bool QgsAttributeTableModel::removeRows( int row, int count, const QModelIndex &parent )
{
  Q_UNUSED( parent );
  QgsDebugMsgLevel( QString( "remove %2 rows at %1 (rows %3, ids %4)" ).arg( row ).arg( count ).arg( mRowIdMap.size() ).arg( mIdRowMap.size() ), 3 );

  // clean old references
  for ( int i = row; i < row + count; i++ )
  {
    mIdRowMap.remove( mRowIdMap[ i ] );
    mRowIdMap.remove( i );
  }

  // update maps
  int n = mRowIdMap.size() + count;
  for ( int i = row + count; i < n; i++ )
  {
    QgsFeatureId id = mRowIdMap[i];
    mIdRowMap[ id ] -= count;
    mRowIdMap[ i-count ] = id;
    mRowIdMap.remove( i );
  }

#ifdef QGISDEBUG
  QgsDebugMsgLevel( QString( "after removal rows %1, ids %2" ).arg( mRowIdMap.size() ).arg( mIdRowMap.size() ), 4 );
  QgsDebugMsgLevel( "id->row", 4 );
  for ( QHash<QgsFeatureId, int>::iterator it = mIdRowMap.begin(); it != mIdRowMap.end(); ++it )
    QgsDebugMsgLevel( QString( "%1->%2" ).arg( FID_TO_STRING( it.key() ) ).arg( *it ), 4 );

  QHash<QgsFeatureId, int>::iterator idit;

  QgsDebugMsgLevel( "row->id", 4 );
  for ( QHash<int, QgsFeatureId>::iterator it = mRowIdMap.begin(); it != mRowIdMap.end(); ++it )
    QgsDebugMsgLevel( QString( "%1->%2" ).arg( it.key() ).arg( FID_TO_STRING( *it ) ), 4 );
#endif

  Q_ASSERT( mRowIdMap.size() == mIdRowMap.size() );

  return true;
}

QgsRasterBlock * QgsRasterResampleFilter::block( int bandNo, QgsRectangle  const & extent, int width, int height, QgsRasterBlockFeedback* feedback )
{
  Q_UNUSED( bandNo );
  QgsDebugMsgLevel( QString( "width = %1 height = %2 extent = %3" ).arg( width ).arg( height ).arg( extent.toString() ), 4 );
  QgsRasterBlock *outputBlock = new QgsRasterBlock();
  if ( !mInput ) return outputBlock;

  double oversampling = 1.0; // approximate global oversampling factor

  if ( mZoomedInResampler || mZoomedOutResampler )
  {
    QgsRasterDataProvider *provider = dynamic_cast<QgsRasterDataProvider*>( mInput->sourceInput() );
    if ( provider && ( provider->capabilities() & QgsRasterDataProvider::Size ) )
    {
      double xRes = extent.width() / width;
      double providerXRes = provider->extent().width() / provider->xSize();
      double pixelRatio = xRes / providerXRes;
      oversampling = ( pixelRatio > mMaxOversampling ) ? mMaxOversampling : pixelRatio;
      QgsDebugMsgLevel( QString( "xRes = %1 providerXRes = %2 pixelRatio = %3 oversampling = %4" ).arg( xRes ).arg( providerXRes ).arg( pixelRatio ).arg( oversampling ), 4 );
    }
    else
    {
      // We don't know exact data source resolution (WMS) so we expect that
      // server data have higher resolution (which is not always true) and use
      // mMaxOversampling
      oversampling = mMaxOversampling;
    }
  }

  QgsDebugMsgLevel( QString( "oversampling %1" ).arg( oversampling ), 4 );

  int bandNumber = 1;

  // Do no oversampling if no resampler for zoomed in / zoomed out (nearest neighbour)
  // We do mZoomedInResampler if oversampling == 1 (otherwise for example reprojected
  // zoom in rasters are never resampled because projector limits resolution.
  if ((( oversampling < 1.0 || qgsDoubleNear( oversampling, 1.0 ) ) && !mZoomedInResampler ) || ( oversampling > 1.0 && !mZoomedOutResampler ) )
  {
    QgsDebugMsgLevel( "No oversampling.", 4 );
    delete outputBlock;
    return mInput->block( bandNumber, extent, width, height, feedback );
  }

  //effective oversampling factors are different to global one because of rounding
  double oversamplingX = ( static_cast< double >( width ) * oversampling ) / width;
  double oversamplingY = ( static_cast< double >( height ) * oversampling ) / height;

  // TODO: we must also increase the extent to get correct result on borders of parts

  int resWidth = width * oversamplingX;
  int resHeight = height * oversamplingY;

  QgsRasterBlock *inputBlock = mInput->block( bandNumber, extent, resWidth, resHeight, feedback );
  if ( !inputBlock || inputBlock->isEmpty() )
  {
    QgsDebugMsg( "No raster data!" );
    delete inputBlock;
    return outputBlock;
  }

  if ( !outputBlock->reset( Qgis::ARGB32_Premultiplied, width, height ) )
  {
    delete inputBlock;
    return outputBlock;
  }

  //resample image
  QImage img = inputBlock->image();

  QImage dstImg = QImage( width, height, QImage::Format_ARGB32_Premultiplied );

  if ( mZoomedInResampler && ( oversamplingX < 1.0 || qgsDoubleNear( oversampling, 1.0 ) ) )
  {
    QgsDebugMsgLevel( "zoomed in resampling", 4 );
    mZoomedInResampler->resample( img, dstImg );
  }
  else if ( mZoomedOutResampler && oversamplingX > 1.0 )
  {
    QgsDebugMsgLevel( "zoomed out resampling", 4 );
    mZoomedOutResampler->resample( img, dstImg );
  }
  else
  {
    // Should not happen
    QgsDebugMsg( "Unexpected resampling" );
    dstImg = img.scaled( width, height );
  }

  outputBlock->setImage( &dstImg );

  delete inputBlock;
  return outputBlock; // No resampling
}

QgsRasterBlock *QgsRasterDataProvider::block( int bandNo, QgsRectangle  const &boundingBox, int width, int height, QgsRasterBlockFeedback *feedback )
{
  QgsDebugMsgLevel( QString( "bandNo = %1 width = %2 height = %3" ).arg( bandNo ).arg( width ).arg( height ), 4 );
  QgsDebugMsgLevel( QString( "boundingBox = %1" ).arg( boundingBox.toString() ), 4 );

