qgsgrassprovider.cpp

/***************************************************************************
    qgsgrassprovider.cpp -  Data provider for GRASS format
                             -------------------
    begin                : March, 2004
    copyright            : (C) 2004 by Gary E.Sherman, Radim Blazek
    email                : sherman@mrcc.com, blazek@itc.it
 ***************************************************************************/
/***************************************************************************
 *                                                                         *
 *   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 <cstring>
#include <vector>
#include <cfloat>

#include <QString>
#include <QDateTime>

#include "qgis.h"
#include "qgsdataprovider.h"
#include "qgsfeature.h"
#include "qgsfield.h"
#include "qgslinestringv2.h"
#include "qgspointv2.h"
#include "qgspolygonv2.h"
#include "qgsrectangle.h"
#include "qgsvectorlayer.h"
#include "qgsvectorlayereditbuffer.h"

#include "qgsgrass.h"
#include "qgsgrassprovider.h"
#include "qgsgrassfeatureiterator.h"
#include "qgsgrassvector.h"

#include "qgsapplication.h"
#include "qgscoordinatereferencesystem.h"
#include "qgslogger.h"

#include <QByteArray>
#include <QDir>
#include <QFile>
#include <QFileInfo>
#include <QMessageBox>
#include <QTextCodec>

#ifdef _MSC_VER
// enable grass prototypes
#define __STDC__ 1
#endif

extern "C"
{
#include <grass/version.h>
#include <grass/gprojects.h>
#include <grass/gis.h>
#include <grass/dbmi.h>
#if GRASS_VERSION_MAJOR < 7
#include <grass/Vect.h>
#else
#include <grass/vector.h>
#define BOUND_BOX bound_box
#endif
}

#ifdef _MSC_VER
#undef __STDC__
#endif

// Vect_rewrite_line and Vect_delete_line use int in GRASS 6 and off_t in GRASS 7 for line id argument.
// off_t size is not specified by C, POSIX specifies it as signed integer and its size depends on compiler.
// In OSGeo4W 32bit the off_t size is 8 bytes in GRASS (32bit, compiled with MinGW, 'g.version -g' prints build_off_t_size=8 )
// and 4 bytes QGIS (32bit, compiled with MSVC), which is causing crashes.
// The problem with off_t size was also reported for custom build of QGIS on Xubuntu 14.04 LTS using GRASS 7.0.1-2~ubuntu14.04.1.
// See: https://lists.osgeo.org/pipermail/grass-dev/2015-June/075539.html
//      https://lists.osgeo.org/pipermail/grass-dev/2015-September/076338.html
// TODO: get real off_t size from GRASS, probably contribute a patch which will save 'g.version -g' to a header file during compilation
#if GRASS_VERSION_MAJOR < 7
typedef int Vect_rewrite_line_function_type( struct Map_info *, int, int, struct line_pnts *, struct line_cats * );
typedef int Vect_delete_line_function_type( struct Map_info *, int );
#else
#ifdef Q_OS_WIN
typedef qint64 grass_off_t;
#else
typedef off_t grass_off_t;
#endif
typedef grass_off_t Vect_rewrite_line_function_type( struct Map_info *, grass_off_t, int, const struct line_pnts *, const struct line_cats * );
typedef int Vect_delete_line_function_type( struct Map_info *, grass_off_t );
#endif
Vect_rewrite_line_function_type *Vect_rewrite_line_function_pointer = (Vect_rewrite_line_function_type *)Vect_rewrite_line;
Vect_delete_line_function_type *Vect_delete_line_function_pointer = (Vect_delete_line_function_type *)Vect_delete_line;

static QString GRASS_KEY = "grass";

QgsGrassProvider::QgsGrassProvider( QString uri )
    : QgsVectorDataProvider( uri )
    , mLayerField( -1 )
    , mLayerType( POINT )
    , mGrassType( 0 )
    , mQgisType( QGis::WKBUnknown )
    , mLayer( 0 )
    , mMapVersion( 0 )
    , mNumberFeatures( 0 )
    , mEditBuffer( 0 )
    , mEditLayer( 0 )
    , mNewFeatureType( 0 )
    , mPoints( 0 )
    , mCats( 0 )
{
  QgsDebugMsg( "uri = " + uri );

  mValid = false;
  if ( !QgsGrass::init() )
  {
    appendError( QgsGrass::errorMessage() );
    return;
  }

  QTime time;
  time.start();

  mPoints = Vect_new_line_struct();
  mCats = Vect_new_cats_struct();

  // Parse URI
  QDir dir( uri );   // it is not a directory in fact
  QString myURI = dir.path();  // no dupl '/'

  mLayerName = dir.dirName();
  myURI = myURI.left( dir.path().lastIndexOf( '/' ) );
  dir = QDir( myURI );
  QString mapName = dir.dirName();
  dir.cdUp();
  QString mapset = dir.dirName();
  dir.cdUp();
  QString location = dir.dirName();
  dir.cdUp();
  QString gisdbase = dir.path();

  mGrassObject = QgsGrassObject( gisdbase, location, mapset, mapName );
  QgsDebugMsg( "mGrassObject = " + mGrassObject.toString() + " mLayerName = " + mLayerName );

  /* Parse Layer, supported layers <field>_point, <field>_line, <field>_area
  *  Layer is opened even if it is empty (has no features)
  */
  if ( mLayerName.compare( "boundary" ) == 0 ) // currently not used
  {
    mLayerType = BOUNDARY;
    mGrassType = GV_BOUNDARY;
  }
  else if ( mLayerName.compare( "centroid" ) == 0 ) // currently not used
  {
    mLayerType = CENTROID;
    mGrassType = GV_CENTROID;
  }
  else if ( mLayerName == "topo_point" )
  {
    mLayerType = TOPO_POINT;
    mGrassType = GV_POINTS;
  }
  else if ( mLayerName == "topo_line" )
  {
    mLayerType = TOPO_LINE;
    mGrassType = GV_LINES;
  }
  else if ( mLayerName == "topo_node" )
  {
    mLayerType = TOPO_NODE;
    mGrassType = 0;
  }
  else
  {
    mLayerField = grassLayer( mLayerName );
    if ( mLayerField == -1 )
    {
      QgsDebugMsg( QString( "Invalid layer name, no underscore found: %1" ).arg( mLayerName ) );
      return;
    }

    mGrassType = grassLayerType( mLayerName );

    if ( mGrassType == GV_POINT )
    {
      mLayerType = POINT;
    }
    else if ( mGrassType == GV_LINES )
    {
      mLayerType = LINE;
    }
    else if ( mGrassType == GV_FACE )
    {
      mLayerType = FACE;
    }
    else if ( mGrassType == GV_AREA )
    {
      mLayerType = POLYGON;
    }
    else
    {
      QgsDebugMsg( QString( "Invalid layer name, wrong type: %1" ).arg( mLayerName ) );
      return;
    }

  }
  QgsDebugMsg( QString( "mLayerField: %1" ).arg( mLayerField ) );
  QgsDebugMsg( QString( "mLayerType: %1" ).arg( mLayerType ) );

  if ( mLayerType == BOUNDARY || mLayerType == CENTROID )
  {
    QgsDebugMsg( "Layer type not supported." );
    return;
  }

  // Set QGIS type
  switch ( mLayerType )
  {
    case POINT:
    case CENTROID:
    case TOPO_POINT:
    case TOPO_NODE:
      mQgisType = QGis::WKBPoint;
      break;
    case LINE:
    case BOUNDARY:
    case TOPO_LINE:
      mQgisType = QGis::WKBLineString;
      break;
    case POLYGON:
    case FACE:
      mQgisType = QGis::WKBPolygon;
      break;
  }

  if ( !openLayer() )
  {
    QgsDebugMsg( "Cannot open layer" );
    return;
  }

  loadMapInfo();
  setTopoFields();

  connect( mLayer->map(), SIGNAL( dataChanged() ), SLOT( onDataChanged() ) );

