VirtualObject.h

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//
// Created by Nico on 27/08/2019.
//
 
#ifndef JODA_VIRTUALOBJECT_H
#define JODA_VIRTUALOBJECT_H
 
#include <glog/logging.h>
#include <joda/misc/RJFwd.h>
#include <string>
#include "ViewStructure.h"
 
class VirtualObject {
 public:
  VirtualObject() = default;
  explicit VirtualObject(ViewStructure *struc);
  VirtualObject(const VirtualObject &o) = delete;
  VirtualObject &operator=(const VirtualObject &o) = delete;
  VirtualObject(VirtualObject &&o) = default;
  VirtualObject &operator=(VirtualObject &&o) = default;
 
  /*
   * Special Access
   */
  size_t size() const;
  std::vector<std::string> attributes() const;
  RJValue deepCopy(RJMemoryPoolAlloc &alloc) const;
 
  void addMember(ViewStructure::ID, const RJValue *val);
  void addMember(ViewStructure::ID, const VirtualObject *val);
  void reserve(size_t r);
 
 private:
  size_t start_ = 0, end_ = 0, size_ = 0;
  ViewStructure *struc = nullptr;
 
  template <typename F>
  auto iterateMemberRetAll(F &&lambda) const {
    std::vector<
        typename std::result_of<F(const ViewStructure::ObjectMember &)>::type>
        ret;
    iterateMember([&ret, &lambda](const ViewStructure::ObjectMember &o) {
      ret.emplace_back(lambda(o));
    });
    return ret;
  }
 
  template <typename Ret, typename F>
  auto iterateMemberRetOne(F &&lambda, Ret &&init) const {
    Ret ret = init;
    iterateMember([&ret, &lambda](const ViewStructure::ObjectMember &o) {
      ret = lambda(o, ret);
    });
    return ret;
  }
 
  template <typename F>
  void iterateMember(F &&lambda) const {
    auto it = struc->beginMember();
    it += start_;
    DCHECK(end_ - start_ >= size_);
    for (size_t j = 0; j < size_; ++j) {
      const auto &member = *it;
      lambda(member);
      it++;
    }
  }
 
 public:
  /*
   * Accepter
   */
  template <typename Handler>
  bool Accept(Handler &handler) const {
    if (RAPIDJSON_UNLIKELY(!handler.StartObject())) return false;
 
    if (!iterateMemberRetOne<bool>(
            [this, &handler](const ViewStructure::ObjectMember &member,
                             bool &prev) {
              if (!prev) return false;
              auto name = struc->getKey(member.key);
              DCHECK(name != nullptr);
              if (RAPIDJSON_UNLIKELY(
                      !handler.Key(name->c_str(), name->size(), true)))
                return false;
 
              if (member.val != nullptr) {
                if (RAPIDJSON_UNLIKELY(!member.val->Accept(handler)))
                  return false;
              } else {
                if (member.obj == nullptr) {
                  if (RAPIDJSON_UNLIKELY(!RJValue().Accept(handler)))
                    return false;
                } else {
                  if (RAPIDJSON_UNLIKELY(!member.obj->Accept(handler)))
                    return false;
                }
              }
              return true;
            },
            true))
      return false;
 
    return handler.EndObject(size_);
  }
};
 
#endif  // JODA_VIRTUALOBJECT_H