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- //-----------------------------------------------------------------------------
- // boost-libs variant/test/variant_nonempty_check.cpp source file
- // See http://www.boost.org for updates, documentation, and revision history.
- //-----------------------------------------------------------------------------
- //
- // Copyright (c) 2014-2019 Antony Polukhin
- //
- // Distributed under the Boost Software License, Version 1.0. (See
- // accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- // In this file we are making tests to ensure that variant guarantees nonemptiness.
- //
- // For that purpose we create a `throwing_class`, that throws exception at a specified
- // assignment attempt. If exception was thrown during move/assignemnt operation we make sure
- // that data in variant is same as before move/assignemnt operation or that a fallback type is
- // stored in variant.
- //
- // Different nonthrowing_class'es are used to tests different variant internal policies:
- // with/without fallback type + throw/nothrow copyable + throw/nothrow movable
- #include "boost/variant/variant.hpp"
- #include "boost/variant/get.hpp"
- #include "boost/core/lightweight_test.hpp"
- #include <stdexcept>
- struct exception_on_assignment : std::exception {};
- struct exception_on_move_assignment : exception_on_assignment {};
- void prevent_compiler_noexcept_detection() {
- char* p = new char;
- *p = '\0';
- delete p;
- }
- struct throwing_class {
- int trash;
- enum helper_enum {
- do_not_throw = 780,
- throw_after_5,
- throw_after_4,
- throw_after_3,
- throw_after_2,
- throw_after_1
- };
- bool is_throw() {
- if (trash < do_not_throw) {
- return true;
- }
- if (trash > do_not_throw && trash <= throw_after_1) {
- ++ trash;
- return false;
- }
- return trash != do_not_throw;
- }
- throwing_class(int value = 123) BOOST_NOEXCEPT_IF(false) : trash(value) {
- prevent_compiler_noexcept_detection();
- }
- throwing_class(const throwing_class& b) BOOST_NOEXCEPT_IF(false) : trash(b.trash) {
- if (is_throw()) {
- throw exception_on_assignment();
- }
- }
- const throwing_class& operator=(const throwing_class& b) BOOST_NOEXCEPT_IF(false) {
- trash = b.trash;
- if (is_throw()) {
- throw exception_on_assignment();
- }
- return *this;
- }
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- throwing_class(throwing_class&& b) BOOST_NOEXCEPT_IF(false) : trash(b.trash) {
- if (is_throw()) {
- throw exception_on_move_assignment();
- }
- }
- const throwing_class& operator=(throwing_class&& b) BOOST_NOEXCEPT_IF(false) {
- trash = b.trash;
- if (is_throw()) {
- throw exception_on_move_assignment();
- }
- return *this;
- }
- #endif
- virtual ~throwing_class() {}
- };
- struct nonthrowing_class {
- int trash;
- nonthrowing_class() BOOST_NOEXCEPT_IF(false) : trash(123) {
- prevent_compiler_noexcept_detection();
- }
- nonthrowing_class(const nonthrowing_class&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- }
- const nonthrowing_class& operator=(const nonthrowing_class&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- return *this;
- }
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- nonthrowing_class(nonthrowing_class&&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- }
- const nonthrowing_class& operator=(nonthrowing_class&&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- return *this;
- }
- #endif
- };
- struct nonthrowing_class2 {
- int trash;
- nonthrowing_class2() BOOST_NOEXCEPT_IF(false) : trash(123) {
- prevent_compiler_noexcept_detection();
- }
- };
- struct nonthrowing_class3 {
- int trash;
- nonthrowing_class3() BOOST_NOEXCEPT_IF(true) : trash(123) {}
- nonthrowing_class3(const nonthrowing_class3&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- }
- const nonthrowing_class3& operator=(const nonthrowing_class3&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- return *this;
- }
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- nonthrowing_class3(nonthrowing_class3&&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- }
