Common: Add scope_exit.h

src/common/CMakeLists.txt

@@ -16,6 +16,7 @@ set(HEADERS
     logging/log.h
     memory_util.h
     mp.h
+    scope_exit.h
     string_util.h
     x64/abi.h
     x64/cpu_detect.h

src/common/scope_exit.h

@@ -0,0 +1,42 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <utility>
+
+namespace detail {
+    template <typename Func>
+    struct ScopeExitHelper {
+        explicit ScopeExitHelper(Func&& func) : func(std::move(func)) {}
+        ~ScopeExitHelper() { func(); }
+
+        Func func;
+    };
+
+    template <typename Func>
+    ScopeExitHelper<Func> ScopeExit(Func&& func) { return ScopeExitHelper<Func>(std::move(func)); }
+}
+
+#define CONCAT2(x, y) DO_CONCAT2(x, y)
+#define DO_CONCAT2(x, y) x ## y
+
+/**
+ * This macro allows you to conveniently specify a block of code that will run on scope exit. Handy
+ * for doing ad-hoc clean-up tasks in a function with multiple returns.
+ *
+ * Example usage:
+ * \code
+ * const int saved_val = g_foo;
+ * g_foo = 55;
+ * SCOPE_EXIT({ g_foo = saved_val; });
+ *
+ * if (Bar()) {
+ *     return 0;
+ * } else {
+ *     return 20;
+ * }
+ * \endcode
+ */
+#define SCOPE_EXIT(body) auto CONCAT2(scope_exit_helper_, __LINE__) = detail::ScopeExit([&]() body)