stl_type_traits.h

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// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

// Thie file provides the IsStrictlyBaseOfAndConvertibleToSTLContainer type
// trait metafunction to assist in working with the _GLIBCXX_DEBUG debug
// wrappers of STL containers.
//
// DO NOT INCLUDE THIS FILE DIRECTLY. Use this file by including
// absl/strings/str_split.h.
//
// IWYU pragma: private, include "absl/strings/str_split.h"

#ifndef ABSL_STRINGS_INTERNAL_STL_TYPE_TRAITS_H_
#define ABSL_STRINGS_INTERNAL_STL_TYPE_TRAITS_H_

#include <array>
#include <bitset>
#include <deque>
#include <forward_list>
#include <list>
#include <map>
#include <set>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include "absl/meta/type_traits.h"

namespace absl {
namespace strings_internal {

template <typename C, template <typename...> class T>
struct IsSpecializationImpl : std::false_type {};
template <template <typename...> class T, typename... Args>
struct IsSpecializationImpl<T<Args...>, T> : std::true_type {};
template <typename C, template <typename...> class T>
using IsSpecialization = IsSpecializationImpl<absl::decay_t<C>, T>;

template <typename C>
struct IsArrayImpl : std::false_type {};
template <template <typename, size_t> class A, typename T, size_t N>
struct IsArrayImpl<A<T, N>> : std::is_same<A<T, N>, std::array<T, N>> {};
template <typename C>
using IsArray = IsArrayImpl<absl::decay_t<C>>;

template <typename C>
struct IsBitsetImpl : std::false_type {};
template <template <size_t> class B, size_t N>
struct IsBitsetImpl<B<N>> : std::is_same<B<N>, std::bitset<N>> {};
template <typename C>
using IsBitset = IsBitsetImpl<absl::decay_t<C>>;

template <typename C>
struct IsSTLContainer
    : absl::disjunction<
          IsArray<C>, IsBitset<C>, IsSpecialization<C, std::deque>,
          IsSpecialization<C, std::forward_list>,
          IsSpecialization<C, std::list>, IsSpecialization<C, std::map>,
          IsSpecialization<C, std::multimap>, IsSpecialization<C, std::set>,
          IsSpecialization<C, std::multiset>,
          IsSpecialization<C, std::unordered_map>,
          IsSpecialization<C, std::unordered_multimap>,
          IsSpecialization<C, std::unordered_set>,
          IsSpecialization<C, std::unordered_multiset>,
          IsSpecialization<C, std::vector>> {};

template <typename C, template <typename...> class T, typename = void>
struct IsBaseOfSpecializationImpl : std::false_type {};
// IsBaseOfSpecializationImpl needs multiple partial specializations to SFINAE
// on the existence of container dependent types and plug them into the STL
// template.
template <typename C, template <typename, typename> class T>
struct IsBaseOfSpecializationImpl<
    C, T, absl::void_t<typename C::value_type, typename C::allocator_type>>
    : std::is_base_of<C,
                      T<typename C::value_type, typename C::allocator_type>> {};
template <typename C, template <typename, typename, typename> class T>
struct IsBaseOfSpecializationImpl<
    C, T,
    absl::void_t<typename C::key_type, typename C::key_compare,
                 typename C::allocator_type>>
    : std::is_base_of<C, T<typename C::key_type, typename C::key_compare,
                           typename C::allocator_type>> {};
template <typename C, template <typename, typename, typename, typename> class T>
struct IsBaseOfSpecializationImpl<
    C, T,
    absl::void_t<typename C::key_type, typename C::mapped_type,
                 typename C::key_compare, typename C::allocator_type>>
    : std::is_base_of<C,
                      T<typename C::key_type, typename C::mapped_type,
                        typename C::key_compare, typename C::allocator_type>> {
};
template <typename C, template <typename, typename, typename, typename> class T>
struct IsBaseOfSpecializationImpl<
    C, T,
    absl::void_t<typename C::key_type, typename C::hasher,
                 typename C::key_equal, typename C::allocator_type>>
    : std::is_base_of<C, T<typename C::key_type, typename C::hasher,
                           typename C::key_equal, typename C::allocator_type>> {
};
template <typename C,
          template <typename, typename, typename, typename, typename> class T>
struct IsBaseOfSpecializationImpl<
    C, T,
    absl::void_t<typename C::key_type, typename C::mapped_type,
                 typename C::hasher, typename C::key_equal,
                 typename C::allocator_type>>
    : std::is_base_of<C, T<typename C::key_type, typename C::mapped_type,
                           typename C::hasher, typename C::key_equal,
                           typename C::allocator_type>> {};
template <typename C, template <typename...> class T>
using IsBaseOfSpecialization = IsBaseOfSpecializationImpl<absl::decay_t<C>, T>;

template <typename C>
struct IsBaseOfArrayImpl : std::false_type {};
template <template <typename, size_t> class A, typename T, size_t N>
struct IsBaseOfArrayImpl<A<T, N>> : std::is_base_of<A<T, N>, std::array<T, N>> {
};
template <typename C>
using IsBaseOfArray = IsBaseOfArrayImpl<absl::decay_t<C>>;

template <typename C>
struct IsBaseOfBitsetImpl : std::false_type {};
template <template <size_t> class B, size_t N>
struct IsBaseOfBitsetImpl<B<N>> : std::is_base_of<B<N>, std::bitset<N>> {};
template <typename C>
using IsBaseOfBitset = IsBaseOfBitsetImpl<absl::decay_t<C>>;