- const nonthrowing_class3& operator=(nonthrowing_class3&&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- return *this;
- }
- #endif
- };
- struct nonthrowing_class4 {
- int trash;
- nonthrowing_class4() BOOST_NOEXCEPT_IF(false) : trash(123) {
- prevent_compiler_noexcept_detection();
- }
- nonthrowing_class4(const nonthrowing_class4&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- }
- const nonthrowing_class4& operator=(const nonthrowing_class4&) BOOST_NOEXCEPT_IF(false) {
- prevent_compiler_noexcept_detection();
- return *this;
- }
- #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
- nonthrowing_class4(nonthrowing_class4&&) BOOST_NOEXCEPT_IF(true) {
- }
- const nonthrowing_class4& operator=(nonthrowing_class4&&) BOOST_NOEXCEPT_IF(true) {
- return *this;
- }
- #endif
- };
- // Tests /////////////////////////////////////////////////////////////////////////////////////
- template <class Nonthrowing>
- inline void check_1_impl(int helper)
- {
- boost::variant<throwing_class, Nonthrowing> v;
- try {
- v = throwing_class(helper);
- BOOST_TEST(!v.which());
- BOOST_TEST(boost::get<throwing_class>(&v));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(!v.which());
- BOOST_TEST(boost::get<throwing_class>(&v));
- }
- try {
- throwing_class tc(helper);
- v = tc;
- BOOST_TEST(!v.which());
- BOOST_TEST(boost::get<throwing_class>(&v));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(!v.which());
- BOOST_TEST(boost::get<throwing_class>(&v));
- }
- }
- inline void check_1(int helper = 1)
- {
- check_1_impl<nonthrowing_class>(helper);
- check_1_impl<nonthrowing_class2>(helper);
- check_1_impl<nonthrowing_class3>(helper);
- check_1_impl<nonthrowing_class4>(helper);
- check_1_impl<boost::blank>(helper);
- }
- template <class Nonthrowing>
- inline void check_2_impl(int helper)
- {
- boost::variant<Nonthrowing, throwing_class> v;
- try {
- v = throwing_class(helper);
- BOOST_TEST(v.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(!v.which());
- BOOST_TEST(boost::get<Nonthrowing>(&v));
- }
- try {
- throwing_class cl(helper);
- v = cl;
- BOOST_TEST(v.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(!v.which());
- BOOST_TEST(boost::get<Nonthrowing>(&v));
- }
- }
- inline void check_2(int helper = 1)
- {
- check_2_impl<nonthrowing_class>(helper);
- check_2_impl<nonthrowing_class2>(helper);
- check_2_impl<nonthrowing_class3>(helper);
- check_2_impl<nonthrowing_class4>(helper);
- check_2_impl<boost::blank>(helper);
- }
- template <class Nonthrowing>
- inline void check_3_impl(int helper)
- {
- boost::variant<Nonthrowing, throwing_class> v1, v2;
- swap(v1, v2);
- try {
- v1 = throwing_class(helper);
- BOOST_TEST(v1.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v1));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(!v1.which());
- BOOST_TEST(boost::get<Nonthrowing>(&v1));
- }
- try {
- v2 = throwing_class(helper);
- BOOST_TEST(v2.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v2));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(!v2.which());
- BOOST_TEST(boost::get<Nonthrowing>(&v2));
- }
- if (!v1.which() && !v2.which()) {
- swap(v1, v2); // Make sure that two backup holders swap well
- BOOST_TEST(!v1.which());
- BOOST_TEST(boost::get<Nonthrowing>(&v1));
- BOOST_TEST(!v2.which());
- BOOST_TEST(boost::get<Nonthrowing>(&v2));
- v1 = v2;
- }
- }
- inline void check_3(int helper = 1)
- {
- check_3_impl<nonthrowing_class>(helper);
- check_3_impl<nonthrowing_class2>(helper);
- check_3_impl<nonthrowing_class3>(helper);
- check_3_impl<nonthrowing_class4>(helper);
- check_3_impl<boost::blank>(helper);
- }
- inline void check_4(int helper = 1)
- {
- // This one has a fallback
- boost::variant<int, throwing_class> v1, v2;
- swap(v1, v2);
- try {
- v1 = throwing_class(helper);
- BOOST_TEST(v1.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v1));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(!v1.which());
- BOOST_TEST(boost::get<int>(&v1));
