Use std::unique_ptr<podio::CollectionBase> to save collections in the…

… store

Also fix a leak in the Writer that without this change would have
been difficult to fix.

k4FWCore/components/CollectionMerger.cpp

@@ -38,12 +38,11 @@
 #include "k4FWCore/Transformer.h"
 
 #include <map>
-#include <memory>
 #include <string>
 #include <string_view>
 
-struct CollectionMerger final : k4FWCore::Transformer<std::shared_ptr<podio::CollectionBase>(
-                                    const std::vector<const std::shared_ptr<podio::CollectionBase>*>&)> {
+struct CollectionMerger final
+    : k4FWCore::Transformer<podio::CollectionBase*(const std::vector<const podio::CollectionBase*>&)> {
   CollectionMerger(const std::string& name, ISvcLocator* svcLoc)
       : Transformer(name, svcLoc, {KeyValues("InputCollections", {"MCParticles"})},
                     {KeyValues("OutputCollection", {"NewMCParticles"})}) {
@@ -91,43 +90,38 @@ struct CollectionMerger final : k4FWCore::Transformer<std::shared_ptr<podio::Col
         &CollectionMerger::mergeCollections<edm4hep::GeneratorPdfInfoCollection>;
   }
 
-  std::shared_ptr<podio::CollectionBase> operator()(
-      const std::vector<const std::shared_ptr<podio::CollectionBase>*>& input) const override {
-    std::shared_ptr<podio::CollectionBase> ret;
+  podio::CollectionBase* operator()(const std::vector<const podio::CollectionBase*>& input) const override {
+    podio::CollectionBase* ret = nullptr;
     debug() << "Merging " << input.size() << " collections" << endmsg;
     std::string_view type = "";
     for (const auto& coll : input) {
-      debug() << "Merging collection of type " << (*coll)->getTypeName() << " with " << (*coll)->size() << " elements"
+      debug() << "Merging collection of type " << coll->getTypeName() << " with " << coll->size() << " elements"
               << endmsg;
       if (type.empty()) {
-        type = (*coll)->getTypeName();
-      } else if (type != (*coll)->getTypeName()) {
+        type = coll->getTypeName();
+      } else if (type != coll->getTypeName()) {
         throw std::runtime_error("Different collection types are not supported");
-        return ret;
       }
-      (this->*m_map.at((*coll)->getTypeName()))(*coll, ret);
+      (this->*m_map.at(coll->getTypeName()))(coll, ret);
     }
     return ret;
   }
 
 private:
-  using MergeType = void (CollectionMerger::*)(const std::shared_ptr<podio::CollectionBase>&,
-                                               std::shared_ptr<podio::CollectionBase>&) const;
+  using MergeType = void (CollectionMerger::*)(const podio::CollectionBase*, podio::CollectionBase*&) const;
   std::map<std::string_view, MergeType> m_map;
   Gaudi::Property<bool>                 m_copy{this, "Copy", false,
                                "Copy the elements of the collections instead of creating a subset collection"};
 
-  template <typename T>
-  void mergeCollections(const std::shared_ptr<podio::CollectionBase>& source,
-                        std::shared_ptr<podio::CollectionBase>&       ret) const {
+  template <typename T> void mergeCollections(const podio::CollectionBase* source, podio::CollectionBase*& ret) const {
     if (!ret) {
-      ret = std::make_shared<T>();
+      ret = new T();
       if (!m_copy) {
         ret->setSubsetCollection();
       }
     }
-    const auto ptr        = std::static_pointer_cast<T>(ret);
-    const auto sourceColl = std::static_pointer_cast<T>(source);
+    const auto ptr        = static_cast<T*>(ret);
+    const auto sourceColl = static_cast<const T*>(source);
     if (m_copy) {
       for (const auto& elem : *sourceColl) {
         ptr->push_back(elem.clone());

k4FWCore/components/IIOSvc.h

@@ -39,7 +39,7 @@ class IIOSvc : virtual public IInterface {
    * @brief Read the next event from the input file
    * @return A tuple containing the collections read, the collection names and the frame that owns the collections
    */
-  virtual std::tuple<std::vector<std::shared_ptr<podio::CollectionBase>>, std::vector<std::string>, podio::Frame>
+  virtual std::tuple<std::vector<podio::CollectionBase*>, std::vector<std::string>, podio::Frame>
                                                     next()                     = 0;
   virtual std::shared_ptr<std::vector<std::string>> getCollectionNames() const = 0;
 

