Add m_datasetDefined

See in-code documentation.

Author: franzpoeschel

include/openPMD/RecordComponent.hpp

@@ -440,11 +440,14 @@ OPENPMD_protected
 
     inline Data_t const &get() const
     {
+        // cannot call this in the const overload
+        // datasetDefined(*m_recordComponentData);
         return *m_recordComponentData;
     }
 
     inline Data_t &get()
     {
+        setDatasetDefined(*m_recordComponentData);
         return *m_recordComponentData;
     }
 

include/openPMD/backend/BaseRecordComponent.hpp

@@ -49,6 +49,13 @@ namespace internal
          * instead defined via light-weight attributes.
          */
         bool m_isConstant = false;
+        /**
+         * Tracks if there was any write access to the record component.
+         * Necessary in BaseRecord<T> to track if the scalar component has been
+         * used and is used by BaseRecord<T> to determine the return value of
+         * the BaseRecord<T>::scalar() method.
+         */
+        bool m_datasetDefined = false;
 
         BaseRecordComponentData(BaseRecordComponentData const &) = delete;
         BaseRecordComponentData(BaseRecordComponentData &&) = delete;
@@ -166,6 +173,10 @@ class BaseRecordComponent : virtual public Attributable
         Attributable::setData(m_baseRecordComponentData);
     }
 
+    void setDatasetDefined(Data_t &);
+
+    bool datasetDefined() const;
+
     BaseRecordComponent();
     BaseRecordComponent(NoInit);
 }; // BaseRecordComponent

include/openPMD/backend/PatchRecordComponent.hpp

@@ -124,11 +124,14 @@ OPENPMD_protected
 
     inline Data_t const &get() const
     {
+        // cannot call this in the const overload
+        // setDatasetDefined(*m_recordComponentData);
         return *m_patchRecordComponentData;
     }
 
     inline Data_t &get()
     {
+        setDatasetDefined(*m_patchRecordComponentData);
         return *m_patchRecordComponentData;
     }
 

src/backend/BaseRecordComponent.cpp

@@ -92,4 +92,16 @@ BaseRecordComponent::BaseRecordComponent() : Attributable(NoInit())
 
 BaseRecordComponent::BaseRecordComponent(NoInit) : Attributable(NoInit())
 {}
+
+void BaseRecordComponent::setDatasetDefined(
+    internal::BaseRecordComponentData &data)
+{
+    data.m_datasetDefined = true;
+}
+
+bool BaseRecordComponent::datasetDefined() const
+{
+    auto & data = get();
+    return data.m_datasetDefined;
+}
 } // namespace openPMD