MetaContDataBucket.icc

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/*
  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
*/
/**
 * @file AthenaKernel/MetaContDataBucket.icc
 * @author scott snyder <snyder@bnl.gov>
 * @date Jan, 2018
 * @brief Allow converting MetaCont<T> to T.
 */
 
 
namespace SG {
 
 
/**
 * @brief Return the contents of the @c DataBucket,
 *        converted to type given by @a clid.  Note that only
 *        derived->base conversions are allowed here.
 * @param clid The class ID to which to convert.
 * @param irt To be called if we make a new instance.
 * @param isConst True if the object being converted is regarded as const.
 */
template <class T>
void* MetaContDataBucket<T>::cast (CLID clid,
                                   IRegisterTransient* irt /*= 0*/,
                                   bool isConst /*= true*/)
{
  // First try normal conversion.
  if (void* ret = DataBucket<T>::cast (clid, irt, isConst)) {
    return ret;
  }
 
  // Otherwise, try to retrieve the payload and cast it as requested.
  typename T::Payload_t* payload = nullptr;
  if (this->ptr()->find (getSID(), payload)) {
    return SG::BaseInfo<typename T::Payload_t>::cast (payload, clid);
  }
  return nullptr;
}
 
  
/**
 * @brief Return the contents of the @c DataBucket,
 *        converted to type given by @a std::type_info.  Note that only
 *        derived->base conversions are allowed here.
 * @param clid The @a std::type_info of the type to which to convert.
 * @param irt To be called if we make a new instance.
 * @param isConst True if the object being converted is regarded as const.
 */
template <class T>
void* MetaContDataBucket<T>::cast (const std::type_info& tinfo,
                                   IRegisterTransient* irt /*= 0*/,
                                   bool isConst /*= true*/)
{
  if (void* ret = DataBucket<T>::cast (tinfo, irt, isConst)) {
    return ret;
  }
  // Otherwise, try to retrieve the payload and cast it as requested.
  typename T::Payload_t* payload = nullptr;
  if (this->ptr()->find (getSID(), payload)) {
    return SG::BaseInfo<typename T::Payload_t>::cast (payload, tinfo);
  }
  return nullptr;
}
 
 
/**
 * @brief Return the contents of the @c DataBucket,
 *        converted to type given by @a clid.  Note that only
 *        derived->base conversions are allowed here.
 * @param clid The class ID to which to convert.
 * @param tinfo The @a std::type_info of the type to which to convert.
 * @param irt To be called if we make a new instance.
 * @param isConst True if the object being converted is regarded as const.
 *
 * This allows the callee to choose whether to use clid or tinfo.
 * Here we use clid.
 */
template <class T>
inline
void* MetaContDataBucket<T>::cast (CLID clid,
                                   const std::type_info& /*tinfo*/,
                                   SG::IRegisterTransient* irt /*= 0*/,
                                   bool isConst /*= true*/)
{
  return MetaContDataBucket::cast (clid, irt, isConst);
}
 
 
/**
 * @brief Return the metadata source id for the current event store.
 *        Returns an empty string if there's no source ID set.
 */
template <class T>
const SourceID MetaContDataBucket<T>::getSID() const
{
  const EventContext& ctx = Gaudi::Hive::currentContext();
  const IProxyDict* store = 
    Atlas::getExtendedEventContext(ctx).proxy();
  return store->sourceID();
}
 
 
} // namespace SG