include/nlohmann/detail/exceptions.hpp

//     __ _____ _____ _____
//  __|  |   __|     |   | |  JSON for Modern C++
// |  |  |__   |  |  | | | |  version 3.11.3
// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2023 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT

#pragma once

#include <cstddef>    // nullptr_t
#include <exception>  // exception
#if JSON_DIAGNOSTICS
    #include <numeric>  // accumulate
#endif
#include <stdexcept>  // runtime_error
#include <string>     // to_string
#include <vector>     // vector

#include <nlohmann/detail/input/position_t.hpp>
#include <nlohmann/detail/macro_scope.hpp>
#include <nlohmann/detail/meta/cpp_future.hpp>
#include <nlohmann/detail/meta/type_traits.hpp>
#include <nlohmann/detail/string_concat.hpp>
#include <nlohmann/detail/string_escape.hpp>
#include <nlohmann/detail/value_t.hpp>

NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
{

////////////////
// exceptions //
////////////////

/// @brief general exception of the @ref basic_json class
/// @sa https://json.nlohmann.me/api/basic_json/exception/
class exception : public std::exception
{
  public:
    /// returns the explanatory string
    const char* what() const noexcept override
    {
        return m.what();
    }

    /// the id of the exception
    const int id;  // NOLINT(cppcoreguidelines-non-private-member-variables-in-classes)

  protected:
    JSON_HEDLEY_NON_NULL(3)
    exception(int id_, const char* what_arg)
      : id(id_)
      , m(what_arg)  // NOLINT(bugprone-throw-keyword-missing)
    {}

    static std::string name(const std::string& ename, int id_)
    {
        return concat("[json.exception.", ename, '.', std::to_string(id_), "] ");
    }

    static std::string diagnostics(std::nullptr_t /*leaf_element*/)
    {
        return "";
    }

    template<typename BasicJsonType>
    static std::string diagnostics(const BasicJsonType* leaf_element)
    {
#if JSON_DIAGNOSTICS
        std::vector<std::string> tokens;
        for (const auto* current = leaf_element; current != nullptr && current->m_parent != nullptr; current = current->m_parent)
        {
            switch (current->m_parent->type())
            {
                case value_t::array:
                {
                    for (std::size_t i = 0; i < current->m_parent->m_data.m_value.array->size(); ++i)
                    {
                        if (&current->m_parent->m_data.m_value.array->operator[](i) == current)
                        {
                            tokens.emplace_back(std::to_string(i));
                            break;
                        }
                    }
                    break;
                }

                case value_t::object:
                {
                    for (const auto& element : *current->m_parent->m_data.m_value.object)
                    {
                        if (&element.second == current)
                        {
                            tokens.emplace_back(element.first.c_str());
                            break;
                        }
                    }
                    break;
                }

                case value_t::null:             // LCOV_EXCL_LINE
                case value_t::string:           // LCOV_EXCL_LINE
                case value_t::boolean:          // LCOV_EXCL_LINE
                case value_t::number_integer:   // LCOV_EXCL_LINE
                case value_t::number_unsigned:  // LCOV_EXCL_LINE
                case value_t::number_float:     // LCOV_EXCL_LINE
                case value_t::binary:           // LCOV_EXCL_LINE
                case value_t::discarded:        // LCOV_EXCL_LINE
                default:                        // LCOV_EXCL_LINE
                    break;                      // LCOV_EXCL_LINE
            }
        }

        if (tokens.empty())
        {
            return "";
        }

        auto str = std::accumulate(tokens.rbegin(), tokens.rend(), std::string{}, [](const std::string& a, const std::string& b) {
            return concat(a, '/', detail::escape(b));
        });
        return concat('(', str, ") ");
#else
        static_cast<void>(leaf_element);
        return "";
#endif
    }

  private:
    /// an exception object as storage for error messages
    std::runtime_error m;
};

