Principal.cc

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#include "FWCore/Framework/interface/Principal.h"

#include "DataFormats/Provenance/interface/ProcessHistoryRegistry.h"
#include "DataFormats/Provenance/interface/ProductHolderIndexHelper.h"
#include "DataFormats/Provenance/interface/ProductRegistry.h"
#include "FWCore/Framework/interface/DelayedReader.h"
#include "FWCore/Framework/interface/HistoryAppender.h"
#include "FWCore/Framework/interface/ProductDeletedException.h"
#include "FWCore/Utilities/interface/Algorithms.h"
#include "FWCore/Utilities/interface/EDMException.h"
#include "FWCore/Utilities/interface/DictionaryTools.h"
#include "FWCore/Utilities/interface/ProductHolderIndex.h"
#include "FWCore/Utilities/interface/TypeID.h"
#include "FWCore/Utilities/interface/WrappedClassName.h"

#include <algorithm>
#include <cstring>
#include <limits>
#include <sstream>
#include <stdexcept>
#include <typeinfo>

namespace edm {

  ProcessHistory const Principal::emptyProcessHistory_;

  static
  void
  maybeThrowMissingDictionaryException(TypeID const& productType, bool isElement, std::vector<std::string> const& missingDictionaries) {
    if(binary_search_all(missingDictionaries, productType.className())) {
      checkDictionaries(isElement ? productType.className() : wrappedClassName(productType.className()), false);
      throwMissingDictionariesException();
    }
  }

  static
  void
  throwProductNotFoundException(char const* where, errors::ErrorCodes error, BranchID const& bid) {
    throw Exception(error, "InvalidID")
      << "Principal::" << where << ": no product with given branch id: "<< bid << "\n";
  }

  static
  void
  throwCorruptionException(char const* where, std::string const& branchName) {
    throw Exception(errors::EventCorruption)
       << "Principal::" << where <<": Product on branch " << branchName << " occurs twice in the same event.\n";
  }

  static
  boost::shared_ptr<cms::Exception>
  makeNotFoundException(char const* where, KindOfType kindOfType,
                        TypeID const& productType, std::string const& label, std::string const& instance, std::string const& process) {
    boost::shared_ptr<cms::Exception> exception(new Exception(errors::ProductNotFound));
    if (kindOfType == PRODUCT_TYPE) {
      *exception << "Principal::" << where << ": Found zero products matching all criteria\nLooking for type: " << productType << "\n"
                 << "Looking for module label: " << label << "\n" << "Looking for productInstanceName: " << instance << "\n"
                 << (process.empty() ? "" : "Looking for process: ") << process << "\n";
    } else {
      *exception << "Principal::" << where << ": Found zero products matching all criteria\nLooking for a container with elements of type: " << productType << "\n"
                 << "Looking for module label: " << label << "\n" << "Looking for productInstanceName: " << instance << "\n"
                 << (process.empty() ? "" : "Looking for process: ") << process << "\n";
    }
    return exception;
  }

  static
  void
  throwProductDeletedException(const char* where, TypeID const& productType,std::string const& label, std::string const& instance, std::string const& process) {
    ProductDeletedException exception;
    exception << "Principal::" << where << ": The product matching all criteria\nLooking for type: " << productType << "\n"
      << "Looking for module label: " << label << "\n" << "Looking for productInstanceName: " << instance << "\n"
      << (process.empty() ? "" : "Looking for process: ") << process << "\n"
      << "Was already deleted. This means there is a configuration error.\n"
      << "The module which is asking for this data must be configured to state that it will read this data.";
    throw exception;
  }

  static
  void
  throwAmbiguousException(const char* where, TypeID const& productType,std::string const& label, std::string const& instance, std::string const& process) {
    cms::Exception exception("AmbiguousProduct");
    exception << "Principal::" << where << ": More than 1 product matches all criteria\nLooking for type: " << productType << "\n"
    << "Looking for module label: " << label << "\n" << "Looking for productInstanceName: " << instance << "\n"
    << (process.empty() ? "" : "Looking for process: ") << process << "\n"
    << "This can only occur with get function calls using a Handle<View> argument.\n"
    << "Try a get not using a View or change the instance name of one of the products";
    throw exception;
    
