Common: Add scope_guard.h from Dolphin

src/common/scope_guard.h

@@ -0,0 +1,41 @@
+// Copyright 2015 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <optional>
+
+namespace Common
+{
+template <typename Callable>
+class ScopeGuard final
+{
+public:
+  ScopeGuard(Callable&& finalizer) : m_finalizer(std::forward<Callable>(finalizer)) {}
+
+  ScopeGuard(ScopeGuard&& other) : m_finalizer(std::move(other.m_finalizer))
+  {
+    other.m_finalizer = nullptr;
+  }
+
+  ~ScopeGuard() { Exit(); }
+  void Dismiss() { m_finalizer.reset(); }
+  void Exit()
+  {
+    if (m_finalizer)
+    {
+      (*m_finalizer)();  // must not throw
+      m_finalizer.reset();
+    }
+  }
+
+  ScopeGuard(const ScopeGuard&) = delete;
+
+  void operator=(const ScopeGuard&) = delete;
+
+private:
+  std::optional<Callable> m_finalizer;
+};
+
+}  // Namespace Common