json/test/src/unit-udt.cpp

/*
    __ _____ _____ _____
 __|  |   __|     |   | |  JSON for Modern C++ (test suite)
|  |  |__   |  |  | | | |  version 2.0.7
|_____|_____|_____|_|___|  https://github.com/nlohmann/json

Licensed under the MIT License <http://opensource.org/licenses/MIT>.
Copyright (c) 2013-2016 Niels Lohmann <http://nlohmann.me>.

Permission is hereby  granted, free of charge, to any  person obtaining a copy
of this software and associated  documentation files (the "Software"), to deal
in the Software  without restriction, including without  limitation the rights
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copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

#include <array>
#include <string>
#include <memory>
#include "catch.hpp"

#include "json.hpp"

namespace udt
{
  struct age
  {
    int m_val;
  };

  struct name
  {
    std::string m_val;
  };

  struct address
  {
    std::string m_val;
  };

  struct person
  {
    age m_age;
    name m_name;
  };

  struct contact
  {
    person m_person;
    address m_address;
  };

  struct contact_book
  {
    name m_book_name;
    std::vector<contact> m_contacts;
  };
}

// to_json methods for default basic_json
namespace udt
{
  void to_json(nlohmann::json& j, age a)
  {
    j = a.m_val;
  }

  void to_json(nlohmann::json& j, name const& n)
  {
    j = n.m_val;
  }

  void to_json(nlohmann::json& j, person const& p)
  {
    using nlohmann::json;
    j = json{{"age", p.m_age}, {"name", p.m_name}};
  }

  void to_json(nlohmann::json& j, address const& a)
  {
    j = a.m_val;
  }

  void to_json(nlohmann::json& j, contact const& c)
  {
    using nlohmann::json;
    j = json{{"person", c.m_person}, {"address", c.m_address}};
  }

  void to_json(nlohmann::json& j, contact_book const& cb)
  {
    using nlohmann::json;
    j = json{{"name", cb.m_book_name}, {"contacts", cb.m_contacts}};
  }

  // operators
  bool operator==(age lhs, age rhs)
  {
    return lhs.m_val == rhs.m_val;
  }

  bool operator==(address const &lhs, address const &rhs)
  {
    return lhs.m_val == rhs.m_val;
  }

  bool operator==(name const &lhs, name const &rhs)
  {
    return lhs.m_val == rhs.m_val;
  }

  bool operator==(person const &lhs, person const &rhs)
  {
    return std::tie(lhs.m_name, lhs.m_age) == std::tie(rhs.m_name, rhs.m_age);
  }

  bool operator==(contact const &lhs, contact const &rhs)
  {
    return std::tie(lhs.m_person, lhs.m_address) ==
           std::tie(rhs.m_person, rhs.m_address);
  }

  bool operator==(contact_book const &lhs, contact_book const &rhs)
  {
    return std::tie(lhs.m_book_name, lhs.m_contacts) ==
           std::tie(rhs.m_book_name, rhs.m_contacts);
  }
}

// from_json methods for default basic_json
namespace udt
{
  void from_json(nlohmann::json const& j, age &a)
  {
    a.m_val = j.get<int>();
  }

  void from_json(nlohmann::json const& j, name &n)
  {
    n.m_val = j.get<std::string>();
  }

  void from_json(nlohmann::json const& j, person &p)
  {
    p.m_age = j["age"].get<age>();
    p.m_name = j["name"].get<name>();
  }

  void from_json(nlohmann::json const &j, address &a)
  {
    a.m_val = j.get<std::string>();
  }

  void from_json(nlohmann::json const& j, contact &c)
  {
    c.m_person = j["person"].get<person>();
    c.m_address = j["address"].get<address>();
  }

  void from_json(nlohmann::json const&j, contact_book &cb)
  {
    cb.m_book_name = j["name"].get<name>();
    cb.m_contacts = j["contacts"].get<std::vector<contact>>();
  }
}

TEST_CASE("basic usage", "[udt]")
{
  using nlohmann::json;

  // a bit narcissic maybe :) ?
  const udt::age a{23};
  const udt::name n{"theo"};
  const udt::person sfinae_addict{a, n};
  const udt::address addr{"Paris"};
  const udt::contact cpp_programmer{sfinae_addict, addr};
  const udt::contact_book book{{"C++"}, {cpp_programmer, cpp_programmer}};

