Fix vtkJSONDataSetWriter with invalid field name

Author: jourdain

IO/Export/vtkJSONDataSetWriter.cxx

@@ -44,6 +44,7 @@ vtkStandardNewMacro(vtkJSONDataSetWriter);
 vtkJSONDataSetWriter::vtkJSONDataSetWriter()
 {
   this->FileName = nullptr;
+  this->ValidStringCount = 1;
 }
 
 // ----------------------------------------------------------------------------
@@ -142,7 +143,7 @@ std::string vtkJSONDataSetWriter::WriteArray(
   std::stringstream ss;
   ss << "{\n"
      << INDENT << "  \"vtkClass\": \"" << className << "\",\n"
-     << INDENT << "  \"name\": \"" << (arrayName == nullptr ? array->GetName() : arrayName) << "\",\n"
+     << INDENT << "  \"name\": \"" << this->GetValidString(arrayName == nullptr ? array->GetName() : arrayName) << "\",\n"
      << INDENT << "  \"numberOfComponents\": " << array->GetNumberOfComponents() << ",\n"
      << INDENT << "  \"dataType\": \"" << vtkJSONDataSetWriter::GetShortType(array, needConvert) << "Array\",\n"
      << INDENT << "  \"ref\": {\n"
@@ -387,6 +388,20 @@ std::string vtkJSONDataSetWriter::GetUID(vtkDataArray* input, bool& needConversi
 
 // ----------------------------------------------------------------------------
 
+std::string vtkJSONDataSetWriter::GetValidString(const char* name)
+{
+  if (name != nullptr && strlen(name))
+  {
+    return name;
+  }
+  std::stringstream ss;
+  ss << "invalid_" << this->ValidStringCount++;
+
+  return ss.str();
+}
+
+// ----------------------------------------------------------------------------
+
 bool vtkJSONDataSetWriter::WriteArrayAsRAW(vtkDataArray* input, const char* filePath)
 {
   if (input->GetDataTypeSize() == 0)

IO/Export/vtkJSONDataSetWriter.h

@@ -72,6 +72,13 @@ class VTKIOEXPORT_EXPORT vtkJSONDataSetWriter : public vtkWriter
   static std::string GetUID(vtkDataArray*, bool& needConversion);
   //@}
 
+  //@{
+  /**
+   * Return a Unique identifier for any invalid string
+   */
+  std::string GetValidString(const char*);
+  //@}
+
   //@{
   /**
    * Write the content of the vtkDataArray to disk based on the filePath
@@ -117,6 +124,7 @@ class VTKIOEXPORT_EXPORT vtkJSONDataSetWriter : public vtkWriter
 
   char* FileName;
   bool ValidDataSet;
+  int ValidStringCount;
 
   int FillInputPortInformation(int port, vtkInformation* info) override;