media_factory.h

/*
* Copyright (c) 2020-2022, Intel Corporation
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* copy of this software and associated documentation files (the "Software"),
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*
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#ifndef __MEDIA_FACTORY_H__
#define __MEDIA_FACTORY_H__

#include "mos_utilities.h"
#include <map>
#include "media_class_trace.h"

//!
//! \class    MediaFactory
//! \brief    Media factory
//!
template <typename KeyType, class T>
class MediaFactory
{
public:
    typedef T *Type;
    typedef Type (*Creator)();
    typedef Type (*PlaceCreator)(void *);
    typedef std::map<KeyType, Creator>  Creators;
    typedef std::map<KeyType, PlaceCreator>  PlaceCreators;
    typedef std::map<KeyType, uint32_t>  Sizes;
    typedef typename Creators::iterator Iterator;
    typedef typename Sizes::iterator Iterator_Sizes;
    typedef typename PlaceCreators::iterator Iterator_PlaceCreators;

    //!
    //! \brief    register one Class C with key.
    //! \details  Use the member template to register class C with key and C is the
    //!           derived class of base class T.
    //!
    //! \param    [in] key
    //!           KeyType, the type alias of uint32_t.
    //!
    //! \param    [in] forceReplace
    //!           if force to replace the exsiting Creator, default is false.
    //!
    //! \return   true is returned if class C is successfully registerted with key
    //!           false is returned if key is already registered and doesn't register
    //!           class C with key.
    //!
    template <class C>
    static bool Register(KeyType key, bool forceReplace = false)
    {
        Creators &creators = GetCreators();
        Sizes    &sizes    = GetSizes();
        PlaceCreators &placecreators = GetPlaceCreators();
        Iterator creator = creators.find(key);
        if (creator == creators.end())
        {
            std::pair<Iterator, bool> result = creators.emplace(key, Create<C>);
            sizes.emplace(key, (uint32_t)sizeof(C));
            placecreators.emplace(key, PlaceCreate<C>);
            return result.second;
        }
        else
        {
            if (forceReplace)
            {
                creators.erase(creator);
                std::pair<Iterator, bool> result = creators.emplace(key, Create<C>);
                return result.second;
            }
            return true; //If it is registered, do nothing then return true.
        }
    }

    //!
    //! \brief    create a new object that is registered with key.
    //! \details  create and return one new object that is registered with key. And Args is passed to create
    //!           the new object.
    //!
    //! \param    [in] key
    //!           KeyType, the type alias of uint32_t.
    //!
    //! \return   the derived object of T is returned if key is found and the object is created.
    //!           nullptr is returned if key is not found
    //!
    static Type Create(
        KeyType key)
    {
        Creators &creators = GetCreators();
        Iterator creator = creators.find(key);
        if (creator != creators.end())
        {
            return (creator->second)();
        }

        return nullptr;
    }

    static Type PlaceCreate(
        KeyType key, void* privateData)
    {
        PlaceCreators &placecreators = GetPlaceCreators();
        Iterator_PlaceCreators placecreator = placecreators.find(key);
        if (placecreator != placecreators.end())
        {
            return (placecreator->second)(privateData);
        };

        return nullptr;
    }

    static uint32_t ReturnClassSize(KeyType key)
    {
        Sizes    &sizes    = GetSizes();
        Iterator_Sizes sizeit = sizes.find(key);
        if (sizeit != sizes.end())
        {
            return sizeit->second;
        }

        return 0; 
    }
    //!
    //! \brief    check object that is registered with key.
    //! \details  check object that is registered with key. And Args is passed to check the object.
    //!
    //! \param    [in] key
    //!           KeyType, the type alias of uint32_t.
    //!
    //! \return   true if object exists, else not
    //!
    static bool IsRegistered(
        KeyType key)
    {
        Creators &creators = GetCreators();
        return creators.find(key) != creators.end();
    }
private:

    //!
    //! \brief    the callback function with key.
    //! \details  The member template to create the derived object
    //!
    //! \param    [in] arg
    //!           ArgType, the type alias of class template parameter.
    //!
    //! \return   the created object with arg input for C constructor.
    //!
    template <class C>
    static Type Create()
    {
        // The factory only provide the method to create but not keep the pointer to the memory.
        // So the memory free is owned by who call the factory to create it.
        return MOS_New(C);
    }

    template <class C>
    static Type PlaceCreate(void *privateData)
    {
        // The factory only provide the method to create but not keep the pointer to the memory.
        // So the memory free is owned by who call the factory to create it.
        return new (privateData)C;
    }

    //!
    //! \brief    obtain the static pair table of param@ key and callback function
    //! \details  obtain the static pair table that is registerted with param@key and callback function
    //!
    //! \return   return the static pair table about the param @key and callback function
    //!
    static Creators &GetCreators()
    {
        static Creators creators;

        return creators;
    }

    static PlaceCreators &GetPlaceCreators()
    {
        static PlaceCreators placecreators;

        return placecreators;
    }

    static Sizes &GetSizes()
    {
        static Sizes sizes;

        return sizes;
    }


MEDIA_CLASS_DEFINE_END(MediaFactory)
};

#define MEDIA_EXT_FLAG  0x10000000

#endif