diff --git a/src/json.hpp b/src/json.hpp index 3c615451..2df26ae0 100644 --- a/src/json.hpp +++ b/src/json.hpp @@ -748,8 +748,7 @@ struct is_basic_json_nested_type static auto constexpr value = std::is_same::value or std::is_same::value or std::is_same::value or - std::is_same::value or - std::is_same::value; + std::is_same::value; }; template @@ -1320,6 +1319,335 @@ struct adl_serializer } }; +/*! +@brief JSON Pointer + +A JSON pointer defines a string syntax for identifying a specific value +within a JSON document. It can be used with functions `at` and +`operator[]`. Furthermore, JSON pointers are the base for JSON patches. + +@sa [RFC 6901](https://tools.ietf.org/html/rfc6901) + +@since version 2.0.0 +*/ +class json_pointer +{ + /// allow basic_json to access private members + NLOHMANN_BASIC_JSON_TPL_DECLARATION + friend class basic_json; + + public: + /*! + @brief create JSON pointer + + Create a JSON pointer according to the syntax described in + [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3). + + @param[in] s string representing the JSON pointer; if omitted, the + empty string is assumed which references the whole JSON + value + + @throw parse_error.107 if the given JSON pointer @a s is nonempty and + does not begin with a slash (`/`); see example below + + @throw parse_error.108 if a tilde (`~`) in the given JSON pointer @a s + is not followed by `0` (representing `~`) or `1` (representing `/`); + see example below + + @liveexample{The example shows the construction several valid JSON + pointers as well as the exceptional behavior.,json_pointer} + + @since version 2.0.0 + */ + explicit json_pointer(const std::string& s = "") : reference_tokens(split(s)) {} + + /*! + @brief return a string representation of the JSON pointer + + @invariant For each JSON pointer `ptr`, it holds: + @code {.cpp} + ptr == json_pointer(ptr.to_string()); + @endcode + + @return a string representation of the JSON pointer + + @liveexample{The example shows the result of `to_string`., + json_pointer__to_string} + + @since version 2.0.0 + */ + std::string to_string() const noexcept + { + return std::accumulate(reference_tokens.begin(), reference_tokens.end(), + std::string{}, + [](const std::string & a, const std::string & b) + { + return a + "/" + escape(b); + }); + } + + /// @copydoc to_string() + operator std::string() const + { + return to_string(); + } + + private: + /*! + @brief remove and return last reference pointer + @throw out_of_range.405 if JSON pointer has no parent + */ + std::string pop_back() + { + if (is_root()) + { + JSON_THROW( + detail::out_of_range::create(405, "JSON pointer has no parent")); + } + + auto last = reference_tokens.back(); + reference_tokens.pop_back(); + return last; + } + + /// return whether pointer points to the root document + bool is_root() const + { + return reference_tokens.empty(); + } + + json_pointer top() const + { + if (is_root()) + { + JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent")); + } + + json_pointer result = *this; + result.reference_tokens = {reference_tokens[0]}; + return result; + } + + + /*! + @brief create and return a reference to the pointed to value + + @complexity Linear in the number of reference tokens. + + @throw parse_error.109 if array index is not a number + @throw type_error.313 if value cannot be unflattened + */ + NLOHMANN_BASIC_JSON_TPL_DECLARATION + NLOHMANN_BASIC_JSON_TPL& get_and_create(NLOHMANN_BASIC_JSON_TPL& j) const; + + /*! + @brief return a reference to the pointed to value + + @note This version does not throw if a value is not present, but tries + to create nested values instead. For instance, calling this function + with pointer `"/this/that"` on a null value is equivalent to calling + `operator[]("this").operator[]("that")` on that value, effectively + changing the null value to an object. + + @param[in] ptr a JSON value + + @return reference to the JSON value pointed to by the JSON pointer + + @complexity Linear in the length of the JSON pointer. + + @throw parse_error.106 if an array index begins with '0' + @throw parse_error.109 if an array index was not a number + @throw out_of_range.404 if the JSON pointer can not be resolved + */ + NLOHMANN_BASIC_JSON_TPL_DECLARATION + NLOHMANN_BASIC_JSON_TPL& get_unchecked(NLOHMANN_BASIC_JSON_TPL* ptr) const; + + /*! + @throw parse_error.106 if an array index begins with '0' + @throw parse_error.109 if an array index was not a number + @throw out_of_range.402 if the array index '-' is used + @throw out_of_range.404 if the JSON pointer can not be resolved + */ + NLOHMANN_BASIC_JSON_TPL_DECLARATION + NLOHMANN_BASIC_JSON_TPL& get_checked(NLOHMANN_BASIC_JSON_TPL* ptr) const; + + /*! + @brief