  // TODO: types according to database
  mNativeTypes
  << QgsVectorDataProvider::NativeType( tr( "Whole number (integer)" ), "integer", QVariant::Int, -1, -1, -1, -1 )
  << QgsVectorDataProvider::NativeType( tr( "Decimal number (real)" ), "double precision", QVariant::Double, -1, -1, -1, -1 )
  << QgsVectorDataProvider::NativeType( tr( "Text, limited variable length (varchar)" ), "varchar", QVariant::String, 1, -1, -1, -1 );
  // TODO:
  // << QgsVectorDataProvider::NativeType( tr( "Date" ), "date", QVariant::Date, 8, 8 );

  mValid = true;

  QgsDebugMsg( QString( "New GRASS layer opened, time (ms): %1" ).arg( time.elapsed() ) );
}

QgsGrassProvider::~QgsGrassProvider()
{
  QgsDebugMsg( "entered" );
  if ( mLayer )
  {
    mLayer->close();
  }
  if ( mPoints )
  {
    Vect_destroy_line_struct( mPoints );
  }
  if ( mCats )
  {
    Vect_destroy_cats_struct( mCats );
  }
}

int QgsGrassProvider::capabilities() const
{
  // for now, only one map may be edited at time
  if ( mEditBuffer || ( mLayer && mLayer->map() && !mLayer->map()->isEdited() ) )
  {
    return AddFeatures | DeleteFeatures | ChangeGeometries | AddAttributes | DeleteAttributes | ChangeAttributeValues;
  }
  return 0;
}

bool QgsGrassProvider::openLayer()
{
  QgsDebugMsg( "entered" );
  // the map may be invalid (e.g. wrong uri or open failed)
  QgsGrassVectorMap *vectorMap = QgsGrassVectorMapStore::instance()->openMap( mGrassObject );
  if ( !vectorMap ) // should not happen
  {
    QgsDebugMsg( "Cannot open map" );
    return false;
  }
  if ( !vectorMap->isValid() ) // may happen
  {
    QgsDebugMsg( "vectorMap is not valid" );
    return false;
  }

  mLayer = vectorMap->openLayer( mLayerField );

  if ( !mLayer ) // should not happen
  {
    QgsDebugMsg( "Cannot open layer" );
    return false;
  }
  if ( !mLayer->map() || !mLayer->map()->map() ) // should not happen
  {
    QgsDebugMsg( "map is null" );
    return false;
  }
  mMapVersion = mLayer->map()->version();
  return true;
}

void QgsGrassProvider::loadMapInfo()
{
  // Getting the total number of features in the layer
  int cidxFieldIndex = -1;
  mNumberFeatures = 0;
  if ( mLayerType == TOPO_POINT )
  {
    mNumberFeatures = Vect_get_num_primitives( map(), GV_POINTS );
  }
  else if ( mLayerType == TOPO_LINE )
  {
    mNumberFeatures = Vect_get_num_primitives( map(), GV_LINES );
  }
  else if ( mLayerType == TOPO_NODE )
  {
    mNumberFeatures = Vect_get_num_nodes( map() );
  }
  else
  {
    if ( mLayerField >= 0 )
    {
      cidxFieldIndex = Vect_cidx_get_field_index( map(), mLayerField );
      if ( cidxFieldIndex >= 0 )
      {
        mNumberFeatures = Vect_cidx_get_type_count( map(), mLayerField, mGrassType );
      }
    }
    else
    {
      // TODO nofield layers
      mNumberFeatures = 0;
    }
  }
  QgsDebugMsg( QString( "mNumberFeatures = %1 cidxFieldIndex = %2" ).arg( mNumberFeatures ).arg( cidxFieldIndex ) );
}

void QgsGrassProvider::update()
{
  QgsDebugMsg( "entered" );

  mValid = false;

  if ( mLayer )
  {
    mLayer->close();
    mLayer = 0;
  }

  if ( !openLayer() )
  {
    QgsDebugMsg( "Cannot open layer" );
    return;
  }

  loadMapInfo();

  mValid = true;
}

QgsAbstractFeatureSource* QgsGrassProvider::featureSource() const
{
  const_cast<QgsGrassProvider*>( this )->ensureUpdated();
  return new QgsGrassFeatureSource( this );
}


QString QgsGrassProvider::storageType() const
{
  return "GRASS (Geographic Resources Analysis and Support System) file";
}



QgsFeatureIterator QgsGrassProvider::getFeatures( const QgsFeatureRequest& request )
{
  if ( !mValid )
  {
    return QgsFeatureIterator();
  }

  // check if outdated and update if necessary
  ensureUpdated();

  QgsGrassFeatureSource * source = new QgsGrassFeatureSource( this );
  QgsGrassFeatureIterator * iterator = new QgsGrassFeatureIterator( source, true, request );
  return QgsFeatureIterator( iterator );
}

QgsRectangle QgsGrassProvider::extent()
{
  if ( isValid() )
  {
    BOUND_BOX box;
    Vect_get_map_box( map(), &box );
    return QgsRectangle( box.W, box.S, box.E, box.N );
  }
  return QgsRectangle();
}

/**
* Return the feature type
*/
QGis::WkbType QgsGrassProvider::geometryType() const
{
  return mQgisType;
}

long QgsGrassProvider::featureCount() const
{
  return mNumberFeatures;
}

const QgsFields & QgsGrassProvider::fields() const
{
  if ( isTopoType() )
  {
    return mTopoFields;
  }
  else
  {
    // Original fields must be returned during editing because edit buffer updates fields by indices
    if ( mEditBuffer )
    {
      return mLayer->fields();
    }
    else
    {
      return mLayer->tableFields();
    }
  }
}

int QgsGrassProvider::keyField()
{
  return mLayer->keyColumn();
}

QVariant QgsGrassProvider::minimumValue( int index )
{
  if ( isValid() )
  {
    return mLayer->minMax().value( index ).first;
  }
  return QVariant();
}


QVariant QgsGrassProvider::maxValue( int index )
{
  if ( isValid() )
  {
    return mLayer->minMax().value( index ).second;
  }
  return QVariant();
}

bool QgsGrassProvider::isValid()
{
  QgsDebugMsg( QString( "returned: %1" ).arg( mValid ) );

  return mValid && mLayer && mLayer->map() && mLayer->map()->map();
}

QgsCoordinateReferenceSystem QgsGrassProvider::crs()
{
  QString error;
  return QgsGrass::crs( mGrassObject.gisdbase(), mGrassObject.location(), error );
}

int QgsGrassProvider::grassLayer()
{
  return mLayerField;
}

int QgsGrassProvider::grassLayer( QString name )
{
  // Get field number
  int pos = name.indexOf( '_' );

  if ( pos == -1 )
  {
    return -1;
  }

  return name.left( pos ).toInt();
}

int QgsGrassProvider::grassLayerType( QString name )
{
  int pos = name.indexOf( '_' );

  if ( pos == -1 )
  {
    return -1;
  }

  QString ts = name.right( name.length() - pos - 1 );
  if ( ts.compare( "point" ) == 0 )
  {
    return GV_POINT; // ?! centroids may be points
  }
  else if ( ts.compare( "line" ) == 0 )
  {
    return GV_LINES;
  }
  else if ( ts.compare( "face" ) == 0 )
  {
    return GV_FACE;
  }
  else if ( ts.compare( "polygon" ) == 0 )
  {
    return GV_AREA;
  }

  return -1;
}

void QgsGrassProvider::onDataChanged()
{
  QgsDebugMsg( "entered" );
  update();
  emit dataChanged();
}

