DtVirtualBaseClassCreator.h

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/******************************************************************************
 * Copyright (c) 2021 MAK Technologies, Inc.
 * All rights reserved.
 ******************************************************************************/
 
#pragma once

#include <vrvCore/vrvCore.h>
#include <vrvCore/DtDe.h>
#include <vrvUtil/DtVirtualBaseClass.h>

namespace makVrv
{
   template<class ClassToCreate, class ...ConstructorArgs>
   class DtVirtualBaseClassCreator : public DtVirtualBaseClass
   {
   public:
      virtual ~DtVirtualBaseClassCreator();

      DtVirtualBaseClassCreator() = delete;
      DtVirtualBaseClassCreator(const DtVirtualBaseClassCreator &other) = delete;
      DtVirtualBaseClassCreator &operator=(const DtVirtualBaseClassCreator &other) = delete;
      
   protected:
      DtVirtualBaseClassCreator(DtDe& de);

   public:
      static DtVirtualBaseClassCreator& instance(DtDe& de);

   public:
      virtual ClassToCreate* create(ConstructorArgs&&... constructorArgs);


   protected:
      
      DtDe& myDe;
      
      static ClassToCreate* classToCreateType;

   };

   //Deleted the general case of this function since it must be correctly specialized by the 
   // class that this templated class is creating. For example:
   //typedef DtVirtualBaseClassCreator<DtDepthOfFieldDrawable> DtDepthOfFieldDrawableCreator;
   //
   //template <>
   //inline const char* creatorTypeName<DtDepthOfFieldDrawable>(void) { return "DtDepthOfFieldDrawableCreator"; }
   template <typename ClassToCreate>
   inline const char* creatorTypeName(void) = delete;

   template<class ClassToCreate, class ...ConstructorArgs>
   DtVirtualBaseClassCreator<ClassToCreate, ConstructorArgs...>::DtVirtualBaseClassCreator(DtDe& de)
      : myDe(de)
   {
      // nop
   }

   template<class ClassToCreate, class ...ConstructorArgs>
   DtVirtualBaseClassCreator<ClassToCreate, ConstructorArgs...>::~DtVirtualBaseClassCreator()
   {
      // nop
   }

   template<class ClassToCreate, class ...ConstructorArgs>
   DtVirtualBaseClassCreator<ClassToCreate, ConstructorArgs...>& DtVirtualBaseClassCreator<ClassToCreate, ConstructorArgs...>::instance(DtDe& de)
   {
      std::string creatorType = creatorTypeName<ClassToCreate>();
      DtVirtualBaseClassCreator<ClassToCreate, ConstructorArgs...>* inst = dynamic_cast<DtVirtualBaseClassCreator<ClassToCreate, ConstructorArgs...>*>(
         de.findInstance(creatorType));
      if (!inst)
      {
         inst = new DtVirtualBaseClassCreator<ClassToCreate, ConstructorArgs...>(de);
         de.registerInstance(creatorType, inst);
      }
      return *inst;
   }

   template<class ClassToCreate, class ...ConstructorArgs>
   ClassToCreate* DtVirtualBaseClassCreator<ClassToCreate, ConstructorArgs...>::create(ConstructorArgs&&... constructorArgs)
   {
      //Perfect forwarding of the ConstructorArgs
      return new ClassToCreate(myDe, std::forward<ConstructorArgs>(constructorArgs)...);
   }

}