objectfactory.h

/* Copyright (C) 2004-2010 MBSim Development Team
 *
 * This library is free software; you can redistribute it and/or 
 * modify it under the terms of the GNU Lesser General Public 
 * License as published by the Free Software Foundation; either 
 * version 2.1 of the License, or (at your option) any later version. 
 *  
 * This library 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 
 * Lesser General Public License for more details. 
 *  
 * You should have received a copy of the GNU Lesser General Public 
 * License along with this library; if not, write to the Free Software 
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 *
 * Contact: friedrich.at.gc@googlemail.com
 */
 
#ifndef _MBSIM_OBJECTFACTORY_H_
#define _MBSIM_OBJECTFACTORY_H_
 
#include "objectfactory_part.h"
#include <utility>
#include <vector>
#include <functional>
#include <stdexcept>
#include <typeinfo>
#include <mbsim/mbsim_event.h>
#include <xercesc/dom/DOMAttr.hpp>
#include <mbxmlutilshelper/utils.h>
#include "fmatvec/atom.h"
#include <boost/core/demangle.hpp>
 
namespace MBSim {
 
/* A tree of DOMEvalException's which store the tree of failed objects
 * creations of the object factory */
class DOMEvalExceptionStack : public MBXMLUtils::DOMEvalException {
  public:
    DOMEvalExceptionStack(const xercesc::DOMElement *element) : MBXMLUtils::DOMEvalException("", element) {}
    DOMEvalExceptionStack(const DOMEvalExceptionStack &src) : MBXMLUtils::DOMEvalException(src), exVec(src.exVec) {}
    ~DOMEvalExceptionStack() noexcept override = default;
    void add(const std::string &type, const std::shared_ptr<MBXMLUtils::DOMEvalException> &ex);
    const char* what() const noexcept override;
    std::vector<std::pair<std::string, std::shared_ptr<MBXMLUtils::DOMEvalException>>> &getExceptionVector();
  protected:
    std::vector<std::pair<std::string, std::shared_ptr<MBXMLUtils::DOMEvalException>>> exVec;
    mutable std::string whatStr;
    void generateWhat(std::stringstream &str, const std::string &indent) const;
};
 
/* Just to distinguish a wrong type (not castable) error of the object factory
 * from others */
class DOMEvalExceptionWrongType : public MBXMLUtils::DOMEvalException {
  public:
    DOMEvalExceptionWrongType(const std::string &type, const xercesc::DOMElement *element) :
      MBXMLUtils::DOMEvalException(type, element) {}
    DOMEvalExceptionWrongType(const DOMEvalExceptionWrongType &src)  = default;
    ~DOMEvalExceptionWrongType() noexcept override = default;
};
 
class ObjectFactory {
 
  friend void registerClass_internal(const MBXMLUtils::FQN &name, const AllocateBase *alloc, const DeallocateBase *dealloc);
  friend void deregisterClass_internal(const MBXMLUtils::FQN &name, const AllocateBase *alloc);
 
  public:
 
    template<class ContainerType>
    static ContainerType* createAndInit(const xercesc::DOMElement *element);
 
    static void addErrorMsg(const std::string &msg);
    static std::string getAndClearErrorMsg();
 
  private:
 
    // convinence typedefs
    typedef std::pair<const AllocateBase*, const DeallocateBase*> AllocDeallocPair;
    typedef std::vector<AllocDeallocPair> AllocDeallocVector;
    typedef AllocDeallocVector::iterator AllocDeallocVectorIt;
    typedef std::map<MBXMLUtils::FQN, AllocDeallocVector> NameMap;
    typedef NameMap::iterator NameMapIt;
 
    // private ctor
    ObjectFactory() = default;
 
    // create an singleton instance of the object factory.
    static ObjectFactory& instance();
 
