ObjectHandle.hpp

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/*
 * Copyright (C) 2015-2022 The ESPResSo project
 *
 * This file is part of ESPResSo.
 *
 * ESPResSo is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ESPResSo 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "Variant.hpp"
 
#include <algorithm>
#include <memory>
#include <string>
#include <string_view>
#include <utility>
#include <vector>
 
namespace ScriptInterface {
class Context;
 
/**
 * @brief Base class for interface handles.
 */
class ObjectHandle {
public:
  ObjectHandle() = default;
 
  /* Copy has unclear semantics, so it should not be allowed. */
  ObjectHandle(ObjectHandle const &) = delete;
  ObjectHandle &operator=(ObjectHandle const &) = delete;
  virtual ~ObjectHandle() = default;
 
private:
  friend class Context;
  std::shared_ptr<Context> m_context = {};
 
public:
  std::string_view name() const;
 
public:
  /**
   * @brief Responsible context.
   */
  Context *context() const { return m_context.get(); }
 
public:
  /**
   * @brief Construct the handled object.
   *
   * This function is called on object creation with user
   * provided parameters. This can be used if the SO has required parameters,
   * it represents some type that can not reasonably be default constructed,
   * or if the core implementation has to be chosen by a parameter. It is
   * guaranteed that no getter or setter functions from this interface is
   * called before construction (only @ref name() and @ref valid_parameters()),
   * and it is only called once.
   *
   * The default implementation just calls @ref set_parameter for every
   * parameter.
   *
   * @param params The parameters to the constructor. Only parameters that
   *               are valid for a default-constructed object are valid.
   */
  void construct(VariantMap const &params) { do_construct(params); }
 
  virtual void do_construct(VariantMap const &params) {
    for (auto const &[key, value] : params) {
      do_set_parameter(key, value);
    }
  }
 
public:
  /**
   * @brief Get current parameters.
   * @return Parameters set in class.
   */
  VariantMap get_parameters() const {
    VariantMap values;
 
    for (auto const &name : valid_parameters()) {
      values[std::string{name}] = get_parameter(std::string{name});
    }
 
    return values;
  }
 
  /**
   * @brief Get required and optional parameters for class.
   * @return Expected parameters.
   */
  virtual std::vector<std::string_view> valid_parameters() const { return {}; }
 
  virtual bool has_parameter(std::string const &needle) const {
    auto const names = valid_parameters();
    return std::ranges::find(names, std::string_view{needle}) != names.end();
  }
 
  /**
   * @brief Get single parameter.
   *
   * @param name Name of the parameter
   * @return Value of parameter @p name
   */
  virtual Variant get_parameter(std::string const &name) const {
    static_cast<void>(name);
    return {};
  }
 
  /**
   * @brief Set single parameter.
   * Can only be called on the head node.
   */
  void set_parameter(const std::string &name, const Variant &value);
 
  /**
   * @brief Local implementation of @ref set_parameter.
   */
  virtual void do_set_parameter(const std::string &, const Variant &) {}
 
public:
  /**
   * @brief Call a method on the object.
   * Can only be called on the head node.
   */
  Variant call_method(const std::string &name, const VariantMap &params);
 
  /**
   * @brief Local implementation of @c call_method.
   *
   * If not overridden by the implementation, this does nothing.
   */
  virtual Variant do_call_method(const std::string &, const VariantMap &) {
    return none;
  }
 
public:
  std::string serialize() const;
 
  /**
   * @brief Make object from serialized state.
   */
  static ObjectRef deserialize(const std::string &state, Context &ctx);
 
  /**
   * @brief Serialize parameters.
   * Can be overridden to e.g. serialize parameters in a specific order.
   */
  virtual std::vector<std::pair<std::string, Variant>>
  serialize_parameters() const {
    auto const params = this->get_parameters();
    return {params.begin(), params.end()};
  }
 
private:
  virtual std::string get_internal_state() const { return {}; }
  virtual void set_internal_state(std::string const &) {}
};
} /* namespace ScriptInterface */