Don't double-rethrow std::exception_ptr (#53)

It's unnecessary to throw and then rethrow std::exception_ptr, just derive clone_base separately. nb. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110835
boostorg · Aug 5, 2023 · ea70868 · ea70868
1 parent 03aa58e
commit ea70868
Showing 1 changed file with 32 additions and 24 deletions.
diff --git a/include/boost/exception/detail/exception_ptr.hpp b/include/boost/exception/detail/exception_ptr.hpp
@@ -44,27 +44,48 @@ boost
     exception_detail
         {
 #ifndef BOOST_NO_CXX11_HDR_EXCEPTION
-        struct
-        std_exception_ptr_wrapper:
-            std::exception
+        class
+        BOOST_SYMBOL_VISIBLE
+        std_exception_ptr_clone_impl:
+            public virtual clone_base
             {
-            std::exception_ptr p;
-            explicit std_exception_ptr_wrapper( std::exception_ptr const & ptr ) BOOST_NOEXCEPT:
-                p(ptr)
+            std::exception_ptr p_;
+
+            public:
+
+            explicit std_exception_ptr_clone_impl( std::exception_ptr const & ptr ) BOOST_NOEXCEPT:
+                p_(ptr)
                 {
                 }
-#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
-            explicit std_exception_ptr_wrapper( std::exception_ptr && ptr ) BOOST_NOEXCEPT:
-                p(static_cast<std::exception_ptr &&>(ptr))
+
+            ~std_exception_ptr_clone_impl() BOOST_NOEXCEPT_OR_NOTHROW
                 {
                 }
-#endif
+
+            private:
+
+            std_exception_ptr_clone_impl( std_exception_ptr_clone_impl const & x ):
+                p_(x.p_)
+                {
+                }
+
+            clone_base const*
+            clone() const
+                {
+                return new std_exception_ptr_clone_impl(*this);
+                }
+
+            void
+            rethrow() const
+                {
+                std::rethrow_exception(p_);
+                }
             };
         shared_ptr<exception_detail::clone_base const>
         inline
         wrap_exception_ptr( std::exception_ptr const & e )
             {
-            exception_detail::clone_base const & base = boost::enable_current_exception(std_exception_ptr_wrapper(e));
+            exception_detail::clone_base const & base = std_exception_ptr_clone_impl(e);
             return shared_ptr<exception_detail::clone_base const>(base.clone());
             }
 #endif
@@ -536,20 +557,7 @@ boost
         rethrow_exception_( exception_ptr const & p )
             {
             BOOST_ASSERT(p);
-#if defined( BOOST_NO_CXX11_HDR_EXCEPTION ) || defined( BOOST_NO_EXCEPTIONS )
             p.ptr_->rethrow();
-#else
-            try
-                {
-                p.ptr_->rethrow();
-                }
-            catch(
-            std_exception_ptr_wrapper const & wrp)
-                {
-                // if an std::exception_ptr was wrapped above then rethrow it
-                std::rethrow_exception(wrp.p);
-                }
-#endif
             }
         }