  SECTION("conversion to json via free-functions")
  {
    CHECK(json(a) == json(23));
    CHECK(json(n) == json("theo"));
    CHECK(json(sfinae_addict) == R"({"name":"theo", "age":23})"_json);
    CHECK(json("Paris") == json(addr));
    CHECK(json(cpp_programmer) ==
          R"({"person" : {"age":23, "name":"theo"}, "address":"Paris"})"_json);

    CHECK(
        json(book) ==
        R"({"name":"C++", "contacts" : [{"person" : {"age":23, "name":"theo"}, "address":"Paris"}, {"person" : {"age":23, "name":"theo"}, "address":"Paris"}]})"_json);
  }

  SECTION("conversion from json via free-functions")
  {
    const auto big_json =
        R"({"name":"C++", "contacts" : [{"person" : {"age":23, "name":"theo"}, "address":"Paris"}, {"person" : {"age":23, "name":"theo"}, "address":"Paris"}]})"_json;
    const auto parsed_book = big_json.get<udt::contact_book>();
    const auto book_name = big_json["name"].get<udt::name>();
    const auto contacts = big_json["contacts"].get<std::vector<udt::contact>>();
    const auto contact_json = big_json["contacts"].at(0);
    const auto contact = contact_json.get<udt::contact>();
    const auto person = contact_json["person"].get<udt::person>();
    const auto address = contact_json["address"].get<udt::address>();
    const auto age = contact_json["person"]["age"].get<udt::age>();
    const auto name = contact_json["person"]["name"].get<udt::name>();

    CHECK(age == a);
    CHECK(name == n);
    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);
  }
}

namespace udt
{
template <typename T>
class optional_type
{
public:
  optional_type() = default;
  optional_type(T t) { _impl = std::make_shared<T>(std::move(t)); }
  optional_type(std::nullptr_t) { _impl = nullptr; }

  optional_type &operator=(std::nullptr_t)
  {
    _impl = nullptr;
    return *this;
  }

  optional_type& operator=(T t)
  {
    _impl = std::make_shared<T>(std::move(t));
    return *this;
  }

  explicit operator bool() const noexcept { return _impl != nullptr; }
  T const &operator*() const noexcept { return *_impl; }
  T &operator*() noexcept { return *_impl; }

private:
  std::shared_ptr<T> _impl;
};

struct legacy_type
{
  std::string number;
};
}

namespace nlohmann
{
template <typename T>
struct adl_serializer<udt::optional_type<T>>
{
  static void to_json(json& j, udt::optional_type<T> const& opt)
  {
    if (opt)
      j = *opt;
    else
      j = nullptr;
  }

  static void from_json(json const &j, udt::optional_type<T> &opt)
  {
    if (j.is_null())
      opt = nullptr;
    else
      opt = j.get<T>();
  }
};

template <>
struct adl_serializer<udt::legacy_type>
{
  static void to_json(json& j, udt::legacy_type const& l)
  {
    j = std::stoi(l.number);
  }

  static void from_json(json const& j, udt::legacy_type& l)
  {
    l.number = std::to_string(j.get<int>());
  }
};
}

TEST_CASE("adl_serializer specialization", "[udt]")
{
  using nlohmann::json;

  SECTION("partial specialization")
  {
    SECTION("to_json")
    {
      udt::optional_type<udt::person> optPerson;

      json j = optPerson;
      CHECK(j.is_null());

      optPerson = udt::person{{42}, {"John Doe"}};
      j = optPerson;
      CHECK_FALSE(j.is_null());

      CHECK(j.get<udt::person>() == *optPerson);
    }

    SECTION("from_json")
    {
      auto person = udt::person{{42}, {"John Doe"}};
      json j = person;

      auto optPerson = j.get<udt::optional_type<udt::person>>();
      REQUIRE(optPerson);
      CHECK(*optPerson == person);

      j = nullptr;
      optPerson = j.get<udt::optional_type<udt::person>>();
      CHECK(!optPerson);
    }
  }

  SECTION("total specialization")
  {
    SECTION("to_json")
    {
      udt::legacy_type lt{"4242"};

      json j = lt;
      CHECK(j.get<int>() == 4242);
    }

    SECTION("from_json")
    {
      json j = 4242;
      auto lt = j.get<udt::legacy_type>();
      CHECK(lt.number == "4242");
    }
  }
}