Cut the ScopeGuard alias now that we have auto

[folly.git] / folly / ExceptionWrapper.h

diff --git a/folly/ExceptionWrapper.h b/folly/ExceptionWrapper.h
index 0d028714231fa5ad6fde57055c41b6734b13356f..fc0cac77529b58165c6029137d5aa7c0bc9bf012 100644 (file)
--- a/folly/ExceptionWrapper.h
+++ b/folly/ExceptionWrapper.h
@@ -162,7 +162,7 @@ auto fold(Fn&& fn, A&& a, B&& b, Bs&&... bs) {
 //! \endcode
 class exception_wrapper final {
  private:
-  struct AnyException : std::exception {
+  struct FOLLY_EXPORT AnyException : std::exception {
     std::type_info const* typeinfo_;
     template <class T>
     /* implicit */ AnyException(T&& t) noexcept : typeinfo_(&typeid(t)) {}
@@ -235,18 +235,20 @@ class exception_wrapper final {
     Ex const& as() const noexcept;
   };
 
-  enum class Placement { kInSitu, kOnHeap };
+  struct ThrownTag {};
+  struct InSituTag {};
+  struct OnHeapTag {};
+
   template <class T>
-  using PlacementOf = std::integral_constant<
-      Placement,
-      sizeof(T) <= sizeof(Buffer::Storage) &&
+  using PlacementOf = _t<std::conditional<
+      !IsStdException<T>::value,
+      ThrownTag,
+      _t<std::conditional<
+          sizeof(T) <= sizeof(Buffer::Storage) &&
               alignof(T) <= alignof(Buffer::Storage) &&
-              noexcept(T(std::declval<T&&>()))
-          ? Placement::kInSitu
-          : Placement::kOnHeap>;
-
-  using InSituTag = std::integral_constant<Placement, Placement::kInSitu>;
-  using OnHeapTag = std::integral_constant<Placement, Placement::kOnHeap>;
+              noexcept(T(std::declval<T&&>())),
+          InSituTag,
+          OnHeapTag>>>>;
 
   static std::exception const* as_exception_or_null_(std::exception const& ex);
   static std::exception const* as_exception_or_null_(AnyException);
@@ -280,6 +282,7 @@ class exception_wrapper final {
 
   template <class Ex>
   struct InPlace {
+    static_assert(IsStdException<Ex>::value, "only deriving std::exception");
     static void copy_(exception_wrapper const* from, exception_wrapper* to);
     static void move_(exception_wrapper* from, exception_wrapper* to);
     static void delete_(exception_wrapper* that);
@@ -308,6 +311,7 @@ class exception_wrapper final {
     };
     template <class Ex>
     struct Impl final : public Base {
+      static_assert(IsStdException<Ex>::value, "only deriving std::exception");
       Ex ex_;
       Impl() = default;
       template <typename... As>
@@ -336,6 +340,9 @@ class exception_wrapper final {
   };
   VTable const* vptr_{&uninit_};
 
+  template <class Ex, typename... As>
+  exception_wrapper(ThrownTag, in_place_type_t<Ex>, As&&... as);
+
   template <class Ex, typename... As>
   exception_wrapper(OnHeapTag, in_place_type_t<Ex>, As&&... as);