  QgsRasterBlock *block = new QgsRasterBlock( dataType( bandNo ), width, height );
  if ( sourceHasNoDataValue( bandNo ) && useSourceNoDataValue( bandNo ) )
  {
    block->setNoDataValue( sourceNoDataValue( bandNo ) );
  }

  if ( block->isEmpty() )
  {
    QgsDebugMsg( "Couldn't create raster block" );
    return block;
  }

  // Read necessary extent only
  QgsRectangle tmpExtent = extent().intersect( &boundingBox );

  if ( tmpExtent.isEmpty() )
  {
    QgsDebugMsg( "Extent outside provider extent" );
    block->setIsNoData();
    return block;
  }

  double xRes = boundingBox.width() / width;
  double yRes = boundingBox.height() / height;
  double tmpXRes, tmpYRes;
  double providerXRes = 0;
  double providerYRes = 0;
  if ( capabilities() & Size )
  {
    providerXRes = extent().width() / xSize();
    providerYRes = extent().height() / ySize();
    tmpXRes = std::max( providerXRes, xRes );
    tmpYRes = std::max( providerYRes, yRes );
    if ( qgsDoubleNear( tmpXRes, xRes ) ) tmpXRes = xRes;
    if ( qgsDoubleNear( tmpYRes, yRes ) ) tmpYRes = yRes;
  }
  else
  {
    tmpXRes = xRes;
    tmpYRes = yRes;
  }

  if ( tmpExtent != boundingBox ||
       tmpXRes > xRes || tmpYRes > yRes )
  {
    // Read smaller extent or lower resolution

    if ( !extent().contains( boundingBox ) )
    {
      QRect subRect = QgsRasterBlock::subRect( boundingBox, width, height, extent() );
      block->setIsNoDataExcept( subRect );
    }

    // Calculate row/col limits (before tmpExtent is aligned)
    int fromRow = std::round( ( boundingBox.yMaximum() - tmpExtent.yMaximum() ) / yRes );
    int toRow = std::round( ( boundingBox.yMaximum() - tmpExtent.yMinimum() ) / yRes ) - 1;
    int fromCol = std::round( ( tmpExtent.xMinimum() - boundingBox.xMinimum() ) / xRes );
    int toCol = std::round( ( tmpExtent.xMaximum() - boundingBox.xMinimum() ) / xRes ) - 1;

    QgsDebugMsgLevel( QString( "fromRow = %1 toRow = %2 fromCol = %3 toCol = %4" ).arg( fromRow ).arg( toRow ).arg( fromCol ).arg( toCol ), 4 );

    if ( fromRow < 0 || fromRow >= height || toRow < 0 || toRow >= height ||
         fromCol < 0 || fromCol >= width || toCol < 0 || toCol >= width )
    {
      // Should not happen
      QgsDebugMsg( "Row or column limits out of range" );
      return block;
    }

    // If lower source resolution is used, the extent must beS aligned to original
    // resolution to avoid possible shift due to resampling
    if ( tmpXRes > xRes )
    {
      int col = std::floor( ( tmpExtent.xMinimum() - extent().xMinimum() ) / providerXRes );
      tmpExtent.setXMinimum( extent().xMinimum() + col * providerXRes );
      col = std::ceil( ( tmpExtent.xMaximum() - extent().xMinimum() ) / providerXRes );
      tmpExtent.setXMaximum( extent().xMinimum() + col * providerXRes );
    }
    if ( tmpYRes > yRes )
    {
      int row = std::floor( ( extent().yMaximum() - tmpExtent.yMaximum() ) / providerYRes );
      tmpExtent.setYMaximum( extent().yMaximum() - row * providerYRes );
      row = std::ceil( ( extent().yMaximum() - tmpExtent.yMinimum() ) / providerYRes );
      tmpExtent.setYMinimum( extent().yMaximum() - row * providerYRes );
    }
    int tmpWidth = std::round( tmpExtent.width() / tmpXRes );
    int tmpHeight = std::round( tmpExtent.height() / tmpYRes );
    tmpXRes = tmpExtent.width() / tmpWidth;
    tmpYRes = tmpExtent.height() / tmpHeight;

    QgsDebugMsgLevel( QString( "Reading smaller block tmpWidth = %1 height = %2" ).arg( tmpWidth ).arg( tmpHeight ), 4 );
    QgsDebugMsgLevel( QString( "tmpExtent = %1" ).arg( tmpExtent.toString() ), 4 );

    QgsRasterBlock *tmpBlock = new QgsRasterBlock( dataType( bandNo ), tmpWidth, tmpHeight );
    if ( sourceHasNoDataValue( bandNo ) && useSourceNoDataValue( bandNo ) )
//.........这里部分代码省略.........

bool QgsVectorLayerRenderer::render()
{
  if ( mGeometryType == QgsWkbTypes::NullGeometry || mGeometryType == QgsWkbTypes::UnknownGeometry )
    return true;

  if ( !mRenderer )
  {
    mErrors.append( QObject::tr( "No renderer for drawing." ) );
    return false;
  }

  bool usingEffect = false;
  if ( mRenderer->paintEffect() && mRenderer->paintEffect()->enabled() )
  {
    usingEffect = true;
    mRenderer->paintEffect()->begin( mContext );
  }