    // a vector of all registered types
    NameMap registeredType;
 
    static std::string errorMsg;
};
 
template<class ContainerType>
ContainerType* ObjectFactory::createAndInit(const xercesc::DOMElement *element) {
  // just check if ContainerType is derived from fmatvec::Atom if not throw a compile error
  static_assert(std::is_convertible<ContainerType*, fmatvec::Atom*>::value,
    "In MBSim::ObjectFactory::create<ContainerType>(...) ContainerType must be derived from fmatvec::Atom.");
  // throw error if NULL is supplied as element
  if(element==nullptr)
    throw std::runtime_error("Internal error: NULL argument specified.");
  // get all allocate functions for the given name
  MBXMLUtils::FQN fqn=MBXMLUtils::E(element)->getTagName();
  auto nameIt=instance().registeredType.find(fqn);
  if(nameIt==instance().registeredType.end())
    throw MBXMLUtils::DOMEvalException("Internal error: No objects of name {"+fqn.first+"}"+fqn.second+" registred", element);
  DOMEvalExceptionStack allErrors(static_cast<xercesc::DOMElement*>(element->getParentNode()));
  // try to create and init a object which each of the allocate function
  for(auto & allocDeallocIt : nameIt->second) {
    // create element
    fmatvec::Atom *ele=(*allocDeallocIt.first)();
    // try to cast the element to ContainerType
    auto *ret=dynamic_cast<ContainerType*>(ele);
    if(!ret) {
      // cast not possible -> deallocate again and try next
      allErrors.add(boost::core::demangle(typeid(*ele).name()),
                    std::make_shared<DOMEvalExceptionWrongType>(
                    boost::core::demangle(typeid(ContainerType).name()), element));
      (*allocDeallocIt.second)(ele); 
      continue;
    }
    try {
      ret->initializeUsingXML(const_cast<xercesc::DOMElement*>(element));
      return ret;
    }
    catch(DOMEvalExceptionStack &ex) {
      allErrors.add(boost::core::demangle(typeid(*ele).name()), std::make_shared<DOMEvalExceptionStack>(ex));
    }
    catch(MBXMLUtils::DOMEvalException &ex) {
      allErrors.add(boost::core::demangle(typeid(*ele).name()), std::make_shared<MBXMLUtils::DOMEvalException>(ex));
    }
    catch(std::exception &ex) { // handles also MBSimError
      allErrors.add(boost::core::demangle(typeid(*ele).name()),
                    std::make_shared<MBXMLUtils::DOMEvalException>(ex.what(), element));
    }
    catch(...) {
      allErrors.add(boost::core::demangle(typeid(*ele).name()),
                    std::make_shared<MBXMLUtils::DOMEvalException>("Unknwon exception", element));
    }
    (*allocDeallocIt.second)(ele);
  }
  // if all failed -> return errors of all trys
  throw allErrors;
}
 
// a wrapper to allocate an object of type CreateType
template<class CreateType>
struct Allocate : public AllocateBase {
  // create a new object of type CreateType using new
  fmatvec::Atom* operator()() const override {
    return new CreateType;
  }
  // check if this Allocator allocates the same object as other.
  // This is the case if the type of this template class matches
  // the type of other.
  bool isEqual(const AllocateBase& other) const override {
    return typeid(*this)==typeid(other);
  }
};
 
// a wrapper to deallocate an object created by allocate
struct Deallocate : public DeallocateBase {
  // deallocate a object using delete
  void operator()(fmatvec::Atom *obj) const override {
    delete obj;
  }
};
 
template<class CreateType>
class ObjectFactoryRegisterClassHelper {
 
  public:
 
    ObjectFactoryRegisterClassHelper(MBXMLUtils::FQN name_) noexcept : name(std::move(name_)) {
      try {
        MBSim::registerClass_internal(name, new Allocate<CreateType>(), new Deallocate());
      }
      catch(std::exception &ex) {
        ObjectFactory::addErrorMsg(ex.what());
      }
      catch(...) {
        ObjectFactory::addErrorMsg("Unknown error");
      }
    }
 
