Add m_datasetDefined

Todo: Merge functionality with openPMD#1316

Author: franzpoeschel

include/openPMD/RecordComponent.hpp

@@ -440,12 +440,15 @@ OPENPMD_protected
 
     inline Data_t const &get() const
     {
+        // cannot call this in the const overload
+        // datasetDefined(*m_recordComponentData);
         return dynamic_cast<Data_t const &>(*m_attri);
     }
 
     inline Data_t &get()
     {
         auto &res = dynamic_cast<Data_t &>(*m_attri);
+        datasetDefined(res);
         return res;
     }
 

include/openPMD/backend/BaseRecordComponent.hpp

@@ -47,6 +47,10 @@ namespace internal
          * instead defined via light-weight attributes.
          */
         bool m_isConstant = false;
+        /*
+         * ... document this ...
+         */
+        bool m_datasetDefined = false;
 
         BaseRecordComponentData(BaseRecordComponentData const &) = delete;
         BaseRecordComponentData(BaseRecordComponentData &&) = delete;
@@ -112,6 +116,8 @@ class BaseRecordComponent : virtual public Attributable
         return dynamic_cast<Data_t &>(*m_attri);
     }
 
+    void datasetDefined(Data_t &);
+
     BaseRecordComponent();
 }; // BaseRecordComponent
 

include/openPMD/backend/PatchRecordComponent.hpp

@@ -121,12 +121,15 @@ OPENPMD_protected
 
     inline Data_t const &get() const
     {
+        // cannot call this in the const overload
+        // datasetDefined(*m_recordComponentData);
         return dynamic_cast<Data_t const &>(*m_attri);
     }
 
     inline Data_t &get()
     {
         auto &res = dynamic_cast<Data_t &>(*m_attri);
+        datasetDefined(res);
         return res;
     }
 }; // PatchRecordComponent

src/backend/BaseRecordComponent.cpp

@@ -71,4 +71,9 @@ BaseRecordComponent::BaseRecordComponent()
         std::make_shared<internal::BaseRecordComponentData>());
 }
 
+void BaseRecordComponent::datasetDefined(
+    internal::BaseRecordComponentData &data)
+{
+    data.m_datasetDefined = true;
+}
 } // namespace openPMD