  // Per feature blending mode
  if ( mContext.useAdvancedEffects() && mFeatureBlendMode != QPainter::CompositionMode_SourceOver )
  {
    // set the painter to the feature blend mode, so that features drawn
    // on this layer will interact and blend with each other
    mContext.painter()->setCompositionMode( mFeatureBlendMode );
  }

  mRenderer->startRender( mContext, mFields );

  QString rendererFilter = mRenderer->filter( mFields );

  QgsRectangle requestExtent = mContext.extent();
  mRenderer->modifyRequestExtent( requestExtent, mContext );

  QgsFeatureRequest featureRequest = QgsFeatureRequest()
                                     .setFilterRect( requestExtent )
                                     .setSubsetOfAttributes( mAttrNames, mFields )
                                     .setExpressionContext( mContext.expressionContext() );
  if ( mRenderer->orderByEnabled() )
  {
    featureRequest.setOrderBy( mRenderer->orderBy() );
  }

  const QgsFeatureFilterProvider *featureFilterProvider = mContext.featureFilterProvider();
  if ( featureFilterProvider )
  {
    featureFilterProvider->filterFeatures( mLayer, featureRequest );
  }
  if ( !rendererFilter.isEmpty() && rendererFilter != QLatin1String( "TRUE" ) )
  {
    featureRequest.combineFilterExpression( rendererFilter );
  }

  // enable the simplification of the geometries (Using the current map2pixel context) before send it to renderer engine.
  if ( mSimplifyGeometry )
  {
    double map2pixelTol = mSimplifyMethod.threshold();
    bool validTransform = true;

    const QgsMapToPixel &mtp = mContext.mapToPixel();
    map2pixelTol *= mtp.mapUnitsPerPixel();
    QgsCoordinateTransform ct = mContext.coordinateTransform();

    // resize the tolerance using the change of size of an 1-BBOX from the source CoordinateSystem to the target CoordinateSystem
    if ( ct.isValid() && !ct.isShortCircuited() )
    {
      try
      {
        QgsPointXY center = mContext.extent().center();
        double rectSize = ct.sourceCrs().isGeographic() ? 0.0008983 /* ~100/(40075014/360=111319.4833) */ : 100;

        QgsRectangle sourceRect = QgsRectangle( center.x(), center.y(), center.x() + rectSize, center.y() + rectSize );
        QgsRectangle targetRect = ct.transform( sourceRect );

        QgsDebugMsgLevel( QStringLiteral( "Simplify - SourceTransformRect=%1" ).arg( sourceRect.toString( 16 ) ), 4 );
        QgsDebugMsgLevel( QStringLiteral( "Simplify - TargetTransformRect=%1" ).arg( targetRect.toString( 16 ) ), 4 );

        if ( !sourceRect.isEmpty() && sourceRect.isFinite() && !targetRect.isEmpty() && targetRect.isFinite() )
        {
          QgsPointXY minimumSrcPoint( sourceRect.xMinimum(), sourceRect.yMinimum() );
          QgsPointXY maximumSrcPoint( sourceRect.xMaximum(), sourceRect.yMaximum() );
          QgsPointXY minimumDstPoint( targetRect.xMinimum(), targetRect.yMinimum() );
          QgsPointXY maximumDstPoint( targetRect.xMaximum(), targetRect.yMaximum() );

          double sourceHypothenuse = std::sqrt( minimumSrcPoint.sqrDist( maximumSrcPoint ) );
          double targetHypothenuse = std::sqrt( minimumDstPoint.sqrDist( maximumDstPoint ) );

          QgsDebugMsgLevel( QStringLiteral( "Simplify - SourceHypothenuse=%1" ).arg( sourceHypothenuse ), 4 );
          QgsDebugMsgLevel( QStringLiteral( "Simplify - TargetHypothenuse=%1" ).arg( targetHypothenuse ), 4 );

          if ( !qgsDoubleNear( targetHypothenuse, 0.0 ) )
            map2pixelTol *= ( sourceHypothenuse / targetHypothenuse );
        }
      }
      catch ( QgsCsException &cse )
      {
        QgsMessageLog::logMessage( QObject::tr( "Simplify transform error caught: %1" ).arg( cse.what() ), QObject::tr( "CRS" ) );
        validTransform = false;
      }
    }

//.........这里部分代码省略.........

bool QgsVectorDataProvider::supportedType( const QgsField &field ) const
{
  int i;
  QgsDebugMsgLevel( QString( "field name = %1 type = %2 length = %3 precision = %4" )
                    .arg( field.name(),
                          QVariant::typeToName( field.type() ) )
                    .arg( field.length() )
                    .arg( field.precision() ), 2 );
  for ( i = 0; i < mNativeTypes.size(); i++ )
  {
    QgsDebugMsgLevel( QString( "native field type = %1 min length = %2 max length = %3 min precision = %4 max precision = %5" )
                      .arg( QVariant::typeToName( mNativeTypes[i].mType ) )
                      .arg( mNativeTypes[i].mMinLen )
                      .arg( mNativeTypes[i].mMaxLen )
                      .arg( mNativeTypes[i].mMinPrec )
                      .arg( mNativeTypes[i].mMaxPrec ), 2 );

    if ( field.type() != mNativeTypes[i].mType )
      continue;

    if ( field.length() == -1 )
    {
      // source length unlimited
      if ( mNativeTypes[i].mMinLen > -1 || mNativeTypes[i].mMaxLen > -1 )
      {
        // destination limited
        continue;
      }
    }
    else
    {
      // source length limited
      if ( mNativeTypes[i].mMinLen > -1 && mNativeTypes[i].mMaxLen > -1 &&
           ( field.length() < mNativeTypes[i].mMinLen || field.length() > mNativeTypes[i].mMaxLen ) )
      {
        // source length exceeds destination limits
        continue;
      }
    }

    if ( field.precision() == -1 )
    {
      // source precision unlimited / n/a
      if ( mNativeTypes[i].mMinPrec > -1 || mNativeTypes[i].mMaxPrec > -1 )
      {
        // destination limited
        continue;
      }
    }
    else
    {
      // source precision unlimited / n/a
      if ( mNativeTypes[i].mMinPrec > -1 && mNativeTypes[i].mMaxPrec > -1 &&
           ( field.precision() < mNativeTypes[i].mMinPrec || field.precision() > mNativeTypes[i].mMaxPrec ) )
      {
        // source precision exceeds destination limits
        continue;
      }
    }