k4FWCore/components/IOSvc.cpp

@@ -109,15 +109,14 @@ StatusCode IOSvc::initialize() {
 
 StatusCode IOSvc::finalize() { return Service::finalize(); }
 
-std::tuple<std::vector<std::shared_ptr<podio::CollectionBase>>, std::vector<std::string>, podio::Frame> IOSvc::next() {
+std::tuple<std::vector<podio::CollectionBase*>, std::vector<std::string>, podio::Frame> IOSvc::next() {
   podio::Frame frame;
   {
     std::scoped_lock<std::mutex> lock(m_changeBufferLock);
     if (m_nextEntry < m_entries) {
       frame = podio::Frame(m_reader->readEvent(m_nextEntry));
     } else {
-      return std::make_tuple(std::vector<std::shared_ptr<podio::CollectionBase>>(), std::vector<std::string>(),
-                             std::move(frame));
+      return std::make_tuple(std::vector<podio::CollectionBase*>(), std::vector<std::string>(), std::move(frame));
     }
     m_nextEntry++;
     if (m_collectionNames.empty()) {
@@ -134,11 +133,11 @@ std::tuple<std::vector<std::shared_ptr<podio::CollectionBase>>, std::vector<std:
     }
   }
 
-  std::vector<std::shared_ptr<podio::CollectionBase>> collections;
+  std::vector<podio::CollectionBase*> collections;
 
   for (const auto& name : m_collectionNames) {
     auto ptr = const_cast<podio::CollectionBase*>(frame.get(name));
-    collections.push_back(std::shared_ptr<podio::CollectionBase>(ptr));
+    collections.push_back(ptr);
   }
 
   return std::make_tuple(collections, m_collectionNames, std::move(frame));

k4FWCore/components/IOSvc.h

@@ -43,7 +43,7 @@ class IOSvc : public extends<Service, IIOSvc, IIncidentListener> {
   StatusCode initialize() override;
   StatusCode finalize() override;
 
-  std::tuple<std::vector<std::shared_ptr<podio::CollectionBase>>, std::vector<std::string>, podio::Frame> next()
+  std::tuple<std::vector<podio::CollectionBase*>, std::vector<std::string>, podio::Frame> next()
       override;
 
   std::shared_ptr<std::vector<std::string>> getCollectionNames() const override {

k4FWCore/components/Reader.cpp

@@ -16,12 +16,12 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-#include <GaudiKernel/SmartIF.h>
 #include "Gaudi/Functional/details.h"
 #include "Gaudi/Functional/utilities.h"
 #include "GaudiKernel/AnyDataWrapper.h"
 #include "GaudiKernel/FunctionalFilterDecision.h"
 #include "GaudiKernel/IDataProviderSvc.h"
+#include "GaudiKernel/SmartIF.h"
 #include "GaudiKernel/StatusCode.h"
 
 #include "podio/CollectionBase.h"
@@ -32,18 +32,16 @@
 
 #include <memory>
 
-template <typename Container> using vector_of_ = std::vector<Container>;
-
 class CollectionPusher : public Gaudi::Functional::details::BaseClass_t<Gaudi::Functional::Traits::useDefaults> {
   using Traits_    = Gaudi::Functional::Traits::useDefaults;
-  using Out        = std::shared_ptr<podio::CollectionBase>;
+  using Out        = std::unique_ptr<podio::CollectionBase>;
   using base_class = Gaudi::Functional::details::BaseClass_t<Traits_>;
   static_assert(std::is_base_of_v<Algorithm, base_class>, "BaseClass must inherit from Algorithm");
 
   template <typename T>
   using OutputHandle_t = Gaudi::Functional::details::OutputHandle_t<Traits_, std::remove_pointer_t<T>>;
-  std::vector<OutputHandle_t<std::shared_ptr<podio::CollectionBase>>> m_outputs;
-  Gaudi::Property<std::vector<std::string>>                           m_inputCollections{
+  std::vector<OutputHandle_t<Out>>          m_outputs;
+  Gaudi::Property<std::vector<std::string>> m_inputCollections{
       this, "InputCollections", {"First collection"}, "List of input collections"};
   // Gaudi::Property<std::string>                                        m_input{this, "Input", "Event", "Input file"};
 
@@ -73,7 +71,7 @@ class CollectionPusher : public Gaudi::Functional::details::BaseClass_t<Gaudi::F
     try {
       auto out = (*this)();
 
-      auto outColls        = std::get<std::vector<std::shared_ptr<podio::CollectionBase>>>(out);
+      auto outColls        = std::get<std::vector<podio::CollectionBase*>>(out);
       auto outputLocations = std::get<std::vector<std::string>>(out);
 