return a const reference to the pointed to value + + @param[in] ptr a JSON value + + @return const reference to the JSON value pointed to by the JSON + pointer + + @throw parse_error.106 if an array index begins with '0' + @throw parse_error.109 if an array index was not a number + @throw out_of_range.402 if the array index '-' is used + @throw out_of_range.404 if the JSON pointer can not be resolved + */ + NLOHMANN_BASIC_JSON_TPL_DECLARATION + const NLOHMANN_BASIC_JSON_TPL& get_unchecked(const NLOHMANN_BASIC_JSON_TPL* ptr) const; + + /*! + @throw parse_error.106 if an array index begins with '0' + @throw parse_error.109 if an array index was not a number + @throw out_of_range.402 if the array index '-' is used + @throw out_of_range.404 if the JSON pointer can not be resolved + */ + NLOHMANN_BASIC_JSON_TPL_DECLARATION + const NLOHMANN_BASIC_JSON_TPL& get_checked(const NLOHMANN_BASIC_JSON_TPL* ptr) const; + + /*! + @brief split the string input to reference tokens + + @note This function is only called by the json_pointer constructor. + All exceptions below are documented there. + + @throw parse_error.107 if the pointer is not empty or begins with '/' + @throw parse_error.108 if character '~' is not followed by '0' or '1' + */ + static std::vector split(const std::string& reference_string) + { + std::vector result; + + // special case: empty reference string -> no reference tokens + if (reference_string.empty()) + { + return result; + } + + // check if nonempty reference string begins with slash + if (reference_string[0] != '/') + { + JSON_THROW(detail::parse_error::create( + 107, 1, + "JSON pointer must be empty or begin with '/' - was: '" + + reference_string + "'")); + } + + // extract the reference tokens: + // - slash: position of the last read slash (or end of string) + // - start: position after the previous slash + for ( + // search for the first slash after the first character + size_t slash = reference_string.find_first_of('/', 1), + // set the beginning of the first reference token + start = 1; + // we can stop if start == string::npos+1 = 0 + start != 0; + // set the beginning of the next reference token + // (will eventually be 0 if slash == std::string::npos) + start = slash + 1, + // find next slash + slash = reference_string.find_first_of('/', start)) + { + // use the text between the beginning of the reference token + // (start) and the last slash (slash). + auto reference_token = reference_string.substr(start, slash - start); + + // check reference tokens are properly escaped + for (size_t pos = reference_token.find_first_of('~'); + pos != std::string::npos; + pos = reference_token.find_first_of('~', pos + 1)) + { + assert(reference_token[pos] == '~'); + + // ~ must be followed by 0 or 1 + if (pos == reference_token.size() - 1 or + (reference_token[pos + 1] != '0' and + reference_token[pos + 1] != '1')) + { + JSON_THROW(detail::parse_error::create( + 108, 0, "escape character '~' must be followed with '0' or '1'")); + } + } + + // finally, store the reference token + unescape(reference_token); + result.push_back(reference_token); + } + + return result; + } + + /*! + @brief replace all occurrences of a substring by another string + + @param[in,out] s the string to manipulate; changed so that all + occurrences of @a f are replaced with @a t + @param[in] f the substring to replace with @a t + @param[in] t the string to replace @a f + + @pre The search string @a f must not be empty. **This precondition is + enforced with an assertion.** + + @since version 2.0.0 + */ + static void replace_substring(std::string& s, const std::string& f, + const std::string& t) + { + assert(not f.empty()); + + for (size_t pos = s.find(f); // find first occurrence of f + pos != std::string::npos; // make sure f was found + s.replace(pos, f.size(), t), // replace with t + pos = s.find(f, pos + t.size()) // find next occurrence of f + ) + ; + } + + /// escape tilde and slash + static std::string escape(std::string s) + { + // escape "~"" to "~0" and "/" to "~1" + replace_substring(s, "~", "~0"); + replace_substring(s, "/", "~1"); + return s; + } + + /// unescape tilde and slash + static void unescape(std::string& s) + { + // first transform any occurrence of the sequence '~1' to '/' + replace_substring(s, "~1", "/"); + // then transform any occurrence of the sequence '~0' to '~' + replace_substring(s, "~0", "~"); + } + + /*! + @param[in] reference_string the reference string to the current value + @param[in] value the value to consider + @param[in,out] result the result object to insert values to + + @note Empty objects or arrays are flattened to `null`. + */ + NLOHMANN_BASIC_JSON_TPL_DECLARATION + static void flatten(const std::string& reference_string, + const NLOHMANN_BASIC_JSON_TPL& value, + NLOHMANN_BASIC_JSON_TPL& result); + + /*! + @param[in] value flattened JSON + + @return unflattened JSON + + @throw parse_error.109 if array index is not a number + @throw type_error.314 if value is not an object + @throw type_error.315 if object values are not primitive + @throw type_error.313 if value cannot be unflattened + */ + NLOHMANN_BASIC_JSON_TPL_DECLARATION + static NLOHMANN_BASIC_JSON_TPL + unflatten(const NLOHMANN_BASIC_JSON_TPL& value); + + friend bool operator==(json_pointer const& lhs, + json_pointer const& rhs) noexcept; + + friend bool operator!