unwrapTryTuple only accepted rvalue tuple types

[folly.git] / folly / Try-inl.h

diff --git a/folly/Try-inl.h b/folly/Try-inl.h
index 8adeb42384f876ac241af12d844c92d0a177ac08..e70fce72c8d807e50ad3beb79732d50ab0e68dc1 100644 (file)
--- a/folly/Try-inl.h
+++ b/folly/Try-inl.h
@@ -16,8 +16,10 @@
 
 #pragma once
 
-#include <folly/detail/TryDetail.h>
+#include <folly/Utility.h>
+
 #include <stdexcept>
+#include <tuple>
 
 namespace folly {
 
@@ -163,10 +165,31 @@ makeTryWith(F&& f) {
   }
 }
 
-template <typename... Ts>
-std::tuple<Ts...> unwrapTryTuple(std::tuple<folly::Try<Ts>...>&& ts) {
-  return detail::TryTuple<Ts...>::unwrap(
-      std::forward<std::tuple<folly::Try<Ts>...>>(ts));
+namespace try_detail {
+
+/**
+ * Trait that removes the layer of Try abstractions from the passed in type
+ */
+template <typename Type>
+struct RemoveTry;
+template <template <typename...> class TupleType, typename... Types>
+struct RemoveTry<TupleType<folly::Try<Types>...>> {
+  using type = TupleType<Types...>;
+};
+
+template <std::size_t... Indices, typename Tuple>
+auto unwrapTryTupleImpl(folly::index_sequence<Indices...>, Tuple&& instance) {
+  using std::get;
+  using ReturnType = typename RemoveTry<typename std::decay<Tuple>::type>::type;
+  return ReturnType{(get<Indices>(std::forward<Tuple>(instance)).value())...};
+}
+} // namespace try_detail
+
+template <typename Tuple>
+auto unwrapTryTuple(Tuple&& instance) {
+  using TupleDecayed = typename std::decay<Tuple>::type;
+  using Seq = folly::make_index_sequence<std::tuple_size<TupleDecayed>::value>;
+  return try_detail::unwrapTryTupleImpl(Seq{}, std::forward<Tuple>(instance));
 }
 
 } // namespace folly