    QgsDebugMsg( "native type matches" );
    return true;
  }

  QgsDebugMsg( "no sufficient native type found" );
  return false;
}

//.........这里部分代码省略.........
            if ( db_fetch( &databaseCursor, DB_NEXT, &more ) != DB_OK )
            {
              QgsDebugMsg( "Cannot fetch DB record" );
              break;
            }
            if ( !more )
            {
              break; // no more records
            }

            // Check cat value
            dbColumn *column = db_get_table_column( databaseTable, mKeyColumn );
            dbValue *value = db_get_column_value( column );

            if ( db_test_value_isnull( value ) )
            {
              continue;
            }
            int cat = db_get_value_int( value );
            if ( cat < 0 )
            {
              continue;
            }

            QList<QVariant> values;
            for ( int i = 0; i < nColumns; i++ )
            {
              column = db_get_table_column( databaseTable, i );
              int sqltype = db_get_column_sqltype( column );
              int ctype = db_sqltype_to_Ctype( sqltype );
              value = db_get_column_value( column );
              db_convert_value_to_string( value, sqltype, &dbstr );

              QgsDebugMsgLevel( QString( "column = %1 value = %2" ).arg( db_get_column_name( column ), db_get_string( &dbstr ) ), 3 );

              QVariant variant;
              if ( !db_test_value_isnull( value ) )
              {
                int iv;
                double dv;
                //layer.mAttributes[layer.nAttributes].values[i] = strdup( db_get_string( &dbstr ) );
                switch ( ctype )
                {
                  case DB_C_TYPE_INT:
                    iv = db_get_value_int( value );
                    variant = QVariant( iv );
                    mMinMax[i].first = std::min( mMinMax[i].first, ( double )iv );
                    mMinMax[i].second = std::min( mMinMax[i].second, ( double )iv );
                    break;
                  case DB_C_TYPE_DOUBLE:
                    dv = db_get_value_double( value );
                    variant = QVariant( dv );
                    mMinMax[i].first = std::min( mMinMax[i].first, dv );
                    mMinMax[i].second = std::min( mMinMax[i].second, dv );
                    break;
                  case DB_C_TYPE_STRING:
                    // Store as byte array so that codec may be used later
                    variant = QVariant( QByteArray( db_get_value_string( value ) ) );
                    break;
                  case DB_C_TYPE_DATETIME:
                    variant = QVariant( QByteArray( db_get_string( &dbstr ) ) );
                    break;
                  default:
                    variant = QVariant( QByteArray( db_get_string( &dbstr ) ) );
                }
              }

bool QgsPostgresFeatureIterator::getFeature( QgsPostgresResult &queryResult, int row, QgsFeature &feature )
{
  try
  {
    feature.initAttributes( P->fields().count() );

    int col = 0;

    if ( !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) )
    {
      int returnedLength = ::PQgetlength( queryResult.result(), row, col );
      if ( returnedLength > 0 )
      {
        unsigned char *featureGeom = new unsigned char[returnedLength + 1];
        memset( featureGeom, 0, returnedLength + 1 );
        memcpy( featureGeom, PQgetvalue( queryResult.result(), row, col ), returnedLength );
        feature.setGeometryAndOwnership( featureGeom, returnedLength + 1 );
      }
      else
      {
        feature.setGeometryAndOwnership( 0, 0 );
      }

      col++;
    }

    QgsFeatureId fid = 0;

    bool subsetOfAttributes = mRequest.flags() & QgsFeatureRequest::SubsetOfAttributes;
    const QgsAttributeList& fetchAttributes = mRequest.subsetOfAttributes();

    switch ( P->mPrimaryKeyType )
    {
      case QgsPostgresProvider::pktOid:
      case QgsPostgresProvider::pktTid:
      case QgsPostgresProvider::pktInt:
        fid = P->mConnectionRO->getBinaryInt( queryResult, row, col++ );
        if ( P->mPrimaryKeyType == QgsPostgresProvider::pktInt &&
             ( !subsetOfAttributes || fetchAttributes.contains( P->mPrimaryKeyAttrs[0] ) ) )
          feature.setAttribute( P->mPrimaryKeyAttrs[0], fid );
        break;

      case QgsPostgresProvider::pktFidMap:
      {
        QList<QVariant> primaryKeyVals;

        foreach ( int idx, P->mPrimaryKeyAttrs )
        {
          const QgsField &fld = P->field( idx );

          QVariant v = P->convertValue( fld.type(), queryResult.PQgetvalue( row, col ) );
          primaryKeyVals << v;

          if ( !subsetOfAttributes || fetchAttributes.contains( idx ) )
            feature.setAttribute( idx, v );

          col++;
        }

        fid = P->lookupFid( QVariant( primaryKeyVals ) );
      }
      break;

      case QgsPostgresProvider::pktUnknown:
        Q_ASSERT( !"FAILURE: cannot get feature with unknown primary key" );
        return false;
    }

    feature.setFeatureId( fid );
    QgsDebugMsgLevel( QString( "fid=%1" ).arg( fid ), 4 );