//-----------------------------------------  Edit -------------------------------------------------------

bool QgsGrassProvider::isGrassEditable( void )
{
  QgsDebugMsg( "entered" );

  if ( !isValid() )
    return false;

  /* Check if current user is owner of mapset */
  if ( G__mapset_permissions2( mGrassObject.gisdbase().toUtf8().data(), mGrassObject.location().toUtf8().data(), mGrassObject.mapset().toUtf8().data() ) != 1 )
    return false;

  // TODO: check format? (cannot edit OGR layers)

  return true;
}

bool QgsGrassProvider::isEdited( void )
{
  QgsDebugMsgLevel( "entered", 3 );
  return ( mEditBuffer );
}

void QgsGrassProvider::freeze()
{
  QgsDebugMsg( "entered" );

  if ( !isValid() )
  {
    return;
  }

  mValid = false;

  if ( mLayer )
  {
    mLayer->close();
    mLayer->map()->close(); // closes all iterators, blocking
    mLayer = 0;
  }
}

void QgsGrassProvider::thaw()
{
  QgsDebugMsg( "entered" );

  if ( !openLayer() )
  {
    QgsDebugMsg( "Cannot open layer" );
    return;
  }

  loadMapInfo();

  mValid = true;
}

bool QgsGrassProvider::closeEdit( bool newMap, QgsVectorLayer *vectorLayer )
{
  QgsDebugMsg( "entered" );

  if ( !isValid() )
  {
    QgsDebugMsg( "not valid" );
    return false;
  }

  mEditBuffer = 0;
  mEditLayer = 0;
  mLayer->closeEdit();
  if ( mLayer->map()->closeEdit( newMap ) )
  {
    loadMapInfo();
    if ( vectorLayer )
    {
      vectorLayer->updateFields();
    }
    connect( mLayer->map(), SIGNAL( dataChanged() ), SLOT( onDataChanged() ) );
    emit fullExtentCalculated();
    return true;
  }
  return false;
}

void QgsGrassProvider::ensureUpdated()
{
  // TODO
#if 0
  int mapId = mLayers[mLayerId].mapId;
  if ( mapOutdated( mapId ) )
  {
    updateMap( mapId );
  }
  if ( map()Version < map()s[mapId].version )
  {
    update();
  }
  if ( attributesOutdated( mapId ) )
  {
    loadAttributes( mLayers[mLayerId] );
  }
#endif
}

int QgsGrassProvider::numLines( void )
{
  QgsDebugMsg( "entered" );

  //return ( Vect_get_num_lines( map() ) );
  return mLayer->map()->numLines();
}

int QgsGrassProvider::numNodes( void )
{
  QgsDebugMsg( "entered" );

  return ( Vect_get_num_nodes( map() ) );
}

int QgsGrassProvider::readLine( struct line_pnts *Points, struct line_cats *Cats, int line )
{
  QgsDebugMsgLevel( "entered", 3 );

  if ( Points )
  {
    Vect_reset_line( Points );
  }

  if ( Cats )
  {
    Vect_reset_cats( Cats );
  }

  if ( !map() )
  {
    return -1;
  }

  if ( !Vect_line_alive( map(), line ) )
  {
    return -1;
  }

  int type = -1;
  G_TRY
  {
    type = Vect_read_line( map(), mPoints, mCats, line );
  }
  G_CATCH( QgsGrass::Exception &e )
  {
    QgsDebugMsg( QString( "Cannot read line : %1" ).arg( e.what() ) );
  }
  return type;
}

bool QgsGrassProvider::nodeCoor( int node, double *x, double *y )
{
  QgsDebugMsgLevel( "entered", 3 );

  if ( !Vect_node_alive( map(), node ) )
  {
    *x = 0.0;
    *y = 0.0;
    return false;
  }

  Vect_get_node_coor( map(), node, x, y, NULL );
  return true;
}

bool QgsGrassProvider::lineNodes( int line, int *node1, int *node2 )
{
  QgsDebugMsgLevel( "entered", 3 );

  if ( !Vect_line_alive( map(), line ) )
  {
    *node1 = 0;
    *node2 = 0;
    return false;
  }

#if GRASS_VERSION_MAJOR < 7
  Vect_get_line_nodes( map(), line, node1, node2 );
#else
  /* points don't have topology in GRASS >= 7 */
  *node1 = 0;
  *node2 = 0;
#endif
  return true;
}

int QgsGrassProvider::writeLine( int type, struct line_pnts *Points, struct line_cats *Cats )
{
  QgsDebugMsg( QString( "n_points = %1 n_cats = %2" ).arg( Points->n_points ).arg( Cats->n_cats ) );

  if ( !isEdited() )
    return -1;

  return (( int ) Vect_write_line( map(), type, Points, Cats ) );
}

int QgsGrassProvider::rewriteLine( int oldLid, int type, struct line_pnts *Points, struct line_cats *Cats )
{
  QgsDebugMsg( QString( "n_points = %1 n_cats = %2" ).arg( Points->n_points ).arg( Cats->n_cats ) );

  if ( !map() || !isEdited() )
  {
    return -1;
  }

  int newLid = -1;
  G_TRY
  {
    newLid = Vect_rewrite_line_function_pointer( map(), oldLid, type, Points, Cats );

    // oldLids are maping to the very first, original version (used by undo)
    int oldestLid = oldLid;
    if ( mLayer->map()->oldLids().contains( oldLid ) ) // if it was changed already
    {
      oldestLid = mLayer->map()->oldLids().value( oldLid );
    }

    QgsDebugMsg( QString( "oldLid = %1 oldestLid = %2 newLine = %3" ).arg( oldLid ).arg( oldestLid ).arg( newLid ) );
    QgsDebugMsg( QString( "oldLids : %1 -> %2" ).arg( newLid ).arg( oldestLid ) );
    mLayer->map()->oldLids()[newLid] = oldestLid;
    QgsDebugMsg( QString( "newLids : %1 -> %2" ).arg( oldestLid ).arg( newLid ) );
    mLayer->map()->newLids()[oldestLid] = newLid;
  }
  G_CATCH( QgsGrass::Exception &e )
  {
    QgsDebugMsg( QString( "Cannot write line : %1" ).arg( e.what() ) );
  }
  return newLid;
}


int QgsGrassProvider::deleteLine( int line )
{
  QgsDebugMsg( "entered" );

  if ( !isEdited() )
    return -1;

  return ( Vect_delete_line_function_pointer( map(), line ) );
}

int QgsGrassProvider::findLine( double x, double y, int type, double threshold )
{
  QgsDebugMsgLevel( "entered", 3 );

  return ( Vect_find_line( map(), x, y, 0, type, threshold, 0, 0 ) );
}

int QgsGrassProvider::findNode( double x, double y, double threshold )
{
  return ( Vect_find_node( map(), x, y, 0, threshold, 0 ) );
}

bool QgsGrassProvider::lineAreas( int line, int *left, int *right )
{
  QgsDebugMsgLevel( "entered", 3 );

  if ( !Vect_line_alive( map(), line ) )
  {
    *left = 0;
    *right = 0;
    return false;
  }