  }

  static
  void
  throwNotFoundException(char const* where, TypeID const& productType, InputTag const& tag) {
    boost::shared_ptr<cms::Exception> exception = makeNotFoundException(where, PRODUCT_TYPE, productType, tag.label(), tag.instance(), tag.process());
    throw *exception;
  }
  

  Principal::Principal(boost::shared_ptr<ProductRegistry const> reg,
                       boost::shared_ptr<ProductHolderIndexHelper const> productLookup,
                       ProcessConfiguration const& pc,
                       BranchType bt,
                       HistoryAppender* historyAppender) :
    EDProductGetter(),
    processHistoryPtr_(nullptr),
    processHistoryID_(),
    processConfiguration_(&pc),
    productHolders_(reg->getNextIndexValue(bt), SharedProductPtr()),
    preg_(reg),
    productLookup_(productLookup),
    lookupProcessOrder_(productLookup->lookupProcessNames().size(), 0),
    reader_(),
    productPtrs_(),
    branchType_(bt),
    historyAppender_(historyAppender) {

    //Now that these have been set, we can create the list of Branches we need.
    std::string const source("source");
    ProductRegistry::ProductList const& prodsList = reg->productList();
    // The constructor of an alias product holder takes as an argument the product holder for which it is an alias.
    // So, the non-alias product holders must be created first.
    // Therefore, on this first pass, skip current EDAliases.
    bool hasAliases = false;
    for(auto const& prod : prodsList) {
      BranchDescription const& bd = prod.second;
      if(bd.branchType() == branchType_) {
        if(bd.isAlias()) {
          hasAliases = true;
        } else {
          boost::shared_ptr<ConstBranchDescription> cbd(new ConstBranchDescription(bd));
          if(bd.produced()) {
            if(bd.moduleLabel() == source) {
              addSourceProduct(cbd);
            } else if(bd.onDemand()) {
              assert(branchType_ == InEvent);
              addUnscheduledProduct(cbd);
            } else {
              addScheduledProduct(cbd);
            }
          } else {
            addInputProduct(cbd);
          }
        }
      }
    }
    // Now process any EDAliases
    if(hasAliases) {
      for(auto const& prod : prodsList) {
        BranchDescription const& bd = prod.second;
        if(bd.isAlias() && bd.branchType() == branchType_) {
          boost::shared_ptr<ConstBranchDescription> cbd(new ConstBranchDescription(bd));
          addAliasedProduct(cbd);
        }
      }
    }

    // Now create the ProductHolders that search in reverse process
    // order and are used for queries where the process name is the
    // empty string
    std::vector<std::string> const& lookupProcessNames = productLookup_->lookupProcessNames();
    std::vector<ProductHolderIndex> matchingHolders(lookupProcessNames.size(), ProductHolderIndexInvalid);
    std::vector<bool> ambiguous(lookupProcessNames.size(), false);
    unsigned int beginElements = productLookup_->beginElements();
    std::vector<TypeID> const& sortedTypeIDs = productLookup_->sortedTypeIDs();
    std::vector<ProductHolderIndexHelper::Range> const& ranges = productLookup_->ranges();
    std::vector<ProductHolderIndexHelper::IndexAndNames> const& indexAndNames = productLookup_->indexAndNames();
    std::vector<char> const& processNamesCharArray = productLookup_->processNames();

