Added support for recursive complex data type (#1656)

The Opc.Ua.Client.ComplexTypes package does not support recursive structs, i.e. a struct with a field that has the same data type as the struct. An example of a recursive struct data type may look as follows: PersonStructDataType - Name <String> - Age <Int32> - Children <PersonStructDataType[ ]> (ValueRank == 1)
OPCFoundation · Jan 11, 2022 · b41fb36 · b41fb36
1 parent 9188dcf
commit b41fb36
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Showing 2 changed files with 29 additions and 2 deletions.
diff --git a/Libraries/Opc.Ua.Client.ComplexTypes/ComplexTypeSystem.cs b/Libraries/Opc.Ua.Client.ComplexTypes/ComplexTypeSystem.cs
@@ -1066,7 +1066,8 @@ ExpandedNodeId xmlEncodingId
             foreach (StructureField field in structureDefinition.Fields)
             {
                 var newType = GetFieldType(field);
-                if (newType == null)
+                var isRecursiveDataType = IsRecursiveDataType(ExpandedNodeId.ToNodeId(complexTypeId, m_session.NamespaceUris), field.DataType);
+                if (newType == null && !isRecursiveDataType)
                 {
                     throw new DataTypeNotFoundException(field.DataType);
                 }
@@ -1085,13 +1086,35 @@ ExpandedNodeId xmlEncodingId
             foreach (StructureField field in structureDefinition.Fields)
             {
                 typeListEnumerator.MoveNext();
-                fieldBuilder.AddField(field, typeListEnumerator.Current, order);
+
+                // check for recursive data type:
+                //    field has the same data type as the parent structure
+                var isRecursiveDataType = IsRecursiveDataType(ExpandedNodeId.ToNodeId(complexTypeId, m_session.NamespaceUris), field.DataType);
+                if (isRecursiveDataType)
+                {
+                    if (field.ValueRank < 0) // scalar
+                    {
+                        fieldBuilder.AddField(field, (fieldBuilder as ComplexTypeFieldBuilder).StructureTypeBuilder, order);
+                    }
+                    else // array
+                    {
+                        var arrayType = (fieldBuilder as ComplexTypeFieldBuilder).StructureTypeBuilder.MakeArrayType();
+                        fieldBuilder.AddField(field, arrayType, order);
+                    }
+                }
+                else
+                {
+                    fieldBuilder.AddField(field, typeListEnumerator.Current, order);
+                }
                 order++;
             }
 
             return fieldBuilder.CreateType();
         }
 
+        private bool IsRecursiveDataType(NodeId structureDataType, NodeId fieldDataType)
+            => fieldDataType.Equals(structureDataType);
+
         /// <summary>
         /// Determine the type of a field in a StructureField definition.
         /// </summary>

diff --git a/Libraries/Opc.Ua.Client.ComplexTypes/TypeBuilder/ComplexTypeFieldBuilder.cs b/Libraries/Opc.Ua.Client.ComplexTypes/TypeBuilder/ComplexTypeFieldBuilder.cs
@@ -127,6 +127,10 @@ public Type CreateType()
         }
         #endregion Public Properties
 
+        #region Internal Properties
+        internal TypeBuilder StructureTypeBuilder { get => this.m_structureBuilder; }
+        #endregion
+
         #region Private Member
         private TypeBuilder m_structureBuilder;
         private StructureType m_structureType;