qgsfeature.cpp

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/***************************************************************************
                qgsfeature.cpp - Spatial Feature Implementation
                     --------------------------------------
Date                 : 09-Sep-2003
Copyright            : (C) 2003 by Gary E.Sherman
email                : sherman at mrcc.com
 ***************************************************************************
 *                                                                         *
 *   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 "qgsfeature.h"
#include "qgsfeature_p.h"
#include "qgsfields.h"
#include "qgsgeometry.h"
#include "qgsrectangle.h"
#include "qgsfield_p.h" // for approximateMemoryUsage()
#include "qgsfields_p.h" // for approximateMemoryUsage()
 
#include "qgsmessagelog.h"
 
#include <QDataStream>
 
/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in testqgsfeature.cpp.
 * See details in QEP #17
 ****************************************************************************/
 
 
//
// QgsFeature
//
 
QgsFeature::QgsFeature( QgsFeatureId id )
{
  d = new QgsFeaturePrivate( id );
}
 
QgsFeature::QgsFeature( const QgsFields &fields, QgsFeatureId id )
{
  d = new QgsFeaturePrivate( id );
  d->fields = fields;
  initAttributes( d->fields.count() );
}
 
QgsFeature::QgsFeature( const QgsFeature &rhs ) //NOLINT
  : d( rhs.d )
{
}
 
QgsFeature &QgsFeature::operator=( const QgsFeature &rhs )   //NOLINT
{
  d = rhs.d;
  return *this;
}
 
bool QgsFeature::operator ==( const QgsFeature &other ) const
{
  if ( d == other.d )
    return true;
 
  if ( d->fid == other.d->fid
       && d->valid == other.d->valid
       && d->fields == other.d->fields
       && d->attributes == other.d->attributes
       && d->geometry.equals( other.d->geometry ) )
    return true;
 
  return false;
}
 
bool QgsFeature::operator!=( const QgsFeature &other ) const
{
  return !( *this == other );
}
 
QgsFeature::~QgsFeature() //NOLINT
{
}
 
/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in testqgsfeature.cpp.
 * See details in QEP #17
 ****************************************************************************/
 
QgsFeatureId QgsFeature::id() const
{
  return d->fid;
}
 
void QgsFeature::deleteAttribute( int field )
{
  d.detach();
  d->attributes.remove( field );
}
 
QgsGeometry QgsFeature::geometry() const
{
  return d->geometry;
}
 
/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in testqgsfeature.cpp.
 * See details in QEP #17
 ****************************************************************************/
 
void QgsFeature::setId( QgsFeatureId id )
{
  if ( id == d->fid )
    return;
 
  d.detach();
  d->fid = id;
  d->valid = true;
}
 
QgsAttributes QgsFeature::attributes() const
{
  return d->attributes;
}
 
int QgsFeature::attributeCount() const
{
  return d->attributes.size();
}
 
void QgsFeature::setAttributes( const QgsAttributes &attrs )
{
  if ( attrs == d->attributes )
    return;
 
  d.detach();
  d->attributes = attrs;
  d->valid = true;
}
 
void QgsFeature::setGeometry( const QgsGeometry &geometry )
{
  d.detach();
  d->geometry = geometry;
  d->valid = true;
}
 
void QgsFeature::setGeometry( std::unique_ptr<QgsAbstractGeometry> geometry )
{
  d.detach();
  d->geometry = QgsGeometry( std::move( geometry ) );
  d->valid = true;
}
 
void QgsFeature::clearGeometry()
{
  setGeometry( QgsGeometry() );
}
 
/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in testqgsfeature.cpp.
 * See details in QEP #17
 ****************************************************************************/
 
void QgsFeature::setFields( const QgsFields &fields, bool init )
{
  d.detach();
  d->fields = fields;
  if ( init )
  {
    initAttributes( d->fields.count() );
  }
}
 
QgsFields QgsFeature::fields() const
{
  return d->fields;
}
 
/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in testqgsfeature.cpp.
 * See details in QEP #17
 ****************************************************************************/
 
bool QgsFeature::isValid() const
{
  return d->valid;
}
 
void QgsFeature::setValid( bool validity )
{
  if ( d->valid == validity )
    return;
 
  d.detach();
  d->valid = validity;
}
 
bool QgsFeature::hasGeometry() const
{
  return !d->geometry.isNull();
}
 
void QgsFeature::initAttributes( int fieldCount )
{
  d.detach();
  d->attributes.resize( 0 ); // clears existing elements, while still preserving the currently allocated capacity of the list (unlike clear)
  // ensures ALL attributes, including previously existing ones are default constructed.
  // doing it this way also avoids clearing individual QVariants -- which can trigger a detachment. Cheaper just to make a new one.
  d->attributes.resize( fieldCount );
}
 
void QgsFeature::resizeAttributes( int fieldCount )
{
  if ( fieldCount == d->attributes.size() )
    return;
 
  d.detach();
  d->attributes.resize( fieldCount );
}
 
void QgsFeature::padAttributes( int count )
{
  if ( count == 0 )
    return;
 