    if (!sortedTypeIDs.empty()) {
      ProductHolderIndex productHolderIndex = ProductHolderIndexInvalid;
      for(unsigned int k = 0, kEnd = sortedTypeIDs.size(); k < kEnd; ++k) {
        ProductHolderIndexHelper::Range const& range = ranges.at(k);
        for (unsigned int i = range.begin(); i < range.end(); ++i) {
          ProductHolderIndexHelper::IndexAndNames const& product = indexAndNames.at(i);
          if (product.startInProcessNames() == 0) {
            if (productHolderIndex != ProductHolderIndexInvalid) {
              boost::shared_ptr<ProductHolderBase> newHolder(new NoProcessProductHolder(matchingHolders, ambiguous, this));
              productHolders_.at(productHolderIndex) = newHolder;
              matchingHolders.assign(lookupProcessNames.size(), ProductHolderIndexInvalid);
              ambiguous.assign(lookupProcessNames.size(), false);
            }
            productHolderIndex = product.index();
          } else {
            std::string process(&processNamesCharArray.at(product.startInProcessNames()));
            auto iter = std::find(lookupProcessNames.begin(), lookupProcessNames.end(), process);
            assert(iter != lookupProcessNames.end());
            ProductHolderIndex iMatchingIndex = product.index();
            assert(iMatchingIndex != ProductHolderIndexInvalid);
            if (iMatchingIndex == ProductHolderIndexAmbiguous) {
              assert(k >= beginElements);
              ambiguous.at(iter - lookupProcessNames.begin()) = true;
            } else {
              matchingHolders.at(iter - lookupProcessNames.begin()) = iMatchingIndex;
            }
          }
        }
      }
      boost::shared_ptr<ProductHolderBase> newHolder(new NoProcessProductHolder(matchingHolders, ambiguous, this));
      productHolders_.at(productHolderIndex) = newHolder;
    }
  }

  Principal::~Principal() {
  }

  // Number of products in the Principal.
  // For products in an input file and not yet read in due to delayed read,
  // this routine assumes a real product is there.
  size_t
  Principal::size() const {
    size_t size = 0U;
    for(auto const& prod : *this) {
      if(prod->singleProduct() && // Not a NoProcessProductHolder
         !prod->productUnavailable() &&
         !prod->onDemand() &&
         !prod->branchDescription().dropped()) {
        ++size;
      }
    }
    return size;
  }

  // adjust provenance for input products after new input file has been merged
  bool
  Principal::adjustToNewProductRegistry(ProductRegistry const& reg) {
    ProductRegistry::ProductList const& prodsList = reg.productList();
    for(auto const& prod : prodsList) {
      BranchDescription const& bd = prod.second;
      if(!bd.produced() && (bd.branchType() == branchType_)) {
        boost::shared_ptr<ConstBranchDescription> cbd(new ConstBranchDescription(bd));
        ProductHolderBase* phb = getExistingProduct(cbd->branchID());
        if(phb == nullptr || phb->branchDescription().branchName() != cbd->branchName()) {
            return false;
        }
        phb->resetBranchDescription(cbd);
      }
    }
    return true;
  }

  void
  Principal::addScheduledProduct(boost::shared_ptr<ConstBranchDescription> bd) {
    std::auto_ptr<ProductHolderBase> phb(new ScheduledProductHolder(bd));
    addProductOrThrow(phb);
  }

  void
  Principal::addSourceProduct(boost::shared_ptr<ConstBranchDescription> bd) {
    std::auto_ptr<ProductHolderBase> phb(new SourceProductHolder(bd));
    addProductOrThrow(phb);
  }

  void
  Principal::addInputProduct(boost::shared_ptr<ConstBranchDescription> bd) {
    std::auto_ptr<ProductHolderBase> phb(new InputProductHolder(bd, this));
    addProductOrThrow(phb);
  }

  void
  Principal::addUnscheduledProduct(boost::shared_ptr<ConstBranchDescription> bd) {
    std::auto_ptr<ProductHolderBase> phb(new UnscheduledProductHolder(bd, this));
    addProductOrThrow(phb);
  }

  void
  Principal::addAliasedProduct(boost::shared_ptr<ConstBranchDescription> bd) {
    ProductHolderIndex index = preg_->indexFrom(bd->originalBranchID());
    assert(index != ProductHolderIndexInvalid);

    std::auto_ptr<ProductHolderBase> phb(new AliasProductHolder(bd, dynamic_cast<ProducedProductHolder&>(*productHolders_[index])));
    addProductOrThrow(phb);
  }