    // iterate attributes
    if ( subsetOfAttributes )
    {
      foreach ( int idx, fetchAttributes )
        getFeatureAttribute( idx, queryResult, row, col, feature );
    }
    else
    {
      for ( int idx = 0; idx < P->mAttributeFields.count(); ++idx )
        getFeatureAttribute( idx, queryResult, row, col, feature );
    }

    return true;
  }

//.........这里部分代码省略.........

  mTestSubset = mSource->mSubsetExpression;
  mTestGeometry = false;

  mMode = FileScan;
  if ( request.filterType() == QgsFeatureRequest::FilterFid )
  {
    QgsDebugMsg( "Configuring for returning single id" );
    mFeatureIds.append( request.filterFid() );
    mMode = FeatureIds;
    mTestSubset = false;
  }
  // If have geometry and testing geometry then evaluate options...
  // If we don't have geometry then all records pass geometry filter.
  // CC: 2013-05-09
  // Not sure about intended relationship between filtering on geometry and
  // requesting no geometry? Have preserved current logic of ignoring spatial filter
  // if not requesting geometry.

  else if ( request.filterType() == QgsFeatureRequest::FilterRect && hasGeometry )
  {
    QgsDebugMsg( "Configuring for rectangle select" );
    mTestGeometry = true;
    // Exact intersection test only applies for WKT geometries
    mTestGeometryExact = mRequest.flags() & QgsFeatureRequest::ExactIntersect
                         && mSource->mGeomRep == QgsDelimitedTextProvider::GeomAsWkt;

    QgsRectangle rect = request.filterRect();

    // If request doesn't overlap extents, then nothing to return
    if ( ! rect.intersects( mSource->mExtent ) )
    {
      QgsDebugMsg( "Rectangle outside layer extents - no features to return" );
      mMode = FeatureIds;
    }
    // If the request extents include the entire layer, then revert to
    // a file scan

    else if ( rect.contains( mSource->mExtent ) )
    {
      QgsDebugMsg( "Rectangle contains layer extents - bypass spatial filter" );
      mTestGeometry = false;
    }
    // If we have a spatial index then use it.  The spatial index already accounts
    // for the subset.  Also means we don't have to test geometries unless doing exact
    // intersection

    else if ( mSource->mUseSpatialIndex )
    {
      mFeatureIds = mSource->mSpatialIndex->intersects( rect );
      // Sort for efficient sequential retrieval
      qSort( mFeatureIds.begin(), mFeatureIds.end() );
      QgsDebugMsg( QString( "Layer has spatial index - selected %1 features from index" ).arg( mFeatureIds.size() ) );
      mMode = FeatureIds;
      mTestSubset = false;
      mTestGeometry = mTestGeometryExact;
    }
  }

  // If we have a subset index then use it..
  if ( mMode == FileScan && mSource->mUseSubsetIndex )
  {
    QgsDebugMsg( QString( "Layer has subset index - use %1 items from subset index" ).arg( mSource->mSubsetIndex.size() ) );
    mTestSubset = false;
    mMode = SubsetIndex;
  }

  // Otherwise just have to scan the file
  if ( mMode == FileScan )
  {
    QgsDebugMsg( "File will be scanned for desired features" );
  }

  // If the layer has geometry, do we really need to load it?
  // We need it if it is asked for explicitly in the request,
  // if we are testing geometry (ie spatial filter), or
  // if testing the subset expression.
  if ( hasGeometry
       && (
         !( mRequest.flags() & QgsFeatureRequest::NoGeometry )
         || mTestGeometry
         || ( mTestSubset && mSource->mSubsetExpression->needsGeometry() )
       )
     )
  {
    mLoadGeometry = true;
  }
  else
  {
    QgsDebugMsgLevel( "Feature geometries not required", 4 );
    mLoadGeometry = false;
  }

  QgsDebugMsg( QString( "Iterator is scanning file: " ) + ( mMode == FileScan ? "Yes" : "No" ) );
  QgsDebugMsg( QString( "Iterator is loading geometries: " ) + ( mLoadGeometry ? "Yes" : "No" ) );
  QgsDebugMsg( QString( "Iterator is testing geometries: " ) + ( mTestGeometry ? "Yes" : "No" ) );
  QgsDebugMsg( QString( "Iterator is testing subset: " ) + ( mTestSubset ? "Yes" : "No" ) );

  rewind();
}

void QgsBrowserModel::addRootItems()
{
  updateProjectHome();

  // give the home directory a prominent third place
  QgsDirectoryItem *item = new QgsDirectoryItem( nullptr, tr( "Home" ), QDir::homePath(), QStringLiteral( HOME_PREFIX ) + QDir::homePath() );
  item->setSortKey( QStringLiteral( " 2" ) );
  setupItemConnections( item );
  mRootItems << item;

  // add favorite directories
  mFavorites = new QgsFavoritesItem( nullptr, tr( "Favorites" ) );
  if ( mFavorites )
  {
    setupItemConnections( mFavorites );
    mRootItems << mFavorites;
  }

  // add drives
  Q_FOREACH ( const QFileInfo &drive, QDir::drives() )
  {
    const QString path = drive.absolutePath();

    if ( QgsDirectoryItem::hiddenPath( path ) )
      continue;

    QgsDirectoryItem *item = new QgsDirectoryItem( nullptr, path, path );
    item->setSortKey( QStringLiteral( " 3 %1" ).arg( path ) );
    mDriveItems.insert( path, item );

    setupItemConnections( item );
    mRootItems << item;
  }

#ifdef Q_OS_MAC
  QString path = QString( "/Volumes" );
  QgsDirectoryItem *vols = new QgsDirectoryItem( nullptr, path, path );
  mRootItems << vols;
#endif

