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Use safe fallback with uses-allocator construction when prefix or suffix calls are not available. Instead of being ill-formed, ignore allocator argument, just like when uses_allocator<T>::value is false.

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Ion Gaztañaga
2025-11-29 21:54:21 +01:00
parent fdf6b37b67
commit e2d3cf7bd2
1 changed files with 44 additions and 43 deletions
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87
include/boost/container/detail/dispatch_uses_allocator.hpp
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@@ -38,45 +38,8 @@ namespace boost { namespace container {
namespace dtl {
// Check if we can detect is_convertible using advanced SFINAE expressions
#if !defined(BOOST_NO_CXX11_DECLTYPE) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
//! Code inspired by Mathias Gaunard's is_convertible.cpp found in the Boost mailing list
//! http://boost.2283326.n4.nabble.com/type-traits-is-constructible-when-decltype-is-supported-td3575452.html
//! Thanks Mathias!
//With variadic templates, we need a single class to implement the trait
template<class T, class ...Args>
struct is_constructible
{
typedef char yes_type;
struct no_type
{ char padding[2]; };
template<std::size_t N>
struct dummy;
template<class X>
static decltype(X(boost::move_detail::declval<Args>()...), true_type()) test(int);
template<class X>
static no_type test(...);
BOOST_STATIC_CONSTEXPR bool value = sizeof(test<T>(0)) == sizeof(yes_type);
};
template <class T, class InnerAlloc, class ...Args>
struct is_constructible_with_allocator_prefix
: is_constructible<T, allocator_arg_t, InnerAlloc, Args...>
{};
#else // #if !defined(BOOST_NO_SFINAE_EXPR) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
//Without advanced SFINAE expressions, we can't use is_constructible
//so backup to constructible_with_allocator_xxx
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
template <class T, class InnerAlloc, class ...Args>
struct is_constructible_with_allocator_prefix
@@ -92,13 +55,9 @@ namespace dtl {
template<class T, class InnerAlloc, BOOST_MOVE_CLASSDFLT9, class = void>
struct is_constructible_with_allocator_prefix;
: constructible_with_allocator_prefix<T>
{};
template<class T, class InnerAlloc, BOOST_MOVE_CLASSDFLT9, class = void>
struct is_constructible_with_allocator_suffix;
: constructible_with_allocator_suffix<T>
{};
#define BOOST_INTRUSIVE_IS_CONSTRUCTIBLE_WITH_ALLOCATOR(N) \
template <typename T, class InnerAlloc BOOST_MOVE_I##N BOOST_MOVE_CLASS##N>\
@@ -166,11 +125,32 @@ inline typename dtl::enable_if_and
, dtl::is_not_pair<T>
, uses_allocator<T, typename remove_cvref<ArgAlloc>::type>
, dtl::not_<is_constructible_with_allocator_prefix<T, ArgAlloc, Args...> >
, is_constructible_with_allocator_suffix<T, ArgAlloc, Args...>
>::type dispatch_uses_allocator
( ConstructAlloc& construct_alloc, BOOST_FWD_REF(ArgAlloc) arg_alloc, T* p, BOOST_FWD_REF(Args)...args)
{
allocator_traits<ConstructAlloc>::construct
(construct_alloc, p, ::boost::forward<Args>(args)..., ::boost::forward<ArgAlloc>(arg_alloc));
( construct_alloc, p, ::boost::forward<Args>(args)...
, ::boost::forward<ArgAlloc>(arg_alloc));
}
// allocator suffix
template < typename ConstructAlloc
, typename ArgAlloc
, typename T
, class ...Args
>
inline typename dtl::enable_if_and
< void
, dtl::is_not_pair<T>
, uses_allocator<T, typename remove_cvref<ArgAlloc>::type>
, dtl::not_<is_constructible_with_allocator_prefix<T, ArgAlloc, Args...> >
, dtl::not_<is_constructible_with_allocator_suffix<T, ArgAlloc, Args...> >
>::type dispatch_uses_allocator
( ConstructAlloc& construct_alloc, BOOST_FWD_REF(ArgAlloc) arg_alloc, T* p, BOOST_FWD_REF(Args)...args)
{
(void)arg_alloc;
allocator_traits<ConstructAlloc>::construct(construct_alloc, p, ::boost::forward<Args>(args)...);
}
#else //#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
@@ -217,6 +197,7 @@ BOOST_MOVE_ITERATE_0TO9(BOOST_CONTAINER_SCOPED_ALLOCATOR_DISPATCH_USES_ALLOCATOR
, dtl::is_not_pair<T>\
, uses_allocator<T, typename remove_cvref<ArgAlloc>::type>\
, dtl::not_<is_constructible_with_allocator_prefix<T, ArgAlloc BOOST_MOVE_I##N BOOST_MOVE_TARG##N> >\
, is_constructible_with_allocator_suffix<T, ArgAlloc BOOST_MOVE_I##N BOOST_MOVE_TARG##N>\
>::type\
dispatch_uses_allocator\
(ConstructAlloc& construct_alloc, BOOST_FWD_REF(ArgAlloc) arg_alloc, T* p BOOST_MOVE_I##N BOOST_MOVE_UREF##N)\
@@ -228,6 +209,26 @@ BOOST_MOVE_ITERATE_0TO9(BOOST_CONTAINER_SCOPED_ALLOCATOR_DISPATCH_USES_ALLOCATOR
BOOST_MOVE_ITERATE_0TO9(BOOST_CONTAINER_SCOPED_ALLOCATOR_DISPATCH_USES_ALLOCATOR_CODE)
#undef BOOST_CONTAINER_SCOPED_ALLOCATOR_DISPATCH_USES_ALLOCATOR_CODE
#define BOOST_CONTAINER_SCOPED_ALLOCATOR_DISPATCH_USES_ALLOCATOR_CODE(N) \
template < typename ConstructAlloc, typename ArgAlloc, typename T BOOST_MOVE_I##N BOOST_MOVE_CLASS##N >\
inline typename dtl::enable_if_and\
< void\
, dtl::is_not_pair<T>\
, uses_allocator<T, typename remove_cvref<ArgAlloc>::type>\
, dtl::not_<is_constructible_with_allocator_prefix<T, ArgAlloc BOOST_MOVE_I##N BOOST_MOVE_TARG##N> >\
, dtl::not_<is_constructible_with_allocator_suffix<T, ArgAlloc BOOST_MOVE_I##N BOOST_MOVE_TARG##N> >\
>::type\
dispatch_uses_allocator\
(ConstructAlloc& construct_alloc, BOOST_FWD_REF(ArgAlloc) arg_alloc, T* p BOOST_MOVE_I##N BOOST_MOVE_UREF##N)\
{\
(void)arg_alloc;\
allocator_traits<ConstructAlloc>::construct(construct_alloc, p BOOST_MOVE_I##N BOOST_MOVE_FWD##N);\
}\
//
BOOST_MOVE_ITERATE_0TO9(BOOST_CONTAINER_SCOPED_ALLOCATOR_DISPATCH_USES_ALLOCATOR_CODE)
#undef BOOST_CONTAINER_SCOPED_ALLOCATOR_DISPATCH_USES_ALLOCATOR_CODE
#endif //#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
template < typename ConstructAlloc