  Vect_get_line_areas( map(), line, left, right );
  return true;
}

int QgsGrassProvider::isleArea( int isle )
{
  QgsDebugMsgLevel( "entered", 3 );

  if ( !Vect_isle_alive( map(), isle ) )
  {
    return 0;
  }

  return ( Vect_get_isle_area( map(), isle ) );
}

int QgsGrassProvider::centroidArea( int centroid )
{
  QgsDebugMsgLevel( "entered", 3 );

  if ( !Vect_line_alive( map(), centroid ) )
  {
    return 0;
  }

  return ( Vect_get_centroid_area( map(), centroid ) );
}

int QgsGrassProvider::nodeNLines( int node )
{
  QgsDebugMsgLevel( "entered", 3 );

  if ( !Vect_node_alive( map(), node ) )
  {
    return 0;
  }

  return ( Vect_get_node_n_lines( map(), node ) );
}

int QgsGrassProvider::nodeLine( int node, int idx )
{
  QgsDebugMsgLevel( "entered", 3 );

  if ( !Vect_node_alive( map(), node ) )
  {
    return 0;
  }

  return ( Vect_get_node_line( map(), node, idx ) );
}

int QgsGrassProvider::lineAlive( int line )
{
  QgsDebugMsgLevel( "entered", 3 );

  return ( Vect_line_alive( map(), line ) );
}

int QgsGrassProvider::nodeAlive( int node )
{
  QgsDebugMsgLevel( "QgsGrassProvider::nodeAlive", 3 );

  return ( Vect_node_alive( map(), node ) );
}

int QgsGrassProvider::numUpdatedLines( void )
{
  QgsDebugMsg( QString( "numUpdatedLines = %1" ).arg( Vect_get_num_updated_lines( map() ) ) );

  return ( Vect_get_num_updated_lines( map() ) );
}

int QgsGrassProvider::numUpdatedNodes( void )
{
  QgsDebugMsg( QString( "numUpdatedNodes = %1" ).arg( Vect_get_num_updated_nodes( map() ) ) );

  return ( Vect_get_num_updated_nodes( map() ) );
}

int QgsGrassProvider::updatedLine( int idx )
{
  QgsDebugMsg( QString( "idx = %1" ).arg( idx ) );
  QgsDebugMsg( QString( "  updatedLine = %1" ).arg( Vect_get_updated_line( map(), idx ) ) );

  return ( Vect_get_updated_line( map(), idx ) );
}

int QgsGrassProvider::updatedNode( int idx )
{
  QgsDebugMsg( QString( "idx = %1" ).arg( idx ) );
  QgsDebugMsg( QString( "  updatedNode = %1" ).arg( Vect_get_updated_node( map(), idx ) ) );

  return ( Vect_get_updated_node( map(), idx ) );
}

// ------------------ Attributes -------------------------------------------------

QString QgsGrassProvider::key( int field )
{
  QgsDebugMsg( QString( "field = %1" ).arg( field ) );

  struct field_info *fi = Vect_get_field( map(), field ); // should work also with field = 0
  if ( !fi )
  {
    QgsDebugMsg( "No field info -> no attributes" );
    return QString();
  }

  return QString::fromUtf8( fi->key );
}

QgsAttributeMap *QgsGrassProvider::attributes( int field, int cat )
{
  QgsDebugMsg( QString( "field = %1 cat = %2" ).arg( field ).arg( cat ) );

  QgsAttributeMap *att = new QgsAttributeMap;

  struct  field_info *fi = Vect_get_field( map(), field ); // should work also with field = 0

  // Read attributes
  if ( !fi )
  {
    QgsDebugMsg( "No field info -> no attributes" );
    return att;
  }

  QgsDebugMsg( "Field info found -> open database" );
  setMapset();
  dbDriver *driver = db_start_driver_open_database( fi->driver, fi->database );

  if ( !driver )
  {
    QgsDebugMsg( QString( "Cannot open database %1 by driver %2" ).arg( fi->database ).arg( fi->driver ) );
    return att;
  }

  QgsDebugMsg( "Database opened -> read attributes" );

  dbString dbstr;
  db_init_string( &dbstr );
  QString query;
  query.sprintf( "select * from %s where %s = %d", fi->table, fi->key, cat );
  db_set_string( &dbstr, query.toUtf8().data() );

  QgsDebugMsg( QString( "SQL: %1" ).arg( db_get_string( &dbstr ) ) );

  dbCursor databaseCursor;
  if ( db_open_select_cursor( driver, &dbstr, &databaseCursor, DB_SCROLL ) != DB_OK )
  {
    db_close_database_shutdown_driver( driver );
    QgsDebugMsg( "Cannot select attributes from table" );
    return att;
  }

  int nRecords = db_get_num_rows( &databaseCursor );
  QgsDebugMsg( QString( "Number of records: %1" ).arg( nRecords ) );

  if ( nRecords < 1 )
  {
    db_close_database_shutdown_driver( driver );
    QgsDebugMsg( "No DB record" );
    return att;
  }

  dbTable  *databaseTable = db_get_cursor_table( &databaseCursor );
  int nColumns = db_get_table_number_of_columns( databaseTable );

  int more;
  if ( db_fetch( &databaseCursor, DB_NEXT, &more ) != DB_OK )
  {
    db_close_database_shutdown_driver( driver );
    QgsDebugMsg( "Cannot fetch DB record" );
    return att;
  }

  // Read columns' description
  for ( int i = 0; i < nColumns; i++ )
  {
    dbColumn *column = db_get_table_column( databaseTable, i );
    db_convert_column_value_to_string( column, &dbstr );

    QString v = mEncoding->toUnicode( db_get_string( &dbstr ) );
    QgsDebugMsg( QString( "Value: %1" ).arg( v ) );
    att->insert( i, QVariant( v ) );
  }

  db_close_cursor( &databaseCursor );
  db_close_database_shutdown_driver( driver );
  db_free_string( &dbstr );

  return att;
}



int QgsGrassProvider::numDbLinks( void )
{
  QgsDebugMsg( "entered" );

  return ( Vect_get_num_dblinks( map() ) );
}

int QgsGrassProvider::dbLinkField( int link )
{
  QgsDebugMsg( "entered" );

  struct  field_info *fi = Vect_get_dblink( map(), link );

  if ( !fi )
    return 0;

  return ( fi->number );
}

bool QgsGrassProvider::isTopoType() const
{
  return isTopoType( mLayerType );
}

bool QgsGrassProvider::isTopoType( int layerType )
{
  return layerType == TOPO_POINT || layerType == TOPO_LINE || layerType == TOPO_NODE;
}

void QgsGrassProvider::setTopoFields()
{
  mTopoFields.append( QgsField( "id", QVariant::Int ) );

  if ( mLayerType == TOPO_POINT )
  {
    mTopoFields.append( QgsField( "type", QVariant::String ) );
    mTopoFields.append( QgsField( "node", QVariant::Int ) );
  }
  else if ( mLayerType == TOPO_LINE )
  {
    mTopoFields.append( QgsField( "type", QVariant::String ) );
    mTopoFields.append( QgsField( "node1", QVariant::Int ) );
    mTopoFields.append( QgsField( "node2", QVariant::Int ) );
    mTopoFields.append( QgsField( "left", QVariant::Int ) );
    mTopoFields.append( QgsField( "right", QVariant::Int ) );
  }
  else if ( mLayerType == TOPO_NODE )
  {
    mTopoFields.append( QgsField( "lines", QVariant::String ) );
  }
}

void QgsGrassProvider::startEditing( QgsVectorLayer *vectorLayer )
{
  QgsDebugMsg( "uri = " +  dataSourceUri() );
  if ( !vectorLayer || !vectorLayer->editBuffer() )
  {
    QgsDebugMsg( "vector or buffer is null" );
    return;
  }
  mEditLayer = vectorLayer;
  if ( !isValid() || !isGrassEditable() )
  {
    QgsDebugMsg( "not valid or not editable" );
    return;
  }
  if ( mEditBuffer )
  {
    QgsDebugMsg( "already edited" );
    return;
  }

