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# -*- coding: utf-8 -*-
"""
***************************************************************************
CreateAttributeIndex.py
-----------------------
Date : November 2016
Copyright : (C) 2016 by Nyall Dawson
Email : nyall dot dawson at gmail dot com
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""
__author__ = 'Nyall Dawson'
__date__ = 'November 2016'
__copyright__ = '(C) 2016, Nyall Dawson'
from qgis.core import (QgsVectorDataProvider,
QgsFields,
QgsProcessing,
QgsProcessingAlgorithm,
QgsProcessingParameterVectorLayer,
QgsProcessingParameterField,
QgsProcessingOutputVectorLayer)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
class CreateAttributeIndex(QgisAlgorithm):
INPUT = 'INPUT'
FIELD = 'FIELD'
OUTPUT = 'OUTPUT'
def group(self):
return self.tr('Vector general')
def groupId(self):
return 'vectorgeneral'
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(QgsProcessingParameterVectorLayer(self.INPUT,
self.tr('Input Layer'),
types=[QgsProcessing.TypeVector]))
self.addParameter(QgsProcessingParameterField(self.FIELD,
self.tr('Attribute to index'), None, self.INPUT))
self.addOutput(QgsProcessingOutputVectorLayer(self.OUTPUT, self.tr('Indexed layer')))
def flags(self):
return super().flags() | QgsProcessingAlgorithm.FlagNoThreading
def name(self):
return 'createattributeindex'
def displayName(self):
return self.tr('Create attribute index')
def processAlgorithm(self, parameters, context, feedback):
layer = self.parameterAsVectorLayer(parameters, self.INPUT, context)
field = self.parameterAsString(parameters, self.FIELD, context)
provider = layer.dataProvider()
field_index = layer.fields().lookupField(field)
if field_index < 0 or layer.fields().fieldOrigin(field_index) != QgsFields.OriginProvider:
feedback.pushInfo(self.tr('Can not create attribute index on "{}"').format(field))
else:
provider_index = layer.fields().fieldOriginIndex(field_index)
if provider.capabilities() & QgsVectorDataProvider.CreateAttributeIndex:
if not provider.createAttributeIndex(provider_index):
feedback.pushInfo(self.tr('Could not create attribute index'))
else:
feedback.pushInfo(self.tr("Layer's data provider does not support "
"creating attribute indexes"))
return {self.OUTPUT: layer.id()}