  // "Zero" the principal so it can be reused for another Event.
  void
  Principal::clearPrincipal() {
    processHistoryPtr_ = 0;
    processHistoryID_ = ProcessHistoryID();
    reader_ = 0;
    for(auto const& prod : *this) {
      prod->resetProductData();
    }
    productPtrs_.clear();
  }

  void
  Principal::deleteProduct(BranchID const& id) {
    ProductHolderBase* phb = getExistingProduct(id);
    assert(nullptr != phb);
    auto itFound = productPtrs_.find(phb->product().get());
    if(itFound != productPtrs_.end()) {
      productPtrs_.erase(itFound);
    } 
    phb->deleteProduct();
  }
  
  // Set the principal for the Event, Lumi, or Run.
  void
  Principal::fillPrincipal(ProcessHistoryID const& hist, DelayedReader* reader) {
    if(reader) {
      reader_ = reader;
    }

    ProcessHistory const* inputProcessHistory = 0;
    if (historyAppender_ && productRegistry().anyProductProduced()) {
      CachedHistory const& cachedHistory = 
        historyAppender_->appendToProcessHistory(hist,
                                                *processConfiguration_);
      processHistoryPtr_ = cachedHistory.processHistory();
      processHistoryID_ = cachedHistory.processHistoryID();
      inputProcessHistory = cachedHistory.inputProcessHistory();
    }
    else {
      if (hist.isValid()) {
        ProcessHistoryRegistry* registry = ProcessHistoryRegistry::instance();
        inputProcessHistory = registry->getMapped(hist);
        if (inputProcessHistory == 0) {
          throw Exception(errors::LogicError)
            << "Principal::fillPrincipal\n"
            << "Input ProcessHistory not found in registry\n"
            << "Contact a Framework developer\n";
        }
      } else {
        inputProcessHistory = &emptyProcessHistory_;
      }
      processHistoryID_ = hist;
      processHistoryPtr_ = inputProcessHistory;        
    }

    if (orderProcessHistoryID_ != processHistoryID_) {
      std::vector<std::string> const& lookupProcessNames = productLookup_->lookupProcessNames();
      lookupProcessOrder_.assign(lookupProcessNames.size(), 0);
      unsigned int k = 0;
      for (auto iter = processHistoryPtr_->rbegin(),
                iEnd = processHistoryPtr_->rend();
           iter != iEnd; ++iter) {
        auto nameIter = std::find(lookupProcessNames.begin(), lookupProcessNames.end(), iter->processName());
        if (nameIter == lookupProcessNames.end()) {
          continue;
        }
        lookupProcessOrder_.at(k) = nameIter - lookupProcessNames.begin();
        ++k;
      }
      orderProcessHistoryID_ = processHistoryID_;
    }
  }

  ProductHolderBase*
  Principal::getExistingProduct(BranchID const& branchID) {
    ProductHolderIndex index = preg_->indexFrom(branchID);
    assert(index != ProductHolderIndexInvalid);
    SharedProductPtr ptr = productHolders_.at(index);
    return ptr.get();
  }

  ProductHolderBase*
  Principal::getExistingProduct(ProductHolderBase const& productHolder) {
    ProductHolderBase* phb = getExistingProduct(productHolder.branchDescription().branchID());
    assert(nullptr == phb || BranchKey(productHolder.branchDescription()) == BranchKey(phb->branchDescription()));
    return phb;
  }

  void
  Principal::addProduct_(std::auto_ptr<ProductHolderBase> productHolder) {
    ConstBranchDescription const& bd = productHolder->branchDescription();
    assert (!bd.className().empty());
    assert (!bd.friendlyClassName().empty());
    assert (!bd.moduleLabel().empty());
    assert (!bd.processName().empty());
    SharedProductPtr phb(productHolder);