  // disconnect dataChanged() because the changes are done here and we know about them
  disconnect( mLayer->map(), SIGNAL( dataChanged() ), this, SLOT( onDataChanged() ) );
  mLayer->map()->startEdit();
  mLayer->startEdit();

  mEditBuffer = vectorLayer->editBuffer();
  connect( mEditBuffer, SIGNAL( featureAdded( QgsFeatureId ) ), SLOT( onFeatureAdded( QgsFeatureId ) ) );
  connect( mEditBuffer, SIGNAL( featureDeleted( QgsFeatureId ) ), SLOT( onFeatureDeleted( QgsFeatureId ) ) );
  connect( mEditBuffer, SIGNAL( geometryChanged( QgsFeatureId, QgsGeometry & ) ), SLOT( onGeometryChanged( QgsFeatureId, QgsGeometry & ) ) );
  connect( mEditBuffer, SIGNAL( attributeValueChanged( QgsFeatureId, int, const QVariant & ) ), SLOT( onAttributeValueChanged( QgsFeatureId, int, const QVariant & ) ) );
  connect( mEditBuffer, SIGNAL( attributeAdded( int ) ), SLOT( onAttributeAdded( int ) ) );
  connect( mEditBuffer, SIGNAL( attributeDeleted( int ) ), SLOT( onAttributeDeleted( int ) ) );
  connect( vectorLayer, SIGNAL( beforeCommitChanges() ), SLOT( onBeforeCommitChanges() ) );
  connect( vectorLayer, SIGNAL( beforeRollBack() ), SLOT( onBeforeRollBack() ) );
  connect( vectorLayer, SIGNAL( editingStopped() ), SLOT( onEditingStopped() ) );

  connect( vectorLayer->undoStack(), SIGNAL( indexChanged( int ) ), this, SLOT( onUndoIndexChanged( int ) ) );

  // let qgis know (attribute table etc.) that we added topo symbol field
  vectorLayer->updateFields();
  mEditLayerFields = vectorLayer->fields();

  // TODO: enable cats editing once all consequences are implemented
  // disable cat and topo symbol editing
  vectorLayer->setFieldEditable( mLayer->keyColumn(), false );
  vectorLayer->setFieldEditable( mLayer->fields().size() - 1, false );

  QgsDebugMsg( "edit started" );
}

void QgsGrassProvider::setPoints( struct line_pnts *points, const QgsAbstractGeometryV2 * geometry )
{
  if ( !points )
  {
    return;
  }
  Vect_reset_line( points );
  if ( !geometry )
  {
    return;
  }
  if ( geometry->wkbType() == QgsWKBTypes::Point )
  {
    const QgsPointV2* point = dynamic_cast<const QgsPointV2*>( geometry );
    if ( point )
    {
      Vect_append_point( points, point->x(), point->y(), point->z() );
      QgsDebugMsg( QString( "x = %1 y = %2" ).arg( point->x() ).arg( point->y() ) );
    }
  }
  else if ( geometry->wkbType() == QgsWKBTypes::LineString )
  {
    const QgsLineStringV2* lineString = dynamic_cast<const QgsLineStringV2*>( geometry );
    if ( lineString )
    {
      for ( int i = 0; i < lineString->numPoints(); i++ )
      {
        QgsPointV2 point = lineString->pointN( i );
        Vect_append_point( points, point.x(), point.y(), point.z() );
      }
    }
  }
  else if ( geometry->wkbType() == QgsWKBTypes::Polygon )
  {
    const QgsPolygonV2* polygon = dynamic_cast<const QgsPolygonV2*>( geometry );
    if ( polygon && polygon->exteriorRing() )
    {
      QgsLineStringV2* lineString = polygon->exteriorRing()->curveToLine();
      if ( lineString )
      {
        for ( int i = 0; i < lineString->numPoints(); i++ )
        {
          QgsPointV2 point = lineString->pointN( i );
          Vect_append_point( points, point.x(), point.y(), point.z() );
        }
      }
    }
  }
  else
  {
    QgsDebugMsg( "unknown type : " + geometry->geometryType() );
  }
}

void QgsGrassProvider::onFeatureAdded( QgsFeatureId fid )
{
  // fid is negative for new features

  int lid = QgsGrassFeatureIterator::lidFromFid( fid );
  int cat = QgsGrassFeatureIterator::catFromFid( fid );

  QgsDebugMsg( QString( "fid = %1 lid = %2 cat = %3" ).arg( fid ).arg( lid ).arg( cat ) );

  Vect_reset_cats( mCats );
  int realLine = 0; // number of line to be rewritten if exists
  int newCat = 0;

  // TODO: get also old type if it is feature previously deleted
  int type = 0;

  if ( FID_IS_NEW( fid ) )
  {
    type = mNewFeatureType == GV_AREA ? GV_BOUNDARY : mNewFeatureType;
    // geometry
    const QgsAbstractGeometryV2 *geometry = 0;
    if ( !mEditBuffer->addedFeatures().contains( fid ) )
    {
#ifdef QGISDEBUG
      QgsDebugMsg( "the feature is missing in buffer addedFeatures :" );

      Q_FOREACH ( QgsFeatureId id, mEditBuffer->addedFeatures().keys() )
      {
        QgsDebugMsg( QString( "addedFeatures : id = %1" ).arg( id ) );
      }
#endif
      return;
    }
    QgsFeature feature = mEditBuffer->addedFeatures().value( fid );
    if ( feature.geometry() )
    {
      geometry = feature.geometry()->geometry();
    }
    else
    {
      QgsDebugMsg( "feature does not have geometry" );
    }
    if ( !geometry )
    {
      QgsDebugMsg( "geometry is null" );
      return;
    }

    setPoints( mPoints, geometry );

    QgsFeatureMap& addedFeatures = const_cast<QgsFeatureMap&>( mEditBuffer->addedFeatures() );

    // change polygon to linestring
    QgsWKBTypes::Type wkbType = QgsWKBTypes::flatType( geometry->wkbType() );
    if ( wkbType == QgsWKBTypes::Polygon )
    {
      const QgsPolygonV2* polygon = dynamic_cast<const QgsPolygonV2*>( addedFeatures[fid].geometry()->geometry() );
      if ( polygon )
      {
        QgsLineStringV2* lineString = polygon->exteriorRing()->curveToLine();
        addedFeatures[fid].setGeometry( new QgsGeometry( lineString ) );
      }
      // TODO: create also centroid and add it to undo
    }

    // add new category
    // TODO: add category also to boundary if user defined at least one attribute?
    if ( type != GV_BOUNDARY )
    {
      // TODO: redo of deleted new features - save new cats somewhere,
      // resetting fid probably is not possible because it is stored in undo commands and used in buffer maps

      // It may be that user manualy entered cat value
      const QgsFeature &feature = mEditBuffer->addedFeatures()[fid];
      int catIndex = feature.fields()->indexFromName( mLayer->keyColumnName() );
      if ( catIndex != -1 )
      {
        QVariant userCatVariant = feature.attributes().value( catIndex );
        if ( !userCatVariant.isNull() )
        {
          newCat = userCatVariant.toInt();
          QgsDebugMsg( QString( "user defined newCat = %1" ).arg( newCat ) );
        }
      }
      if ( newCat == 0 )
      {
        QgsDebugMsg( QString( "get new cat for cidxFieldIndex() = %1" ).arg( mLayer->cidxFieldIndex() ) );
        if ( mLayer->cidxFieldIndex() == -1 )
        {
          // No features with this field yet in map
          newCat = 1;
        }
        else
        {
          newCat = cidxGetMaxCat( mLayer->cidxFieldIndex() ) + 1;
        }
      }
      QgsDebugMsg( QString( "newCat = %1" ).arg( newCat ) );
      Vect_cat_set( mCats, mLayerField, newCat );

      if ( mLayer->hasTable() )
      {
        addedFeatures[fid].setAttribute( mLayer->keyColumn(), newCat );
      }
      else
      {
        addedFeatures[fid].setAttribute( 0, newCat );
      }
      mLayer->map()->newCats()[fid] = newCat;
      QgsDebugMsg( QString( "newCats[%1] = %2" ).arg( fid ).arg( newCat ) );

