config_reader.h

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/* Copyright (c) 2021, 2024, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
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   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have either included with
   the program or referenced in the documentation.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef CONFIG_READER_INCLUDED
#define CONFIG_READER_INCLUDED
 
#include <string>
 
#define RAPIDJSON_HAS_STDSTRING 1
 
#include "my_rapidjson_size_t.h"
 
#include <rapidjson/document.h>
 
namespace keyring_common::config {
 
class Config_reader {
 public:
  /**
    Constructor
 
    Reads JSON from config file and stores it in memory.
 
    @param [in] config_file_path Full path to configuration file
  */
  explicit Config_reader(std::string config_file_path);
 
  /**
    Get an element value from JSON document.
    Assumption: Type is compatible with Get() function and
                type of element is matching with template argument.
 
    @param [in]  element_name  Name of the element being searched
    @param [out] element_value Value of the element
 
    @returns status of search operation
      @retval false Element found. Refer to element_value
      @retval true  Element missing.
  */
  template <typename T>
  bool get_element(const std::string &element_name, T &element_value) {
    if (!valid_ || !data_.HasMember(element_name)) return true;
    element_value = data_[element_name].Get<T>();
    return false;
  }
 
 private:
  /** Configuration file path */
  std::string config_file_path_;
  /** Configuration data in JSON */
  rapidjson::Document data_;
  /** Validity of configuration data */
  bool valid_;
};
 
}  // namespace keyring_common::config
 
#endif  // !CONFIG_READER_INCLUDED