template <typename C>
struct IsBaseOfSTLContainer
    : absl::disjunction<IsBaseOfArray<C>, IsBaseOfBitset<C>,
                        IsBaseOfSpecialization<C, std::deque>,
                        IsBaseOfSpecialization<C, std::forward_list>,
                        IsBaseOfSpecialization<C, std::list>,
                        IsBaseOfSpecialization<C, std::map>,
                        IsBaseOfSpecialization<C, std::multimap>,
                        IsBaseOfSpecialization<C, std::set>,
                        IsBaseOfSpecialization<C, std::multiset>,
                        IsBaseOfSpecialization<C, std::unordered_map>,
                        IsBaseOfSpecialization<C, std::unordered_multimap>,
                        IsBaseOfSpecialization<C, std::unordered_set>,
                        IsBaseOfSpecialization<C, std::unordered_multiset>,
                        IsBaseOfSpecialization<C, std::vector>> {};

template <typename C, template <typename...> class T, typename = void>
struct IsConvertibleToSpecializationImpl : std::false_type {};
// IsConvertibleToSpecializationImpl needs multiple partial specializations to
// SFINAE on the existence of container dependent types and plug them into the
// STL template.
template <typename C, template <typename, typename> class T>
struct IsConvertibleToSpecializationImpl<
    C, T, absl::void_t<typename C::value_type, typename C::allocator_type>>
    : std::is_convertible<
          C, T<typename C::value_type, typename C::allocator_type>> {};
template <typename C, template <typename, typename, typename> class T>
struct IsConvertibleToSpecializationImpl<
    C, T,
    absl::void_t<typename C::key_type, typename C::key_compare,
                 typename C::allocator_type>>
    : std::is_convertible<C, T<typename C::key_type, typename C::key_compare,
                               typename C::allocator_type>> {};
template <typename C, template <typename, typename, typename, typename> class T>
struct IsConvertibleToSpecializationImpl<
    C, T,
    absl::void_t<typename C::key_type, typename C::mapped_type,
                 typename C::key_compare, typename C::allocator_type>>
    : std::is_convertible<
          C, T<typename C::key_type, typename C::mapped_type,
               typename C::key_compare, typename C::allocator_type>> {};
template <typename C, template <typename, typename, typename, typename> class T>
struct IsConvertibleToSpecializationImpl<
    C, T,
    absl::void_t<typename C::key_type, typename C::hasher,
                 typename C::key_equal, typename C::allocator_type>>
    : std::is_convertible<
          C, T<typename C::key_type, typename C::hasher, typename C::key_equal,
               typename C::allocator_type>> {};
template <typename C,
          template <typename, typename, typename, typename, typename> class T>
struct IsConvertibleToSpecializationImpl<
    C, T,
    absl::void_t<typename C::key_type, typename C::mapped_type,
                 typename C::hasher, typename C::key_equal,
                 typename C::allocator_type>>
    : std::is_convertible<C, T<typename C::key_type, typename C::mapped_type,
                               typename C::hasher, typename C::key_equal,
                               typename C::allocator_type>> {};
template <typename C, template <typename...> class T>
using IsConvertibleToSpecialization =
    IsConvertibleToSpecializationImpl<absl::decay_t<C>, T>;

template <typename C>
struct IsConvertibleToArrayImpl : std::false_type {};
template <template <typename, size_t> class A, typename T, size_t N>
struct IsConvertibleToArrayImpl<A<T, N>>
    : std::is_convertible<A<T, N>, std::array<T, N>> {};
template <typename C>
using IsConvertibleToArray = IsConvertibleToArrayImpl<absl::decay_t<C>>;

template <typename C>
struct IsConvertibleToBitsetImpl : std::false_type {};
template <template <size_t> class B, size_t N>
struct IsConvertibleToBitsetImpl<B<N>>
    : std::is_convertible<B<N>, std::bitset<N>> {};
template <typename C>
using IsConvertibleToBitset = IsConvertibleToBitsetImpl<absl::decay_t<C>>;

template <typename C>
struct IsConvertibleToSTLContainer
    : absl::disjunction<
          IsConvertibleToArray<C>, IsConvertibleToBitset<C>,
          IsConvertibleToSpecialization<C, std::deque>,
          IsConvertibleToSpecialization<C, std::forward_list>,
          IsConvertibleToSpecialization<C, std::list>,
          IsConvertibleToSpecialization<C, std::map>,
          IsConvertibleToSpecialization<C, std::multimap>,
          IsConvertibleToSpecialization<C, std::set>,
          IsConvertibleToSpecialization<C, std::multiset>,
          IsConvertibleToSpecialization<C, std::unordered_map>,
          IsConvertibleToSpecialization<C, std::unordered_multimap>,
          IsConvertibleToSpecialization<C, std::unordered_set>,
          IsConvertibleToSpecialization<C, std::unordered_multiset>,
          IsConvertibleToSpecialization<C, std::vector>> {};

template <typename C>
struct IsStrictlyBaseOfAndConvertibleToSTLContainer
    : absl::conjunction<absl::negation<IsSTLContainer<C>>,
                        IsBaseOfSTLContainer<C>,
                        IsConvertibleToSTLContainer<C>> {};

}  // namespace strings_internal
}  // namespace absl
#endif  // ABSL_STRINGS_INTERNAL_STL_TYPE_TRAITS_H_