      QString error;
      // if the cat is user defined, the record may alredy exist
      if ( mLayer->attributes().contains( newCat ) )
      {
        QgsDebugMsg( "record exists" );
        // TODO: open warning dialog?
        // For now we are expecting that user knows what he is doing.
        // We update existing record by non null values and set feature null values to existing values
        mLayer->updateAttributes( newCat, feature, error ); // also updates feature by existing non null attributes

        // There may be other new features with the same cat which we have to update
        QgsFeatureMap& addedFeatures = const_cast<QgsFeatureMap&>( mEditBuffer->addedFeatures() );
        Q_FOREACH ( QgsFeatureId addedFid, addedFeatures.keys() )
        {
          if ( addedFid == fid )
          {
            continue;
          }
          int addedCat = mLayer->map()->newCats().value( addedFid ); // it should always exist
          QgsDebugMsg( QString( "addedFid = %1 addedCat = %2" ).arg( addedFid ).arg( addedCat ) );
          if ( addedCat == newCat )
          {
            QgsFeature addedFeature = addedFeatures[addedFid];
            // TODO: better to update form mLayer->attributes() ?
            for ( int i = 0; i < feature.fields()->size(); i++ )
            {
              if ( feature.fields()->field( i ).name() == QgsGrassVectorMap::topoSymbolFieldName() )
              {
                continue;
              }
              if ( feature.attributes()[i].isNull() )
              {
                continue;
              }
              addedFeature.setAttribute( i, feature.attributes()[i] );
            }
            addedFeatures[addedFid] = addedFeature;
          }
        }

        // Update all changed attributes
        // TODO: table does not get refreshed immediately
        QgsChangedAttributesMap &changedAttributes = const_cast<QgsChangedAttributesMap &>( mEditBuffer->changedAttributeValues() );
        Q_FOREACH ( QgsFeatureId changedFid, changedAttributes.keys() )
        {
          int changedCat = QgsGrassFeatureIterator::catFromFid( changedFid );
          int realChangedCat = changedCat;
          if ( mLayer->map()->newCats().contains( changedFid ) )
          {
            realChangedCat = mLayer->map()->newCats().value( changedFid );
          }
          QgsDebugMsg( QString( "changedFid = %1 changedCat = %2 realChangedCat = %3" )
                       .arg( changedFid ).arg( changedCat ).arg( realChangedCat ) );
          if ( realChangedCat == newCat )
          {
            QgsAttributeMap attributeMap = changedAttributes[changedFid];
            Q_FOREACH ( int index, attributeMap.keys() )
            {
              attributeMap[index] = feature.attributes().value( index );
            }
            changedAttributes[changedFid] = attributeMap;
          }
        }
      }
      else
      {
        if ( mLayer->hasTable() )
        {
          mLayer->insertAttributes( newCat, feature, error );
          if ( !error.isEmpty() )
          {
            QgsGrass::warning( error );
          }
        }
      }
    }
  }
  else
  {
    QgsDebugMsg( "undo of old deleted feature" );
    int oldLid = lid;
    realLine = oldLid;
    int realCat = cat;
    if ( mLayer->map()->newLids().contains( oldLid ) ) // if it was changed already
    {
      realLine = mLayer->map()->newLids().value( oldLid );
    }
    if ( mLayer->map()->newCats().contains( fid ) )
    {
      realCat = mLayer->map()->newCats().value( fid );
    }
    QgsDebugMsg( QString( "fid = %1 lid = %2 realLine = %3 cat = %4 realCat = %5" )
                 .arg( fid ).arg( lid ).arg( realLine ).arg( cat ).arg( realCat ) );

    if ( realLine > 0 )
    {
      QgsDebugMsg( QString( "reading realLine = %1" ).arg( realLine ) );
      int realType = readLine( mPoints, mCats, realLine );
      if ( realType > 0 )
      {
        QgsDebugMsg( QString( "the line exists realType = %1, add the cat to that line" ).arg( realType ) );
        type = realType;
      }
      else // should not happen
      {
        QgsDebugMsg( "cannot read realLine" );
        return;
      }
    }
    else
    {
      QgsDebugMsg( QString( "the line does not exist -> restore old geometry" ) );
      const QgsAbstractGeometryV2 *geometry = 0;

      // If it is not new feature, we should have the geometry in oldGeometries
      if ( mLayer->map()->oldGeometries().contains( lid ) )
      {
        geometry = mLayer->map()->oldGeometries().value( lid );
        type = mLayer->map()->oldTypes().value( lid );
      }
      else
      {
        QgsDebugMsg( "geometry of old, previously deleted feature not found" );
        return;
      }
      if ( !geometry )
      {
        QgsDebugMsg( "geometry is null" );
        return;
      }
      setPoints( mPoints, geometry );
    }

    // TODO: orig field, maybe different?
    int field = mLayerField;
    QgsDebugMsg( QString( "field = %1 realCat = %2" ).arg( field ).arg( realCat ) );
    if ( realCat > 0 )
    {
      Vect_cat_set( mCats, field, realCat );
    }

    // restore attributes
    if ( realCat > 0 )
    {
      QString error;
      bool recordExists = mLayer->recordExists( realCat, error );
      QgsDebugMsg( QString( "recordExists = %1 error = %2" ).arg( recordExists ).arg( error ) );
      if ( !recordExists && error.isEmpty() )
      {
        QgsDebugMsg( "record does not exist -> restore attributes" );
        error.clear();
        mLayer->reinsertAttributes( realCat, error );
        if ( !error.isEmpty() )
        {
          QgsGrass::warning( tr( "Cannot restore record with cat %1" ).arg( realCat ) );
        }
      }
    }
  }

  QgsDebugMsg( QString( "type = %1 mPoints->n_points = %2" ).arg( type ).arg( mPoints->n_points ) );
  if ( type > 0 && mPoints->n_points > 0 )
  {
    int newLid = 0;
    mLayer->map()->lockReadWrite();
    if ( realLine > 0 )
    {
      newLid = rewriteLine( realLine, type, mPoints, mCats );
    }
    else
    {
      // TODO: use writeLine() and move setting oldLids, newLids there
      newLid = Vect_write_line( map(), type, mPoints, mCats );
      // fid may be new (negative) or old, if this is delete undo
      int oldLid = QgsGrassFeatureIterator::lidFromFid( fid );

      mLayer->map()->oldLids()[newLid] = oldLid;
      mLayer->map()->newLids()[oldLid] = newLid;
      QgsDebugMsg( QString( "oldLid = %1 newLine = %2" ).arg( oldLid ).arg( newLid ) );

      QgsDebugMsg( QString( "oldLids : %1 -> %2" ).arg( newLid ).arg( oldLid ) );
      mLayer->map()->oldLids()[newLid] = oldLid;
      QgsDebugMsg( QString( "newLids : %1 -> %2" ).arg( oldLid ).arg( newLid ) );
      mLayer->map()->newLids()[oldLid] = newLid;
    }
    mLayer->map()->unlockReadWrite();

