simdjson-simdjson/include/simdjson/generic/ondemand/object.h

#include "simdjson/error.h"

namespace simdjson {
namespace SIMDJSON_IMPLEMENTATION {
namespace ondemand {

/**
 * A forward-only JSON object field iterator.
 */
class object {
public:
  /**
   * Create a new invalid object.
   *
   * Exists so you can declare a variable and later assign to it before use.
   */
  simdjson_really_inline object() noexcept = default;

  simdjson_really_inline simdjson_result<object_iterator> begin() noexcept;
  simdjson_really_inline simdjson_result<object_iterator> end() noexcept;

  /**
   * Look up a field by name on an object (order-sensitive).
   *
   * The following code reads z, then y, then x, and thus will not retrieve x or y if fed the
   * JSON `{ "x": 1, "y": 2, "z": 3 }`:
   *
   * ```c++
   * simdjson::ondemand::parser parser;
   * auto obj = parser.parse(R"( { "x": 1, "y": 2, "z": 3 } )"_padded);
   * double z = obj.find_field("z");
   * double y = obj.find_field("y");
   * double x = obj.find_field("x");
   * ```
   *
   * **Raw Keys:** The lookup will be done against the *raw* key, and will not unescape keys.
   * e.g. `object["a"]` will match `{ "a": 1 }`, but will *not* match `{ "\u0061": 1 }`.
   *
   * @param key The key to look up.
   * @returns The value of the field, or NO_SUCH_FIELD if the field is not in the object.
   */
  simdjson_really_inline simdjson_result<value> find_field(std::string_view key) & noexcept;
  /** @overload simdjson_really_inline simdjson_result<value> find_field(std::string_view key) & noexcept; */
  simdjson_really_inline simdjson_result<value> find_field(std::string_view key) && noexcept;

  /**
   * Look up a field by name on an object, without regard to key order.
   *
   * **Performance Notes:** This is a bit less performant than find_field(), though its effect varies
   * and often appears negligible. It starts out normally, starting out at the last field; but if
   * the field is not found, it scans from the beginning of the object to see if it missed it. That
   * missing case has a non-cache-friendly bump and lots of extra scanning, especially if the object
   * in question is large. The fact that the extra code is there also bumps the executable size.
   *
   * It is the default, however, because it would be highly surprising (and hard to debug) if the
   * default behavior failed to look up a field just because it was in the wrong order--and many
   * APIs assume this. Therefore, you must be explicit if you want to treat objects as out of order.
   *
   * Use find_field() if you are sure fields will be in order (or are willing to treat it as if the
   * field wasn't there when they aren't).
   *
   * @param key The key to look up.
   * @returns The value of the field, or NO_SUCH_FIELD if the field is not in the object.
   */
  simdjson_really_inline simdjson_result<value> find_field_unordered(std::string_view key) & noexcept;
  /** @overload simdjson_really_inline simdjson_result<value> find_field_unordered(std::string_view key) & noexcept; */
  simdjson_really_inline simdjson_result<value> find_field_unordered(std::string_view key) && noexcept;
  /** @overload simdjson_really_inline simdjson_result<value> find_field_unordered(std::string_view key) & noexcept; */
  simdjson_really_inline simdjson_result<value> operator[](std::string_view key) & noexcept;
  /** @overload simdjson_really_inline simdjson_result<value> find_field_unordered(std::string_view key) & noexcept; */
  simdjson_really_inline simdjson_result<value> operator[](std::string_view key) && noexcept;

protected:
  static simdjson_really_inline simdjson_result<object> start(value_iterator &iter) noexcept;
  static simdjson_really_inline simdjson_result<object> start_root(value_iterator &iter) noexcept;
  static simdjson_really_inline object started(value_iterator &iter) noexcept;
  static simdjson_really_inline object resume(const value_iterator &iter) noexcept;
  simdjson_really_inline object(const value_iterator &iter) noexcept;

  simdjson_warn_unused simdjson_really_inline error_code find_field_raw(const std::string_view key) noexcept;

  value_iterator iter{};

  friend class value;
  friend class document;
  friend struct simdjson_result<object>;
};

} // namespace ondemand
} // namespace SIMDJSON_IMPLEMENTATION
} // namespace simdjson

namespace simdjson {

template<>
struct simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::object> : public SIMDJSON_IMPLEMENTATION::implementation_simdjson_result_base<SIMDJSON_IMPLEMENTATION::ondemand::object> {
public:
  simdjson_really_inline simdjson_result(SIMDJSON_IMPLEMENTATION::ondemand::object &&value) noexcept; ///< @private
  simdjson_really_inline simdjson_result(error_code error) noexcept; ///< @private
  simdjson_really_inline simdjson_result() noexcept = default;

  simdjson_really_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::object_iterator> begin() noexcept;
  simdjson_really_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::object_iterator> end() noexcept;
  simdjson_really_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> find_field(std::string_view key) & noexcept;
  simdjson_really_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> find_field(std::string_view key) && noexcept;
  simdjson_really_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> find_field_unordered(std::string_view key) & noexcept;
  simdjson_really_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> find_field_unordered(std::string_view key) && noexcept;
  simdjson_really_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> operator[](std::string_view key) & noexcept;
  simdjson_really_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> operator[](std::string_view key) && noexcept;
};

} // namespace simdjson