[WIP] Implement series.iterations[0]["meshes"].asContainerOf<Mesh>()

Author: franzpoeschel

include/openPMD/CustomHierarchy.hpp

@@ -73,6 +73,8 @@ namespace internal
         explicit CustomHierarchyData();
 
         Container<RecordComponent> m_embeddedDatasets;
+        Container<Mesh> m_embeddedMeshes;
+        Container<ParticleSpecies> m_embeddedParticles;
     };
 } // namespace internal
 
@@ -99,14 +101,19 @@ class CustomHierarchy : public Container<CustomHierarchy>
         return *m_customHierarchyData;
     }
 
-    void readMeshes(std::string const &meshesPath);
-    void readParticles(std::string const &particlesPath);
+    void readNonscalarMesh(std::string const &name);
+    void readScalarMesh(std::string const &name);
+    void readParticleSpecies(std::string const &name);
 
     void flush_internal(
         internal::FlushParams const &,
         internal::MeshesParticlesPath &,
         std::vector<std::string> currentPath);
 
+    template <typename T>
+    static void
+    synchronizeContainers(Container<T> &target, Container<T> &source);
+
 protected:
     CustomHierarchy();
     CustomHierarchy(NoInit);
@@ -145,7 +152,10 @@ class CustomHierarchy : public Container<CustomHierarchy>
 
     Container<RecordComponent> datasets();
 
+    template <typename ContainedType>
+    auto asContainerOf() -> Container<ContainedType>;
+
     Container<Mesh> meshes{};
-    Container<ParticleSpecies> particles{}; // particleSpecies?
+    Container<ParticleSpecies> particles{};
 };
 } // namespace openPMD

include/openPMD/backend/Attributable.hpp

@@ -50,12 +50,14 @@ class AbstractFilePosition;
 class Attributable;
 class Iteration;
 class Series;
+class CustomHierarchy;
 
 namespace internal
 {
     class AttributableData
     {
         friend class openPMD::Attributable;
+        friend class openPMD::CustomHierarchy;
 
     public:
         AttributableData();
@@ -83,6 +85,7 @@ namespace internal
 
     template <typename, typename>
     class BaseRecordData;
+    struct CustomHierarchyData;
 } // namespace internal
 
 /** @brief Layer to manage storage of attributes associated with file objects.
@@ -110,6 +113,7 @@ class Attributable
     friend class Writable;
     friend class WriteIterations;
     friend class CustomHierarchy;
+    friend class internal::CustomHierarchyData;
 
 protected:
     // tag for internal constructor