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libcxx/test/support/variant_test_helpers.h

90 lines
2.4 KiB
C++

// -*- 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 SUPPORT_VARIANT_TEST_HELPERS_H
#define SUPPORT_VARIANT_TEST_HELPERS_H
#include <type_traits>
#include <utility>
#include <cassert>
#include "test_macros.h"
#if TEST_STD_VER <= 14
#error This file requires C++17
#endif
// FIXME: Currently the variant<T&> tests are disabled using this macro.
#define TEST_VARIANT_HAS_NO_REFERENCES
#ifdef _LIBCPP_ENABLE_NARROWING_CONVERSIONS_IN_VARIANT
# define TEST_VARIANT_ALLOWS_NARROWING_CONVERSIONS
#endif
#ifdef TEST_VARIANT_ALLOWS_NARROWING_CONVERSIONS
constexpr bool VariantAllowsNarrowingConversions = true;
#else
constexpr bool VariantAllowsNarrowingConversions = false;
#endif
#ifndef TEST_HAS_NO_EXCEPTIONS
struct CopyThrows {
CopyThrows() = default;
CopyThrows(CopyThrows const&) { throw 42; }
CopyThrows& operator=(CopyThrows const&) { throw 42; }
};
struct MoveThrows {
static int alive;
MoveThrows() { ++alive; }
MoveThrows(MoveThrows const&) {++alive;}
MoveThrows(MoveThrows&&) { throw 42; }
MoveThrows& operator=(MoveThrows const&) { return *this; }
MoveThrows& operator=(MoveThrows&&) { throw 42; }
~MoveThrows() { --alive; }
};
int MoveThrows::alive = 0;
struct MakeEmptyT {
static int alive;
MakeEmptyT() { ++alive; }
MakeEmptyT(MakeEmptyT const&) {
++alive;
// Don't throw from the copy constructor since variant's assignment
// operator performs a copy before committing to the assignment.
}
MakeEmptyT(MakeEmptyT &&) {
throw 42;
}
MakeEmptyT& operator=(MakeEmptyT const&) {
throw 42;
}
MakeEmptyT& operator=(MakeEmptyT&&) {
throw 42;
}
~MakeEmptyT() { --alive; }
};
static_assert(std::is_swappable_v<MakeEmptyT>, ""); // required for test
int MakeEmptyT::alive = 0;
template <class Variant>
void makeEmpty(Variant& v) {
Variant v2(std::in_place_type<MakeEmptyT>);
try {
v = std::move(v2);
assert(false);
} catch (...) {
assert(v.valueless_by_exception());
}
}
#endif // TEST_HAS_NO_EXCEPTIONS
#endif // SUPPORT_VARIANT_TEST_HELPERS_H