[libc++] Add containter_traits (prework for std::flat_map)

huixie90 · huixie90 · commit f3c685c165dd · 2024-09-28T10:06:47.000+01:00
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
@@ -748,6 +748,7 @@ set(files
   __type_traits/common_type.h
   __type_traits/conditional.h
   __type_traits/conjunction.h
+  __type_traits/container_traits.h
   __type_traits/copy_cv.h
   __type_traits/copy_cvref.h
   __type_traits/datasizeof.h
diff --git a/libcxx/include/__type_traits/container_traits.h b/libcxx/include/__type_traits/container_traits.h
@@ -0,0 +1,28 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___TYPE_TRAITS_CONTAINER_TRAITS_H
+#define _LIBCPP___TYPE_TRAITS_CONTAINER_TRAITS_H
+
+#include <__config>
+#include <__type_traits/integral_constant.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct __container_traits {
+  using __emplacement_has_strong_exception_safety_guarantee = false_type;
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___TYPE_TRAITS_CONTAINER_TRAITS_H
diff --git a/libcxx/include/deque b/libcxx/include/deque
@@ -220,6 +220,8 @@ template <class T, class Allocator, class Predicate>
 #include <__ranges/size.h>
 #include <__split_buffer>
 #include <__type_traits/conditional.h>
+#include <__type_traits/container_traits.h>
+#include <__type_traits/disjunction.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_allocator.h>
 #include <__type_traits/is_convertible.h>
@@ -2609,6 +2611,18 @@ inline constexpr bool __format::__enable_insertable<std::deque<wchar_t>> = true;
 
 #endif // _LIBCPP_STD_VER >= 20
 
+template <class _Tp, class _Allocator>
+struct __container_traits<deque<_Tp, _Allocator> > {
+  // http://eel.is/c++draft/deque.modifiers#3
+  //  If an exception is thrown other than by the copy constructor, move constructor, assignment operator, or move
+  //  assignment operator of T, there are no effects. If an exception is thrown while inserting a single element at
+  //  either end, there are no effects. Otherwise, if an exception is thrown by the move constructor of a
+  //  non-Cpp17CopyInsertable T, the effects are unspecified.
+  using __emplacement_has_strong_exception_safety_guarantee =
+      _Or<is_nothrow_move_constructible<_Tp>,
+          __is_cpp17_copy_insertable<typename deque<_Tp, _Allocator>::allocator_type> >;
+};
+
 _LIBCPP_END_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
diff --git a/libcxx/include/forward_list b/libcxx/include/forward_list
@@ -218,6 +218,7 @@ template <class T, class Allocator, class Predicate>
 #include <__ranges/container_compatible_range.h>
 #include <__ranges/from_range.h>
 #include <__type_traits/conditional.h>
+#include <__type_traits/container_traits.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_allocator.h>
 #include <__type_traits/is_const.h>
@@ -1544,6 +1545,17 @@ erase(forward_list<_Tp, _Allocator>& __c, const _Up& __v) {
 }
 #endif
 
+template <class _Tp, class _Allocator>
+struct __container_traits<forward_list<_Tp, _Allocator> > {
+  // http://eel.is/c++draft/container.reqmts
+  // 66 Unless otherwise specified (see [associative.reqmts.except], [unord.req.except], [deque.modifiers],
+  // [inplace.vector.modifiers], and [vector.modifiers]) all container types defined in this Clause meet the following
+  // additional requirements:
+  // - (66.1) If an exception is thrown by an insert() or emplace() function while inserting a single element, that
+  // function has no effects.
+  using __emplacement_has_strong_exception_safety_guarantee = true_type;
+};
+
 _LIBCPP_END_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
diff --git a/libcxx/include/list b/libcxx/include/list
@@ -225,6 +225,7 @@ template <class T, class Allocator, class Predicate>
 #include <__ranges/container_compatible_range.h>
 #include <__ranges/from_range.h>
 #include <__type_traits/conditional.h>
+#include <__type_traits/container_traits.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_allocator.h>
 #include <__type_traits/is_nothrow_assignable.h>
@@ -1715,6 +1716,17 @@ inline constexpr bool __format::__enable_insertable<std::list<wchar_t>> = true;
 
