E-Agle TRT

Serializers

Serializers is a code generation library for C++ to be used with Google's Protocol Buffers.

Given the .proto files, it generates a header file and a source file for each proto, besides creating a CMakeLists.txt file to integrate the code with your main project and a header "serializers.h".

The library wraps the pb files generated by protoc, providing a simple and convenient interface to handle, serialize and deserialize the defined proto messages. It also provides functions to convert and parse the messages to JSON format.

The generated header consist in a struct for each proto Message and the following methods for serialization:

std::string serializeAsJsonString() const;
std::string serializeAsProtobufString() const;
bool deserializeFromJsonString(const std::string& str);
bool deserializeFromProtobufString(const std::string& str);

The methods implementation is built upon the pb files, which have to be added to the main project and included in the global include path.

Example

bar.proto (input)

syntax = "proto3";

package bar;

enum MyEnum
{
    MY_ENUM_0 = 0;
    My_ENUM_1 = 1;
}

message MySmallMessage
{
    int64 val = 1;
}

message MyMessage
{
    double val = 1;
    string str = 2;
    MySmallMessage mySmallMessage = 3;
    repeated MyEnum enumVec = 4;
    map<uint32, MySmallMessage> structMap = 5;
}

bar.h (output)

#ifndef BAR_H
#define BAR_H

#include "bar.pb.h"

[...]

namespace Serializers
{
enum class MyEnum
{
    MY_ENUM_0 = 0,
    My_ENUM_1 = 1
};

struct MySmallMessage
{
    int64_t val;

    [...]
};

struct MyMessage
{
    double val;
    std::string str;
    MySmallMessage mySmallMessage;
    std::vector<MyEnum> enumVec;
    std::unordered_map<uint32_t, MySmallMessage> structMap;

    MyMessage() = default;
    MyMessage(const bar::MyMessage& proto);
    operator bar::MyMessage() const;

    std::string serializeAsJsonString() const;
    std::string serializeAsProtobufString() const;
    bool deserializeFromJsonString(const std::string& str);
    bool deserializeFromProtobufString(const std::string& str);
};
}

#endif

Usage

• Generate the code with src/generator/main.py proto_dir output_dir.
• Copy the output directory in your project and generate the pb files with protoc, using the files in output_dir/proto.
• Add add_subdirectory(path/to/output/directory) to your main CMakeLists.txt.
• Include "serializers.h" in your files and use the library code.

#include "serializers.h"

#include <iostream>
#include <string>

int main()
{
    Serializers::MySmallMessage mySmallMessage;
    mySmallMessage.val = 3.14;

    Serializers::MyMessage myMessage;
    myMessage.str = "Federico Carbone";
    myMessage.enumVec.push_back(Serializers::MyEnum::MY_ENUM_0);
    myMessage.structMap.emplace(404, mySmallMessage);

    std::string myMessageSerialized = myMessage.serializeAsProtobufString();

    std::cout << myMessage.serializeAsJsonString() << std::endl;

    return 0;
}

Features

Implemented / Not implemented yet

• Multiple file packages
• All primitive fieldtypes support
• Enum
• "repeated" option
• Maps
• Package check
• Import external proto definitions
• Nested types
• OneOf
• Custom options

Not planned

• Any (google.protobuf.Any)
• Services (RPC)