// __ _____ _____ _____ // __| | __| | | | JSON for Modern C++ (supporting code) // | | |__ | | | | | | version 3.11.2 // |_____|_____|_____|_|___| https://github.com/nlohmann/json // // SPDX-FileCopyrightText: 2013-2022 Niels Lohmann // SPDX-License-Identifier: MIT #include "doctest_compatibility.h" // disable -Wnoexcept due to class Evil DOCTEST_GCC_SUPPRESS_WARNING_PUSH DOCTEST_GCC_SUPPRESS_WARNING("-Wnoexcept") #include using nlohmann::json; #ifdef JSON_TEST_NO_GLOBAL_UDLS using namespace nlohmann::literals; // NOLINT(google-build-using-namespace) #endif #include #include #include #include namespace udt { enum class country { china, france, russia }; struct age { int m_val; age(int rhs = 0) : m_val(rhs) {} }; struct name { std::string m_val; name(std::string rhs = "") : m_val(std::move(rhs)) {} }; struct address { std::string m_val; address(std::string rhs = "") : m_val(std::move(rhs)) {} }; struct person { age m_age{}; name m_name{}; country m_country{}; person() = default; person(const age& a, name n, const country& c) : m_age(a), m_name(std::move(n)), m_country(c) {} }; struct contact { person m_person{}; address m_address{}; contact() = default; contact(person p, address a) : m_person(std::move(p)), m_address(std::move(a)) {} }; struct contact_book { name m_book_name{}; std::vector m_contacts{}; contact_book() = default; contact_book(name n, std::vector c) : m_book_name(std::move(n)), m_contacts(std::move(c)) {} }; } // namespace udt // to_json methods namespace udt { // templates because of the custom_json tests (see below) template static void to_json(BasicJsonType& j, age a) { j = a.m_val; } template static void to_json(BasicJsonType& j, const name& n) { j = n.m_val; } template static void to_json(BasicJsonType& j, country c) { switch (c) { case country::china: j = "中华人民共和国"; return; case country::france: j = "France"; return; case country::russia: j = "Российская Федерация"; return; default: break; } } template static void to_json(BasicJsonType& j, const person& p) { j = BasicJsonType{{"age", p.m_age}, {"name", p.m_name}, {"country", p.m_country}}; } static void to_json(nlohmann::json& j, const address& a) { j = a.m_val; } static void to_json(nlohmann::json& j, const contact& c) { j = json{{"person", c.m_person}, {"address", c.m_address}}; } static void to_json(nlohmann::json& j, const contact_book& cb) { j = json{{"name", cb.m_book_name}, {"contacts", cb.m_contacts}}; } // operators static bool operator==(age lhs, age rhs) { return lhs.m_val == rhs.m_val; } static bool operator==(const address& lhs, const address& rhs) { return lhs.m_val == rhs.m_val; } static bool operator==(const name& lhs, const name& rhs) { return lhs.m_val == rhs.m_val; } static bool operator==(const person& lhs, const person& rhs) { return std::tie(lhs.m_name, lhs.m_age) == std::tie(rhs.m_name, rhs.m_age); } static bool operator==(const contact& lhs, const contact& rhs) { return std::tie(lhs.m_person, lhs.m_address) == std::tie(rhs.m_person, rhs.m_address); } static bool operator==(const contact_book& lhs, const contact_book& rhs) { return std::tie(lhs.m_book_name, lhs.m_contacts) == std::tie(rhs.m_book_name, rhs.m_contacts); } } // namespace udt // from_json methods namespace udt { template static void from_json(const BasicJsonType& j, age& a) { a.m_val = j.template get(); } template static void from_json(const BasicJsonType& j, name& n) { n.m_val = j.template get(); } template static void from_json(const BasicJsonType& j, country& c) { const auto str = j.template get(); const std::map m = { {"中华人民共和国", country::china}, {"France", country::france}, {"Российская Федерация", country::russia} }; const auto it = m.find(str); // TODO(nlohmann) test exceptions c = it->second; } template static void from_json(const BasicJsonType& j, person& p) { p.m_age = j["age"].template get(); p.m_name = j["name"].template get(); p.m_country = j["country"].template get(); } static void from_json(const nlohmann::json& j, address& a) { a.m_val = j.get(); } static void from_json(const nlohmann::json& j, contact& c) { c.m_person = j["person"].get(); c.m_address = j["address"].get