  d.detach();
  d->attributes.resize( d->attributes.size() + count );
}
 
bool QgsFeature::setAttribute( int idx, const QVariant &value )
{
  if ( idx < 0 || idx >= d->attributes.size() )
  {
    QgsMessageLog::logMessage( QObject::tr( "Attribute index %1 out of bounds [0;%2]" ).arg( idx ).arg( d->attributes.size() ), QString(), Qgis::Warning );
    return false;
  }
 
  d.detach();
  d->attributes[idx] = value;
  d->valid = true;
  return true;
}
 
/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in testqgsfeature.cpp.
 * See details in QEP #17
 ****************************************************************************/
 
bool QgsFeature::setAttribute( const QString &name, const QVariant &value )
{
  int fieldIdx = fieldNameIndex( name );
  if ( fieldIdx == -1 )
    return false;
 
  d.detach();
  d->attributes[fieldIdx] = value;
  d->valid = true;
  return true;
}
 
bool QgsFeature::deleteAttribute( const QString &name )
{
  int fieldIdx = fieldNameIndex( name );
  if ( fieldIdx == -1 )
    return false;
 
  d.detach();
  d->attributes[fieldIdx].clear();
  return true;
}
 
QVariant QgsFeature::attribute( int fieldIdx ) const
{
  if ( fieldIdx < 0 || fieldIdx >= d->attributes.count() )
    return QVariant();
 
  return d->attributes.at( fieldIdx );
}
 
QVariant QgsFeature::attribute( const QString &name ) const
{
  int fieldIdx = fieldNameIndex( name );
  if ( fieldIdx == -1 )
    return QVariant();
 
  return d->attributes.at( fieldIdx );
}
 
/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in testqgsfeature.cpp.
 * See details in QEP #17
 ****************************************************************************/
 
int QgsFeature::fieldNameIndex( const QString &fieldName ) const
{
  return d->fields.lookupField( fieldName );
}
 
static size_t qgsQStringApproximateMemoryUsage( const QString &str )
{
  return sizeof( QString ) + str.size() * sizeof( QChar );
}
 
static size_t qgsQVariantApproximateMemoryUsage( const QVariant &v )
{
  // A QVariant has a private structure that is a union of things whose larger
  // size if a long long, and a int
  size_t s = sizeof( QVariant ) + sizeof( long long ) + sizeof( int );
  if ( v.type() == QVariant::String )
  {
    s += qgsQStringApproximateMemoryUsage( v.toString() );
  }
  else if ( v.type() == QVariant::StringList )
  {
    for ( const QString &str : v.toStringList() )
      s += qgsQStringApproximateMemoryUsage( str );
  }
  else if ( v.type() == QVariant::List )
  {
    for ( const QVariant &subV : v.toList() )
      s += qgsQVariantApproximateMemoryUsage( subV );
  }
  return s;
}
 
int QgsFeature::approximateMemoryUsage() const
{
  size_t s = sizeof( *this ) + sizeof( *d );
 
  // Attributes
  for ( const QVariant &attr : qgis::as_const( d->attributes ) )
  {
    s += qgsQVariantApproximateMemoryUsage( attr );
  }
 
  // Geometry
  s += sizeof( QAtomicInt ) + sizeof( void * ); // ~ sizeof(QgsGeometryPrivate)
  // For simplicity we consider that the RAM usage is the one of the WKB
  // representation
  s += d->geometry.wkbSize();
 
  // Fields
  s += sizeof( QgsFieldsPrivate );
  // TODO potentially: take into account the length of the name, comment, default value, etc...
  s += d->fields.size() * ( sizeof( QgsField )  + sizeof( QgsFieldPrivate ) );
 
  return static_cast<int>( s );
}
 
 
/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in testqgsfeature.cpp.
 * See details in QEP #17
 ****************************************************************************/
 
QDataStream &operator<<( QDataStream &out, const QgsFeature &feature )
{
  out << feature.id();
  out << feature.attributes();
  if ( feature.hasGeometry() )
  {
    out << ( feature.geometry() );
  }
  else
  {
    QgsGeometry geometry;
    out << geometry;
  }
  out << feature.isValid();
  return out;
}
 
QDataStream &operator>>( QDataStream &in, QgsFeature &feature )
{
  QgsFeatureId id;
  QgsGeometry geometry;
  bool valid;
  QgsAttributes attr;
  in >> id >> attr >> geometry >> valid;
  feature.setId( id );
  feature.setGeometry( geometry );
  feature.setAttributes( attr );
  feature.setValid( valid );
  return in;
}
 
uint qHash( const QgsFeature &key, uint seed )
{
  uint hash = seed;
  const auto constAttributes = key.attributes();
  for ( const QVariant &attr : constAttributes )
  {
    hash ^= qHash( attr.toString() );
  }
 
  hash ^= qHash( key.geometry().asWkt() );
  hash ^= qHash( key.id() );
 
  return hash;
}