proto_reader_writer.h

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//    Copyright 2022, farm-ng inc.
//
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
//
//        http://www.apache.org/licenses/LICENSE-2.0
//
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
 
#pragma once
 
#include "farm_ng/core/logging/expected.h"
#include "farm_ng/core/logging/logger.h"
 
#include <google/protobuf/text_format.h>
#include <google/protobuf/util/json_util.h>
 
#include <filesystem>
#include <fstream>
 
namespace farm_ng {
 
/// TODO: Add API docs.
 
Expected<Success> writeProtobufToJsonFile(
    std::filesystem::path const& path, google::protobuf::Message const& proto);
 
Expected<Success> writeProtobufToBinaryFile(
    std::filesystem::path const& path, google::protobuf::Message const& proto);
 
Expected<std::string> readJsonStringFromJsonFile(
    std::filesystem::path const& path);
 
template <class TProtobufT>
Expected<TProtobufT> readProtobufFromJsonFile(
    std::filesystem::path const& path) {
  FARM_TRY(std::string, json_string, readJsonStringFromJsonFile(path));
  TProtobufT message;
  google::protobuf::util::JsonParseOptions parse_options;  // default
  auto status = google::protobuf::util::JsonStringToMessage(
      json_string, &message, parse_options);
  if (!status.ok()) {
    return FARM_UNEXPECTED("Failed to parse json string: {}", status);
  }
  return message;
}
 
Expected<std::string> readBytesFromBinaryFile(
    std::filesystem::path const& path);
 
template <class TProtobufT>
Expected<TProtobufT> readProtobufFromBinaryFile(
    std::filesystem::path const& path) {
  TProtobufT message;
  FARM_TRY(std::string, bytes, readBytesFromBinaryFile(path));
  if (message.ParseFromString(bytes)) {
    return FARM_UNEXPECTED("Failed to parse {}", path.string());
  }
  return message;
}
 
}  // namespace farm_ng