1 /***************************************************************************
2 qgsalgorithmdropfields.cpp
3 ---------------------------------
4 begin : November 2020
5 copyright : (C) 2020 by Nyall Dawson
6 email : nyall dot dawson at gmail dot com
7 ***************************************************************************/
8
9 /***************************************************************************
10 * *
11 * This program is free software; you can redistribute it and/or modify *
12 * it under the terms of the GNU General Public License as published by *
13 * the Free Software Foundation; either version 2 of the License, or *
14 * (at your option) any later version. *
15 * *
16 ***************************************************************************/
17
18 #include "qgsalgorithmdropfields.h"
19
20 ///@cond PRIVATE
21
flags() const22 QgsProcessingAlgorithm::Flags QgsDropTableFieldsAlgorithm::flags() const
23 {
24 return QgsProcessingFeatureBasedAlgorithm::flags() & ~QgsProcessingAlgorithm::FlagSupportsInPlaceEdits;
25 }
26
name() const27 QString QgsDropTableFieldsAlgorithm::name() const
28 {
29 return QStringLiteral( "deletecolumn" );
30 }
31
displayName() const32 QString QgsDropTableFieldsAlgorithm::displayName() const
33 {
34 return QObject::tr( "Drop field(s)" );
35 }
36
shortHelpString() const37 QString QgsDropTableFieldsAlgorithm::shortHelpString() const
38 {
39 return QObject::tr( "This algorithm takes a vector layer and generates a new one that has the exact same content but without the selected columns." );
40 }
41
shortDescription() const42 QString QgsDropTableFieldsAlgorithm::shortDescription() const
43 {
44 return QObject::tr( "Deletes fields from a vector layer." );
45 }
46
tags() const47 QStringList QgsDropTableFieldsAlgorithm::tags() const
48 {
49 return QObject::tr( "drop,delete,remove,fields,columns,attributes" ).split( ',' );
50 }
51
group() const52 QString QgsDropTableFieldsAlgorithm::group() const
53 {
54 return QObject::tr( "Vector table" );
55 }
56
groupId() const57 QString QgsDropTableFieldsAlgorithm::groupId() const
58 {
59 return QStringLiteral( "vectortable" );
60 }
61
outputName() const62 QString QgsDropTableFieldsAlgorithm::outputName() const
63 {
64 return QObject::tr( "Remaining fields" );
65 }
66
inputLayerTypes() const67 QList<int> QgsDropTableFieldsAlgorithm::inputLayerTypes() const
68 {
69 return QList<int>() << QgsProcessing::TypeVector;
70 }
71
sourceFlags() const72 QgsProcessingFeatureSource::Flag QgsDropTableFieldsAlgorithm::sourceFlags() const
73 {
74 return QgsProcessingFeatureSource::FlagSkipGeometryValidityChecks;
75 }
76
createInstance() const77 QgsDropTableFieldsAlgorithm *QgsDropTableFieldsAlgorithm::createInstance() const
78 {
79 return new QgsDropTableFieldsAlgorithm();
80 }
81
initParameters(const QVariantMap &)82 void QgsDropTableFieldsAlgorithm::initParameters( const QVariantMap & )
83 {
84 addParameter( new QgsProcessingParameterField( QStringLiteral( "COLUMN" ), QObject::tr( "Fields to drop" ), QVariant(), QStringLiteral( "INPUT" ), QgsProcessingParameterField::Any, true ) );
85 }
86
outputFields(const QgsFields & inputFields) const87 QgsFields QgsDropTableFieldsAlgorithm::outputFields( const QgsFields &inputFields ) const
88 {
89 QgsFields outFields = inputFields;
90 // loop through twice - first we need to build up a list of original attribute indices
91 for ( const QString &field : mFieldsToDelete )
92 {
93 const int index = inputFields.lookupField( field );
94 if ( index >= 0 )
95 mFieldIndices.append( index );
96 }
97
98 // important - make sure we remove from the end so we aren't changing used indices as we go
99 std::sort( mFieldIndices.begin(), mFieldIndices.end(), std::greater< int >() );
100
101 // this second time we make a cleaned version of the fields
102 for ( const int index : std::as_const( mFieldIndices ) )
103 {
104 outFields.remove( index );
105 }
106 return outFields;
107 }
108
prepareAlgorithm(const QVariantMap & parameters,QgsProcessingContext & context,QgsProcessingFeedback * feedback)109 bool QgsDropTableFieldsAlgorithm::prepareAlgorithm( const QVariantMap ¶meters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
110 {
111 mFieldsToDelete = parameterAsFields( parameters, QStringLiteral( "COLUMN" ), context );
112
113 if ( feedback )
114 {
115 std::unique_ptr< QgsProcessingFeatureSource> source( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
116 if ( source )
117 {
118 for ( const QString &field : std::as_const( mFieldsToDelete ) )
119 {
120 const int index = source->fields().lookupField( field );
121 if ( index < 0 )
122 {
123 feedback->pushInfo( QObject::tr( "Field “%1” does not exist in input layer " ).arg( field ) );
124 }
125 }
126 }
127 }
128
129 return true;
130 }
131
processFeature(const QgsFeature & feature,QgsProcessingContext &,QgsProcessingFeedback *)132 QgsFeatureList QgsDropTableFieldsAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &, QgsProcessingFeedback * )
133 {
134 QgsFeature f = feature;
135 QgsAttributes attributes = f.attributes();
136 for ( const int index : mFieldIndices )
137 {
138 attributes.remove( index );
