Delay constructing transition wrappers

FWCore/Framework/interface/Event.h

@@ -33,6 +33,7 @@ For its usage, see "FWCore/Framework/interface/PrincipalGetAdapter.h"
 #include "FWCore/Common/interface/EventBase.h"
 #include "FWCore/Framework/interface/Frameworkfwd.h"
 #include "FWCore/Framework/interface/PrincipalGetAdapter.h"
+#include "FWCore/Framework/interface/LuminosityBlock.h"
 #include "FWCore/Utilities/interface/TypeID.h"
 #include "FWCore/Utilities/interface/EDGetToken.h"
 #include "FWCore/Utilities/interface/EDPutToken.h"
@@ -94,7 +95,12 @@ namespace edm {
     ///\return The id for the particular Stream processing the Event
     StreamID streamID() const { return streamID_; }
 
-    LuminosityBlock const& getLuminosityBlock() const { return *luminosityBlock_; }
+    LuminosityBlock const& getLuminosityBlock() const {
+      if (not luminosityBlock_) {
+        fillLuminosityBlock();
+      }
+      return *luminosityBlock_;
+    }
 
     Run const& getRun() const;
 
@@ -255,6 +261,8 @@ namespace edm {
 
     EventPrincipal const& eventPrincipal() const;
 
+    void fillLuminosityBlock() const;
+
     ProductID makeProductID(BranchDescription const& desc) const;
 
     //override used by EventBase class
@@ -298,7 +306,7 @@ namespace edm {
     ProductPtrVec putProducts_;
 
     EventAuxiliary const& aux_;
-    std::shared_ptr<LuminosityBlock const> const luminosityBlock_;
+    mutable std::optional<LuminosityBlock> luminosityBlock_;
 
     // gotBranchIDs_ must be mutable because it records all 'gets',
     // which do not logically modify the PrincipalGetAdapter. gotBranchIDs_ is

FWCore/Framework/interface/LuminosityBlock.h

@@ -22,6 +22,7 @@ For its usage, see "FWCore/Framework/interface/PrincipalGetAdapter.h"
 #include "FWCore/Common/interface/LuminosityBlockBase.h"
 #include "FWCore/Framework/interface/Frameworkfwd.h"
 #include "FWCore/Framework/interface/PrincipalGetAdapter.h"
+#include "FWCore/Framework/interface/Run.h"
 #include "FWCore/Utilities/interface/EDGetToken.h"
 #include "FWCore/Utilities/interface/EDPutToken.h"
 #include "FWCore/Utilities/interface/ProductKindOfType.h"
@@ -33,6 +34,7 @@ For its usage, see "FWCore/Framework/interface/PrincipalGetAdapter.h"
 #include <string>
 #include <typeinfo>
 #include <vector>
+#include <optional>
 
 namespace edm {
   class ModuleCallingContext;
@@ -100,7 +102,12 @@ namespace edm {
     template <typename PROD>
     void getManyByType(std::vector<Handle<PROD>>& results) const;
 
-    Run const& getRun() const { return *run_; }
+    Run const& getRun() const {
+      if (not run_) {
+        fillRun();
+      }
+      return run_.value();
+    }
 
     ///Put a new product.
     template <typename PROD>
@@ -157,6 +164,8 @@ namespace edm {
     ProductPtrVec& putProducts() { return putProducts_; }
     ProductPtrVec const& putProducts() const { return putProducts_; }
 
+    void fillRun() const;
+
     // commit_() is called to complete the transaction represented by
     // this PrincipalGetAdapter. The friendships required seems gross, but any
     // alternative is not great either.  Putting it into the
@@ -171,7 +180,7 @@ namespace edm {
     PrincipalGetAdapter provRecorder_;
     ProductPtrVec putProducts_;
     LuminosityBlockAuxiliary const& aux_;
-    std::shared_ptr<Run const> const run_;
+    mutable std::optional<Run> run_;
     ModuleCallingContext const* moduleCallingContext_;
 
     static const std::string emptyString_;

FWCore/Framework/interface/PrincipalGetAdapter.h

@@ -141,8 +141,10 @@ namespace edm {
     //size_t size() const;
 
     void setConsumer(EDConsumerBase const* iConsumer) { consumer_ = iConsumer; }
+    EDConsumerBase const* getConsumer() const { return consumer_; }
 
     void setSharedResourcesAcquirer(SharedResourcesAcquirer* iSra) { resourcesAcquirer_ = iSra; }
+    SharedResourcesAcquirer* getSharedResourcesAcquirer() const { return resourcesAcquirer_; }
 
     void setProducer(ProducerBase const* iProd) { prodBase_ = iProd; }
 
@@ -172,6 +174,7 @@ namespace edm {
 
     BranchDescription const& getBranchDescription(unsigned int iPutTokenIndex) const;
     ProductID const& getProductID(unsigned int iPutTokenIndex) const;
+    ModuleDescription const& moduleDescription() const { return md_; }
 
     std::vector<edm::ProductResolverIndex> const& putTokenIndexToProductResolverIndex() const;
 

