f(std::move(rhs.f))
        , active_(rhs.active)
    {
        rhs.dismiss();
    }
};

template <class Fun>
ScopeGuard<Fun> scopeGuard(Fun f)
{
    return ScopeGuard<Fun>(std::move(f));
}

namespace detail
{
    enum class ScopeGuardOnExit {};

    template <typename Fun>
    ScopeGuard<Fun> operator + (ScopeGuardOnExit, Fun&& fn)
    {
        return ScopeGuard<Fun>(std::forward<Fun>(fn));
    }
}


#define SCOPE_GUARD_CONCATENATE_IMPL(s1, s2) s1##s2
#define SCOPE_GUARD_CONCATENATE(s1, s2) SCOPE_GUARD_CONCATENATE_IMPL(s1, s2)

#ifdef __COUNTER__
#  define SCOPE_GUARD_ANONYMOUS_VARIABLE(str) SCOPE_GUARD_CONCATENATE(str, __COUNTER__)
#else
#  define SCOPE_GUARD_ANONYMOUS_VARIABLE(str) SCOPE_GUARD_CONCATENATE(str, __LINE__)
#endif

#define SCOPE_EXIT auto SCOPE_GUARD_ANONYMOUS_VARIABLE(SCOPE_EXIT_STATE) = ::detail::ScopeGuardOnExit() + [&]()