139 }
140 f.setAttributes( attributes );
141 return QgsFeatureList() << f;
142 }
143
supportInPlaceEdit(const QgsMapLayer * layer) const144 bool QgsDropTableFieldsAlgorithm::supportInPlaceEdit( const QgsMapLayer *layer ) const
145 {
146 Q_UNUSED( layer )
147 return false;
148 }
149
150
151
152 //
153 // QgsRetainTableFieldsAlgorithm
154 //
155
flags() const156 QgsProcessingAlgorithm::Flags QgsRetainTableFieldsAlgorithm::flags() const
157 {
158 return QgsProcessingFeatureBasedAlgorithm::flags() & ~QgsProcessingAlgorithm::FlagSupportsInPlaceEdits;
159 }
160
name() const161 QString QgsRetainTableFieldsAlgorithm::name() const
162 {
163 return QStringLiteral( "retainfields" );
164 }
165
displayName() const166 QString QgsRetainTableFieldsAlgorithm::displayName() const
167 {
168 return QObject::tr( "Retain fields" );
169 }
170
shortHelpString() const171 QString QgsRetainTableFieldsAlgorithm::shortHelpString() const
172 {
173 return QObject::tr( "This algorithm takes a vector layer and generates a new one that retains only the selected fields. All other fields will be dropped." );
174 }
175
shortDescription() const176 QString QgsRetainTableFieldsAlgorithm::shortDescription() const
177 {
178 return QObject::tr( "Retains selected fields from a vector layer." );
179 }
180
tags() const181 QStringList QgsRetainTableFieldsAlgorithm::tags() const
182 {
183 return QObject::tr( "drop,delete,remove,retain,keep,other,fields,columns,attributes" ).split( ',' );
184 }
185
group() const186 QString QgsRetainTableFieldsAlgorithm::group() const
187 {
188 return QObject::tr( "Vector table" );
189 }
190
groupId() const191 QString QgsRetainTableFieldsAlgorithm::groupId() const
192 {
193 return QStringLiteral( "vectortable" );
194 }
195
outputName() const196 QString QgsRetainTableFieldsAlgorithm::outputName() const
197 {
198 return QObject::tr( "Retained fields" );
199 }
200
inputLayerTypes() const201 QList<int> QgsRetainTableFieldsAlgorithm::inputLayerTypes() const
202 {
203 return QList<int>() << QgsProcessing::TypeVector;
204 }
205
sourceFlags() const206 QgsProcessingFeatureSource::Flag QgsRetainTableFieldsAlgorithm::sourceFlags() const
207 {
208 return QgsProcessingFeatureSource::FlagSkipGeometryValidityChecks;
209 }
210
createInstance() const211 QgsRetainTableFieldsAlgorithm *QgsRetainTableFieldsAlgorithm::createInstance() const
212 {
213 return new QgsRetainTableFieldsAlgorithm();
214 }
215
initParameters(const QVariantMap &)216 void QgsRetainTableFieldsAlgorithm::initParameters( const QVariantMap & )
217 {
218 addParameter( new QgsProcessingParameterField( QStringLiteral( "FIELDS" ), QObject::tr( "Fields to retain" ), QVariant(), QStringLiteral( "INPUT" ), QgsProcessingParameterField::Any, true ) );
219 }
220
outputFields(const QgsFields & inputFields) const221 QgsFields QgsRetainTableFieldsAlgorithm::outputFields( const QgsFields &inputFields ) const
222 {
223 // loop through twice - first we need to build up a list of original attribute indices
224 for ( const QString &field : mFieldsToRetain )
225 {
226 const int index = inputFields.lookupField( field );
227 if ( index >= 0 )
228 mFieldIndices.append( index );
229 }
230
231 std::sort( mFieldIndices.begin(), mFieldIndices.end() );
232
233 // this second time we make a cleaned version of the fields
234 QgsFields outFields;
235 for ( const int index : std::as_const( mFieldIndices ) )
236 {
237 outFields.append( inputFields.at( index ) );
238 }
239 return outFields;
240 }
241
prepareAlgorithm(const QVariantMap & parameters,QgsProcessingContext & context,QgsProcessingFeedback * feedback)242 bool QgsRetainTableFieldsAlgorithm::prepareAlgorithm( const QVariantMap ¶meters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
243 {
244 mFieldsToRetain = parameterAsFields( parameters, QStringLiteral( "FIELDS" ), context );
245
246 if ( feedback )
247 {
248 std::unique_ptr< QgsProcessingFeatureSource> source( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
249 if ( source )
250 {
251 for ( const QString &field : std::as_const( mFieldsToRetain ) )
252 {
253 const int index = source->fields().lookupField( field );
254 if ( index < 0 )
255 {
256 feedback->pushInfo( QObject::tr( "Field “%1” does not exist in input layer " ).arg( field ) );
257 }
258 }
259 }
260 }
261
262 return true;
263 }
264
processFeature(const QgsFeature & feature,QgsProcessingContext &,QgsProcessingFeedback *)265 QgsFeatureList QgsRetainTableFieldsAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &, QgsProcessingFeedback * )
266 {
267 QgsFeature f = feature;
268 const QgsAttributes inputAttributes = f.attributes();
269 QgsAttributes outputAttributes;
270 outputAttributes.reserve( mFieldIndices.count() );
271 for ( const int index : mFieldIndices )
272 {
273 outputAttributes.append( inputAttributes.at( index ) );
274 }
275 f.setAttributes( outputAttributes );
276 return QgsFeatureList() << f;
277 }
278
supportInPlaceEdit(const QgsMapLayer * layer) const279 bool QgsRetainTableFieldsAlgorithm::supportInPlaceEdit( const QgsMapLayer *layer ) const
280 {
281 Q_UNUSED( layer )
282 return false;
283 }
284
285 ///@endcond
286