  // container for displaying providers as sorted groups (by QgsDataProvider::DataCapability enum)
  QMap<int, QgsDataItem *> providerMap;

  Q_FOREACH ( QgsDataItemProvider *pr, QgsApplication::dataItemProviderRegistry()->providers() )
  {
    int capabilities = pr->capabilities();
    if ( capabilities == QgsDataProvider::NoDataCapabilities )
    {
      QgsDebugMsgLevel( pr->name() + " does not have any dataCapabilities", 4 );
      continue;
    }

    QgsDataItem *item = pr->createDataItem( QString(), nullptr );  // empty path -> top level
    if ( item )
    {
      // Forward the signal from the root items to the model (and then to the app)
      connect( item, &QgsDataItem::connectionsChanged, this, &QgsBrowserModel::connectionsChanged );
      QgsDebugMsgLevel( "Add new top level item : " + item->name(), 4 );
      setupItemConnections( item );
      providerMap.insertMulti( capabilities, item );
    }
  }

void QgsMapLayer::connectNotify( const char * signal )
{
  Q_UNUSED( signal );
  QgsDebugMsgLevel( "QgsMapLayer connected to " + QString( signal ), 3 );
} //  QgsMapLayer::connectNotify

/** Read property of QString layerName. */
QString const & QgsMapLayer::name() const
{
  QgsDebugMsgLevel( "returning name '" + mLayerName + "'", 3 );
  return mLayerName;
}

QgsRasterBlock *QgsSingleBandGrayRenderer::block( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback *feedback )
{
  Q_UNUSED( bandNo );
  QgsDebugMsgLevel( QStringLiteral( "width = %1 height = %2" ).arg( width ).arg( height ), 4 );

  std::unique_ptr< QgsRasterBlock > outputBlock( new QgsRasterBlock() );
  if ( !mInput )
  {
    return outputBlock.release();
  }

  std::shared_ptr< QgsRasterBlock > inputBlock( mInput->block( mGrayBand, extent, width, height, feedback ) );
  if ( !inputBlock || inputBlock->isEmpty() )
  {
    QgsDebugMsg( QStringLiteral( "No raster data!" ) );
    return outputBlock.release();
  }

  std::shared_ptr< QgsRasterBlock > alphaBlock;

  if ( mAlphaBand > 0 && mGrayBand != mAlphaBand )
  {
    alphaBlock.reset( mInput->block( mAlphaBand, extent, width, height, feedback ) );
    if ( !alphaBlock || alphaBlock->isEmpty() )
    {
      // TODO: better to render without alpha
      return outputBlock.release();
    }
  }
  else if ( mAlphaBand > 0 )
  {
    alphaBlock = inputBlock;
  }

  if ( !outputBlock->reset( Qgis::ARGB32_Premultiplied, width, height ) )
  {
    return outputBlock.release();
  }

  QRgb myDefaultColor = NODATA_COLOR;
  bool isNoData = false;
  for ( qgssize i = 0; i < ( qgssize )width * height; i++ )
  {
    double grayVal = inputBlock->valueAndNoData( i, isNoData );

    if ( isNoData )
    {
      outputBlock->setColor( i, myDefaultColor );
      continue;
    }

    double currentAlpha = mOpacity;
    if ( mRasterTransparency )
    {
      currentAlpha = mRasterTransparency->alphaValue( grayVal, mOpacity * 255 ) / 255.0;
    }
    if ( mAlphaBand > 0 )
    {
      currentAlpha *= alphaBlock->value( i ) / 255.0;
    }

    if ( mContrastEnhancement )
    {
      if ( !mContrastEnhancement->isValueInDisplayableRange( grayVal ) )
      {
        outputBlock->setColor( i, myDefaultColor );
        continue;
      }
      grayVal = mContrastEnhancement->enhanceContrast( grayVal );
    }

    if ( mGradient == WhiteToBlack )
    {
      grayVal = 255 - grayVal;
    }

    if ( qgsDoubleNear( currentAlpha, 1.0 ) )
    {
      outputBlock->setColor( i, qRgba( grayVal, grayVal, grayVal, 255 ) );
    }
    else
    {
      outputBlock->setColor( i, qRgba( currentAlpha * grayVal, currentAlpha * grayVal, currentAlpha * grayVal, currentAlpha * 255 ) );
    }
  }

  return outputBlock.release();
}

void QgsCoordinateTransform::transformCoords( int numPoints, double *x, double *y, double *z, TransformDirection direction ) const
{
  if ( !d->mIsValid || d->mShortCircuit )
    return;
  // Refuse to transform the points if the srs's are invalid
  if ( !d->mSourceCRS.isValid() )
  {
    QgsMessageLog::logMessage( QObject::tr( "The source spatial reference system (CRS) is not valid. "
                                            "The coordinates can not be reprojected. The CRS is: %1" )
                               .arg( d->mSourceCRS.toProj4() ), QObject::tr( "CRS" ) );
    return;
  }
  if ( !d->mDestCRS.isValid() )
  {
    QgsMessageLog::logMessage( QObject::tr( "The destination spatial reference system (CRS) is not valid. "
                                            "The coordinates can not be reprojected. The CRS is: %1" ).arg( d->mDestCRS.toProj4() ), QObject::tr( "CRS" ) );
    return;
  }

#ifdef COORDINATE_TRANSFORM_VERBOSE
  double xorg = *x;
  double yorg = *y;
  QgsDebugMsg( QStringLiteral( "[[[[[[ Number of points to transform: %1 ]]]]]]" ).arg( numPoints ) );
#endif

#ifdef QGISDEBUG
  if ( !mHasContext )
    QgsDebugMsgLevel( QStringLiteral( "No QgsCoordinateTransformContext context set for transform" ), 4 );
#endif

