Refactor to simplify resize(n) and resize(n, value)

Author: winner245

libcxx/include/forward_list

@@ -806,7 +806,9 @@ public:
   }
 #  endif // _LIBCPP_CXX03_LANG
   _LIBCPP_HIDE_FROM_ABI iterator insert_after(const_iterator __p, const value_type& __v);
-  _LIBCPP_HIDE_FROM_ABI iterator insert_after(const_iterator __p, size_type __n, const value_type& __v);
+  _LIBCPP_HIDE_FROM_ABI iterator insert_after(const_iterator __p, size_type __n, const value_type& __v) {
+    return __insert_after(__p, __n, __v);
+  }
   template <class _InputIterator, __enable_if_t<__has_input_iterator_category<_InputIterator>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI iterator insert_after(const_iterator __p, _InputIterator __f, _InputIterator __l);
 
@@ -876,6 +878,9 @@ private:
   template <class _Iter, class _Sent>
   _LIBCPP_HIDE_FROM_ABI void __assign_with_sentinel(_Iter __f, _Sent __l);
 
+  template <class... _Args>
+  _LIBCPP_HIDE_FROM_ABI iterator __insert_after(const_iterator __p, size_type __n, _Args&&... __args);
+
   template <class _Compare>
   static _LIBCPP_HIDE_FROM_ABI __node_pointer __merge(__node_pointer __f1, __node_pointer __f2, _Compare& __comp);
 
@@ -1129,17 +1134,18 @@ forward_list<_Tp, _Alloc>::insert_after(const_iterator __p, const value_type& __
 }
 
 template <class _Tp, class _Alloc>
+template <class... _Args>
 typename forward_list<_Tp, _Alloc>::iterator
-forward_list<_Tp, _Alloc>::insert_after(const_iterator __p, size_type __n, const value_type& __v) {
+forward_list<_Tp, _Alloc>::__insert_after(const_iterator __p, size_type __n, _Args&&... __args) {
   __begin_node_pointer __r = __p.__get_begin();
   if (__n > 0) {
-    __node_pointer __first = this->__create_node(/* next = */ nullptr, __v);
+    __node_pointer __first = this->__create_node(/* next = */ nullptr, std::forward<_Args>(__args)...);
     __node_pointer __last  = __first;
 #  if _LIBCPP_HAS_EXCEPTIONS
     try {
 #  endif // _LIBCPP_HAS_EXCEPTIONS
       for (--__n; __n != 0; --__n, __last = __last->__next_) {
-        __last->__next_ = this->__create_node(/* next = */ nullptr, __v);
+        __last->__next_ = this->__create_node(/* next = */ nullptr, std::forward<_Args>(__args)...);
       }
 #  if _LIBCPP_HAS_EXCEPTIONS
     } catch (...) {
@@ -1239,33 +1245,8 @@ void forward_list<_Tp, _Alloc>::resize(size_type __n) {
     ;
   if (__i != __e)
     erase_after(__p, __e);
-  else {
-    __n -= __sz;
-    __begin_node_pointer __r = __p.__get_begin();
-    if (__n > 0) {
-      __node_pointer __first = this->__create_node(/* next = */ nullptr);
-      __node_pointer __last  = __first;
-#  if _LIBCPP_HAS_EXCEPTIONS
-      try {
-#  endif // _LIBCPP_HAS_EXCEPTIONS
-        for (--__n; __n != 0; --__n, __last = __last->__next_) {
-          __last->__next_ = this->__create_node(/* next = */ nullptr);
-        }
-#  if _LIBCPP_HAS_EXCEPTIONS
-      } catch (...) {
-        while (__first != nullptr) {
-          __node_pointer __next = __first->__next_;
-          this->__delete_node(__first);
-          __first = __next;
-        }
-        throw;
-      }
-#  endif // _LIBCPP_HAS_EXCEPTIONS
-      __last->__next_ = __r->__next_;
-      __r->__next_    = __first;
-      __r             = static_cast<__begin_node_pointer>(__last);
-    }
-  }
+  else
+    __insert_after(__p, __n - __sz);
 }
 
 template <class _Tp, class _Alloc>
@@ -1278,9 +1259,8 @@ void forward_list<_Tp, _Alloc>::resize(size_type __n, const value_type& __v) {
     ;
   if (__i != __e)
     erase_after(__p, __e);
-  else {
-    insert_after(__p, __n - __sz, __v);
-  }
+  else
+    __insert_after(__p, __n - __sz, __v);
 }
 
 template <class _Tp, class _Alloc>