=(json_pointer const& lhs, + json_pointer const& rhs) noexcept; + + /// the reference tokens + std::vector reference_tokens; +}; /*! @brief a class to store JSON values @@ -1409,13 +1737,14 @@ class basic_json template friend struct detail::external_constructor; /// workaround type for MSVC using basic_json_t = NLOHMANN_BASIC_JSON_TPL; + friend ::nlohmann::json_pointer; public: using value_t = detail::value_t; // forward declarations template class iter_impl; template class json_reverse_iterator; - class json_pointer; + using json_pointer = ::nlohmann::json_pointer; template using json_serializer = JSONSerializer; @@ -13031,685 +13360,6 @@ scan_number_done: }; public: - /*! - @brief JSON Pointer - - A JSON pointer defines a string syntax for identifying a specific value - within a JSON document. It can be used with functions `at` and - `operator[]`. Furthermore, JSON pointers are the base for JSON patches. - - @sa [RFC 6901](https://tools.ietf.org/html/rfc6901) - - @since version 2.0.0 - */ - class json_pointer - { - /// allow basic_json to access private members - friend class basic_json; - - public: - /*! - @brief create JSON pointer - - Create a JSON pointer according to the syntax described in - [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3). - - @param[in] s string representing the JSON pointer; if omitted, the - empty string is assumed which references the whole JSON - value - - @throw parse_error.107 if the given JSON pointer @a s is nonempty and - does not begin with a slash (`/`); see example below - - @throw parse_error.108 if a tilde (`~`) in the given JSON pointer @a s - is not followed by `0` (representing `~`) or `1` (representing `/`); - see example below - - @liveexample{The example shows the construction several valid JSON - pointers as well as the exceptional behavior.,json_pointer} - - @since version 2.0.0 - */ - explicit json_pointer(const std::string& s = "") - : reference_tokens(split(s)) - {} - - /*! - @brief return a string representation of the JSON pointer - - @invariant For each JSON pointer `ptr`, it holds: - @code {.cpp} - ptr == json_pointer(ptr.to_string()); - @endcode - - @return a string representation of the JSON pointer - - @liveexample{The example shows the result of `to_string`., - json_pointer__to_string} - - @since version 2.0.0 - */ - std::string to_string() const noexcept - { - return std::accumulate(reference_tokens.begin(), - reference_tokens.end(), std::string{}, - [](const std::string & a, const std::string & b) - { - return a + "/" + escape(b); - }); - } - - /// @copydoc to_string() - operator std::string() const - { - return to_string(); - } - - private: - /*! - @brief remove and return last reference pointer - @throw out_of_range.405 if JSON pointer has no parent - */ - std::string pop_back() - { - if (is_root()) - { - JSON_THROW(out_of_range::create(405, "JSON pointer has no parent")); - } - - auto last = reference_tokens.back(); - reference_tokens.pop_back(); - return last; - } - - /// return whether pointer points to the root document - bool is_root() const - { - return reference_tokens.empty(); - } - - json_pointer top() const - { - if (is_root()) - { - JSON_THROW(out_of_range::create(405, "JSON pointer has no parent")); - } - - json_pointer result = *this; - result.reference_tokens = {reference_tokens[0]}; - return result; - } - - /*! - @brief create and return a reference to the pointed to value - - @complexity Linear in the number of reference tokens. - - @throw parse_error.109 if array index is not a number - @throw type_error.313 if value cannot be unflattened - */ - reference get_and_create(reference j) const - { - pointer result = &j; - - // in case no reference tokens exist, return a reference to the - // JSON value j which will be overwritten by a primitive value - for (const auto& reference_token : reference_tokens) - { - switch (result->m_type) - { - case value_t::null: - { - if (reference_token == "0") - { - // start a new array if reference token is 0 - result = &result->operator[](0); - } - else - { - // start a new object otherwise - result = &result->operator[](reference_token); - } - break; - } - - case value_t::object: - { - // create an entry in the object - result = &result->operator[](reference_token); - break; - } - - case value_t::array: - { - // create an entry in the array - JSON_TRY - { - result = &result->operator[](static_cast(std::stoi(reference_token))); - } - JSON_CATCH (std::invalid_argument&) - { - JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number")); - } - break; - } - - /* - The following code is only reached if there exists a - reference token _and_ the current value is primitive. In - this case, we have an error situation, because primitive - values may only occur as single value; that is, with an - empty list of reference tokens. - */ - default: - { - JSON_THROW(type_error::create(313, "invalid value to unflatten")); - } - } - } - - return *result; - } - - /*! - @brief return a reference to the pointed to value - - @note This version does not throw if a value is not present, but tries - to create nested values instead. For instance, calling this function - with pointer `"/this/that"` on a null value is equivalent to calling - `operator[]("this").operator[]("that")` on that value, effectively - changing the null value to an object. - - @param[in] ptr a JSON value - - @return reference to the JSON value pointed to by the JSON pointer - - @complexity Linear in the length of the JSON pointer. - - @throw parse_error.106 if an array index begins with '0' - @throw parse_error.109 if an array index was not a number - @throw out_of_range.404 if the JSON pointer can not be resolved - */ - reference get_unchecked(pointer ptr) const - { - for (const auto& reference_token : reference_tokens) - { - // convert null values to arrays or objects before continuing - if (ptr->m_type == value_t::null) - { - // check if reference token is a number - const bool nums = std::all_of(reference_token.begin(), - reference_token.end(), - [](const char x) - { - return (x >= '0' and x <= '9'); - }); - - // change value to array for numbers or "-" or to object - // otherwise - if (nums or reference_token == "-") - { - *ptr = value_t::array; - } - else - { - *ptr = value_t::object; - } - } - - switch (ptr->m_type) - { - case value_t::object: - { - // use unchecked object access - ptr = &ptr->operator[](reference_token); - break; - } - - case value_t::array: - { - // error condition (cf. RFC 6901, Sect. 4) - if (reference_token.size() > 1 and reference_token[0] == '0') - { - JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'")); - } - - if (reference_token == "-") - { - // explicitly treat "-" as index beyond the end - ptr = &ptr->operator[](ptr->m_value.array->size()); - } - else - { - // convert array index to number; unchecked access - JSON_TRY - { - ptr = &ptr->operator[](static_cast(std::stoi(reference_token))); - } - JSON_CATCH (std::invalid_argument&) - { - JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number")); - } - } - break; - } - - default: - { - JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'")); - } - } - } - - return *ptr; - } - - /*! - @throw parse_error.106 if an array index begins with '0' - @throw parse_error.109 if an array index was not a number - @throw out_of_range.402 if the array index '-' is used - @throw out_of_range.404 if the JSON pointer can not be resolved - */ - reference get_checked(pointer ptr) const - { - for (const auto& reference_token : reference_tokens) - { - switch (ptr->m_type) - { - case value_t::object: - { - // note: at performs range check - ptr = &ptr->at(reference_token); - break; - } - - case value_t::array: - { - if (reference_token == "-") - { - // "-" always fails the range check - JSON_THROW(out_of_range::create(402, "array index '-' (" + - std::to_string(ptr->m_value.array->size()) + - ") is out of range")); - } - - // error condition (cf. RFC 6901, Sect. 4) - if (reference_token.size() > 1 and reference_token[0] == '0') - { - JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'")); - } - - // note: at performs range check - JSON_TRY - { - ptr = &ptr->at(static_cast(std::stoi(reference_token))); - } - JSON_CATCH (std::invalid_argument&) - { - JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number")); - } - break; - } - - default: - { - JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'")); - } - } - } - - return *ptr; - } - - /*! - @brief return a const reference to the pointed to value - - @param[in] ptr a JSON value - - @return const reference to the JSON value pointed to by the JSON - pointer - - @throw parse_error.106 if an array index begins with '0' - @throw