1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 #ifndef SUPPORT_VARIANT_TEST_HELPERS_H
10 #define SUPPORT_VARIANT_TEST_HELPERS_H
11 
12 #include <type_traits>
13 #include <utility>
14 #include <cassert>
15 
16 #include "test_macros.h"
17 
18 #if TEST_STD_VER <= 14
19 #error This file requires C++17
20 #endif
21 
22 // FIXME: Currently the variant<T&> tests are disabled using this macro.
23 #define TEST_VARIANT_HAS_NO_REFERENCES
24 #ifdef _LIBCPP_ENABLE_NARROWING_CONVERSIONS_IN_VARIANT
25 # define TEST_VARIANT_ALLOWS_NARROWING_CONVERSIONS
26 #endif
27 
28 #ifdef TEST_VARIANT_ALLOWS_NARROWING_CONVERSIONS
29 constexpr bool VariantAllowsNarrowingConversions = true;
30 #else
31 constexpr bool VariantAllowsNarrowingConversions = false;
32 #endif
33 
34 #ifndef TEST_HAS_NO_EXCEPTIONS
35 struct CopyThrows {
36   CopyThrows() = default;
CopyThrowsCopyThrows37   CopyThrows(CopyThrows const&) { throw 42; }
38   CopyThrows& operator=(CopyThrows const&) { throw 42; }
39 };
40 
41 struct MoveThrows {
42   static int alive;
MoveThrowsMoveThrows43   MoveThrows() { ++alive; }
MoveThrowsMoveThrows44   MoveThrows(MoveThrows const&) {++alive;}
MoveThrowsMoveThrows45   MoveThrows(MoveThrows&&) {  throw 42; }
46   MoveThrows& operator=(MoveThrows const&) { return *this; }
47   MoveThrows& operator=(MoveThrows&&) { throw 42; }
~MoveThrowsMoveThrows48   ~MoveThrows() { --alive; }
49 };
50 
51 int MoveThrows::alive = 0;
52 
53 struct MakeEmptyT {
54   static int alive;
MakeEmptyTMakeEmptyT55   MakeEmptyT() { ++alive; }
MakeEmptyTMakeEmptyT56   MakeEmptyT(MakeEmptyT const&) {
57       ++alive;
58       // Don't throw from the copy constructor since variant's assignment
59       // operator performs a copy before committing to the assignment.
60   }
MakeEmptyTMakeEmptyT61   MakeEmptyT(MakeEmptyT &&) {
62       throw 42;
63   }
64   MakeEmptyT& operator=(MakeEmptyT const&) {
65       throw 42;
66   }
67   MakeEmptyT& operator=(MakeEmptyT&&) {
68       throw 42;
69   }
~MakeEmptyTMakeEmptyT70    ~MakeEmptyT() { --alive; }
71 };
72 static_assert(std::is_swappable_v<MakeEmptyT>, ""); // required for test
73 
74 int MakeEmptyT::alive = 0;
75 
76 template <class Variant>
makeEmpty(Variant & v)77 void makeEmpty(Variant& v) {
78     Variant v2(std::in_place_type<MakeEmptyT>);
79     try {
80         v = std::move(v2);
81         assert(false);
82     } catch (...) {
83         assert(v.valueless_by_exception());
84     }
85 }
86 #endif // TEST_HAS_NO_EXCEPTIONS
87 
88 
89 #endif // SUPPORT_VARIANT_TEST_HELPERS_H
90