FWCore/Framework/src/Event.cc

@@ -22,9 +22,7 @@ namespace edm {
   Event::Event(EventPrincipal const& ep, ModuleDescription const& md, ModuleCallingContext const* moduleCallingContext)
       : provRecorder_(ep, md, true /*always at end*/),
         aux_(ep.aux()),
-        luminosityBlock_(ep.luminosityBlockPrincipalPtrValid()
-                             ? new LuminosityBlock(ep.luminosityBlockPrincipal(), md, moduleCallingContext, false)
-                             : nullptr),
+        luminosityBlock_(),
         gotBranchIDs_(),
         gotViews_(),
         streamID_(ep.streamID()),
@@ -37,12 +35,23 @@ namespace edm {
   void Event::setConsumer(EDConsumerBase const* iConsumer) {
     provRecorder_.setConsumer(iConsumer);
     gotBranchIDs_.reserve(provRecorder_.numberOfProductsConsumed());
-    const_cast<LuminosityBlock*>(luminosityBlock_.get())->setConsumer(iConsumer);
+    if (luminosityBlock_) {
+      luminosityBlock_->setConsumer(iConsumer);
+    }
   }
 
   void Event::setSharedResourcesAcquirer(SharedResourcesAcquirer* iResourceAcquirer) {
     provRecorder_.setSharedResourcesAcquirer(iResourceAcquirer);
-    const_cast<LuminosityBlock*>(luminosityBlock_.get())->setSharedResourcesAcquirer(iResourceAcquirer);
+    if (luminosityBlock_) {
+      luminosityBlock_->setSharedResourcesAcquirer(iResourceAcquirer);
+    }
+  }
+
+  void Event::fillLuminosityBlock() const {
+    luminosityBlock_.emplace(
+        eventPrincipal().luminosityBlockPrincipal(), provRecorder_.moduleDescription(), moduleCallingContext_, false);
+    luminosityBlock_->setConsumer(provRecorder_.getConsumer());
+    luminosityBlock_->setSharedResourcesAcquirer(provRecorder_.getSharedResourcesAcquirer());
   }
 
   void Event::setProducerCommon(ProducerBase const* iProd, std::vector<BranchID>* previousParentage) {

FWCore/Framework/src/LuminosityBlock.cc

@@ -13,10 +13,7 @@ namespace edm {
                                    ModuleDescription const& md,
                                    ModuleCallingContext const* moduleCallingContext,
                                    bool isAtEnd)
-      : provRecorder_(lbp, md, isAtEnd),
-        aux_(lbp.aux()),
-        run_(new Run(lbp.runPrincipal(), md, moduleCallingContext, false)),
-        moduleCallingContext_(moduleCallingContext) {}
+      : provRecorder_(lbp, md, isAtEnd), aux_(lbp.aux()), run_(), moduleCallingContext_(moduleCallingContext) {}
 
   LuminosityBlock::~LuminosityBlock() {}
 
@@ -29,13 +26,22 @@ namespace edm {
   void LuminosityBlock::setConsumer(EDConsumerBase const* iConsumer) {
     provRecorder_.setConsumer(iConsumer);
     if (run_) {
-      const_cast<Run*>(run_.get())->setConsumer(iConsumer);
+      run_->setConsumer(iConsumer);
     }
   }
 
   void LuminosityBlock::setSharedResourcesAcquirer(SharedResourcesAcquirer* iResourceAcquirer) {
     provRecorder_.setSharedResourcesAcquirer(iResourceAcquirer);
-    const_cast<Run*>(run_.get())->setSharedResourcesAcquirer(iResourceAcquirer);
+    if (run_) {
+      run_->setSharedResourcesAcquirer(iResourceAcquirer);
+    }
+  }
+
+  void LuminosityBlock::fillRun() const {
+    run_.emplace(
+        luminosityBlockPrincipal().runPrincipal(), provRecorder_.moduleDescription(), moduleCallingContext_, false);
+    run_->setSharedResourcesAcquirer(provRecorder_.getSharedResourcesAcquirer());
+    run_->setConsumer(provRecorder_.getConsumer());
   }
 
   void LuminosityBlock::setProducer(ProducerBase const* iProducer) {