/// @brief exception indicating a parse error
/// @sa https://json.nlohmann.me/api/basic_json/parse_error/
class parse_error : public exception
{
  public:
    /*!
    @brief create a parse error exception
    @param[in] id_       the id of the exception
    @param[in] pos       the position where the error occurred (or with
                         chars_read_total=0 if the position cannot be
                         determined)
    @param[in] what_arg  the explanatory string
    @return parse_error object
    */
    template<typename BasicJsonContext, enable_if_t<is_basic_json_context<BasicJsonContext>::value, int> = 0>
    static parse_error create(int id_, const position_t& pos, const std::string& what_arg, BasicJsonContext context)
    {
        const std::string w = concat(exception::name("parse_error", id_), "parse error", position_string(pos), ": ", exception::diagnostics(context), what_arg);
        return { id_, pos.chars_read_total, w.c_str() };
    }

    template<typename BasicJsonContext, enable_if_t<is_basic_json_context<BasicJsonContext>::value, int> = 0>
    static parse_error create(int id_, std::size_t byte_, const std::string& what_arg, BasicJsonContext context)
    {
        const std::string w = concat(exception::name("parse_error", id_),
                                     "parse error",
                                     (byte_ != 0 ? (concat(" at byte ", std::to_string(byte_))) : ""),
                                     ": ",
                                     exception::diagnostics(context),
                                     what_arg);
        return { id_, byte_, w.c_str() };
    }

    /*!
    @brief byte index of the parse error

    The byte index of the last read character in the input file.

    @note For an input with n bytes, 1 is the index of the first character and
          n+1 is the index of the terminating null byte or the end of file.
          This also holds true when reading a byte vector (CBOR or MessagePack).
    */
    const std::size_t byte;

  private:
    parse_error(int id_, std::size_t byte_, const char* what_arg)
      : exception(id_, what_arg)
      , byte(byte_)
    {}

    static std::string position_string(const position_t& pos)
    {
        return concat(" at line ", std::to_string(pos.lines_read + 1), ", column ", std::to_string(pos.chars_read_current_line));
    }
};

/// @brief exception indicating errors with iterators
/// @sa https://json.nlohmann.me/api/basic_json/invalid_iterator/
class invalid_iterator : public exception
{
  public:
    template<typename BasicJsonContext, enable_if_t<is_basic_json_context<BasicJsonContext>::value, int> = 0>
    static invalid_iterator create(int id_, const std::string& what_arg, BasicJsonContext context)
    {
        const std::string w = concat(exception::name("invalid_iterator", id_), exception::diagnostics(context), what_arg);
        return { id_, w.c_str() };
    }

  private:
    JSON_HEDLEY_NON_NULL(3)
    invalid_iterator(int id_, const char* what_arg)
      : exception(id_, what_arg)
    {}
};

/// @brief exception indicating executing a member function with a wrong type
/// @sa https://json.nlohmann.me/api/basic_json/type_error/
class type_error : public exception
{
  public:
    template<typename BasicJsonContext, enable_if_t<is_basic_json_context<BasicJsonContext>::value, int> = 0>
    static type_error create(int id_, const std::string& what_arg, BasicJsonContext context)
    {
        const std::string w = concat(exception::name("type_error", id_), exception::diagnostics(context), what_arg);
        return { id_, w.c_str() };
    }

  private:
    JSON_HEDLEY_NON_NULL(3)
    type_error(int id_, const char* what_arg)
      : exception(id_, what_arg)
    {}
};

/// @brief exception indicating access out of the defined range
/// @sa https://json.nlohmann.me/api/basic_json/out_of_range/
class out_of_range : public exception
{
  public:
    template<typename BasicJsonContext, enable_if_t<is_basic_json_context<BasicJsonContext>::value, int> = 0>
    static out_of_range create(int id_, const std::string& what_arg, BasicJsonContext context)
    {
        const std::string w = concat(exception::name("out_of_range", id_), exception::diagnostics(context), what_arg);
        return { id_, w.c_str() };
    }

  private:
    JSON_HEDLEY_NON_NULL(3)
    out_of_range(int id_, const char* what_arg)
      : exception(id_, what_arg)
    {}
};

/// @brief exception indicating other library errors
/// @sa https://json.nlohmann.me/api/basic_json/other_error/
class other_error : public exception
{
  public:
    template<typename BasicJsonContext, enable_if_t<is_basic_json_context<BasicJsonContext>::value, int> = 0>
    static other_error create(int id_, const std::string& what_arg, BasicJsonContext context)
    {
        const std::string w = concat(exception::name("other_error", id_), exception::diagnostics(context), what_arg);
        return { id_, w.c_str() };
    }

  private:
    JSON_HEDLEY_NON_NULL(3)
    other_error(int id_, const char* what_arg)
      : exception(id_, what_arg)
    {}
};

}  // namespace detail
NLOHMANN_JSON_NAMESPACE_END