    ProductHolderIndex index = preg_->indexFrom(bd.branchID());
    assert(index != ProductHolderIndexInvalid);
    productHolders_[index] = phb;
  }

  void
  Principal::addProductOrThrow(std::auto_ptr<ProductHolderBase> productHolder) {
    ProductHolderBase const* phb = getExistingProduct(*productHolder);
    if(phb != nullptr) {
      ConstBranchDescription const& bd = productHolder->branchDescription();
      throw Exception(errors::InsertFailure, "AlreadyPresent")
          << "addProductOrThrow: Problem found while adding product, "
          << "product already exists for ("
          << bd.friendlyClassName() << ","
          << bd.moduleLabel() << ","
          << bd.productInstanceName() << ","
          << bd.processName()
          << ")\n";
    }
    addProduct_(productHolder);
  }

  Principal::ConstProductPtr
  Principal::getProductHolder(BranchID const& bid, bool resolveProd, bool fillOnDemand) const {
    ProductHolderIndex index = preg_->indexFrom(bid);
    if(index == ProductHolderIndexInvalid){
       return ConstProductPtr();
    }
    return getProductByIndex(index, resolveProd, fillOnDemand);
  }

  Principal::ConstProductPtr
  Principal::getProductByIndex(ProductHolderIndex const& index, bool resolveProd, bool fillOnDemand) const {

    ConstProductPtr const phb = productHolders_[index].get();
    if(nullptr == phb) {
      return phb;
    }
    if(resolveProd && !phb->productUnavailable()) {
      this->resolveProduct(*phb, fillOnDemand);
    }
    return phb;
  }

  BasicHandle
  Principal::getByLabel(KindOfType kindOfType,
                        TypeID const& typeID,
                        InputTag const& inputTag) const {

    ProductData const* result = findProductByLabel(kindOfType, typeID, inputTag);
    if(result == 0) {
      boost::shared_ptr<cms::Exception> whyFailed =
        makeNotFoundException("getByLabel", kindOfType, typeID, inputTag.label(), inputTag.instance(), inputTag.process());
      return BasicHandle(whyFailed);
    }
    return BasicHandle(*result);
  }

  BasicHandle
  Principal::getByLabel(KindOfType kindOfType,
                        TypeID const& typeID,
                        std::string const& label,
                        std::string const& instance,
                        std::string const& process) const {

    ProductData const* result = findProductByLabel(kindOfType, typeID, label, instance, process);
    if(result == 0) {
      boost::shared_ptr<cms::Exception> whyFailed =
        makeNotFoundException("getByLabel", kindOfType, typeID, label, instance, process);
      return BasicHandle(whyFailed);
    }
    return BasicHandle(*result);
  }

  BasicHandle
  Principal::getByToken(KindOfType kindOfType,
                        TypeID const& typeID,
                        ProductHolderIndex index,
                        bool skipCurrentProcess,
                        bool& ambiguous) const {
    assert(index !=ProductHolderIndexInvalid);
    boost::shared_ptr<ProductHolderBase> const& productHolder = productHolders_[index];
    assert(0!=productHolder.get());
    ProductHolderBase::ResolveStatus resolveStatus;
    ProductData const* productData = productHolder->resolveProduct(resolveStatus, skipCurrentProcess);
    if(resolveStatus == ProductHolderBase::Ambiguous) {
      ambiguous = true;
      return BasicHandle();
    }
    if(productData == 0) {
      return BasicHandle();
    }
    return BasicHandle(*productData);    
  }

  void
  Principal::getManyByType(TypeID const& typeID,
                           BasicHandleVec& results) const {

    assert(results.empty());

    // This finds the indexes to all the ProductHolder's matching the type
    ProductHolderIndexHelper::Matches matches =
      productLookup().relatedIndexes(PRODUCT_TYPE, typeID);

    if (matches.numberOfMatches() == 0) {
      maybeThrowMissingDictionaryException(typeID, false, preg_->missingDictionaries());
      return;
    }

    results.reserve(matches.numberOfMatches());

    // Loop over the ProductHolders. Add the products that are actually
    // present into the results. This will also trigger delayed reading,
    // on demand production, and check for deleted products as appropriate.