(); } static void from_json(const nlohmann::json& j, contact_book& cb) { cb.m_book_name = j["name"].get(); cb.m_contacts = j["contacts"].get>(); } } // namespace udt TEST_CASE("basic usage" * doctest::test_suite("udt")) { // a bit narcissistic maybe :) ? const udt::age a { 23 }; const udt::name n{"theo"}; const udt::country c{udt::country::france}; const udt::person sfinae_addict{a, n, c}; const udt::person senior_programmer{{42}, {"王芳"}, udt::country::china}; const udt::address addr{"Paris"}; const udt::contact cpp_programmer{sfinae_addict, addr}; const udt::contact_book book{{"C++"}, {cpp_programmer, {senior_programmer, addr}}}; SECTION("conversion to json via free-functions") { CHECK(json(a) == json(23)); CHECK(json(n) == json("theo")); CHECK(json(c) == json("France")); CHECK(json(sfinae_addict) == R"({"name":"theo", "age":23, "country":"France"})"_json); CHECK(json("Paris") == json(addr)); CHECK(json(cpp_programmer) == R"({"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"})"_json); CHECK( json(book) == R"({"name":"C++", "contacts" : [{"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"}, {"person" : {"age":42, "country":"中华人民共和国", "name":"王芳"}, "address":"Paris"}]})"_json); } SECTION("conversion from json via free-functions") { const auto big_json = R"({"name":"C++", "contacts" : [{"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"}, {"person" : {"age":42, "country":"中华人民共和国", "name":"王芳"}, "address":"Paris"}]})"_json; SECTION("via explicit calls to get") { const auto parsed_book = big_json.get(); const auto book_name = big_json["name"].get(); const auto contacts = big_json["contacts"].get>(); const auto contact_json = big_json["contacts"].at(0); const auto contact = contact_json.get(); const auto person = contact_json["person"].get(); const auto address = contact_json["address"].get(); const auto age = contact_json["person"]["age"].get(); const auto country = contact_json["person"]["country"].get(); const auto name = contact_json["person"]["name"].get(); CHECK(age == a); CHECK(name == n); CHECK(country == c); CHECK(address == addr); CHECK(person == sfinae_addict); CHECK(contact == cpp_programmer); CHECK(contacts == book.m_contacts); CHECK(book_name == udt::name{"C++"}); CHECK(book == parsed_book); } SECTION("via explicit calls to get_to") { udt::person person; udt::name name; json person_json = big_json["contacts"][0]["person"]; CHECK(person_json.get_to(person) == sfinae_addict); // correct reference gets returned person_json["name"].get_to(name).m_val = "new name"; CHECK(name.m_val == "new name"); } #if JSON_USE_IMPLICIT_CONVERSIONS SECTION("implicit conversions") { const udt::contact_book parsed_book = big_json; const udt::name book_name = big_json["name"]; const std::vector contacts = big_json["contacts"]; const auto contact_json = big_json["contacts"].at(0); const udt::contact contact = contact_json; const udt::person person = contact_json["person"]; const udt::address address = contact_json["address"]; const udt::age age = contact_json["person"]["age"]; const udt::country country = contact_json["person"]["country"]; const udt::name name = contact_json["person"]["name"]; CHECK(age == a); CHECK(name == n); CHECK(country == c); CHECK(address == addr); CHECK(person == sfinae_addict); CHECK(contact == cpp_programmer); CHECK(contacts == book.m_contacts); CHECK(book_name == udt::name{"C++"}); CHECK(book == parsed_book); } #endif } } namespace udt { struct legacy_type { std::string number{}; legacy_type() = default; legacy_type(std::string n) : number(std::move(n)) {} }; } // namespace udt namespace nlohmann { template struct adl_serializer> { static void to_json(json& j, const std::shared_ptr& opt) { if (opt) { j = *opt; } else { j = nullptr; } } static void from_json(const json& j, std::shared_ptr& opt) { if (j.is_null()) { opt = nullptr; } else { opt.reset(new T(j.get())); // NOLINT(cppcoreguidelines-owning-memory) } } }; template <> struct adl_serializer { static void to_json(json& j, const udt::legacy_type& l) { j = std::stoi(l.number); } static void from_json(const json& j, udt::legacy_type& l) { l.number = std::to_string(j.get()); } }; } // namespace nlohmann TEST_CASE("adl_serializer specialization" * doctest::test_suite("udt")) { SECTION("partial specialization") { SECTION("to_json") { std::shared_ptr optPerson; json j = optPerson; CHECK(j.is_null()); optPerson.reset(new udt::person{{42}, {"John