 #endif // _LIBCPP_STD_VER >= 20
 
+template <class _Tp, class _Allocator>
+struct __container_traits<list<_Tp, _Allocator> > {
+  // http://eel.is/c++draft/container.reqmts
+  // 66 Unless otherwise specified (see [associative.reqmts.except], [unord.req.except], [deque.modifiers],
+  // [inplace.vector.modifiers], and [vector.modifiers]) all container types defined in this Clause meet the following
+  // additional requirements:
+  // - (66.1) If an exception is thrown by an insert() or emplace() function while inserting a single element, that
+  // function has no effects.
+  using __emplacement_has_strong_exception_safety_guarantee = true_type;
+};
+
 _LIBCPP_END_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
diff --git a/libcxx/include/map b/libcxx/include/map
@@ -594,6 +594,7 @@ erase_if(multimap<Key, T, Compare, Allocator>& c, Predicate pred);  // C++20
 #include <__ranges/container_compatible_range.h>
 #include <__ranges/from_range.h>
 #include <__tree>
+#include <__type_traits/container_traits.h>
 #include <__type_traits/is_allocator.h>
 #include <__type_traits/remove_const.h>
 #include <__type_traits/type_identity.h>
@@ -1644,6 +1645,14 @@ erase_if(map<_Key, _Tp, _Compare, _Allocator>& __c, _Predicate __pred) {
 }
 #endif
 
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+struct __container_traits<map<_Key, _Tp, _Compare, _Allocator> > {
+  // http://eel.is/c++draft/associative.reqmts.except#2
+  // For associative containers, if an exception is thrown by any operation from within
+  // an insert or emplace function inserting a single element, the insertion has no effect.
+  using __emplacement_has_strong_exception_safety_guarantee = true_type;
+};
+
 template <class _Key, class _Tp, class _Compare = less<_Key>, class _Allocator = allocator<pair<const _Key, _Tp> > >
 class _LIBCPP_TEMPLATE_VIS multimap {
 public:
@@ -2158,6 +2167,14 @@ erase_if(multimap<_Key, _Tp, _Compare, _Allocator>& __c, _Predicate __pred) {
 }
 #endif
 
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+struct __container_traits<multimap<_Key, _Tp, _Compare, _Allocator> > {
+  // http://eel.is/c++draft/associative.reqmts.except#2
+  // For associative containers, if an exception is thrown by any operation from within
+  // an insert or emplace function inserting a single element, the insertion has no effect.
+  using __emplacement_has_strong_exception_safety_guarantee = true_type;
+};
+
 _LIBCPP_END_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
@@ -74,6 +74,7 @@ module std_core [system] {
     module common_type                                { header "__type_traits/common_type.h" }
     module conditional                                { header "__type_traits/conditional.h" }
     module conjunction                                { header "__type_traits/conjunction.h" }
+    module container_traits                           { header "__type_traits/container_traits.h" }
     module copy_cv                                    { header "__type_traits/copy_cv.h" }
     module copy_cvref                                 { header "__type_traits/copy_cvref.h" }
     module datasizeof                                 { header "__type_traits/datasizeof.h" }
diff --git a/libcxx/include/set b/libcxx/include/set
@@ -531,6 +531,7 @@ erase_if(multiset<Key, Compare, Allocator>& c, Predicate pred);  // C++20
 #include <__ranges/container_compatible_range.h>
 #include <__ranges/from_range.h>
 #include <__tree>
+#include <__type_traits/container_traits.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_allocator.h>
 #include <__type_traits/is_nothrow_assignable.h>
@@ -1022,6 +1023,14 @@ erase_if(set<_Key, _Compare, _Allocator>& __c, _Predicate __pred) {
 }
 #endif
 
+template <class _Key, class _Compare, class _Allocator>
+struct __container_traits<set<_Key, _Compare, _Allocator> > {
+  // http://eel.is/c++draft/associative.reqmts.except#2
+  // For associative containers, if an exception is thrown by any operation from within
+  // an insert or emplace function inserting a single element, the insertion has no effect.
+  using __emplacement_has_strong_exception_safety_guarantee = true_type;
+};
+
 template <class _Key, class _Compare = less<_Key>, class _Allocator = allocator<_Key> >
 class _LIBCPP_TEMPLATE_VIS multiset {
 public:
@@ -1481,6 +1490,14 @@ erase_if(multiset<_Key, _Compare, _Allocator>& __c, _Predicate __pred) {
 }
 #endif
 
+template <class _Key, class _Compare, class _Allocator>
+struct __container_traits<multiset<_Key, _Compare, _Allocator> > {
+  // http://eel.is/c++draft/associative.reqmts.except#2
+  // For associative containers, if an exception is thrown by any operation from within
+  // an insert or emplace function inserting a single element, the insertion has no effect.
+  using __emplacement_has_strong_exception_safety_guarantee = true_type;
+};
+
 _LIBCPP_END_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
diff --git a/libcxx/include/unordered_map b/libcxx/include/unordered_map
@@ -604,6 +604,7 @@ template <class Key, class T, class Hash, class Pred, class Alloc>
 #include <__ranges/concepts.h>
 #include <__ranges/container_compatible_range.h>
 #include <__ranges/from_range.h>
+#include <__type_traits/container_traits.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_allocator.h>
 #include <__type_traits/is_integral.h>
@@ -1830,6 +1831,15 @@ inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_map<_Key, _Tp, _Has
 
