map-display/include/kml/engine/entity_mapper.h

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// This file contains the declatation of the EntityMapper class and the
// CreateExpandedEntities function.

#ifndef KML_ENGINE_ENTITY_MAPPER_H__
#define KML_ENGINE_ENTITY_MAPPER_H__

#include "kml/dom.h"
#include "kml/base/string_util.h"
#include "kml/engine/engine_types.h"
#include "kml/engine/kml_file.h"

namespace kmlengine {

// The EntityMapper walks through a given FeaturePtr in a given KmlFile
// and stores to the supplied StringMap any replacable entities and their
// replacement text. If a StringPairVector is supplied, it stores a mapping
// of any <ExtendedData> items and their values. (The utility of this latter
// is seen in Google Earth's behavior if asked to show the description balloon
// for a feature with <ExtendedData> but no <description>. It creates an
// HTML table of name-value pairs from the <ExtendedData> structure.)
//
// For an overview of how this is used within KML, see:
// http://code.google.com/apis/kml/documentation/kmlreference.html#text
// http://code.google.com/apis/kml/documentation/extendeddata.html
//
// Usage:
// kmlbase::StringMap your_entity_map;
// kmlbase::StringPairVector your_alt_text;
// EntityMapper entity_mapper(kml_file, &your_entity_map);
// entity_mapper.GetEntityFields(your_feature_ptr);
class EntityMapper {
 public:
  // Instantiate the class with a reference to a KmlFile object.
  // It is the caller's responsibility to ensure that the pointer to the
  // StringMap instance is not NULL.
  EntityMapper(const KmlFilePtr& kml_file, kmlbase::StringMap* string_map);

  // In addition to the string_map, this constructor also takes a pointer to
  // a StringPairVector which, if non-NULL, will be filled with a mapping
  // of name-value pairs of the ExtendedData items if present. This is
  // really a convenience to simulate the historical behavior of Google Earth
  // which, if given a Feature which has no <description> but does have
  // <ExtendedData>, will display a table of Data or SchemaData names together
  // with their values.
  EntityMapper(const KmlFilePtr& kml_file, kmlbase::StringMap* string_map,
               kmlbase::StringPairVector* alt_markup_map);

  ~EntityMapper();

  // Fills the StringMap supplied in the constructor with a mapping of all
  // replaceable entities in the given feature to their replacment text. The
  // StringMap is not modified in any way before being written into. If a
  // StringPairVector was supplied in the constructor, information from
  // any <ExtendedData> in the feature is stored there as described above. The
  // StringPairVector is not modified before writing. Note that this means
  // that this function is not idempotent if a StringPairVector has been
  // supplied; the StringMap will be overwritten, but the StringPairVector
  // will be created twice if this function is called twice.
  // It is the caller's responsibilty to ensure that the FeaturePtr exists
  // within the KmlFile from which the class was instantiated.
  void GetEntityFields(const kmldom::FeaturePtr& feature);

 private:
  void GatherObjectFields(const kmldom::FeaturePtr& feature);
  void GatherFeatureFields(const kmldom::FeaturePtr& feature);
  void GatherExtendedDataFields(const kmldom::FeaturePtr& feature);
  void GatherDataFields(const kmldom::DataPtr& feature);
  void GatherSchemaDataFields(const kmldom::SchemaDataPtr& feature);
  void GatherSimpleFieldFields(const kmldom::SimpleFieldPtr& simplefield,
                               const kmldom::SchemaPtr& schema);
  void GatherSimpleDataFields(const kmldom::SimpleDataPtr& simpledata);
  void PopulateSimpleFieldNameMap(const kmldom::SchemaPtr& schema);
  const KmlFilePtr kml_file_;
  kmlbase::StringMap* entity_map_;
  kmlbase::StringPairVector* alt_markup_map_;
  kmlbase::StringMap simplefield_name_map_;
  string schemadata_prefix_;
};

// Walks through the given string, replacing all keys in StringMap
// with the corresponding key value. The key strings are wrapped with the
// $[xxx] entity format before searching the string. Returns a new string with
// the replaced entities. The entity_map is typically built with the
// EntityMapper class declared in this file.
string CreateExpandedEntities(const string& in,
                              const kmlbase::StringMap& entity_map);

}  // end namespace kmlengine

#endif  // KML_ENGINE_ENTITY_MAPPER_H__