1 /***************************************************************************
2                               qgsfeaturefilterprovider.h
3                               --------------------------
4   begin                : 22-05-2015
5   copyright            : (C) 2008 by Stéphane Brunner
6   email                : stephane dot brunner at camptocamp 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 #ifndef QGSFEATUREFILTERPROVIDER_H
19 #define QGSFEATUREFILTERPROVIDER_H
20 
21 #include <QtGlobal>
22 #include <QStringList>
23 #include "qgis_sip.h"
24 
25 #include "qgis_core.h"
26 #include "qgsfeaturerequest.h"
27 
28 class QString;
29 class QgsVectorLayer;
30 
31 
32 /**
33  * \ingroup core
34  * \class QgsFeatureFilterProvider
35  * \brief Abstract interface for use by classes that filter the features or attributes of a layer.
36  *
37  * A QgsFeatureFilterProvider provides a method for modifying a QgsFeatureRequest in place to apply
38  * additional filters to the request, since QGIS 3.18 a method to filter allowed attributes is also available.
39  *
40  * \since QGIS 2.14
41  */
42 
43 class CORE_EXPORT QgsFeatureFilterProvider
44 {
45   public:
46 
47 #ifndef SIP_RUN
48 
49     //! Constructor
50     QgsFeatureFilterProvider() = default;
51 
52     virtual ~QgsFeatureFilterProvider() = default;
53 
54 #endif
55 
56     /**
57      * Add additional filters to the feature request to further restrict the features returned by the request.
58      * Derived classes must implement this method.
59      * \param layer the layer to filter
60      * \param featureRequest the feature request to update
61      */
62     virtual void filterFeatures( const QgsVectorLayer *layer, QgsFeatureRequest &featureRequest ) const = 0;
63 
64     /**
65      * Returns the list of visible attribute names from a list of \a attributes names for the given \a layer
66      * \since QGIS 3.18
67      */
68     virtual QStringList layerAttributes( const QgsVectorLayer *layer, const QStringList &attributes ) const = 0;
69 
70     /**
71      * Create a clone of the feature filter provider
72      * \returns a new clone
73      */
74     virtual QgsFeatureFilterProvider *clone() const = 0 SIP_FACTORY;
75 };
76 
77 #endif
78