7a62bee611
This patch adds std::experimental::observer_ptr (n4282) and also fixes LWG2516. Co-Authored-By: Louis Dionne <ldionne.2@gmail.com> Differential Revision: https://reviews.llvm.org/D63230
66 lines
1.3 KiB
C++
66 lines
1.3 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14
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// REQUIRES: c++experimental
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// <experimental/memory>
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// observer_ptr
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//
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// constexpr std::add_lvalue_reference_t<element_type> operator*() const;
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// constexpr element_type* operator->() const noexcept;
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#include <experimental/memory>
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#include <type_traits>
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#include <cassert>
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template <class T, class Object = T>
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constexpr void test_deref() {
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using Ptr = std::experimental::observer_ptr<T>;
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Object obj;
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{
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Ptr const ptr(&obj);
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T& r = *ptr;
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assert(&r == &obj);
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}
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{
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Ptr const ptr(&obj);
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T* r = ptr.operator->();
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assert(r == &obj);
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static_assert(noexcept(ptr.operator->()));
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}
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}
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struct Bar {};
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struct Foo {
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int member = 42;
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};
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constexpr bool test() {
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test_deref<Bar>();
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test_deref<int>();
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{
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Foo foo;
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std::experimental::observer_ptr<Foo> ptr(&foo);
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assert(&ptr->member == &foo.member);
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}
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return true;
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}
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int main(int, char**) {
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test();
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static_assert(test());
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return 0;
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}
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