//

// objectFactory.h

// ofxVisualProgramming

//

// Created by Daan de Lange on 03/03/2020.

//

// Allows objects to register and be instantiated from a string.

//

// Based on code from https://github.com/Karma-Kusala/karmaMapper

#pragma once

// Standard libraries

#include <map>

#include <string>

#include <utility>

#include <vector>

#ifdef DEBUG

#include <iostream>

#endif

class PatchObject; // forward declare

namespace ofxVPObjects {

namespace factory {

typedef PatchObject* (*CreateObjectFunc)();

typedef std::map<std::string, CreateObjectFunc> objectRegistry;

typedef std::map<std::string, std::vector<std::string> > objectCategories;

// getter singletons

inline objectRegistry& getObjectRegistry(){

static objectRegistry singletonReg;

return singletonReg;

}

inline objectCategories& getCategories(){

static objectCategories singletonCats;

return singletonCats;

}

template<class T>

PatchObject* createObject() {

return new T;

}

template<class T>

struct RegistryEntry{

public:

static RegistryEntry<T>& Instance(const std::string& name, const std::string& category="undefined") {

static RegistryEntry<T> inst(name, category);

return inst;

}

private:

RegistryEntry(const std::string& name, const std::string& category="undefined") {

// map name to constructor

objectRegistry& reg = getObjectRegistry();

CreateObjectFunc func = createObject<T>;

std::pair<objectRegistry::iterator, bool> ret = reg.insert(objectRegistry::value_type(name, func));

if (ret.second == false) {

// Object with same name is already registered.

#ifdef DEBUG

std::cout << "Object Factory :: Object «"<< name <<"» already registered, is this behaviour normal ?" << std::endl;

#endif

// go no further

return;

}

// set category

objectCategories& cats = getCategories();

std::vector<std::string> vec;

cats.insert(objectCategories::value_type(category, vec));

cats[category].push_back(name);

}

// C++11 feature : prevent creation of clones

RegistryEntry(const RegistryEntry<T>&) = delete;

RegistryEntry& operator=(const RegistryEntry<T>&) = delete;

};

} // namespace factory

} // namespace ofxVPObjects