parse_error.109 if an array index was not a number - @throw out_of_range.402 if the array index '-' is used - @throw out_of_range.404 if the JSON pointer can not be resolved - */ - const_reference get_unchecked(const_pointer ptr) const - { - for (const auto& reference_token : reference_tokens) - { - switch (ptr->m_type) - { - case value_t::object: - { - // use unchecked object access - ptr = &ptr->operator[](reference_token); - break; - } - - case value_t::array: - { - if (reference_token == "-") - { - // "-" cannot be used for const access - JSON_THROW(out_of_range::create(402, "array index '-' (" + - std::to_string(ptr->m_value.array->size()) + - ") is out of range")); - } - - // error condition (cf. RFC 6901, Sect. 4) - if (reference_token.size() > 1 and reference_token[0] == '0') - { - JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'")); - } - - // use unchecked array access - JSON_TRY - { - ptr = &ptr->operator[](static_cast(std::stoi(reference_token))); - } - JSON_CATCH (std::invalid_argument&) - { - JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number")); - } - break; - } - - default: - { - JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'")); - } - } - } - - return *ptr; - } - - /*! - @throw parse_error.106 if an array index begins with '0' - @throw parse_error.109 if an array index was not a number - @throw out_of_range.402 if the array index '-' is used - @throw out_of_range.404 if the JSON pointer can not be resolved - */ - const_reference get_checked(const_pointer ptr) const - { - for (const auto& reference_token : reference_tokens) - { - switch (ptr->m_type) - { - case value_t::object: - { - // note: at performs range check - ptr = &ptr->at(reference_token); - break; - } - - case value_t::array: - { - if (reference_token == "-") - { - // "-" always fails the range check - JSON_THROW(out_of_range::create(402, "array index '-' (" + - std::to_string(ptr->m_value.array->size()) + - ") is out of range")); - } - - // error condition (cf. RFC 6901, Sect. 4) - if (reference_token.size() > 1 and reference_token[0] == '0') - { - JSON_THROW(parse_error::create(106, 0, "array index '" + reference_token + "' must not begin with '0'")); - } - - // note: at performs range check - JSON_TRY - { - ptr = &ptr->at(static_cast(std::stoi(reference_token))); - } - JSON_CATCH (std::invalid_argument&) - { - JSON_THROW(parse_error::create(109, 0, "array index '" + reference_token + "' is not a number")); - } - break; - } - - default: - { - JSON_THROW(out_of_range::create(404, "unresolved reference token '" + reference_token + "'")); - } - } - } - - return *ptr; - } - - /*! - @brief split the string input to reference tokens - - @note This function is only called by the json_pointer constructor. - All exceptions below are documented there. - - @throw parse_error.107 if the pointer is not empty or begins with '/' - @throw parse_error.108 if character '~' is not followed by '0' or '1' - */ - static std::vector split(const std::string& reference_string) - { - std::vector result; - - // special case: empty reference string -> no reference tokens - if (reference_string.empty()) - { - return result; - } - - // check if nonempty reference string begins with slash - if (reference_string[0] != '/') - { - JSON_THROW(parse_error::create(107, 1, "JSON pointer must be empty or begin with '/' - was: '" + reference_string + "'")); - } - - // extract the reference tokens: - // - slash: position of the last read slash (or end of string) - // - start: position after the previous slash - for ( - // search for the first slash after the first character - size_t slash = reference_string.find_first_of('/', 1), - // set the beginning of the first reference token - start = 1; - // we can stop if start == string::npos+1 = 0 - start != 0; - // set the beginning of the next reference token - // (will eventually be 0 if slash == std::string::npos) - start = slash + 1, - // find next slash - slash = reference_string.find_first_of('/', start)) - { - // use the text between the beginning of the reference token - // (start) and the last slash (slash). - auto reference_token = reference_string.substr(start, slash - start); - - // check reference tokens are properly escaped - for (size_t pos = reference_token.find_first_of('~'); - pos != std::string::npos; - pos = reference_token.find_first_of('~', pos + 1)) - { - assert(reference_token[pos] == '~'); - - // ~ must be followed by 0 or 1 - if (pos == reference_token.size() - 1 or - (reference_token[pos + 1] != '0' and - reference_token[pos + 1] != '1')) - { - JSON_THROW(parse_error::create(108, 0, "escape character '~' must be followed with '0' or '1'")); - } - } - - // finally, store the reference token - unescape(reference_token); - result.push_back(reference_token); - } - - return result; - } - - /*! - @brief replace all occurrences of a substring by another string - - @param[in,out] s the string to manipulate; changed so that all - occurrences of @a f are replaced with @a t - @param[in] f the substring to replace with @a t - @param[in] t the string to replace @a f - - @pre The search string @a f must not be empty. **This precondition is - enforced with an assertion.