DVLDataBucket.icc

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// This file's extension implies that it's C, but it's really -*- C++ -*-.
 
/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
/**
 * @file  AthContainers/tools/DVLDataBucket.icc
 * @author scott snyder
 * @date Mar 2008
 * @brief A @c DataBucket specialized for @c DataVector/@c DataList.
 *
 * Template and inline implementations.
 */
 
 
#include "AthContainers/exceptions.h"
#include "AthenaKernel/IRegisterTransient.h"
#include "CxxUtils/AthUnlikelyMacros.h"
 
 
namespace SG {
 
 
/**
 * @brief Is a @c DataVector we're trying to record actually a @c ViewVector?
 * @param data Object being recorded.
 * @param[out] clid If the object is a @c ViewVector, set to the CLID
 *                  of that class.  Otherwise unchanged.
 * @returns The @c type_info for the object being recorded, either the
 *          @c DataVector or a @c ViewVector that derives from it.
 */
template <class T>
const std::type_info* testViewVector (const DataVector<T>& data,
                                      CLID& clid)
{
  // If this is a view container, test for @c ViewVector.
  if (data.ownPolicy() == SG::VIEW_ELEMENTS) {
    // See if we actually have a @c ViewVector.
    // FIXME: This doesn't work if @c ViewVector is templated on an intermediate
    // class rather than @c DataVector directly.
    if (dynamic_cast<const ViewVector<DataVector<T> >*> (&data)) {
      const std::type_info& ti = typeid(ViewVector<DataVector<T> >);
      const SG::BaseInfoBase* bib = SG::BaseInfoBase::find (ti);
      if (bib) {
        clid = bib->clid();
        if (clid == CLID_NULL)
          SG::throwExcMissingViewVectorCLID (ti);
        return &ti;
      }
      else {
        SG::throwExcMissingBaseInfo (ti);
      }
    }
  }
  return &typeid(DataVector<T>);
}
 
 
/**
 * @brief Is a @c DataVector we're trying to record actually a @c ViewVector?
 *
 * Handle the case where the object being recorded is not a @c DataVector.
 */
template <class T>
const std::type_info* testViewVector (const T& ,
                                      CLID& )
{
  return &typeid(T);
}
 
 
/**
 * @brief Constructor from a payload object.
 * @param data Object to hold in the bucket.
 */
template <class T>
DVLDataBucket<T>::DVLDataBucket (T* data)
  : DataBucket<T> (data)
{
  // cppcheck-suppress useInitializationList
  m_clid = DataBucket<T>::classID();
  m_ti = testViewVector (*this->ptr(), m_clid);
}
 
 
/**
 * @brief Constructor from a payload object.
 * @param data Object to hold in the bucket.
 */
template <class T>
template <class U>
DVLDataBucket<T>::DVLDataBucket (std::unique_ptr<U> data)
  : DataBucket<T> (std::move (data))
{
  // cppcheck-suppress useInitializationList
  m_clid = DataBucket<T>::classID();
  // cppcheck-suppress missingReturn; false positive
  m_ti = testViewVector (*this->ptr(), m_clid);
}
 
 
/**
 * @brief Copy constructor.
 * @param other Bucket to copy.
 */
template <typename T>
DVLDataBucket<T>::DVLDataBucket (const DVLDataBucket& other)
  : SG::DataBucket<T> (new T (*other.cptr())),
    m_copies (other.m_copies),
    m_ti (other.m_ti),
    m_clid (other.m_clid)
{
  // Make a copy of each of the copies.
  vec_t::iterator end = m_copies.end();
  for (vec_t::iterator it = m_copies.begin(); it != end; ++it) {
    it->second = it->first->clone (it->second);
  }
}
 
 
/**
 * @brief Destructor.
 */
template <typename T>
DVLDataBucket<T>::~DVLDataBucket()
{
  // Delete any copies.
  vec_t::iterator end = m_copies.end();
  for (vec_t::iterator it = m_copies.begin(); it != end; ++it) {
    it->first->del (it->second);
  }
}
 
 
/**
 * @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 <typename T> 
void*
DVLDataBucket<T>::cast (CLID clid, IRegisterTransient* irt /*= 0*/,
                        bool /*isConst = true*/)
{
  // Test for trivial conversion.
  // FIXME: Assumes we can reinterpret_cast between DV* and ViewVector<DV>*.
  if (ATH_LIKELY (clid == m_clid) || clid == DataBucket<T>::classID())
    return this->ptr();
 
