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a05d941e4e
Since the underlying issues with the Python bindings are now fixed, in most cases we can safely default to allowing an algorithm to run in a background thread!! So now we make this the default, and require individual algorithms which are NOT thread safe to declare this. This includes algorithms which directly manipulate the current project or layers (such as setting layer styles), alter the selections in layers, or which rely on 3rd party libraries (for now, SAGA and GRASS algorithms are marked as not thread safe... TODO - someone more familiar with these libraries can investigate and remove the flag if appropriate). Also models are marked as non-thread safe. TODO: only flag an individual model as thread-unsafe if any of its child algorithms report this flag.
87 lines
3.4 KiB
Python
87 lines
3.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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CreateAttributeIndex.py
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-----------------------
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Date : November 2016
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Copyright : (C) 2016 by Nyall Dawson
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Email : nyall dot dawson at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Nyall Dawson'
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__date__ = 'November 2016'
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__copyright__ = '(C) 2016, Nyall Dawson'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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from qgis.core import (QgsVectorDataProvider,
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QgsFields,
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QgsProcessingAlgorithm,
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QgsProcessingParameterVectorLayer,
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QgsProcessingParameterField,
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QgsProcessingOutputVectorLayer)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class CreateAttributeIndex(QgisAlgorithm):
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INPUT = 'INPUT'
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FIELD = 'FIELD'
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OUTPUT = 'OUTPUT'
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def group(self):
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return self.tr('Vector general')
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def groupId(self):
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return 'vectorgeneral'
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.addParameter(QgsProcessingParameterVectorLayer(self.INPUT,
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self.tr('Input Layer')))
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self.addParameter(QgsProcessingParameterField(self.FIELD,
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self.tr('Attribute to index'), None, self.INPUT))
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self.addOutput(QgsProcessingOutputVectorLayer(self.OUTPUT, self.tr('Indexed layer')))
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def flags(self):
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return super().flags() | QgsProcessingAlgorithm.FlagNoThreading
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def name(self):
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return 'createattributeindex'
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def displayName(self):
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return self.tr('Create attribute index')
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def processAlgorithm(self, parameters, context, feedback):
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layer = self.parameterAsVectorLayer(parameters, self.INPUT, context)
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field = self.parameterAsString(parameters, self.FIELD, context)
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provider = layer.dataProvider()
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field_index = layer.fields().lookupField(field)
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if field_index < 0 or layer.fields().fieldOrigin(field_index) != QgsFields.OriginProvider:
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feedback.pushInfo(self.tr('Can not create attribute index on "{}"').format(field))
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else:
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provider_index = layer.fields().fieldOriginIndex(field_index)
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if provider.capabilities() & QgsVectorDataProvider.CreateAttributeIndex:
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if not provider.createAttributeIndex(provider_index):
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feedback.pushInfo(self.tr('Could not create attribute index'))
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else:
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feedback.pushInfo(self.tr("Layer's data provider does not support "
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"creating attribute indexes"))
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return {self.OUTPUT: layer.id()}
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