strat: split out common functionality for future meso use

stratosphere/libstratosphere/include/atmosphere/util/util_scope_guard.hpp

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2018-2019 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+ /* Scope guard logic lovingly taken from Andrei Alexandrescu's "Systemic Error Handling in C++" */
+#pragma once
+#include "../defines.hpp"
+
+namespace ams::util {
+
+    namespace impl {
+
+        template<class F>
+        class ScopeGuard {
+            NON_COPYABLE(ScopeGuard);
+            private:
+                F f;
+                bool active;
+            public:
+                constexpr ScopeGuard(F f) : f(std::move(f)), active(true) { }
+                ~ScopeGuard() { if (active) { f(); } }
+                void Cancel() { active = false; }
+
+                ScopeGuard(ScopeGuard&& rhs) : f(std::move(rhs.f)), active(rhs.active) {
+                    rhs.Cancel();
+                }
+        };
+
+        template<class F>
+        constexpr ScopeGuard<F> MakeScopeGuard(F f) {
+            return ScopeGuard<F>(std::move(f));
+        }
+
+        enum class ScopeGuardOnExit {};
+
+        template <typename F>
+        constexpr ScopeGuard<F> operator+(ScopeGuardOnExit, F&& f) {
+            return ScopeGuard<F>(std::forward<F>(f));
+        }
+
+    }
+
+}
+
+#define SCOPE_GUARD ::ams::util::impl::ScopeGuardOnExit() + [&]()
+#define ON_SCOPE_EXIT auto ANONYMOUS_VARIABLE(SCOPE_EXIT_STATE_) = SCOPE_GUARD