  // Try looking for a true base conversion,
  // first using static SG_BASES information.
  // This can all be unfolded at compile time, so is fast, but
  // doesn't take into account SG_ADD_BASES.
  void* ret = this->tryStaticConversion (clid);
  if (ret) {
    return ret;
  }
 
  T* ptr = this->ptr();
 
  // Then try using BaseInfo, in case of SG_ADD_BASES.
  ret = SG::BaseInfo<T>::cast (ptr, clid);
  if (ret) {
    return ret;
  }
 
  // See if we've already made an instance for this type.
  // We don't expect to have more than a few, so no point in doing
  // anything more complicated than a linear search.
  vec_t::iterator end = m_copies.end();
  for (vec_t::iterator it = m_copies.begin(); it != end; ++it) {
    if (clid == it->first->clid()) {
      // Recopy the elements if the container size has changed.
      if (it->first->size (it->second) != ptr->size()) {
        dvl_update (*ptr, it->second, it->first);
      }
      return it->second;
    }
  }
 
  // Try to do a copying conversion.
  DataModel_detail::DVLInfoBase* info;
  void* newcont = dvl_convert (*ptr, clid, info);
  if (newcont) {
    m_copies.push_back (std::make_pair (info, newcont));
    irt->registerTransient (newcont);
  }
 
  return newcont;
}
 
 
/**
 * @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 <typename T> 
void*
DVLDataBucket<T>::cast (const std::type_info& tinfo,
                        IRegisterTransient* irt /*= 0*/,
                        bool /*isConst = true*/)
{
  // Test for trivial conversion.
  // FIXME: Assumes we can reinterpret_cast between DV* and ViewVector<DV>*.
  if (ATH_LIKELY (&tinfo == m_ti) || tinfo == DataBucket<T>::tinfo())
    return this->ptr();
 
  // Try looking for a true base conversion,
  // first using static SG_BASES information.
  // This can all be unfolded at compile time, so is fast, but
  // doesn't take into account SG_ADD_BASES.
  void* ret = this->tryStaticConversion (tinfo);
  if (ret) {
    return ret;
  }
 
  T* ptr = this->ptr();
 
  // Try looking for a true base conversion.
  ret = SG::BaseInfo<T>::cast (ptr, tinfo);
  if (ret) {
    return ret;
  }
 
  // See if we've already made an instance for this type.
  // We don't expect to have more than a few, so no point in doing
  // anything more complicated than a linear search.
  vec_t::iterator end = m_copies.end();
  for (vec_t::iterator it = m_copies.begin(); it != end; ++it) {
    if (tinfo == it->first->tinfo()) {
      // Recopy the elements if the container size has changed.
      if (it->first->size (it->second) != ptr->size()) {
        dvl_update (*ptr, it->second, it->first);
      }
      return it->second;
    }
  }
 
  // Try to do a copying conversion.
  DataModel_detail::DVLInfoBase* info;
  void* newcont = dvl_convert (*ptr, tinfo, info);
  if (newcont) {
    m_copies.push_back (std::make_pair (info, newcont));
    irt->registerTransient (newcont);
  }
 
  return newcont;
}
 
 
/**
 * @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 <typename T>
inline
void* DVLDataBucket<T>::cast (CLID clid,
                              const std::type_info& /*tinfo*/,
                              SG::IRegisterTransient* irt /*= 0*/,
                              bool isConst /*= true*/)
{
  return DVLDataBucket::cast (clid, irt, isConst);
}
 
 
/**
 * @brief The CLID for the class of object we're holding.
 *
 * May be different from that of the base @c DataVector in the case
 * of a @c ViewVector.
 */
template <typename T>
const CLID& DVLDataBucket<T>::clID() const
{
  return m_clid;
}
 
 
/**
 * @brief The std::type_info for the class of object we're holding.
 *
 * May be different from that of the base @c DataVector in the case
 * of a @c ViewVector.
 */
template <typename T>
const std::type_info& DVLDataBucket<T>::tinfo() const
{
  return *m_ti;
}
 
 
} // namespace SG