    ~ObjectFactoryRegisterClassHelper() {
      try {
        MBSim::deregisterClass_internal(name, new Allocate<CreateType>());
      }
      catch(std::exception &ex) {
        fprintf(stderr, "%s\n", ex.what());
      }
      catch(...) {
        fprintf(stderr, "%s\n", "Unknown error");
      }
    }
 
  private:
    MBXMLUtils::FQN name;
 
};
 
template<class EnumType>
class EnumFactory {
 
  template<class EV> friend void registerEnum_internal(const MBXMLUtils::FQN &name, const EV& value);
  template<class EV> friend void deregisterEnum_internal(const MBXMLUtils::FQN &name);
 
  public:
 
    EnumFactory(const EnumType &enumVar, MBXMLUtils::FQN fqn_) : fqn(std::move(fqn_)) {
      try {
        registerEnum_internal<EnumType>(fqn, enumVar);
      }
      catch(std::exception &ex) {
        ObjectFactory::addErrorMsg(ex.what());
      }
      catch(...) {
        ObjectFactory::addErrorMsg("Unknown error");
      }
    }
 
    ~EnumFactory() {
      try {
        deregisterEnum_internal<EnumType>(fqn);
      }
      catch(std::exception &ex) {
        fprintf(stderr, "%s\n", ex.what());
      }
      catch(...) {
        fprintf(stderr, "%s\n", "Unknown error");
      }
    }
 
    static const EnumType& get(const MBXMLUtils::FQN &fqn, const xercesc::DOMElement *e=nullptr) {
      auto it=regmap().find(fqn);
      if(it==regmap().end())
        throw MBXMLUtils::DOMEvalException("No enumeration value named {"+fqn.first+"}"+fqn.second+" registred", e);
      return it->second.get();
    }
 
  private:
    MBXMLUtils::FQN fqn;
 
    // return the register map of the enum factory.
    // (note: this function must not be defined in this file to avoid any imlicit instantation)
    static std::map<MBXMLUtils::FQN, std::reference_wrapper<const EnumType>>& regmap();
};
 
template<class EV>
void registerEnum_internal(const MBXMLUtils::FQN &name, const EV& value) {
  EnumFactory<EV>::regmap().insert(std::make_pair(name, std::ref(value)));
}
 
template<class EV>
void deregisterEnum_internal(const MBXMLUtils::FQN &name) {
  EnumFactory<EV>::regmap().erase(name);
}
 
// fix local xml name (remove template and namespace)
std::string fixXMLLocalName(std::string name);
 
}
 
#define MBSIM_OBJECTFACTORY_REGISTERCLASS(NS, Class) \
  static MBSim::ObjectFactoryRegisterClassHelper<Class> \
    BOOST_PP_CAT(objectFactoryRegistrationDummyVariable_, __LINE__)((NS)%MBSim::fixXMLLocalName(#Class));
 
#define MBSIM_OBJECTFACTORY_REGISTERCLASS_AND_INSTANTIATE(NS, Class) \
  template class Class; \
  static MBSim::ObjectFactoryRegisterClassHelper<Class> \
    BOOST_PP_CAT(objectFactoryRegistrationDummyVariable_, __LINE__)((NS)%MBSim::fixXMLLocalName(#Class));
 
#define MBSIM_OBJECTFACTORY_REGISTERCLASSWITHTEMPLATENAME_AND_INSTANTIATE(NS, Class, TemplateName) \
  template class Class; \
  static MBSim::ObjectFactoryRegisterClassHelper<Class> \
    BOOST_PP_CAT(objectFactoryRegistrationDummyVariable_, __LINE__)((NS)%(MBSim::fixXMLLocalName(#Class)+"_"+#TemplateName));
 
#define MBSIM_OBJECTFACTORY_REGISTERENUM(EnumType, NS, enumName) \
  static MBSim::EnumFactory<EnumType> \
    BOOST_PP_CAT(objectFactoryRegistrationDummyVariable_, __LINE__)(enumName, (NS)%#enumName);
 
#endif