FactoryBase.h

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/**
 *  @file FactoryBase.h
 *  File contains the FactoryBase class declarations.
 */

// This file is part of Cantera. See License.txt in the top-level directory or
// at http://www.cantera.org/license.txt for license and copyright information.

#ifndef CT_FACTORY_BASE
#define CT_FACTORY_BASE

#include <vector>
#include <mutex>
#include <unordered_map>
#include "cantera/base/ctexceptions.h"

namespace Cantera
{

//! Base class for factories.
/*!
 * This class maintains a registry of all factories that derive from it, and
 * deletes them all when its static method deleteFactories is invoked.
 */
class FactoryBase
{
public:

    //! destructor
    virtual ~FactoryBase() {
    }

    //! static function that deletes all factories in the internal registry
    //! maintained in a static variable
    static void deleteFactories() {
        for (const auto& f : s_vFactoryRegistry) {
            f->deleteFactory();
        }
        s_vFactoryRegistry.clear();
    }

protected:

    //! Constructor.
    /*!
     * Adds the current object to the current static list
     */
    FactoryBase() {
        s_vFactoryRegistry.push_back(this);
    }

    //! Virtual abstract function that deletes the factory
    /*!
     *  This must be properly defined in child objects.
     */
    virtual void deleteFactory() = 0;

private:
    //! statically held list of Factories.
    static std::vector<FactoryBase*> s_vFactoryRegistry;
};

//! Factory class that supports registering functions to create objects
//!
//! Template arguments for the class are the base type created by the factory,
//! followed by the types of any arguments which need to be passed to the
//! functions used to create objects, e.g. arguments to the constructor.
template <class T, typename ... Args>
class Factory : public FactoryBase {
public:
    virtual ~Factory() {}

    //! Create an object using the object construction function corresponding to
    //! "name" and the provided constructor arguments
    T* create(const std::string& name, Args... args) {
        try {
            return m_creators.at(name)(args...);
        } catch (std::out_of_range&) {
            throw CanteraError("Factory::create", "No such type: '{}'", name);
        }
    }

    //! Register a new object construction function
    void reg(const std::string& name, std::function<T*(Args...)> f) {
        m_creators[name] = f;
    }

protected:
    std::unordered_map<std::string, std::function<T*(Args...)>> m_creators;
};

}

#endif