- }
- try {
- v2 = throwing_class(helper);
- BOOST_TEST(v2.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v2));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(!v2.which());
- BOOST_TEST(boost::get<int>(&v2));
- }
- if (!v1.which() && !v2.which()) {
- swap(v1, v2);
- BOOST_TEST(!v1.which());
- BOOST_TEST(boost::get<int>(&v1));
- BOOST_TEST(!v2.which());
- BOOST_TEST(boost::get<int>(&v2));
- v1 = v2;
- }
- }
- template <class Nonthrowing>
- inline void check_5_impl(int helper)
- {
- boost::variant<Nonthrowing, throwing_class> v1, v2;
- throwing_class throw_not_now;
- throw_not_now.trash = throwing_class::do_not_throw;
- v1 = throw_not_now;
- v2 = throw_not_now;
- boost::get<throwing_class>(v1).trash = 1;
- boost::get<throwing_class>(v2).trash = 1;
- try {
- v1 = throwing_class(helper);
- BOOST_TEST(v1.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v1));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(v1.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v1));
- }
- boost::get<throwing_class>(v1).trash = throwing_class::do_not_throw;
- boost::get<throwing_class>(v2).trash = throwing_class::do_not_throw;
- v1 = Nonthrowing();
- v2 = Nonthrowing();
- try {
- v1 = throwing_class(helper);
- BOOST_TEST(v1.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v1));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(v1.which() == 0);
- BOOST_TEST(boost::get<Nonthrowing>(&v1));
- }
- int v1_type = v1.which();
- int v2_type = v2.which();
- try {
- swap(v1, v2); // Make sure that backup holders swap well
- BOOST_TEST(v1.which() == v2_type);
- BOOST_TEST(v2.which() == v1_type);
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(v1.which() == v1_type);
- BOOST_TEST(v2.which() == v2_type);
- }
- }
- inline void check_5(int helper = 1)
- {
- check_5_impl<nonthrowing_class>(helper);
- check_5_impl<nonthrowing_class2>(helper);
- check_5_impl<nonthrowing_class3>(helper);
- check_5_impl<nonthrowing_class4>(helper);
- check_5_impl<boost::blank>(helper);
- }
- template <class Nonthrowing>
- inline void check_6_impl(int helper)
- {
- boost::variant<Nonthrowing, throwing_class> v1, v2;
- throwing_class throw_not_now;
- throw_not_now.trash = throwing_class::do_not_throw;
- v1 = throw_not_now;
- v2 = throw_not_now;
- v1 = throw_not_now;
- v2 = throw_not_now;
- swap(v1, v2);
- boost::get<throwing_class>(v1).trash = 1;
- boost::get<throwing_class>(v2).trash = 1;
- v1 = throwing_class(throw_not_now);
- v2 = v1;
- v1 = Nonthrowing();
- try {
- throwing_class tc;
- tc.trash = helper;
- v1 = tc;
- BOOST_TEST(v1.which() == 1);
- BOOST_TEST(boost::get<throwing_class>(&v1));
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(v1.which() == 0);
- }
- v2 = Nonthrowing();
- try {
- v2 = 2;
- BOOST_TEST(false);
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(v2.which() == 0);
- }
- // Probably the most significant test:
- // unsuccessful swap must preserve old values of variant
- v1 = throw_not_now;
- boost::get<throwing_class>(v1).trash = helper;
- try {
- swap(v1, v2);
- } catch (const exception_on_assignment& /*e*/) {
- BOOST_TEST(v1.which() == 1);
- BOOST_TEST(v2.which() == 0);
- BOOST_TEST(boost::get<throwing_class>(v1).trash == helper);
- }
- }
- inline void check_6(int helper = 1)
- {
- check_6_impl<nonthrowing_class>(helper);
- check_6_impl<nonthrowing_class2>(helper);
- check_6_impl<nonthrowing_class3>(helper);
- check_6_impl<nonthrowing_class4>(helper);
- check_6_impl<boost::blank>(helper);
- }
- int main()
- {
- // throwing_class::throw_after_1 + 1 => throw on first assignment/construction
- // throwing_class::throw_after_1 => throw on second assignment/construction
- // throwing_class::throw_after_2 => throw on third assignment/construction
- // ...
- for (int i = throwing_class::throw_after_1 + 1; i != throwing_class::do_not_throw; --i) {
- check_1(i);
- check_2(i);
- check_3(i);
- check_4(i);
- check_5(i);
- check_6(i);
- }
- return boost::report_errors();
- }
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