** - - @since version 2.0.0 - */ - static void replace_substring(std::string& s, - const std::string& f, - const std::string& t) - { - assert(not f.empty()); - - for ( - size_t pos = s.find(f); // find first occurrence of f - pos != std::string::npos; // make sure f was found - s.replace(pos, f.size(), t), // replace with t - pos = s.find(f, pos + t.size()) // find next occurrence of f - ); - } - - /// escape tilde and slash - static std::string escape(std::string s) - { - // escape "~"" to "~0" and "/" to "~1" - replace_substring(s, "~", "~0"); - replace_substring(s, "/", "~1"); - return s; - } - - /// unescape tilde and slash - static void unescape(std::string& s) - { - // first transform any occurrence of the sequence '~1' to '/' - replace_substring(s, "~1", "/"); - // then transform any occurrence of the sequence '~0' to '~' - replace_substring(s, "~0", "~"); - } - - /*! - @param[in] reference_string the reference string to the current value - @param[in] value the value to consider - @param[in,out] result the result object to insert values to - - @note Empty objects or arrays are flattened to `null`. - */ - static void flatten(const std::string& reference_string, - const basic_json& value, - basic_json& result) - { - switch (value.m_type) - { - case value_t::array: - { - if (value.m_value.array->empty()) - { - // flatten empty array as null - result[reference_string] = nullptr; - } - else - { - // iterate array and use index as reference string - for (size_t i = 0; i < value.m_value.array->size(); ++i) - { - flatten(reference_string + "/" + std::to_string(i), - value.m_value.array->operator[](i), result); - } - } - break; - } - - case value_t::object: - { - if (value.m_value.object->empty()) - { - // flatten empty object as null - result[reference_string] = nullptr; - } - else - { - // iterate object and use keys as reference string - for (const auto& element : *value.m_value.object) - { - flatten(reference_string + "/" + escape(element.first), - element.second, result); - } - } - break; - } - - default: - { - // add primitive value with its reference string - result[reference_string] = value; - break; - } - } - } - - /*! - @param[in] value flattened JSON - - @return unflattened JSON - - @throw parse_error.109 if array index is not a number - @throw type_error.314 if value is not an object - @throw type_error.315 if object values are not primitive - @throw type_error.313 if value cannot be unflattened - */ - static basic_json unflatten(const basic_json& value) - { - if (not value.is_object()) - { - JSON_THROW(type_error::create(314, "only objects can be unflattened")); - } - - basic_json result; - - // iterate the JSON object values - for (const auto& element : *value.m_value.object) - { - if (not element.second.is_primitive()) - { - JSON_THROW(type_error::create(315, "values in object must be primitive")); - } - - // assign value to reference pointed to by JSON pointer; Note - // that if the JSON pointer is "" (i.e., points to the whole - // value), function get_and_create returns a reference to - // result itself. An assignment will then create a primitive - // value. - json_pointer(element.first).get_and_create(result) = element.second; - } - - return result; - } - - friend bool operator==(json_pointer const& lhs, - json_pointer const& rhs) noexcept - { - return lhs.reference_tokens == rhs.reference_tokens; - } - - friend bool operator!=(json_pointer const& lhs, - json_pointer const& rhs) noexcept - { - return !(lhs == rhs); - } - - /// the reference tokens - std::vector reference_tokens {}; - }; - ////////////////////////// // JSON Pointer support // ////////////////////////// @@ -14423,6 +14073,432 @@ uses the standard template types. @since version 1.0.0 */ using json = basic_json<>; + +////////////////// +// json_pointer // +////////////////// + +NLOHMANN_BASIC_JSON_TPL_DECLARATION +NLOHMANN_BASIC_JSON_TPL& +json_pointer::get_and_create(NLOHMANN_BASIC_JSON_TPL& j) const +{ + using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type; + auto result = &j; + + // in case no reference tokens exist, return a reference to the + // JSON value j which will be overwritten by a primitive value + for (const auto& reference_token : reference_tokens) + { + switch (result->m_type) + { + case detail::value_t::null: + { + if (reference_token == "0") + { + // start a new array if reference token is 0 + result = &result->operator[](0); + } + else + { + // start a new object otherwise + result = &result->operator[](reference_token); + } + break; + } + + case detail::value_t::object: + { + // create an entry in the object + result = &result->operator[](reference_token); + break; + } + + case detail::value_t::array: + { + // create an entry in the array + JSON_TRY + { + result = &result->operator[]( + static_cast(std::stoi(reference_token))); + } + JSON_CATCH(std::invalid_argument&) + { + JSON_THROW(detail::parse_error::create( + 109, 0, "array index '" + reference_token + "' is not a number")); + } + break; + } + + /* + The following code is only reached if there exists a + reference token _and_ the current value is primitive. In + this case, we have an error situation, because primitive + values may only occur as single value; that is, with an + empty list of reference tokens. + */ + default: + { + JSON_THROW(detail::type_error::create(313, "invalid value to unflatten")); + } + } + } + + return *result; +} + +NLOHMANN_BASIC_JSON_TPL_DECLARATION +NLOHMANN_BASIC_JSON_TPL& +json_pointer::get_unchecked(NLOHMANN_BASIC_JSON_TPL* ptr) const +{ + using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type; + for (const auto& reference_token : reference_tokens) + { + // convert null values to arrays or objects before continuing + if (ptr->m_type == detail::value_t::null) + { + // check if reference token is a number + const bool nums = + std::all_of(reference_token.begin(), reference_token.end(), + [](const char x) + { + return (x >= '0' and x <= '9'); + }); + + // change value to array for numbers or "-" or to object + // otherwise + if (nums or reference_token == "-") + { + *ptr = detail::value_t::array; + } + else + { + *ptr = detail::value_t::object; + } + } + + switch (ptr->m_type) + { + case detail::value_t::object: + { + // use unchecked object access + ptr = &ptr->operator[](reference_token); + break; + } + + case detail::value_t::array: + { + // error condition (cf. RFC 6901, Sect. 4) + if (reference_token.size() > 1 and reference_token[0] == '0') + { + JSON_THROW(detail::parse_error::create(106, 0, + "array index '" + reference_token + + "' must not begin with '0'")); + } + + if (reference_token == "-") + { + // explicitly treat "-" as index beyond the end + ptr = &ptr->operator[](ptr->m_value.array->size()); + } + else + { + // convert array index to number; unchecked access + JSON_TRY + { + ptr = &ptr->operator[]( + static_cast(std::stoi(reference_token))); + } + JSON_CATCH(std::invalid_argument&) + { + JSON_THROW(detail::parse_error::create( + 109, 0, "array index '" + reference_token + "' is not a number")); + } + } + break; + } + + default: + { + JSON_THROW(detail::out_of_range::create( + 404, "unresolved reference token '" + reference_token + "'")); + } + } + } + + return *ptr; +} + +NLOHMANN_BASIC_JSON_TPL_DECLARATION +NLOHMANN_BASIC_JSON_TPL& +json_pointer::get_checked(NLOHMANN_BASIC_JSON_TPL* ptr) const +{ + using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type; + for (const auto& reference_token : reference_tokens) + { + switch (ptr->m_type) + { + case detail::value_t::object: + { + // note: at performs range check + ptr = &ptr->at(reference_token); + break; + } + + case detail::value_t::array: + { + if (reference_token == "-") + { + // "-" always fails the range check + JSON_THROW(detail::out_of_range::create( + 402, + "array index '-' (" + std::to_string(ptr->m_value.array->size()) + + ") is out of range")); + } + + // error condition (cf. RFC 6901, Sect. 4) + if (reference_token.size() > 1 and reference_token[0] == '0') + { + JSON_THROW(detail::parse_error::create(106, 0, + "array index '" + reference_token + + "' must not begin with '0'")); + } + + // note: at performs range check + JSON_TRY + { + ptr = &ptr->at(static_cast(std::stoi(reference_token))); + } + JSON_CATCH(std::invalid_argument&) + { + JSON_THROW(detail::parse_error::create( + 109, 0, "array index '" + reference_token + "' is not a number")); + } + break; + } + + default: + { + JSON_THROW(detail::out_of_range::create( + 404, "unresolved reference token '" + reference_token + "'")); + } + } + } + + return *ptr; +} + +NLOHMANN_BASIC_JSON_TPL_DECLARATION +const NLOHMANN_BASIC_JSON_TPL& +json_pointer::get_unchecked(const NLOHMANN_BASIC_JSON_TPL* ptr) const +{ + using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type; + for (const auto& reference_token : reference_tokens) + { + switch (ptr->m_type) + { + case