 #endif
 
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+struct __container_traits<unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc> > {
+  // http://eel.is/c++draft/unord.req.except#2
+  //  For unordered associative containers, if an exception is thrown by any operation
+  //  other than the container's hash function from within an insert or emplace function
+  //  inserting a single element, the insertion has no effect.
+  using __emplacement_has_strong_exception_safety_guarantee = __nothrow_invokable<_Hash, const _Key&>;
+};
+
 template <class _Key,
           class _Tp,
           class _Hash  = hash<_Key>,
@@ -2520,6 +2530,15 @@ inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_multimap<_Key, _Tp,
 
 #endif
 
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+struct __container_traits<unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc> > {
+  // http://eel.is/c++draft/unord.req.except#2
+  //  For unordered associative containers, if an exception is thrown by any operation
+  //  other than the container's hash function from within an insert or emplace function
+  //  inserting a single element, the insertion has no effect.
+  using __emplacement_has_strong_exception_safety_guarantee = __nothrow_invokable<_Hash, const _Key&>;
+};
+
 _LIBCPP_END_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
diff --git a/libcxx/include/unordered_set b/libcxx/include/unordered_set
@@ -550,6 +550,7 @@ template <class Value, class Hash, class Pred, class Alloc>
 #include <__ranges/concepts.h>
 #include <__ranges/container_compatible_range.h>
 #include <__ranges/from_range.h>
+#include <__type_traits/container_traits.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_allocator.h>
 #include <__type_traits/is_integral.h>
@@ -1183,6 +1184,15 @@ inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_set<_Value, _Hash,
 
 #endif
 
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+struct __container_traits<unordered_set<_Value, _Hash, _Pred, _Alloc> > {
+  // http://eel.is/c++draft/unord.req.except#2
+  //  For unordered associative containers, if an exception is thrown by any operation
+  //  other than the container's hash function from within an insert or emplace function
+  //  inserting a single element, the insertion has no effect.
+  using __emplacement_has_strong_exception_safety_guarantee = __nothrow_invokable<_Hash, const _Value&>;
+};
+
 template <class _Value, class _Hash = hash<_Value>, class _Pred = equal_to<_Value>, class _Alloc = allocator<_Value> >
 class _LIBCPP_TEMPLATE_VIS unordered_multiset {
 public:
@@ -1793,6 +1803,15 @@ inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_multiset<_Value, _H
 
 #endif
 
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+struct __container_traits<unordered_multiset<_Value, _Hash, _Pred, _Alloc> > {
+  // http://eel.is/c++draft/unord.req.except#2
+  //  For unordered associative containers, if an exception is thrown by any operation
+  //  other than the container's hash function from within an insert or emplace function
+  //  inserting a single element, the insertion has no effect.
+  using __emplacement_has_strong_exception_safety_guarantee = __nothrow_invokable<_Hash, const _Value&>;
+};
+
 _LIBCPP_END_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
diff --git a/libcxx/include/vector b/libcxx/include/vector
@@ -356,6 +356,8 @@ template<class T, class charT> requires is-vector-bool-reference<T> // Since C++
 #include <__ranges/size.h>
 #include <__split_buffer>
 #include <__type_traits/conditional.h>
+#include <__type_traits/container_traits.h>
+#include <__type_traits/disjunction.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_allocator.h>
 #include <__type_traits/is_constructible.h>
@@ -3005,6 +3007,19 @@ public:
 };
 #endif // _LIBCPP_STD_VER >= 23
 
+template <class _Tp, class _Allocator>
+struct __container_traits<vector<_Tp, _Allocator> > {
+  // http://eel.is/c++draft/vector.modifiers#2
+  //  If an exception is thrown other than by the copy constructor, move constructor, assignment operator, or move
+  //  assignment operator of T or by any InputIterator operation, there are no effects. If an exception is thrown while
+  //  inserting a single element at the end and T is Cpp17CopyInsertable or is_nothrow_move_constructible_v<T> is true,
+  //  there are no effects. Otherwise, if an exception is thrown by the move constructor of a non-Cpp17CopyInsertable T,
+  //  the effects are unspecified.
+  using __emplacement_has_strong_exception_safety_guarantee =
+      _Or<is_nothrow_move_constructible<_Tp>,
+          __is_cpp17_copy_insertable<typename vector<_Tp, _Allocator>::allocator_type> >;
+};
+
 _LIBCPP_END_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
diff --git a/libcxx/test/libcxx/containers/container_traits.compile.pass.cpp b/libcxx/test/libcxx/containers/container_traits.compile.pass.cpp