    QgsDebugMsg( QString( "newLine = %1" ).arg( newLid ) );

    setAddedFeaturesSymbol();
  }
  QgsDebugMsg( QString( "mLayer->cidxFieldIndex() = %1 cidxFieldNumCats() = %2" )
               .arg( mLayer->cidxFieldIndex() ).arg( mLayer->cidxFieldNumCats() ) );
}

void QgsGrassProvider::onFeatureDeleted( QgsFeatureId fid )
{
  QgsDebugMsg( QString( "fid = %1" ).arg( fid ) );

  int oldLid = QgsGrassFeatureIterator::lidFromFid( fid );
  int cat = QgsGrassFeatureIterator::catFromFid( fid );
  int realLine = oldLid;
  int realCat = cat;
  if ( mLayer->map()->newLids().contains( oldLid ) ) // if it was changed already
  {
    realLine = mLayer->map()->newLids().value( oldLid );
  }
  if ( mLayer->map()->newCats().contains( fid ) )
  {
    realCat = mLayer->map()->newCats().value( fid );
  }

  QgsDebugMsg( QString( "fid = %1 oldLid = %2 realLine = %3 cat = %4 realCat = %5" )
               .arg( fid ).arg( oldLid ).arg( realLine ).arg( cat ).arg( realCat ) );

  int type = 0;
  mLayer->map()->lockReadWrite();
  G_TRY
  {
    int type = readLine( mPoints, mCats, realLine );
    if ( type <= 0 )
    {
      QgsDebugMsg( "cannot read line" );
    }
    else
    {
      // store only the first original geometry if it is not new feature, changed geometries are stored in the buffer
      if ( oldLid > 0 && !mLayer->map()->oldGeometries().contains( oldLid ) )
      {
        QgsAbstractGeometryV2 *geometry = mLayer->map()->lineGeometry( oldLid );
        if ( geometry )
        {
          QgsDebugMsg( QString( "save old geometry of oldLid = %1" ).arg( oldLid ) );
          mLayer->map()->oldGeometries().insert( oldLid, geometry );
          mLayer->map()->oldTypes().insert( oldLid, type );
        }
        else
        {
          QgsDebugMsg( QString( "cannot read geometry of oldLid = %1" ).arg( oldLid ) );
        }
      }

      if ( realCat > 0 )
      {
        if ( Vect_field_cat_del( mCats, mLayerField, realCat ) == 0 )
        {
          // should not happen
          QgsDebugMsg( "the line does not have old category" );
        }
      }
      QgsDebugMsg( QString( "mCats->n_cats = %1" ).arg( mCats->n_cats ) );
      if ( mCats->n_cats > 0 )
      {
        QgsDebugMsg( "the line has more cats -> rewrite" );
        int newLid = rewriteLine( realLine, type, mPoints, mCats );
        Q_UNUSED( newLid )
      }
      else
      {
        QgsDebugMsg( "no more cats on the line -> delete" );

        Vect_delete_line_function_pointer( map(), realLine );
        // oldLids are maping to the very first, original version (used by undo)
        int oldestLid = oldLid;
        if ( mLayer->map()->oldLids().contains( oldLid ) )
        {
          oldestLid = mLayer->map()->oldLids().value( oldLid );
        }
        QgsDebugMsg( QString( "oldLid = %1 oldestLid = %2" ).arg( oldLid ).arg( oldestLid ) );
        QgsDebugMsg( QString( "newLids : %1 -> 0" ).arg( oldestLid ) );
        mLayer->map()->newLids()[oldestLid] = 0;
      }

      // Delete record if orphan
      if ( realCat > 0 )
      {
        QString error;
        bool orphan = mLayer->isOrphan( realCat, error );
        QgsDebugMsg( QString( "orphan = %1 error = %2" ).arg( orphan ).arg( error ) );
        if ( orphan && error.isEmpty() )
        {
          QgsDebugMsg( QString( "realCat = %1 is orphan -> delete record" ).arg( realCat ) );
          error.clear();
          mLayer->deleteAttribute( realCat, error );
          if ( !error.isEmpty() )
          {
            QgsGrass::warning( tr( "Cannot delete orphan record with cat %1" ).arg( realCat ) );
          }
        }
      }
    }
  }
  G_CATCH( QgsGrass::Exception &e )
  {
    QgsDebugMsg( QString( "Cannot rewrite/delete line : %1" ).arg( e.what() ) );
  }
  mLayer->map()->unlockReadWrite();

  if ( type == GV_BOUNDARY || type == GV_CENTROID )
  {
    setAddedFeaturesSymbol();
  }
}

void QgsGrassProvider::onGeometryChanged( QgsFeatureId fid, QgsGeometry &geom )
{
  int oldLid = QgsGrassFeatureIterator::lidFromFid( fid );
  int realLine = oldLid;
  if ( mLayer->map()->newLids().contains( oldLid ) ) // if it was changed already
  {
    realLine = mLayer->map()->newLids().value( oldLid );
  }
  QgsDebugMsg( QString( "fid = %1 oldLid = %2 realLine = %3" ).arg( fid ).arg( oldLid ).arg( realLine ) );

  int type = readLine( mPoints, mCats, realLine );
  QgsDebugMsg( QString( "type = %1 n_points = %2" ).arg( type ).arg( mPoints->n_points ) );
  if ( type < 1 ) // error
  {
    return;
  }

  // store only the first original geometry if it is not new feature, changed geometries are stored in the buffer
  if ( oldLid > 0 && !mLayer->map()->oldGeometries().contains( oldLid ) )
  {
    QgsAbstractGeometryV2 *geometry = mLayer->map()->lineGeometry( oldLid );
    if ( geometry )
    {
      QgsDebugMsg( QString( "save old geometry of oldLid = %1" ).arg( oldLid ) );
      mLayer->map()->oldGeometries().insert( oldLid, geometry );
      mLayer->map()->oldTypes().insert( oldLid, type );
    }
    else
    {
      QgsDebugMsg( QString( "cannot read geometry of oldLid = %1" ).arg( oldLid ) );
    }
  }

  setPoints( mPoints, geom.geometry() );

  mLayer->map()->lockReadWrite();
  // Vect_rewrite_line may delete/write the line with a new id
  int newLid = rewriteLine( realLine, type, mPoints, mCats );
  Q_UNUSED( newLid )

  mLayer->map()->unlockReadWrite();

  if ( type == GV_BOUNDARY || type == GV_CENTROID )
  {
    setAddedFeaturesSymbol();
  }
}

void QgsGrassProvider::onAttributeValueChanged( QgsFeatureId fid, int idx, const QVariant &value )
{
  QgsDebugMsg( QString( "fid = %1 idx = %2 value = %3" ).arg( fid ).arg( idx ).arg( value.toString() ) );

  int oldLid = QgsGrassFeatureIterator::lidFromFid( fid );
  int cat = QgsGrassFeatureIterator::catFromFid( fid );
  int realLine = oldLid;
  int realCat = cat;
  if ( mLayer->map()->newLids().contains( oldLid ) ) // if it was changed already
  {
    realLine = mLayer->map()->newLids().value( oldLid );
  }
  if ( mLayer->map()->newCats().contains( fid ) )
  {
    realCat = mLayer->map()->newCats().value( fid );
  }
  QgsDebugMsg( QString( "fid = %1 oldLid = %2 realLine = %3 cat = %4 realCat = %5" )
               .arg( fid ).arg( oldLid ).arg( realLine ).arg( cat ).arg( realCat ) );

  // index is for current fields
  if ( idx < 0 || idx > mEditLayer->fields().size() )
  {
    QgsDebugMsg( "index out of range" );
    return;
  }
  QgsField field = mEditLayer->fields()[idx];