detail::value_t::object: + { + // use unchecked object access + ptr = &ptr->operator[](reference_token); + break; + } + + case detail::value_t::array: + { + if (reference_token == "-") + { + // "-" cannot be used for const access + JSON_THROW(detail::out_of_range::create( + 402, + "array index '-' (" + std::to_string(ptr->m_value.array->size()) + + ") is out of range")); + } + + // error condition (cf. RFC 6901, Sect. 4) + if (reference_token.size() > 1 and reference_token[0] == '0') + { + JSON_THROW(detail::parse_error::create(106, 0, + "array index '" + reference_token + + "' must not begin with '0'")); + } + + // use unchecked array access + JSON_TRY + { + ptr = &ptr->operator[]( + static_cast(std::stoi(reference_token))); + } + JSON_CATCH(std::invalid_argument&) + { + JSON_THROW(detail::parse_error::create( + 109, 0, "array index '" + reference_token + "' is not a number")); + } + break; + } + + default: + { + JSON_THROW(detail::out_of_range::create( + 404, "unresolved reference token '" + reference_token + "'")); + } + } + } + + return *ptr; +} + +NLOHMANN_BASIC_JSON_TPL_DECLARATION +const NLOHMANN_BASIC_JSON_TPL& +json_pointer::get_checked(const NLOHMANN_BASIC_JSON_TPL* ptr) const +{ + using size_type = typename NLOHMANN_BASIC_JSON_TPL::size_type; + for (const auto& reference_token : reference_tokens) + { + switch (ptr->m_type) + { + case detail::value_t::object: + { + // note: at performs range check + ptr = &ptr->at(reference_token); + break; + } + + case detail::value_t::array: + { + if (reference_token == "-") + { + // "-" always fails the range check + JSON_THROW(detail::out_of_range::create( + 402, + "array index '-' (" + std::to_string(ptr->m_value.array->size()) + + ") is out of range")); + } + + // error condition (cf. RFC 6901, Sect. 4) + if (reference_token.size() > 1 and reference_token[0] == '0') + { + JSON_THROW(detail::parse_error::create(106, 0, + "array index '" + reference_token + + "' must not begin with '0'")); + } + + // note: at performs range check + JSON_TRY + { + ptr = &ptr->at(static_cast(std::stoi(reference_token))); + } + JSON_CATCH(std::invalid_argument&) + { + JSON_THROW(detail::parse_error::create( + 109, 0, "array index '" + reference_token + "' is not a number")); + } + break; + } + + default: + { + JSON_THROW(detail::out_of_range::create( + 404, "unresolved reference token '" + reference_token + "'")); + } + } + } + + return *ptr; +} + +NLOHMANN_BASIC_JSON_TPL_DECLARATION +void json_pointer::flatten(const std::string& reference_string, + const NLOHMANN_BASIC_JSON_TPL& value, + NLOHMANN_BASIC_JSON_TPL& result) +{ + switch (value.m_type) + { + case detail::value_t::array: + { + if (value.m_value.array->empty()) + { + // flatten empty array as null + result[reference_string] = nullptr; + } + else + { + // iterate array and use index as reference string + for (size_t i = 0; i < value.m_value.array->size(); ++i) + { + flatten(reference_string + "/" + std::to_string(i), + value.m_value.array->operator[](i), result); + } + } + break; + } + + case detail::value_t::object: + { + if (value.m_value.object->empty()) + { + // flatten empty object as null + result[reference_string] = nullptr; + } + else + { + // iterate object and use keys as reference string + for (const auto& element : *value.m_value.object) + { + flatten(reference_string + "/" + escape(element.first), element.second, + result); + } + } + break; + } + + default: + { + // add primitive value with its reference string + result[reference_string] = value; + break; + } + } +} + +NLOHMANN_BASIC_JSON_TPL_DECLARATION +NLOHMANN_BASIC_JSON_TPL +json_pointer::unflatten(const NLOHMANN_BASIC_JSON_TPL& value) +{ + if (not value.is_object()) + { + JSON_THROW(detail::type_error::create(314, "only objects can be unflattened")); + } + + NLOHMANN_BASIC_JSON_TPL result; + + // iterate the JSON object values + for (const auto& element : *value.m_value.object) + { + if (not element.second.is_primitive()) + { + JSON_THROW(detail::type_error::create(315, "values in object must be primitive")); + } + + // assign value to reference pointed to by JSON pointer; Note + // that if the JSON pointer is "" (i.e., points to the whole + // value), function get_and_create returns a reference to + // result itself. An assignment will then create a primitive + // value. + json_pointer(element.first).get_and_create(result) = element.second; + } + + return result; +} + +inline bool operator==(json_pointer const& lhs, json_pointer const& rhs) noexcept +{ + return lhs.reference_tokens == rhs.reference_tokens; +} + +inline bool operator!=(json_pointer const& lhs, json_pointer const& rhs) noexcept +{ + return !(lhs == rhs); +} } // namespace nlohmann