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//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// UNSUPPORTED: libcpp-has-no-incomplete-ranges
// constexpr InnerIter operator->() const
// requires has-arrow<InnerIter> && copyable<InnerIter>;
#include <cassert>
#include <ranges>
#include "../types.h"
template <class T>
concept HasArrow = std::input_iterator<T> && (std::is_pointer_v<T> || requires(T i) { i.operator->(); });
template <class Base>
struct move_only_input_iter_with_arrow {
Base it_;
using value_type = std::iter_value_t<Base>;
using difference_type = std::intptr_t;
using iterator_concept = std::input_iterator_tag;
constexpr move_only_input_iter_with_arrow(Base it) : it_(std::move(it)) {}
constexpr move_only_input_iter_with_arrow(move_only_input_iter_with_arrow&&) = default;
constexpr move_only_input_iter_with_arrow(const move_only_input_iter_with_arrow&) = delete;
constexpr move_only_input_iter_with_arrow& operator=(move_only_input_iter_with_arrow&&) = default;
constexpr move_only_input_iter_with_arrow& operator=(const move_only_input_iter_with_arrow&) = delete;
constexpr move_only_input_iter_with_arrow& operator++() {
++it_;
return *this;
}
constexpr void operator++(int) { ++it_; }
constexpr std::iter_reference_t<Base> operator*() const { return *it_; }
constexpr auto operator->() const
requires(HasArrow<Base> && std::copyable<Base>) {
return it_;
}
};
static_assert(!std::copyable<move_only_input_iter_with_arrow<int*>>);
static_assert(std::input_iterator<move_only_input_iter_with_arrow<int*>>);
template <class Base>
struct move_iter_sentinel {
Base it_;
explicit move_iter_sentinel() = default;
constexpr move_iter_sentinel(Base it) : it_(std::move(it)) {}
constexpr bool operator==(const move_only_input_iter_with_arrow<Base>& other) const { return it_ == other.it_; }
};
static_assert(std::sentinel_for<move_iter_sentinel<int*>, move_only_input_iter_with_arrow<int*>>);
struct MoveOnlyIterInner : BufferView<move_only_input_iter_with_arrow<Box*>, move_iter_sentinel<Box*>> {
using BufferView::BufferView;
using iterator = move_only_input_iter_with_arrow<Box*>;
using sentinel = move_iter_sentinel<Box*>;
iterator begin() const { return data_; }
sentinel end() const { return sentinel{data_ + size_}; }
};
static_assert(std::ranges::input_range<MoveOnlyIterInner>);
template <class Base>
struct arrow_input_iter {
Base it_;
using value_type = std::iter_value_t<Base>;
using difference_type = std::intptr_t;
using iterator_concept = std::input_iterator_tag;
arrow_input_iter() = default;
constexpr arrow_input_iter(Base it) : it_(std::move(it)) {}
constexpr arrow_input_iter& operator++() {
++it_;
return *this;
}
constexpr void operator++(int) { ++it_; }
constexpr std::iter_reference_t<Base> operator*() const { return *it_; }
constexpr auto operator->() const { return it_; }
friend constexpr bool operator==(const arrow_input_iter& x, const arrow_input_iter& y) = default;
};
using ArrowInner = BufferView<arrow_input_iter<Box*>>;
static_assert(std::ranges::input_range<ArrowInner>);
static_assert(HasArrow<std::ranges::iterator_t<ArrowInner>>);
constexpr bool test() {
Box buffer[4][4] = {{{1111}, {2222}, {3333}, {4444}},
{{555}, {666}, {777}, {888}},
{{99}, {1010}, {1111}, {1212}},
{{13}, {14}, {15}, {16}}};
{
// Copyable input iterator with arrow.
ValueView<Box> children[4] = {ValueView(buffer[0]), ValueView(buffer[1]), ValueView(buffer[2]),
ValueView(buffer[3])};
std::ranges::join_view jv(ValueView<ValueView<Box>>{children});
assert(jv.begin()->x == 1111);
static_assert(HasArrow<decltype(jv.begin())>);
}
{
std::ranges::join_view jv(buffer);
assert(jv.begin()->x == 1111);
static_assert(HasArrow<decltype(jv.begin())>);
}
{
const std::ranges::join_view jv(buffer);
assert(jv.begin()->x == 1111);
static_assert(HasArrow<decltype(jv.begin())>);
}
{
// LWG3500 `join_view::iterator::operator->()` is bogus
// `operator->` should not be defined if inner iterator is not copyable
// has-arrow<InnerIter> && !copyable<InnerIter>
static_assert(HasArrow<move_only_input_iter_with_arrow<int*>>);
MoveOnlyIterInner inners[2] = {buffer[0], buffer[1]};
std::ranges::join_view jv{inners};
static_assert(HasArrow<decltype(std::ranges::begin(inners[0]))>);
static_assert(!HasArrow<decltype(jv.begin())>);
}
{
// LWG3500 `join_view::iterator::operator->()` is bogus
// `operator->` should not be defined if inner iterator does not have `operator->`
// !has-arrow<InnerIter> && copyable<InnerIter>
using Inner = BufferView<forward_iterator<Box*>>;
Inner inners[2] = {buffer[0], buffer[1]};
std::ranges::join_view jv{inners};
static_assert(!HasArrow<decltype(std::ranges::begin(inners[0]))>);
static_assert(!HasArrow<decltype(jv.begin())>);
}
{
// arrow returns inner iterator
ArrowInner inners[2] = {buffer[0], buffer[1]};
std::ranges::join_view jv{inners};
static_assert(HasArrow<decltype(std::ranges::begin(inners[0]))>);
static_assert(HasArrow<decltype(jv.begin())>);
auto jv_it = jv.begin();
std::same_as<arrow_input_iter<Box*>> auto arrow_it = jv_it.operator->();
assert(arrow_it->x == 1111);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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