qgskeyvaluewidgetfactory.cpp

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/***************************************************************************
    qgskeyvaluewidgetfactory.cpp
     --------------------------------------
    Date                 : 08.2016
    Copyright            : (C) 2016 Patrick Valsecchi
    Email                : [email protected]
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
 
#include "qgskeyvaluewidgetfactory.h"
#include "qgskeyvaluewidgetwrapper.h"
#include "qgsdummyconfigdlg.h"
#include "qgsfields.h"
#include "qgsvectorlayer.h"
 
#include <QVariant>
#include <QSettings>
 
QgsKeyValueWidgetFactory::QgsKeyValueWidgetFactory( const QString &name ):
  QgsEditorWidgetFactory( name )
{
}
 
QgsEditorWidgetWrapper *QgsKeyValueWidgetFactory::create( QgsVectorLayer *vl, int fieldIdx, QWidget *editor, QWidget *parent ) const
{
  return new QgsKeyValueWidgetWrapper( vl, fieldIdx, editor, parent );
}
 
QgsEditorConfigWidget *QgsKeyValueWidgetFactory::configWidget( QgsVectorLayer *vl, int fieldIdx, QWidget *parent ) const
{
  Q_UNUSED( vl )
  Q_UNUSED( fieldIdx )
  Q_UNUSED( parent )
  return new QgsDummyConfigDlg( vl, fieldIdx, parent, QObject::tr( "Key/Value field" ) );
}
 
unsigned int QgsKeyValueWidgetFactory::fieldScore( const QgsVectorLayer *vl, int fieldIdx ) const
{
  const QgsField field = vl->fields().field( fieldIdx );
  if ( field.type() == QMetaType::Type::QVariantMap && ( field.typeName().compare( QStringLiteral( "JSON" ), Qt::CaseSensitivity::CaseInsensitive ) == 0 || field.subType() == QMetaType::Type::QString ) )
  {
    // Look for the first not-null value (limiting to the first 20 features) and check if it is really a map
    const int MAX_FEATURE_LIMIT { 20 };
    QgsFeatureRequest req;
    req.setFlags( Qgis::FeatureRequestFlag::NoGeometry );
    req.setSubsetOfAttributes( { fieldIdx } );
    req.setLimit( MAX_FEATURE_LIMIT );
    QgsFeature f;
    QgsFeatureIterator featureIt { vl->getFeatures( req ) };
    // The counter is an extra safety measure in case the provider does not respect the limit
    int featureCount = 0;
    while ( featureIt.nextFeature( f ) )
    {
      ++featureCount;
      if ( featureCount > MAX_FEATURE_LIMIT )
      {
        break;
      }
      // Get attribute value and check if it is a valid JSON object
      const QVariant value( f.attribute( fieldIdx ) );
      if ( ! value.isNull() )
      {
        switch ( value.type() )
        {
          case QVariant::Type::Map:
          {
            return 20;
          }
          default:
          case QVariant::Type::String:
          {
            const QJsonDocument doc = QJsonDocument::fromJson( value.toString().toUtf8() );
            if ( doc.isObject() )
            {
              return 20;
            }
            else
            {
              return 0;
            }
          }
        }
      }
    }
  }
  return field.type() == QMetaType::Type::QVariantMap && field.subType() != QMetaType::Type::UnknownType ? 20 : 0;
}