Doe"}, udt::country::russia}); // NOLINT(cppcoreguidelines-owning-memory,modernize-make-shared) j = optPerson; CHECK_FALSE(j.is_null()); CHECK(j.get() == *optPerson); } SECTION("from_json") { auto person = udt::person{{42}, {"John Doe"}, udt::country::russia}; json j = person; auto optPerson = j.get>(); REQUIRE(optPerson); CHECK(*optPerson == person); j = nullptr; optPerson = j.get>(); CHECK(!optPerson); } } SECTION("total specialization") { SECTION("to_json") { udt::legacy_type lt{"4242"}; json j = lt; CHECK(j.get() == 4242); } SECTION("from_json") { json j = 4242; auto lt = j.get(); CHECK(lt.number == "4242"); } } } namespace nlohmann { template <> struct adl_serializer> { using type = std::vector; static void to_json(json& j, const type& /*type*/) { j = "hijacked!"; } static void from_json(const json& /*unnamed*/, type& opt) { opt = {42.0, 42.0, 42.0}; } // preferred version static type from_json(const json& /*unnamed*/) { return {4.0, 5.0, 6.0}; } }; } // namespace nlohmann TEST_CASE("even supported types can be specialized" * doctest::test_suite("udt")) { json j = std::vector {1.0, 2.0, 3.0}; CHECK(j.dump() == R"("hijacked!")"); auto f = j.get>(); // the single argument from_json method is preferred CHECK((f == std::vector {4.0, 5.0, 6.0})); } namespace nlohmann { template struct adl_serializer> { static void to_json(json& j, const std::unique_ptr& opt) { if (opt) { j = *opt; } else { j = nullptr; } } // this is the overload needed for non-copyable types, static std::unique_ptr from_json(const json& j) { if (j.is_null()) { return nullptr; } return std::unique_ptr(new T(j.get())); } }; } // namespace nlohmann TEST_CASE("Non-copyable types" * doctest::test_suite("udt")) { SECTION("to_json") { std::unique_ptr optPerson; json j = optPerson; CHECK(j.is_null()); optPerson.reset(new udt::person{{42}, {"John Doe"}, udt::country::russia}); // NOLINT(cppcoreguidelines-owning-memory,modernize-make-unique) j = optPerson; CHECK_FALSE(j.is_null()); CHECK(j.get() == *optPerson); } SECTION("from_json") { auto person = udt::person{{42}, {"John Doe"}, udt::country::russia}; json j = person; auto optPerson = j.get>(); REQUIRE(optPerson); CHECK(*optPerson == person); j = nullptr; optPerson = j.get>(); CHECK(!optPerson); } } // custom serializer - advanced usage // pack structs that are pod-types (but not scalar types) // relies on adl for any other type template struct pod_serializer { // use adl for non-pods, or scalar types template < typename BasicJsonType, typename U = T, typename std::enable_if < !(std::is_pod::value && std::is_class::value), int >::type = 0 > static void from_json(const BasicJsonType& j, U& t) { using nlohmann::from_json; from_json(j, t); } // special behaviour for pods template < typename BasicJsonType, typename U = T, typename std::enable_if < std::is_pod::value && std::is_class::value, int >::type = 0 > static void from_json(const BasicJsonType& j, U& t) { std::uint64_t value = 0; // The following block is no longer relevant in this serializer, make another one that shows the issue // the problem arises only when one from_json method is defined without any constraint // // Why cannot we simply use: j.get() ? // Well, with the current experiment, the get method looks for a from_json // function, which we are currently defining! // This would end up in a stack overflow. Calling nlohmann::from_json is a // workaround (is it?). // I shall find a good way to avoid this once all constructors are converted // to free methods // // In short, constructing a json by constructor calls to_json // calling get calls from_json, for now, we cannot do this in custom // serializers nlohmann::from_json(j, value); auto* bytes = static_cast(static_cast(&value)); std::memcpy(&t, bytes, sizeof(value)); } template < typename BasicJsonType, typename U = T, typename std::enable_if < !