       // if (out.size() != m_outputs.size()) {
@@ -82,7 +80,7 @@ class CollectionPusher : public Gaudi::Functional::details::BaseClass_t<Gaudi::F
       //                        this->name(), StatusCode::FAILURE);
       // }
       for (size_t i = 0; i != outColls.size(); ++i) {
-        m_outputs[i].put(std::move(outColls[i]));
+        m_outputs[i].put(std::unique_ptr<podio::CollectionBase>(outColls[i]));
       }
       return Gaudi::Functional::FilterDecision::PASSED;
     } catch (GaudiException& e) {
@@ -91,7 +89,7 @@ class CollectionPusher : public Gaudi::Functional::details::BaseClass_t<Gaudi::F
     }
   }
 
-  virtual std::tuple<vector_of_<Out>, std::vector<std::string>> operator()() const = 0;
+  virtual std::tuple<std::vector<podio::CollectionBase*>, std::vector<std::string>> operator()() const = 0;
 
 private:
   ServiceHandle<IDataProviderSvc> m_dataSvc{this, "EventDataSvc", "EventDataSvc"};
@@ -108,7 +106,7 @@ class Reader final : public CollectionPusher {
   // Gaudi doesn't run the destructor of the Services so we have to
   // manually ask for the reader to be deleted so it will call finish()
   // See https://gitlab.cern.ch/gaudi/Gaudi/-/issues/169
-  ~Reader() { iosvc->deleteReader(); }
+  ~Reader() override { iosvc->deleteReader(); }
 
   ServiceHandle<IIOSvc> iosvc{this, "IOSvc", "IOSvc"};
 
@@ -131,8 +129,7 @@ class Reader final : public CollectionPusher {
   // The IOSvc takes care of reading and passing the data
   // By convention the Frame is pushed to the store
   // so that it's deleted at the right time
-  std::tuple<std::vector<std::shared_ptr<podio::CollectionBase>>, std::vector<std::string>> operator()()
-      const override {
+  std::tuple<std::vector<podio::CollectionBase*>, std::vector<std::string>> operator()() const override {
     auto val = iosvc->next();
 
     auto eds   = eventSvc().as<IDataProviderSvc>();

k4FWCore/components/Writer.cpp

@@ -185,18 +185,22 @@ class Writer final : public Gaudi::Functional::Consumer<void(const EventContext&
       }
     }
 
-    DataObject*                   p;
-    StatusCode                    code = m_dataSvc->retrieveObject("/Event" + k4FWCore::frameLocation, p);
-    AnyDataWrapper<podio::Frame>* ptr;
+    DataObject* p;
+    StatusCode  code = m_dataSvc->retrieveObject("/Event" + k4FWCore::frameLocation, p);
+    std::unique_ptr<AnyDataWrapper<podio::Frame>> ptr;
     // This is the case when we are reading from a file
+    // Since we unregistered the object, we need to delete it
     if (code.isSuccess()) {
-      m_dataSvc->unregisterObject(p).ignore();
-      ptr = dynamic_cast<AnyDataWrapper<podio::Frame>*>(p);
+      auto sc = m_dataSvc->unregisterObject(p);
+      if (!sc.isSuccess()) {
+        error() << "Failed to unregister object" << endmsg;
+        return;
+      }
+      ptr = std::unique_ptr<AnyDataWrapper<podio::Frame>>(dynamic_cast<AnyDataWrapper<podio::Frame>*>(p));
     }
     // This is the case when no reading is being done
-    // Will be deleted by the store
     else {
-      ptr = new AnyDataWrapper<podio::Frame>(podio::Frame());
+      ptr = std::make_unique<AnyDataWrapper<podio::Frame>>(podio::Frame());
     }
 
     const auto& frameCollections = ptr->getData().getAvailableCollections();
@@ -242,7 +246,7 @@ class Writer final : public Gaudi::Functional::Consumer<void(const EventContext&
         error() << "Failed to unregister collection " << coll << endmsg;
         return;
       }
-      const auto collection = dynamic_cast<AnyDataWrapper<std::shared_ptr<podio::CollectionBase>>*>(storeCollection);
+      const auto collection = dynamic_cast<AnyDataWrapper<std::unique_ptr<podio::CollectionBase>>*>(storeCollection);
       if (!collection) {
         // Check the case when the data has been produced using the old DataHandle
         const auto old_collection = dynamic_cast<DataWrapperBase*>(storeCollection);
@@ -256,7 +260,7 @@ class Writer final : public Gaudi::Functional::Consumer<void(const EventContext&
         }
 