    // Over the years the code that uses getManyByType has grown to depend
    // on the ordering of the results. The order originally was just an
    // accident of how previous versions of the code were written, but
    // here we have to go through some extra effort to preserve that ordering.

    // We build a list of holders that match a particular label and instance.
    // When that list is complete we call findProducts, which loops over
    // that list in reverse order of the ProcessHistory (starts with the
    // most recent).  Then we clear the list and repeat this until all the
    // matching label and instance subsets have been dealt with.

    // Note that the function isFullyResolved returns true for the ProductHolders
    // that are associated with an empty process name. Those are the ones that
    // know how to search for the most recent process name matching
    // a label and instance. We do not need these for getManyByType and
    // skip them. In addition to skipping them, we make use of the fact
    // that they mark the beginning of each subset of holders with the same
    // label and instance. They tell us when to call findProducts. 

    std::vector<ProductHolderBase const*> holders;

    for(unsigned int i = 0; i < matches.numberOfMatches(); ++i) {

      ProductHolderIndex index = matches.index(i);

      if(!matches.isFullyResolved(i)) {
        if(!holders.empty()) {
          // Process the ones with a particular module label and instance
          findProducts(holders, typeID, results);
          holders.clear();
        }
      } else {
        ProductHolderBase const* productHolder = productHolders_.at(index).get();
        assert(productHolder);
        holders.push_back(productHolder);
      }
    }
    // Do not miss the last subset of products
    if(!holders.empty()) {
      findProducts(holders, typeID, results);
    }
    return;
  }

  void
  Principal::findProducts(std::vector<ProductHolderBase const*> const& holders,
                          TypeID const& typeID,
                          BasicHandleVec& results) const {

    for (auto iter = processHistoryPtr_->rbegin(),
              iEnd = processHistoryPtr_->rend();
         iter != iEnd; ++iter) {
      std::string const& process = iter->processName();
      for (auto productHolder : holders) {
        ConstBranchDescription const& bd = productHolder->branchDescription();
        if (process == bd.processName()) {

          // Ignore aliases to avoid matching the same product multiple times.
          if(bd.isAlias()) {
            continue;
          }

          //NOTE sometimes 'productHolder->productUnavailable()' is true if was already deleted
          if(productHolder->productWasDeleted()) {
            throwProductDeletedException("findProducts",
                                         typeID,
                                         bd.moduleLabel(),
                                         bd.productInstanceName(),
                                         bd.processName());
          }

          // Skip product if not available.
          if(!productHolder->productUnavailable()) {

            this->resolveProduct(*productHolder, true);
            // If the product is a dummy filler, product holder will now be marked unavailable.
            // Unscheduled execution can fail to produce the EDProduct so check
            if(productHolder->product() && !productHolder->productUnavailable() && !productHolder->onDemand()) {
              // Found a good match, save it
              BasicHandle bh(productHolder->productData());
              results.push_back(bh);
            }
          }
        }
      }
    }
  }

  ProductData const*
  Principal::findProductByLabel(KindOfType kindOfType,
                                TypeID const& typeID,
                                InputTag const& inputTag) const {

    bool skipCurrentProcess = inputTag.willSkipCurrentProcess();

