C++

C++ loader guide.

API

Data

const ProtobufMessage& Data() const

Get the internal protobuf message data.

Map

const MapValueType* Get(KEY1 k1, KEY2 k2...) const

Get the Nth-level map value. Returns nullptr if the key is not found. Be aware that only applies to each level message’s first map field.

OrderedMap

Prerequisite: You need to set metasheet option OrderedMap to true.

See metatsheet option: OrderedMap.

  • const OrderedMapMap* GetOrderedMap() const: Gets the whole ordered map.
  • const OrderedMapValueType* GetOrderedMap(KEY1 k1) const: Gets the 2nd-level ordered map value. Returns nullptr if the key is not found.

Get the Nth-level ordered map value. Be aware that only applies to each level message’s first map field.

Index

Prerequisite: You need to set metatsheet option Index appropriately.

See metatsheet option: Index.

If index name is Chapter, then the accessers are:

  • const Index_ChapterMap& FindChapterMap() const: Gets the whole hash map.
  • const Index_ChapterMap* FindChapterMap(KEY1 k1, KEY2 k2...) const: Gets the hash map scoped to the upper Nth-level map specified by the given key(s).
  • const vector<ParentType>* FindChapter(KEY1 k1, KEY2 k2...) const: Finds values by key. One key may correspond to multiple values, which are returned by a vector.
  • const ParentType* FindFirstChapter(KEY1 k1, KEY2 k2...) const: Finds the first value by key, or nullptr if no value found.

OrderedIndex

Prerequisite: You need to set metatsheet option OrderedIndex appropriately.

See metatsheet option: OrderedIndex.

If ordered index name is Chapter, then the accessers are:

  • const OrderedIndex_ChapterMap& FindChapterMap() const: Gets the whole ordered map.
  • const OrderedIndex_ChapterMap* FindChapterMap(KEY1 k1, KEY2 k2...) const: Gets the ordered map scoped to the upper Nth-level map specified by the given key(s).
  • const vector<ParentType>* FindChapter(KEY1 k1, KEY2 k2...) const: Finds values by key. One key may correspond to multiple values, which are returned by a vector.
  • const ParentType* FindFirstChapter(KEY1 k1, KEY2 k2...) const: Finds the first value by key, or nullptr if no value found.

Custom messager

If the built-in APIs are not sufficient for your business logic, then you can add a custom messager, where you can write preprocess logic based on loaded config objects.

Example: cpp-tableau-loader/hub/custom

custom_xxx_conf.h:

#pragma once
#include "protoconf/hub.pc.h"
#include "protoconf/xxx_conf.pc.h"
class CustomXXXConf : public tableau::Messager {
 public:
  static const std::string& Name() { return kCustomName; }
  virtual bool Load(const std::filesystem::path&, tableau::Format,
                    std::shared_ptr<const tableau::load::MessagerOptions> options = nullptr) override {
    return true;
  }
  virtual bool ProcessAfterLoadAll(const tableau::Hub& hub) override;

 private:
  static const std::string kCustomName;
  // TODO: add custom data fields.
};

custom_xxx_conf.cpp:

#include "hub/custom/xxx/custom_xxx_conf.h"

const std::string CustomXXXConf::kCustomName = "CustomXXXConf";

bool CustomXXXConf::ProcessAfterLoadAll(const tableau::Hub& hub) {
  // TODO: implement here.
  return true;
}

Plugin: protoc-gen-cpp-tableau-loader

An example to use this protoc plugin: cpp-tableau-loader/gen.sh.

Full example

See cpp-tableau-loader.

Last modified on March 16, 2026
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