exception_wrapper::exception_ptr accesor

Summary: Add accessor family `exception_wrapper::exception_ptr` which returns a reference to the contained `std::exception_ptr`. Follows `std::get`, `std::optional::value`, `std::expected::value`, `std::expected::error`.

Reviewed By: dmm-fb, snarkmaster

Differential Revision: D74182146

fbshipit-source-id: 64b4140996679196ad66154d2e4a5395e6483a81

Author: yfeldblum

folly/ExceptionWrapper-inl.h

@@ -153,10 +153,20 @@ inline std::exception_ptr exception_wrapper::to_exception_ptr()
   return ptr_;
 }
 
-inline std::exception_ptr const& exception_wrapper::exception_ptr_ref()
-    const noexcept {
+inline std::exception_ptr& exception_wrapper::exception_ptr() & noexcept {
   return ptr_;
 }
+inline std::exception_ptr const& exception_wrapper::exception_ptr()
+    const& noexcept {
+  return ptr_;
+}
+inline std::exception_ptr&& exception_wrapper::exception_ptr() && noexcept {
+  return std::move(ptr_);
+}
+inline std::exception_ptr const&& exception_wrapper::exception_ptr()
+    const&& noexcept {
+  return std::move(ptr_);
+}
 
 inline std::type_info const* exception_wrapper::type() const noexcept {
   return exception_ptr_get_type(ptr_);

folly/ExceptionWrapper.h

@@ -228,7 +228,11 @@ class exception_wrapper final {
   std::exception_ptr to_exception_ptr() const& noexcept;
   // NB: Can add this back, if a good use-case arises.
   std::exception_ptr to_exception_ptr() && = delete;
-  std::exception_ptr const& exception_ptr_ref() const noexcept;
+
+  std::exception_ptr& exception_ptr() & noexcept;
+  std::exception_ptr const& exception_ptr() const& noexcept;
+  std::exception_ptr&& exception_ptr() && noexcept;
+  std::exception_ptr const&& exception_ptr() const&& noexcept;
 
   //! \return `true` if the wrappers point to the same exception object
   friend inline bool operator==(

folly/result/result.h

@@ -227,7 +227,7 @@ class non_value_result {
 
   friend inline bool operator==(
       const non_value_result& lhs, const non_value_result& rhs) {
-    return lhs.ew_.exception_ptr_ref() == rhs.ew_.exception_ptr_ref();
+    return lhs.ew_ == rhs.ew_;
   }
 
   // DO NOT USE these "legacy" functions outside of `folly` internals. Instead: