added: scopeguard template a helper class to call code on scope_exit

scopeguard.h

@@ -0,0 +1,60 @@
+#ifndef SCOPEGUARD_H
+#define SCOPEGUARD_H
+
+template<class Fun>
+class ScopeGuard {
+	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 ScopeGuard_detail {
+
+	enum class ScopeGuardOnExit {};
+
+	template<typename Fun>
+	ScopeGuard<Fun> operator+(ScopeGuardOnExit, Fun&& fn) {
+		return ScopeGuard<Fun>(std::forward<Fun>(fn));
+	}
+
+}
+
+#define CONCATENATE_IMPL(s1, s2) s1##s2
+#define CONCATENATE(s1, s2) CONCATENATE_IMPL(s1, s2)
+#ifdef __COUNTER__
+#define ANONYMOUS_VARIABLE(str) \
+	CONCATENATE(str,__COUNTER__)
+#else
+#define ANONYMOUS_VARIABLE(str) \
+	CONCATENATE(str,__LINE__)
+#endif
+
+#define SCOPE_EXIT \
+	auto ANONYMOUS_VARIABLE(SCOPE_EXIT_STATE) \
+		= ::ScopeGuard_detail::ScopeGuardOnExit() + [&]()
+
+#endif // SCOPEGUARD_H