(std::is_pod::value && std::is_class::value), int >::type = 0 > static void to_json(BasicJsonType& j, const T& t) { using nlohmann::to_json; to_json(j, t); } template < typename BasicJsonType, typename U = T, typename std::enable_if < std::is_pod::value && std::is_class::value, int >::type = 0 > static void to_json(BasicJsonType& j, const T& t) noexcept { const auto* bytes = static_cast< const unsigned char*>(static_cast(&t)); std::uint64_t value = 0; std::memcpy(&value, bytes, sizeof(value)); nlohmann::to_json(j, value); } }; namespace udt { struct small_pod { int begin; char middle; short end; }; struct non_pod { std::string s{}; non_pod() = default; non_pod(std::string S) : s(std::move(S)) {} }; template static void to_json(BasicJsonType& j, const non_pod& np) { j = np.s; } template static void from_json(const BasicJsonType& j, non_pod& np) { np.s = j.template get(); } static bool operator==(small_pod lhs, small_pod rhs) noexcept { return std::tie(lhs.begin, lhs.middle, lhs.end) == std::tie(rhs.begin, rhs.middle, rhs.end); } static bool operator==(const non_pod& lhs, const non_pod& rhs) noexcept { return lhs.s == rhs.s; } static std::ostream& operator<<(std::ostream& os, small_pod l) { return os << "begin: " << l.begin << ", middle: " << l.middle << ", end: " << l.end; } } // namespace udt TEST_CASE("custom serializer for pods" * doctest::test_suite("udt")) { using custom_json = nlohmann::basic_json; auto p = udt::small_pod{42, '/', 42}; custom_json j = p; auto p2 = j.get(); CHECK(p == p2); auto np = udt::non_pod{{"non-pod"}}; custom_json j2 = np; auto np2 = j2.get(); CHECK(np == np2); } template struct another_adl_serializer; using custom_json = nlohmann::basic_json; template struct another_adl_serializer { static void from_json(const custom_json& j, T& t) { using nlohmann::from_json; from_json(j, t); } static void to_json(custom_json& j, const T& t) { using nlohmann::to_json; to_json(j, t); } }; TEST_CASE("custom serializer that does adl by default" * doctest::test_suite("udt")) { auto me = udt::person{{23}, {"theo"}, udt::country::france}; json j = me; custom_json cj = me; CHECK(j.dump() == cj.dump()); CHECK(me == j.get()); CHECK(me == cj.get()); } TEST_CASE("different basic_json types conversions") { SECTION("null") { json j; custom_json cj = j; CHECK(cj == nullptr); } SECTION("boolean") { json j = true; custom_json cj = j; CHECK(cj == true); } SECTION("discarded") { json j(json::value_t::discarded); custom_json cj; CHECK_NOTHROW(cj = j); CHECK(cj.type() == custom_json::value_t::discarded); } SECTION("array") { json j = {1, 2, 3}; custom_json cj = j; CHECK((cj == std::vector {1, 2, 3})); } SECTION("integer") { json j = 42; custom_json cj = j; CHECK(cj == 42); } SECTION("float") { json j = 42.0; custom_json cj = j; CHECK(cj == 42.0); } SECTION("unsigned") { json j = 42u; custom_json cj = j; CHECK(cj == 42u); } SECTION("string") { json j = "forty-two"; custom_json cj = j; CHECK(cj == "forty-two"); } SECTION("binary") { json j = json::binary({1, 2, 3}, 42); custom_json cj = j; CHECK(cj.get_binary().subtype() == 42); std::vector cv = cj.get_binary(); std::vector v = j.get_binary(); CHECK(cv == v); } SECTION("object") { json j = {{"forty", "two"}}; custom_json cj = j; auto m = j.get>(); CHECK(cj == m); } SECTION("get") { json j = 42; custom_json cj = j.get(); CHECK(cj == 42); } } namespace { struct incomplete; // std::is_constructible is broken on macOS' libc++ // use the cppreference implementation template struct is_constructible_patched : std::false_type {}; template struct is_constructible_patched())))> : std::true_type {}; } // namespace TEST_CASE("an incomplete type does not trigger a compiler error in non-evaluated context" * doctest::test_suite("udt")) { static_assert(!is_constructible_patched::value, ""); } namespace { class Evil { public: Evil() = default; template Evil(T t) : m_i(sizeof(t)) { static_cast(t); // fix MSVC's C4100 warning } int m_i = 0; }; void from_json(const json& /*unused*/, Evil& /*unused*/) {} } // namespace TEST_CASE("Issue #924") { // Prevent get>() to throw auto j = json::array(); CHECK_NOTHROW(j.get()); CHECK_NOTHROW(j.get>()); // silence Wunused-template warnings Evil e(1); CHECK(e.m_i >= 0); } TEST_CASE("Issue #1237") { struct non_convertible_type {}; static_assert(!std::is_convertible::value, ""); } namespace { class no_iterator_type { public: no_iterator_type(std::initializer_list l) : _v(l) {} std::vector::const_iterator begin() const { return _v.begin(); } std::vector::const_iterator end() const { return _v.end(); } private: std::vector _v; }; } // namespace TEST_CASE("compatible array type, without iterator type alias") { no_iterator_type vec{1, 2, 3}; json j = vec; } DOCTEST_GCC_SUPPRESS_WARNING_POP