RootDelayedReader.cc

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/*----------------------------------------------------------------------
----------------------------------------------------------------------*/
 
#include "RootDelayedReader.h"
#include "InputFile.h"
#include "DataFormats/Common/interface/EDProductGetter.h"
#include "DataFormats/Common/interface/RefCoreStreamer.h"
 
#include "FWCore/Framework/interface/SharedResourcesAcquirer.h"
#include "FWCore/Framework/src/SharedResourcesRegistry.h"
 
#include "IOPool/Common/interface/getWrapperBasePtr.h"
 
#include "FWCore/Utilities/interface/EDMException.h"
 
#include "TBranch.h"
#include "TClass.h"
 
#include <cassert>
 
namespace edm {
 
  RootDelayedReader::RootDelayedReader(RootTree const& tree, std::shared_ptr<InputFile> filePtr, InputType inputType)
      : tree_(tree),
        filePtr_(filePtr),
        nextReader_(),
        inputType_(inputType),
        wrapperBaseTClass_(TClass::GetClass("edm::WrapperBase")) {
    if (inputType == InputType::Primary) {
      auto resources = SharedResourcesRegistry::instance()->createAcquirerForSourceDelayedReader();
      resourceAcquirer_ = std::make_unique<SharedResourcesAcquirer>(std::move(resources.first));
      mutex_ = resources.second;
    }
  }
 
  RootDelayedReader::~RootDelayedReader() {}
 
  std::pair<SharedResourcesAcquirer*, std::recursive_mutex*> RootDelayedReader::sharedResources_() const {
    return std::make_pair(resourceAcquirer_.get(), mutex_.get());
  }
 
  std::shared_ptr<WrapperBase> RootDelayedReader::getProduct_(BranchID const& k, EDProductGetter const* ep) {
    if (lastException_) {
      std::rethrow_exception(lastException_);
    }
    auto branchInfo = getBranchInfo(k);
    if (not branchInfo) {
      if (nextReader_) {
        return nextReader_->getProduct(k, ep);
      } else {
        return std::shared_ptr<WrapperBase>();
      }
    }
    TBranch* br = branchInfo->productBranch_;
    if (br == nullptr) {
      if (nextReader_) {
        return nextReader_->getProduct(k, ep);
      } else {
        return std::shared_ptr<WrapperBase>();
      }
    }
 
    setRefCoreStreamer(ep);
    //make code exception safe
    std::shared_ptr<void> refCoreStreamerGuard(nullptr, [](void*) {
      setRefCoreStreamer(false);
      ;
    });
    TClass* cp = branchInfo->classCache_;
    if (nullptr == cp) {
      branchInfo->classCache_ = TClass::GetClass(branchInfo->branchDescription_.wrappedName().c_str());
      cp = branchInfo->classCache_;
      branchInfo->offsetToWrapperBase_ = cp->GetBaseClassOffset(wrapperBaseTClass_);
    }
    void* p = cp->New();
    std::unique_ptr<WrapperBase> edp = getWrapperBasePtr(p, branchInfo->offsetToWrapperBase_);
    br->SetAddress(&p);
    try {
      //Run, Lumi, and ProcessBlock only have 1 entry number, which is index 0
      tree_.getEntry(br, tree_.entryNumberForIndex(tree_.branchType() == InEvent ? ep->transitionIndex() : 0));
    } catch (edm::Exception& exception) {
      exception.addContext("Rethrowing an exception that happened on a different thread.");
      lastException_ = std::current_exception();
    } catch (...) {
      lastException_ = std::current_exception();
    }
    if (lastException_) {
      std::rethrow_exception(lastException_);
    }
    if (tree_.branchType() == InEvent) {
      // CMS-THREADING For the primary input source calls to this function need to be serialized
      InputFile::reportReadBranch(inputType_, std::string(br->GetName()));
    }
    return edp;
  }
}  // namespace edm