DeferredProductGetter.cc

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#include "art/Framework/Principal/DeferredProductGetter.h"

#include "art/Framework/Principal/Principal.h"
#include "canvas/Utilities/Exception.h"
#include "canvas/Utilities/TypeID.h"

art::DeferredProductGetter::DeferredProductGetter(
  cet::exempt_ptr<Principal const> groupFinder,
  ProductID pid)
  : groupFinder_(groupFinder), pid_(pid), realGetter_()
{}

art::EDProduct const*
art::DeferredProductGetter::getIt() const
{
  return resolveGetter_()->getIt();
}

art::EDProduct const*
art::DeferredProductGetter::anyProduct() const
{
  return resolveGetter_()->anyProduct();
}

art::EDProduct const*
art::DeferredProductGetter::uniqueProduct() const
{
  return resolveGetter_()->uniqueProduct();
}

art::EDProduct const*
art::DeferredProductGetter::uniqueProduct(TypeID const& tid) const
{
  return resolveGetter_()->uniqueProduct(tid);
}

bool
art::DeferredProductGetter::resolveProduct(TypeID const& tid) const
{
  return resolveGetter_()->resolveProduct(tid);
}

bool
art::DeferredProductGetter::resolveProductIfAvailable(TypeID const& tid) const
{
  return resolveGetter_()->resolveProductIfAvailable(tid);
}

cet::exempt_ptr<art::EDProductGetter const>
art::DeferredProductGetter::resolveGetter_() const
{
  auto result = maybeResolveGetter_();
  if (!result) {
    throw Exception(errors::ProductNotFound)
      << "Product corresponding to ProductID " << pid_
      << " not found: possible attempt to resolve a Ptr before its product has "
         "been committed.\n";
  }
  return result;
}

cet::exempt_ptr<art::EDProductGetter const>
art::DeferredProductGetter::maybeResolveGetter_() const
{
  if (realGetter_) {
    return realGetter_;
  } else if ((realGetter_ =
                groupFinder_->getByProductID(pid_).result().get())) {
    return realGetter_;
  } else {
    return cet::exempt_ptr<EDProductGetter const>();
  }
}