edm::ESProductHost< Product, RecordTypes > Class Template Reference

#include <ESProductHost.h>

Inheritance diagram for edm::ESProductHost< Product, RecordTypes >:

Public Member Functions
template<typename... Args>
	ESProductHost (Args &&... args)
template<typename RecordType , typename ContainingRecordType , typename FUNC >
void	ifRecordChanges (ContainingRecordType const &containingRecord, FUNC func)

Static Public Member Functions
template<typename U >
static constexpr std::size_t	index ()
template<std::size_t I, typename U , typename TST , typename... M>
static constexpr std::size_t	indexLoop ()
static constexpr std::size_t	numberOfRecordTypes ()

Private Attributes
std::vector< unsigned long long >	cacheIDs_

Detailed Description

template<typename Product, typename... RecordTypes>
class edm::ESProductHost< Product, RecordTypes >

Description: Helps an ESProducer produce an ESProduct that has complex dependences on multiple record types. In particular, it helps it manage what is executed in the produce function based on which records changed and which did not.

This was designed as a replacement for the EventSetup "dependsOn" functionality and is needed in some cases where the "dependsOn" callbacks would not work well when processing multiple IOVs concurrently.

Usage:

An ESProducer class would use this class.

1. Add to the ESProducer header

   include "FWCore/Framework/interface/ESProductHost.h" include "FWCore/Utilities/interface/ReusableObjectHolder.h"

2. Assume the following only for purposes of this usage example (the actual types in your case would be different). If the produced function was defined as follows:

   std::shared_ptr<ESTestDataB> produce(ESTestRecordB const&);
   

and assume there is some special dependence on ESTestRecordC and ESTestRecordD.

1. Then you would add a data member to the ESProducer similar to the following:

   using HostType = edm::ESProductHost<ESTestDataB,
                                       ESTestRecordC,
                                       ESTestRecordD>;
   
   edm::ReusableObjectHolder<HostType> holder_;
   

2. Then the produce function would be defined something similar to this:

   std::shared_ptr<ESTestDataB> ESTestProducerBUsingHost::produce(ESTestRecordB const& record) {
   
     auto host = holder_.makeOrGet([]() {
       return new HostType;
     });
   
     host->ifRecordChanges<ESTestRecordC>(record,
                                          [this, h=host.get()](auto const& rec) {
   

   Do whatever special needs to be done only when record C changes (If you are using this class to replace a dependsOn callback, you could call the function that dependsOn used as a callback here) });

   host->ifRecordChanges<ESTestRecordD>(record, [this, h=host.get()](auto const& rec) { Do whatever special needs to be done only when record D changes });

   ... repeat for as many record types as you need.

Definition at line 93 of file ESProductHost.h.

Constructor & Destructor Documentation

ESProductHost()

template<typename Product , typename... RecordTypes>

template<typename... Args>

edm::ESProductHost< Product, RecordTypes >::ESProductHost ( Args &&...  args )

inline

Definition at line 96 of file ESProductHost.h.

: Product(std::forward<Args>(args)...), cacheIDs_(numberOfRecordTypes(), 0) {}

Member Function Documentation

ifRecordChanges()

template<typename Product , typename... RecordTypes>

template<typename RecordType , typename ContainingRecordType , typename FUNC >

void edm::ESProductHost< Product, RecordTypes >::ifRecordChanges ( ContainingRecordType const &  containingRecord, FUNC  func  )

inline

Definition at line 103 of file ESProductHost.h.

References edm::ESProductHost< Product, RecordTypes >::cacheIDs_, EcalMonitorTask_cff::func, and AlCaHarvesting_cff::record.

                                                                                  {
      RecordType const& record = containingRecord.template getRecord<RecordType>();
      unsigned long long cacheIdentifier = record.cacheIdentifier();
      std::size_t iRecord = index<RecordType>();
      if (cacheIdentifier != cacheIDs_[iRecord]) {
        cacheIDs_[iRecord] = cacheIdentifier;
        func(record);
      }
    }

index()

template<typename Product , typename... RecordTypes>

template<typename U >

static constexpr std::size_t edm::ESProductHost< Product, RecordTypes >::index ( )

inlinestatic

Definition at line 129 of file ESProductHost.h.

References edm::ESProductHost< Product, RecordTypes >::indexLoop(), edm::ESProductHost< Product, RecordTypes >::numberOfRecordTypes(), and mitigatedMETSequence_cff::U.

                                       {
      static_assert(numberOfRecordTypes() > 0, "no record types in ESProductHost");
      return indexLoop<0, U, RecordTypes...>();
    }

indexLoop()

template<typename Product , typename... RecordTypes>

template<std::size_t I, typename U , typename TST , typename... M>

static constexpr std::size_t edm::ESProductHost< Product, RecordTypes >::indexLoop ( )

inlinestatic

Definition at line 135 of file ESProductHost.h.

References Exhume::I, edm::ESProductHost< Product, RecordTypes >::numberOfRecordTypes(), and mitigatedMETSequence_cff::U.

Referenced by edm::ESProductHost< Product, RecordTypes >::index().

                                           {
      if constexpr (std::is_same_v<U, TST>) {
        return I;
      } else {
        static_assert(I + 1 < numberOfRecordTypes(), "unknown record type passed to ESProductHost::index");
        return indexLoop<I + 1, U, M...>();
      }
    }

numberOfRecordTypes()

template<typename Product , typename... RecordTypes>

static constexpr std::size_t edm::ESProductHost< Product, RecordTypes >::numberOfRecordTypes ( )

inlinestatic

Definition at line 120 of file ESProductHost.h.

Referenced by edm::ESProductHost< Product, RecordTypes >::index(), and edm::ESProductHost< Product, RecordTypes >::indexLoop().

{ return sizeof...(RecordTypes); }

Member Data Documentation

cacheIDs_

template<typename Product , typename... RecordTypes>

std::vector<unsigned long long> edm::ESProductHost< Product, RecordTypes >::cacheIDs_

private

Definition at line 149 of file ESProductHost.h.

Referenced by edm::ESProductHost< Product, RecordTypes >::ifRecordChanges().