  // use proj4 to do the transform

  // if the source/destination projection is lat/long, convert the points to radians
  // prior to transforming
  ProjData projData = d->threadLocalProjData();
#if PROJ_VERSION_MAJOR<6
  bool sourceIsLatLong = false;
  bool destIsLatLong = false;

  projPJ sourceProj = projData.first;
  projPJ destProj = projData.second;
  sourceIsLatLong = pj_is_latlong( sourceProj );
  destIsLatLong = pj_is_latlong( destProj );

  if ( ( destIsLatLong && ( direction == ReverseTransform ) )
       || ( sourceIsLatLong && ( direction == ForwardTransform ) ) )
  {
    for ( int i = 0; i < numPoints; ++i )
    {
      x[i] *= DEG_TO_RAD;
      y[i] *= DEG_TO_RAD;
    }
  }
#endif

  int projResult = 0;
#if PROJ_VERSION_MAJOR>=6
  const bool sourceAxisOrderSwapped =  direction == ForwardTransform ? d->mSourceAxisOrderSwapped : d->mDestAxisOrderSwapped;

  proj_trans_generic( projData, direction == ForwardTransform ? PJ_FWD : PJ_INV,
                      !sourceAxisOrderSwapped ? x : y, sizeof( double ), numPoints,
                      !sourceAxisOrderSwapped ? y : x, sizeof( double ), numPoints,
                      z, sizeof( double ), numPoints,
                      nullptr, sizeof( double ), 0 );
  projResult = proj_errno( projData );
  // ewww - this logic is gross. We should drop support for PROJ 6.0 as quickly as possible and dump this code (in favour of built in methods used for >=6.1 builds)
  if ( projResult == 0 && ( d->mSourceAxisOrderSwapped != d->mDestAxisOrderSwapped ) )
  {
    size_t size = sizeof( double ) * numPoints;
    void *tmp = malloc( size );
    memcpy( tmp, x, size );
    memcpy( x, y, size );
    memcpy( y, tmp, size );
    free( tmp );
  }
#else
  if ( direction == ReverseTransform )
  {
    projResult = pj_transform( destProj, sourceProj, numPoints, 0, x, y, z );
  }
  else
  {
    Q_ASSERT( sourceProj );
    Q_ASSERT( destProj );
    projResult = pj_transform( sourceProj, destProj, numPoints, 0, x, y, z );
  }
#endif

  if ( projResult != 0 )
  {
    //something bad happened....
    QString points;

    for ( int i = 0; i < numPoints; ++i )
    {
      if ( direction == ForwardTransform )
      {
        points += QStringLiteral( "(%1, %2)\n" ).arg( x[i], 0, 'f' ).arg( y[i], 0, 'f' );
      }
      else
//.........这里部分代码省略.........

QgsRectangle QgsCoordinateTransform::transformBoundingBox( const QgsRectangle &rect, TransformDirection direction, const bool handle180Crossover ) const
{
  // Calculate the bounding box of a QgsRectangle in the source CRS
  // when projected to the destination CRS (or the inverse).
  // This is done by looking at a number of points spread evenly
  // across the rectangle

  if ( !d->mIsValid || d->mShortCircuit )
    return rect;

  if ( rect.isEmpty() )
  {
    QgsPointXY p = transform( rect.xMinimum(), rect.yMinimum(), direction );
    return QgsRectangle( p, p );
  }

  // 64 points (<=2.12) is not enough, see #13665, for EPSG:4326 -> EPSG:3574 (say that it is a hard one),
  // are decent result from about 500 points and more. This method is called quite often, but
  // even with 1000 points it takes < 1ms
  // TODO: how to effectively and precisely reproject bounding box?
  const int nPoints = 1000;
  double d = std::sqrt( ( rect.width() * rect.height() ) / std::pow( std::sqrt( static_cast< double >( nPoints ) ) - 1, 2.0 ) );
  int nXPoints = static_cast< int >( std::ceil( rect.width() / d ) ) + 1;
  int nYPoints = static_cast< int >( std::ceil( rect.height() / d ) ) + 1;

  QgsRectangle bb_rect;
  bb_rect.setMinimal();

  // We're interfacing with C-style vectors in the
  // end, so let's do C-style vectors here too.

  QVector<double> x( nXPoints * nYPoints );
  QVector<double> y( nXPoints * nYPoints );
  QVector<double> z( nXPoints * nYPoints );

  QgsDebugMsgLevel( QStringLiteral( "Entering transformBoundingBox..." ), 4 );

  // Populate the vectors

  double dx = rect.width()  / static_cast< double >( nXPoints - 1 );
  double dy = rect.height() / static_cast< double >( nYPoints - 1 );

  double pointY = rect.yMinimum();

  for ( int i = 0; i < nYPoints ; i++ )
  {

    // Start at right edge
    double pointX = rect.xMinimum();

    for ( int j = 0; j < nXPoints; j++ )
    {
      x[( i * nXPoints ) + j] = pointX;
      y[( i * nXPoints ) + j] = pointY;
      // and the height...
      z[( i * nXPoints ) + j] = 0.0;
      // QgsDebugMsg(QString("BBox coord: (%1, %2)").arg(x[(i*numP) + j]).arg(y[(i*numP) + j]));
      pointX += dx;
    }
    pointY += dy;
  }

  // Do transformation. Any exception generated must
  // be handled in above layers.
  try
  {
    transformCoords( nXPoints * nYPoints, x.data(), y.data(), z.data(), direction );
  }
  catch ( const QgsCsException & )
  {
    // rethrow the exception
    QgsDebugMsg( QStringLiteral( "rethrowing exception" ) );
    throw;
  }

