JsonReader.h

#pragma once
 
#include <CesiumJsonReader/JsonHandler.h>
#include <CesiumJsonReader/Library.h>
 
#include <rapidjson/document.h>
 
#include <cstddef>
#include <optional>
#include <span>
#include <string>
#include <vector>
 
namespace rapidjson {
struct MemoryStream;
}
 
namespace CesiumJsonReader {

template <typename T> struct ReadJsonResult {
  std::optional<T> value;

  std::vector<std::string> errors;

  std::vector<std::string> warnings;
};

class CESIUMJSONREADER_API JsonReader {
public:
  template <typename T>
  static ReadJsonResult<typename T::ValueType>
  readJson(const std::span<const std::byte>& data, T& handler) {
    ReadJsonResult<typename T::ValueType> result;
 
    result.value.emplace();
 
    FinalJsonHandler finalHandler(result.warnings);
    handler.reset(&finalHandler, &result.value.value());
 
    JsonReader::internalRead(
        data,
        handler,
        finalHandler,
        result.errors,
        result.warnings);
 
    if (!result.errors.empty()) {
      result.value.reset();
    }
 
    return result;
  }

  template <typename T>
  static ReadJsonResult<typename T::ValueType>
  readJson(const rapidjson::Value& jsonValue, T& handler) {
    ReadJsonResult<typename T::ValueType> result;
 
    result.value.emplace();
 
    FinalJsonHandler finalHandler(result.warnings);
    handler.reset(&finalHandler, &result.value.value());
 
    JsonReader::internalRead(
        jsonValue,
        handler,
        finalHandler,
        result.errors,
        result.warnings);
 
    if (!result.errors.empty()) {
      result.value.reset();
    }
 
    return result;
  }
 
private:
  class FinalJsonHandler : public JsonHandler {
  public:
    FinalJsonHandler(std::vector<std::string>& warnings);
    virtual void reportWarning(
        const std::string& warning,
        std::vector<std::string>&& context) override;
    void setInputStream(rapidjson::MemoryStream* pInputStream) noexcept;
 
  private:
    std::vector<std::string>& _warnings;
    rapidjson::MemoryStream* _pInputStream;
  };
 
  static void internalRead(
      const std::span<const std::byte>& data,
      IJsonHandler& handler,
      FinalJsonHandler& finalHandler,
      std::vector<std::string>& errors,
      std::vector<std::string>& warnings);
 
  static void internalRead(
      const rapidjson::Value& jsonValue,
      IJsonHandler& handler,
      FinalJsonHandler& finalHandler,
      std::vector<std::string>& errors,
      std::vector<std::string>& warnings);
};
 
} // namespace CesiumJsonReader