       } else {
-        std::unique_ptr<podio::CollectionBase> uptr(collection->getData().get());
+        std::unique_ptr<podio::CollectionBase> uptr(std::move(collection->getData()));
         ptr->getData().put(std::move(uptr), coll);
       }
     }

k4FWCore/include/k4FWCore/Consumer.h

@@ -19,9 +19,9 @@
 #ifndef FWCORE_CONSUMER_H
 #define FWCORE_CONSUMER_H
 
-#include <GaudiKernel/FunctionalFilterDecision.h>
 #include "Gaudi/Functional/details.h"
 #include "Gaudi/Functional/utilities.h"
+#include "GaudiKernel/FunctionalFilterDecision.h"
 
 // #include "GaudiKernel/CommonMessaging.h"
 
@@ -43,14 +43,13 @@ namespace k4FWCore {
         : Gaudi::Functional::details::DataHandleMixin<std::tuple<>, std::tuple<>, Traits_> {
       using Gaudi::Functional::details::DataHandleMixin<std::tuple<>, std::tuple<>, Traits_>::DataHandleMixin;
 
-      static_assert(((std::is_base_of_v<podio::CollectionBase, In> || isVectorLike_v<In>)&&...),
+      static_assert(((std::is_base_of_v<podio::CollectionBase, In> || isVectorLike_v<In>) && ...),
                     "Consumer input types must be EDM4hep collections or vectors of collection pointers");
 
-      template <typename T>
-      using InputHandle_t = Gaudi::Functional::details::InputHandle_t<Traits_, std::remove_pointer_t<T>>;
+      template <typename T> using InputHandle_t = Gaudi::Functional::details::InputHandle_t<Traits_, T>;
 
-      std::tuple<std::vector<InputHandle_t<typename transformType<In>::type>>...> m_inputs;
-      std::array<Gaudi::Property<std::vector<DataObjID>>, sizeof...(In)>          m_inputLocations{};
+      std::tuple<std::vector<InputHandle_t<typename EventStoreType<In>::type>>...> m_inputs;
+      std::array<Gaudi::Property<std::vector<DataObjID>>, sizeof...(In)>           m_inputLocations{};
 
       using base_class = Gaudi::Functional::details::DataHandleMixin<std::tuple<>, std::tuple<>, Traits_>;
 
@@ -66,9 +65,9 @@ namespace k4FWCore {
             m_inputLocations{Gaudi::Property<std::vector<DataObjID>>{
                 this, std::get<I>(inputs).first, to_DataObjID(std::get<I>(inputs).second),
                 [this](Gaudi::Details::PropertyBase&) {
-                  std::vector<InputHandle_t<typename transformType<In>::type>> handles;
+                  std::vector<InputHandle_t<EventStoreType_t>> handles;
                   for (auto& value : this->m_inputLocations[I].value()) {
-                    auto handle = InputHandle_t<typename transformType<In>::type>(value, this);
+                    auto handle = InputHandle_t<EventStoreType_t>(value, this);
                     handles.push_back(std::move(handle));
                   }
                   std::get<I>(m_inputs) = std::move(handles);

k4FWCore/include/k4FWCore/DataHandle.h

@@ -27,8 +27,6 @@
 
 #include "edm4hep/Constants.h"
 
-#include "TTree.h"
-
 #include <GaudiKernel/AnyDataWrapper.h>
 #include <type_traits>
 
@@ -133,9 +131,9 @@ template <typename T> const T* DataHandle<T>::get() {
       return reinterpret_cast<const T*>(tmp->collectionBase());
     } else {
       // When a functional has pushed a std::shared_ptr<podio::CollectionBase> into the store
-      auto ptr = static_cast<AnyDataWrapper<std::shared_ptr<podio::CollectionBase>>*>(dataObjectp)->getData();
+      auto ptr = static_cast<AnyDataWrapper<std::unique_ptr<podio::CollectionBase>>*>(dataObjectp);
       if (ptr) {
-        return reinterpret_cast<const T*>(ptr.get());
+        return static_cast<const T*>(ptr->getData().get());
       }
       std::string errorMsg("The type provided for " + DataObjectHandle<DataWrapper<T>>::pythonRepr() +
                            " is different from the one of the object in the store.");

k4FWCore/include/k4FWCore/DataWrapper.h

@@ -41,7 +41,7 @@ template <class T> class GAUDI_API DataWrapper : public DataWrapperBase {
   template <class T2> friend class DataHandle;
 
 public:
-  DataWrapper() : m_data(nullptr){};
+  DataWrapper() : m_data(nullptr) {};
   DataWrapper(T&& coll) {
     m_data   = new T(std::move(coll));
     is_owner = true;