  // Calculate the bounding box and use that for the extent

  for ( int i = 0; i < nXPoints * nYPoints; i++ )
  {
    if ( !std::isfinite( x[i] ) || !std::isfinite( y[i] ) )
    {
      continue;
    }

    if ( handle180Crossover )
    {
      //if crossing the date line, temporarily add 360 degrees to -ve longitudes
      bb_rect.combineExtentWith( x[i] >= 0.0 ? x[i] : x[i] + 360.0, y[i] );
    }
    else
    {
      bb_rect.combineExtentWith( x[i], y[i] );
    }
  }

  if ( bb_rect.isNull() )
  {
    // something bad happened when reprojecting the filter rect... no finite points were left!
    throw QgsCsException( QObject::tr( "Could not transform bounding box to target CRS" ) );
  }
//.........这里部分代码省略.........

qint64 QgsPostgresConn::getBinaryInt( QgsPostgresResult &queryResult, int row, int col )
{
  quint64 oid;
  char *p = PQgetvalue( queryResult.result(), row, col );
  size_t s = PQgetlength( queryResult.result(), row, col );

#ifdef QGISDEBUG
  if ( QgsLogger::debugLevel() >= 4 )
  {
    QString buf;
    for ( size_t i = 0; i < s; i++ )
    {
      buf += QString( "%1 " ).arg( *( unsigned char * )( p + i ), 0, 16, QLatin1Char( ' ' ) );
    }

    QgsDebugMsg( QString( "int in hex:%1" ).arg( buf ) );
  }
#endif

  switch ( s )
  {
    case 2:
      oid = *( quint16 * )p;
      if ( mSwapEndian )
        oid = ntohs( oid );
      break;

    case 6:
    {
      quint64 block  = *( quint32 * ) p;
      quint64 offset = *( quint16 * )( p + sizeof( quint32 ) );

      if ( mSwapEndian )
      {
        block = ntohl( block );
        offset = ntohs( offset );
      }

      oid = ( block << 16 ) + offset;
    }
    break;

    case 8:
    {
      quint32 oid0 = *( quint32 * ) p;
      quint32 oid1 = *( quint32 * )( p + sizeof( quint32 ) );

      if ( mSwapEndian )
      {
        QgsDebugMsgLevel( QString( "swap oid0:%1 oid1:%2" ).arg( oid0 ).arg( oid1 ), 4 );
        oid0 = ntohl( oid0 );
        oid1 = ntohl( oid1 );
      }

      QgsDebugMsgLevel( QString( "oid0:%1 oid1:%2" ).arg( oid0 ).arg( oid1 ), 4 );
      oid   = oid0;
      QgsDebugMsgLevel( QString( "oid:%1" ).arg( oid ), 4 );
      oid <<= 32;
      QgsDebugMsgLevel( QString( "oid:%1" ).arg( oid ), 4 );
      oid  |= oid1;
      QgsDebugMsgLevel( QString( "oid:%1" ).arg( oid ), 4 );
    }
    break;

    default:
      QgsDebugMsg( QString( "unexpected size %1" ).arg( s ) );

    case 4:
      oid = *( quint32 * )p;
      if ( mSwapEndian )
        oid = ntohl( oid );
      break;
  }

  return oid;
}

QgsRasterBlock *QgsRasterProjector::block( int bandNo, QgsRectangle  const &extent, int width, int height, QgsRasterBlockFeedback *feedback )
{
  QgsDebugMsgLevel( QStringLiteral( "extent:\n%1" ).arg( extent.toString() ), 4 );
  QgsDebugMsgLevel( QStringLiteral( "width = %1 height = %2" ).arg( width ).arg( height ), 4 );
  if ( !mInput )
  {
    QgsDebugMsgLevel( QStringLiteral( "Input not set" ), 4 );
    return new QgsRasterBlock();
  }

  if ( feedback && feedback->isCanceled() )
    return new QgsRasterBlock();

  if ( ! mSrcCRS.isValid() || ! mDestCRS.isValid() || mSrcCRS == mDestCRS )
  {
    QgsDebugMsgLevel( QStringLiteral( "No projection necessary" ), 4 );
    return mInput->block( bandNo, extent, width, height, feedback );
  }

  QgsCoordinateTransform inverseCt( mDestCRS, mSrcCRS, mDestDatumTransform, mSrcDatumTransform );

  ProjectorData pd( extent, width, height, mInput, inverseCt, mPrecision );

  QgsDebugMsgLevel( QStringLiteral( "srcExtent:\n%1" ).arg( pd.srcExtent().toString() ), 4 );
  QgsDebugMsgLevel( QStringLiteral( "srcCols = %1 srcRows = %2" ).arg( pd.srcCols() ).arg( pd.srcRows() ), 4 );

  // If we zoom out too much, projector srcRows / srcCols maybe 0, which can cause problems in providers
  if ( pd.srcRows() <= 0 || pd.srcCols() <= 0 )
  {
    QgsDebugMsgLevel( QStringLiteral( "Zero srcRows or srcCols" ), 4 );
    return new QgsRasterBlock();
  }

  std::unique_ptr< QgsRasterBlock > inputBlock( mInput->block( bandNo, pd.srcExtent(), pd.srcCols(), pd.srcRows(), feedback ) );
  if ( !inputBlock || inputBlock->isEmpty() )
  {
    QgsDebugMsg( QStringLiteral( "No raster data!" ) );
    return new QgsRasterBlock();
  }

  qgssize pixelSize = QgsRasterBlock::typeSize( mInput->dataType( bandNo ) );

  std::unique_ptr< QgsRasterBlock > outputBlock( new QgsRasterBlock( inputBlock->dataType(), width, height ) );
  if ( inputBlock->hasNoDataValue() )
  {
    outputBlock->setNoDataValue( inputBlock->noDataValue() );
  }
  if ( !outputBlock->isValid() )
  {
    QgsDebugMsg( QStringLiteral( "Cannot cr