From b38c1d6f5e5a30e54df07191242421ed848ae8de Mon Sep 17 00:00:00 2001
From: tmadlener <thomas.madlener@desy.de>
Date: Wed, 12 Jun 2024 17:13:36 +0200
Subject: [PATCH] Add a loadFrom method to facilitate usage in RDataFrame

---
 include/podio/GenericParameters.h | 16 ++++++++++++++++
 src/RNTupleReader.cc              |  4 +---
 src/ROOTReader.cc                 |  4 +---
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/include/podio/GenericParameters.h b/include/podio/GenericParameters.h
index 9e0fb5e5d..04456920c 100644
--- a/include/podio/GenericParameters.h
+++ b/include/podio/GenericParameters.h
@@ -104,6 +104,10 @@ class GenericParameters {
     set<std::vector<T>>(key, std::move(values));
   }
 
+  /// Load multiple key value pairs simultaneously
+  template <typename T>
+  void loadFrom(std::vector<std::string> keys, std::vector<std::vector<T>> values);
+
   /// Get the number of elements stored under the given key for a type
   template <typename T, typename = EnableIfValidGenericDataType<T>>
   size_t getN(const std::string& key) const;
@@ -272,5 +276,17 @@ std::vector<std::vector<T>> GenericParameters::getValues() const {
   }
   return values;
 }
+
+template <typename T>
+void GenericParameters::loadFrom(std::vector<std::string> keys, std::vector<std::vector<T>> values) {
+  auto& map = getMap<T>();
+  auto& mtx = getMutex<T>();
+
+  std::lock_guard lock{mtx};
+  for (size_t i = 0; i < keys.size(); ++i) {
+    map.emplace(std::move(keys[i]), std::move(values[i]));
+  }
+}
+
 } // namespace podio
 #endif
diff --git a/src/RNTupleReader.cc b/src/RNTupleReader.cc
index a372f6c2f..43c8370aa 100644
--- a/src/RNTupleReader.cc
+++ b/src/RNTupleReader.cc
@@ -18,9 +18,7 @@ void RNTupleReader::readParams(const std::string& name, unsigned entNum, Generic
   auto keyView = m_readers[name][0]->GetView<std::vector<std::string>>(root_utils::getGPKeyName<T>());
   auto valueView = m_readers[name][0]->GetView<std::vector<std::vector<T>>>(root_utils::getGPValueName<T>());
 
-  for (size_t i = 0; i < keyView(entNum).size(); ++i) {
-    params.getMap<T>().emplace(std::move(keyView(entNum)[i]), std::move(valueView(entNum)[i]));
-  }
+  params.loadFrom(keyView(entNum), valueView(entNum));
 }
 
 GenericParameters RNTupleReader::readEventMetaData(const std::string& name, unsigned entNum) {
diff --git a/src/ROOTReader.cc b/src/ROOTReader.cc
index 3e786fb43..60fa37018 100644
--- a/src/ROOTReader.cc
+++ b/src/ROOTReader.cc
@@ -75,9 +75,7 @@ void ROOTReader::readParams(ROOTReader::CategoryInfo& catInfo, podio::GenericPar
   valueBranch->SetAddress(storage.valuesPtr());
   valueBranch->GetEntry(localEntry);
 
-  for (size_t i = 0; i < storage.keys.size(); ++i) {
-    params.getMap<T>().emplace(std::move(storage.keys[i]), std::move(storage.values[i]));
-  }
+  params.loadFrom(std::move(storage.keys), std::move(storage.values));
 }
 
 GenericParameters ROOTReader::readEntryParameters(ROOTReader::CategoryInfo& catInfo, bool reloadBranches,