text: // Copyright 2019 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
  
  #pragma once
  
  #include "docsumfieldwriter.h"
  
  namespace search::attribute { class IAttributeContext; }
  
  namespace search::docsummary {
  
  /**
   * Field writer that filters matched elements (according to the query) from a multi-value or complex field
   * (array of primitive, weighted set of primitive, map of primitives, map of struct, array of struct)
   * that is retrieved from the document store.
   */
  class MatchedElementsFilterDFW : public IDocsumFieldWriter {
  private:
      std::string _input_field_name;
      uint32_t _input_field_enum;
      std::shared_ptr<MatchingElementsFields> _matching_elems_fields;
  
      const std::vector<uint32_t>& get_matching_elements(uint32_t docid, GetDocsumsState& state) const;
  
  public:
      MatchedElementsFilterDFW(const std::string& input_field_name, uint32_t input_field_enum,
                               std::shared_ptr<MatchingElementsFields> matching_elems_fields);
      static std::unique_ptr<IDocsumFieldWriter> create(const std::string& input_field_name, uint32_t input_field_enum,
                                                        std::shared_ptr<MatchingElementsFields> matching_elems_fields);
      static std::unique_ptr<IDocsumFieldWriter> create(const std::string& input_field_name, uint32_t input_field_enum,
                                                        search::attribute::IAttributeContext& attr_ctx,
                                                        std::shared_ptr<MatchingElementsFields> matching_elems_fields);
      ~MatchedElementsFilterDFW();
      bool IsGenerated() const override { return false; }
      void insertField(uint32_t docid, GeneralResult* result, GetDocsumsState *state,
                       ResType type, vespalib::slime::Inserter& target) override;
  };
  
  }
  