blackboard.hpp

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// Copyright (C) 2023 Miguel Ángel González Santamarta
//
// This program 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.
//
// 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 for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
#ifndef YASMIN__BLACKBOARD_HPP_
#define YASMIN__BLACKBOARD_HPP_
 
#include <cxxabi.h>
#include <exception>
#include <map>
#include <memory>
#include <mutex>
#include <stdexcept>
#include <string>
#include <unordered_map>
 
#include "yasmin/logs.hpp"
#include "yasmin/types.hpp"
 
namespace yasmin {

inline std::string demangle_type(const std::string &mangled_name) {
 
  std::string name = mangled_name;
 
#ifdef __GNUG__ // If using GCC/G++
  int status;
  // Demangle the name using GCC's demangling function
  char *demangled =
      abi::__cxa_demangle(name.c_str(), nullptr, nullptr, &status);
  if (status == 0) {
    name = demangled;
  }
  free(demangled);
#endif
 
  return name; // Return the demangled type name
}

class Blackboard {
private:
  mutable std::recursive_mutex mutex;
  std::unordered_map<std::string, std::shared_ptr<void>> values;
  TypeRegistry type_registry;
  Remappings remappings;

  const std::string &remap(const std::string &key) const;
 
public:
  YASMIN_PTR_ALIASES(Blackboard)
 
  
  Blackboard();

  Blackboard(const Blackboard &other);

  template <class T> void set(const std::string &name, T value) {
 
    YASMIN_LOG_DEBUG("Setting '%s' in the blackboard", name.c_str());
 
    std::lock_guard<std::recursive_mutex> lk(this->mutex);
 
    // Apply remapping if exists
    std::string key = this->remap(name);
 
    // If the type is changing, remove the old entry first
    if (this->type_registry.find(key) != this->type_registry.end()) {
      this->values.erase(key);
      this->type_registry.erase(key);
    }
 
    // Insert value and type information if key does not exist
    if (!this->contains(key)) {
      this->values[key] = std::make_shared<T>(value);
      this->type_registry[key] = demangle_type(typeid(T).name());
 
    } else {
      // Check if the type is the same before updating
      if (this->type_registry.at(key) != demangle_type(typeid(T).name())) {
        this->values[key] = std::make_shared<T>(value);
        this->type_registry[key] = demangle_type(typeid(T).name());
        // Update the existing value
      } else {
        *(std::static_pointer_cast<T>(this->values.at(key))) = value;
      }
    }
  }

  template <class T> T get(const std::string &key) const {
 
    YASMIN_LOG_DEBUG("Getting '%s' from the blackboard", key.c_str());
 
    std::lock_guard<std::recursive_mutex> lk(this->mutex);
 
    // Check if the key exists
    if (!this->contains(key)) {
      throw std::runtime_error("Element '" + key +
                               "' does not exist in the blackboard");
    }
 
    // Return the value casted to the requested type
    return *(std::static_pointer_cast<T>(this->values.at(this->remap(key))));
  }

  void remove(const std::string &key);

  bool contains(const std::string &key) const;

  int size() const;

  std::string get_type(const std::string &key) const;

  std::string to_string() const;

  void set_remappings(const Remappings &remappings);

  const Remappings &get_remappings() const noexcept;
};
 
} // namespace yasmin
 
#endif // YASMIN__BLACKBOARD_HPP_