FTL: Add Optional<T>::or_else
Bug: 185536303
Test: ftl_test
Change-Id: Idf0bac4711111c8cb28e8624bb146a76ec1ff38b
diff --git a/include/ftl/details/optional.h b/include/ftl/details/optional.h
index bff7c1e..e45c1f5 100644
--- a/include/ftl/details/optional.h
+++ b/include/ftl/details/optional.h
@@ -54,5 +54,15 @@
template <typename F, typename T>
using and_then_result_t = typename and_then_result<F, T>::type;
+template <typename F, typename T>
+struct or_else_result {
+ using type = remove_cvref_t<std::invoke_result_t<F>>;
+ static_assert(std::is_same_v<type, std::optional<T>> || std::is_same_v<type, Optional<T>>,
+ "or_else function must return an optional T");
+};
+
+template <typename F, typename T>
+using or_else_result_t = typename or_else_result<F, T>::type;
+
} // namespace details
} // namespace android::ftl