  QgsDebugMsg( "field.name() = " + field.name() + " keyColumnName() = " + mLayer->keyColumnName() );
  // TODO: Changing existing category is currently disabled (read only widget set on layer)
  //       bacause it makes it all too complicated
  if ( field.name() == mLayer->keyColumnName() )
  {
    // user changed category -> rewrite line
    QgsDebugMsg( "cat changed -> rewrite line" );
    int type = readLine( mPoints, mCats, realLine );
    if ( type <= 0 )
    {
      QgsDebugMsg( "cannot read line" );
    }
    else
    {
      if ( Vect_field_cat_del( mCats, mLayerField, realCat ) == 0 )
      {
        // should not happen
        QgsDebugMsg( "the line does not have old category" );
      }

      int newCat = value.toInt();
      QgsDebugMsg( QString( "realCat = %1 newCat = %2" ).arg( realCat ).arg( newCat ) );
      if ( newCat == 0 )
      {
        QgsDebugMsg( "new category is 0" );
        // TODO: remove category from line?
      }
      else
      {
        Vect_cat_set( mCats, mLayerField, newCat );
        mLayer->map()->lockReadWrite();
        int newLid = rewriteLine( realLine, type, mPoints, mCats );
        Q_UNUSED( newLid )

        // TODO: - store the new cat somewhere for cats mapping
        //       - insert record if does not exist
        //       - update feature attributes by existing record?

        mLayer->map()->unlockReadWrite();
      }
    }
  }
  else
  {

    if ( realCat > 0 )
    {
      QString error;
      mLayer->changeAttributeValue( realCat, field, value, error );
      if ( !error.isEmpty() )
      {
        QgsGrass::warning( error );
      }
    }
    else
    {
      QgsDebugMsg( "no cat -> add new cat to line" );
      // TODO
    }
  }
}

void QgsGrassProvider::onAttributeAdded( int idx )
{
  QgsDebugMsg( QString( "idx = %1" ).arg( idx ) );
  if ( idx < 0 || idx >= mEditLayer->fields().size() )
  {
    QgsDebugMsg( "index out of range" );
  }
  QString error;
  mLayer->addColumn( mEditLayer->fields()[idx], error );
  if ( !error.isEmpty() )
  {
    QgsDebugMsg( error );
    QgsGrass::warning( error );
    // TODO: remove the column somehow from the layer/buffer - undo?
  }
  else
  {
    mEditLayerFields = mEditLayer->fields();
    emit fieldsChanged();
  }
}

void QgsGrassProvider::onAttributeDeleted( int idx )
{
  QgsDebugMsg( QString( "idx = %1 mEditLayerFields.size() = %2" ).arg( idx ).arg( mEditLayerFields.size() ) );
  // The field was already removed from mEditLayer->fields() -> using stored last version of fields
  if ( idx < 0 || idx >= mEditLayerFields.size() )
  {
    QgsDebugMsg( "index out of range" );
    return;
  }
  QgsField deletedField = mEditLayerFields.at( idx );
  QgsDebugMsg( QString( "deletedField.name() = %1" ).arg( deletedField.name() ) );

  QString error;
  mLayer->deleteColumn( deletedField, error );
  if ( !error.isEmpty() )
  {
    QgsDebugMsg( error );
    QgsGrass::warning( error );
    // TODO: get back the column somehow to the layer/buffer - undo?
  }
  else
  {
    mEditLayerFields = mEditLayer->fields();
    emit fieldsChanged();
  }
}

void QgsGrassProvider::setAddedFeaturesSymbol()
{
  QgsDebugMsg( "entered" );
  if ( !mEditBuffer )
  {
    return;
  }
  QgsFeatureMap& features = const_cast<QgsFeatureMap&>( mEditBuffer->addedFeatures() );
  Q_FOREACH ( QgsFeatureId fid, features.keys() )
  {
    QgsFeature feature = features[fid];
    if ( !feature.geometry() || !feature.geometry()->geometry() )
    {
      continue;
    }
    int lid = QgsGrassFeatureIterator::lidFromFid( fid );
    int realLid = lid;
    if ( mLayer->map()->newLids().contains( lid ) )
    {
      realLid = mLayer->map()->newLids().value( lid );
    }
    QgsDebugMsg( QString( "fid = %1 lid = %2 realLid = %3" ).arg( fid ).arg( lid ).arg( realLid ) );
    QgsGrassVectorMap::TopoSymbol symbol = mLayer->map()->topoSymbol( realLid );
    feature.setAttribute( QgsGrassVectorMap::topoSymbolFieldName(), symbol );
    features[fid] = feature;
  }
}

void QgsGrassProvider::onUndoIndexChanged( int index )
{
  Q_UNUSED( index )
  QgsDebugMsg( QString( "index = %1" ).arg( index ) );
}


bool QgsGrassProvider::addAttributes( const QList<QgsField> &attributes )
{
  Q_UNUSED( attributes );
  // update fields because QgsVectorLayerEditBuffer::commitChanges() checks old /new fields count
  mLayer->updateFields();
  return true;
}

bool QgsGrassProvider::deleteAttributes( const QgsAttributeIds &attributes )
{
  Q_UNUSED( attributes );
  // update fields because QgsVectorLayerEditBuffer::commitChanges() checks old /new fields count
  mLayer->updateFields();
  return true;
}

void QgsGrassProvider::onBeforeCommitChanges()
{
  QgsDebugMsg( "entered" );
}

void QgsGrassProvider::onBeforeRollBack()
{
  QgsDebugMsg( "entered" );
}

void QgsGrassProvider::onEditingStopped()
{
  QgsDebugMsg( "entered" );
  QgsVectorLayer *vectorLayer = qobject_cast<QgsVectorLayer *>( sender() );
  closeEdit( false, vectorLayer );
}

// -------------------------------------------------------------------------------

int QgsGrassProvider::cidxGetNumFields()
{
  return ( Vect_cidx_get_num_fields( map() ) );
}

int QgsGrassProvider::cidxGetFieldNumber( int idx )
{
  if ( idx < 0 || idx >= cidxGetNumFields() )
  {
    QgsDebugMsg( QString( "idx %1 out of range (0,%2)" ).arg( idx ).arg( cidxGetNumFields() - 1 ) );
    return 0;
  }
  return ( Vect_cidx_get_field_number( map(), idx ) );
}

int QgsGrassProvider::cidxGetMaxCat( int idx )
{
  QgsDebugMsg( QString( "idx = %1" ).arg( idx ) );
  if ( idx < 0 || idx >= cidxGetNumFields() )
  {
    QgsDebugMsg( QString( "idx %1 out of range (0,%2)" ).arg( idx ).arg( cidxGetNumFields() - 1 ) );
    return 0;
  }

  int ncats = Vect_cidx_get_num_cats_by_index( map(), idx );
  QgsDebugMsg( QString( "ncats = %1" ).arg( ncats ) );

  if ( ncats == 0 )
  {
    return 0;
  }

  int cat, type, id;
  Vect_cidx_get_cat_by_index( map(), idx, ncats - 1, &cat, &type, &id );

  return cat;
}

QgsGrassVectorMapLayer * QgsGrassProvider::openLayer() const
{
  return mLayer->map()->openLayer( mLayerField );
}

struct Map_info * QgsGrassProvider::map()
{
  Q_ASSERT( mLayer );
  Q_ASSERT( mLayer->map() );
  Q_ASSERT( mLayer->map()->map() );
  return mLayer->map()->map();
}

void QgsGrassProvider::setMapset()
{
  QgsGrass::setMapset( mGrassObject.gisdbase(), mGrassObject.location(), mGrassObject.mapset() );
}

QString QgsGrassProvider::name() const
{
  return GRASS_KEY;
}

QString QgsGrassProvider::description() const
{
  return tr( "GRASS %1 vector provider" ).arg( GRASS_VERSION_MAJOR );
}