    ProductHolderIndex index = inputTag.indexFor(typeID, branchType(), &productRegistry());

    if (index == ProductHolderIndexInvalid) {

      char const* processName = inputTag.process().c_str();
      if (skipCurrentProcess) {
        processName = "\0";
      }

      index = productLookup().index(kindOfType,
                                    typeID,
                                    inputTag.label().c_str(),
                                    inputTag.instance().c_str(),
                                    processName);

      if(index == ProductHolderIndexAmbiguous) {
        throwAmbiguousException("findProductByLabel", typeID, inputTag.label(), inputTag.instance(), inputTag.process());
      } else if (index == ProductHolderIndexInvalid) {
        ProductHolderIndexHelper::Matches matches =
          productLookup().relatedIndexes(kindOfType, typeID);

        if (matches.numberOfMatches() == 0) {
          maybeThrowMissingDictionaryException(typeID, kindOfType == ELEMENT_TYPE, preg_->missingDictionaries());
        }
        return 0;
      }
      inputTag.tryToCacheIndex(index, typeID, branchType(), &productRegistry());
    }

    boost::shared_ptr<ProductHolderBase> const& productHolder = productHolders_[index];

    ProductHolderBase::ResolveStatus resolveStatus;
    ProductData const* productData = productHolder->resolveProduct(resolveStatus, skipCurrentProcess);
    if(resolveStatus == ProductHolderBase::Ambiguous) {
      throwAmbiguousException("findProductByLabel", typeID, inputTag.label(), inputTag.instance(), inputTag.process());
    }
    return productData;
  }

  ProductData const*
  Principal::findProductByLabel(KindOfType kindOfType,
                                TypeID const& typeID,
                                std::string const& label,
                                std::string const& instance,
                                std::string const& process) const {

    ProductHolderIndex index = productLookup().index(kindOfType,
                                                     typeID,
                                                     label.c_str(),
                                                     instance.c_str(),
                                                     process.c_str());
   
    if(index == ProductHolderIndexAmbiguous) {
      throwAmbiguousException("findProductByLabel", typeID, label, instance, process);
    } else if (index == ProductHolderIndexInvalid) {
      ProductHolderIndexHelper::Matches matches =
        productLookup().relatedIndexes(kindOfType, typeID);

      if (matches.numberOfMatches() == 0) {
        maybeThrowMissingDictionaryException(typeID, kindOfType == ELEMENT_TYPE, preg_->missingDictionaries());
      }
      return 0;
    }
    boost::shared_ptr<ProductHolderBase> const& productHolder = productHolders_[index];

    ProductHolderBase::ResolveStatus resolveStatus;
    ProductData const* productData = productHolder->resolveProduct(resolveStatus, false);
    if(resolveStatus == ProductHolderBase::Ambiguous) {
      throwAmbiguousException("findProductByLabel", typeID, label, instance, process);
    }
    return productData;
  }

  ProductData const*
  Principal::findProductByTag(TypeID const& typeID, InputTag const& tag) const {
    ProductData const* productData =
      findProductByLabel(PRODUCT_TYPE,
                         typeID,
                         tag);
    if(productData == nullptr) {
      throwNotFoundException("findProductByTag", typeID, tag);
    }
    return productData;
  }

  OutputHandle
  Principal::getForOutput(BranchID const& bid, bool getProd) const {
    ConstProductPtr const phb = getProductHolder(bid, getProd, true);
    if(phb == nullptr) {
      throwProductNotFoundException("getForOutput", errors::LogicError, bid);
    }
    if (phb->productWasDeleted()) {
      throwProductDeletedException("getForOutput",phb->productType(),
                                   phb->moduleLabel(),
                                   phb->productInstanceName(),
                                   phb->processName());
    }
    if(!phb->provenance() || (!phb->product() && !phb->productProvenancePtr())) {
      return OutputHandle();
    }
    return OutputHandle(WrapperHolder(phb->product().get(), phb->productData().getInterface()), &phb->branchDescription(), phb->productProvenancePtr());
  }

  Provenance
  Principal::getProvenance(BranchID const& bid) const {
    ConstProductPtr const phb = getProductHolder(bid, false, true);
    if(phb == nullptr) {
      throwProductNotFoundException("getProvenance", errors::ProductNotFound, bid);
    }

    if(phb->onDemand()) {
      unscheduledFill(phb->branchDescription().moduleLabel());
    }
    // We already tried to produce the unscheduled products above
    // If they still are not there, then throw
    if(phb->onDemand()) {
      throwProductNotFoundException("getProvenance(onDemand)", errors::ProductNotFound, bid);
    }

    return *phb->provenance();
  }

  // This one is mostly for test printout purposes
  // No attempt to trigger on demand execution
  // Skips provenance when the EDProduct is not there
  void
  Principal::getAllProvenance(std::vector<Provenance const*>& provenances) const {
    provenances.clear();
    for(auto const& productHolder : *this) {
      if(productHolder->singleProduct() && productHolder->provenanceAvailable() && !productHolder->branchDescription().isAlias()) {
        // We do not attempt to get the event/lumi/run status from the provenance,
        // because the per event provenance may have been dropped.
        if(productHolder->provenance()->product().present()) {
           provenances.push_back(productHolder->provenance());
        }
      }
    }
  }

  void
  Principal::recombine(Principal& other, std::vector<BranchID> const& bids) {
    for(auto const& prod : bids) {
      ProductHolderIndex index= preg_->indexFrom(prod);
      assert(index!=ProductHolderIndexInvalid);
      ProductHolderIndex indexO = other.preg_->indexFrom(prod);
      assert(indexO!=ProductHolderIndexInvalid);
      productHolders_[index].swap(other.productHolders_[indexO]);
      productHolders_[index]->setPrincipal(this);
    }
    reader_->mergeReaders(other.reader());
  }

  WrapperHolder
  Principal::getIt(ProductID const&) const {
    assert(nullptr);
    return WrapperHolder();
  }

  void
  Principal::checkUniquenessAndType(WrapperOwningHolder const& prod, ProductHolderBase const* phb) const {
    if(!prod.isValid()) return;
    // These are defensive checks against things that should never happen, but have.
    // Checks that the same physical product has not already been put into the event.
    bool alreadyPresent = !productPtrs_.insert(prod.wrapper()).second;
    if(alreadyPresent) {
      phb->checkType(prod);
      const_cast<WrapperOwningHolder&>(prod).reset();
      throwCorruptionException("checkUniquenessAndType", phb->branchDescription().branchName());
    }
    // Checks that the real type of the product matches the branch.
    phb->checkType(prod);
  }

  void
  Principal::putOrMerge(WrapperOwningHolder const& prod, ProductHolderBase const* phb) const {
    bool willBePut = phb->putOrMergeProduct();
    if(willBePut) {
      checkUniquenessAndType(prod, phb);
      phb->putProduct(prod);
    } else {
      phb->checkType(prod);
      phb->mergeProduct(prod);
    }
  }

  void
  Principal::putOrMerge(WrapperOwningHolder const& prod, ProductProvenance& prov, ProductHolderBase* phb) {
    bool willBePut = phb->putOrMergeProduct();
    if(willBePut) {
      checkUniquenessAndType(prod, phb);
      phb->putProduct(prod, prov);
    } else {
      phb->checkType(prod);
      phb->mergeProduct(prod, prov);
    }
  }

  void
  Principal::adjustIndexesAfterProductRegistryAddition() {
    if(preg_->getNextIndexValue(branchType_) != productHolders_.size()) {
      productHolders_.resize(preg_->getNextIndexValue(branchType_));
      for(auto const& prod : preg_->productList()) {
        BranchDescription const& bd = prod.second;
        if(bd.branchType() == branchType_) {
          ProductHolderIndex index = preg_->indexFrom(bd.branchID());
          assert(index != ProductHolderIndexInvalid);
          if(!productHolders_[index]) {
            // no product holder.  Must add one. The new entry must be an input product holder.
            assert(!bd.produced());
            boost::shared_ptr<ConstBranchDescription> cbd(new ConstBranchDescription(bd));
            addInputProduct(cbd);
          }
        }
      }
    }
    assert(preg_->getNextIndexValue(branchType_) == productHolders_.size());
  }
}