QGIS API Documentation 3.40.0-Bratislava (b56115d8743)
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qgsdataprovider.cpp
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1/***************************************************************************
2 qgsdataprovider.cpp - DataProvider Interface
3 --------------------------------------
4 Date : May 2016
5 Copyright : (C) 2016 by Matthias Kuhn
7 ***************************************************************************
8 * *
9 * This program is free software; you can redistribute it and/or modify *
10 * it under the terms of the GNU General Public License as published by *
11 * the Free Software Foundation; either version 2 of the License, or *
12 * (at your option) any later version. *
13 * *
14 ***************************************************************************/
15
16#include <QMutexLocker>
17#include "qgsdataprovider.h"
19#include "qgsthreadingutils.h"
20
21#define SUBLAYER_SEPARATOR QStringLiteral( "!!::!!" )
22
23QgsDataProvider::QgsDataProvider( const QString &uri, const QgsDataProvider::ProviderOptions &providerOptions,
25 : mDataSourceURI( uri ),
26 mOptions( providerOptions )
27{
29}
30
32{
34
35 return QString();
36}
37
44
51
58
65
72
74{
75 return QString();
76}
77
79{
80 return QString();
81}
82
83bool QgsDataProvider::setSubsetString( const QString &subset, bool updateFeatureCount )
84{
85 // NOP by default
86 Q_UNUSED( subset )
87 Q_UNUSED( updateFeatureCount )
88 return false;
89}
90
92{
93 return false;
94}
95
97{
98 return QString();
99}
100
102{
103 // Because QgsVirtualLayerTask is not thread safe:
105
106 reloadProviderData();
107 emit dataChanged();
108}
109
111{
113
114 mProviderProperties.insert( property, value );
115}
116
117void QgsDataProvider::setProviderProperty( int property, const QVariant &value )
118{
120
121 mProviderProperties.insert( property, value );
122}
123
124QVariant QgsDataProvider::providerProperty( QgsDataProvider::ProviderProperty property, const QVariant &defaultValue ) const
125{
127
128 return mProviderProperties.value( property, defaultValue );
129}
130
131QVariant QgsDataProvider::providerProperty( int property, const QVariant &defaultValue = QVariant() ) const
132{
134
135 return mProviderProperties.value( property, defaultValue );
136}
137
138void QgsDataProvider::setListening( bool isListening )
139{
141
142 Q_UNUSED( isListening )
143}
144
151
153{
155
156 const QMutexLocker locker( &mOptionsMutex );
157 return mOptions.transformContext;
158}
159
161{
163
164 const QMutexLocker locker( &mOptionsMutex );
165 mOptions.transformContext = value;
166}
167
172
QFlags< DataProviderFlag > DataProviderFlags
Data provider flags.
Definition qgis.h:2147
QFlags< DataProviderReadFlag > DataProviderReadFlags
Flags which control data provider construction.
Definition qgis.h:450
QFlags< ProviderStyleStorageCapability > ProviderStyleStorageCapabilities
Definition qgis.h:5030
Contains information about the context in which a coordinate transform is executed.
Base class for handling elevation related properties for a data provider.
Base class for handling properties relating to a data provider's temporal capabilities.
virtual QString subsetString() const
Returns the subset definition string currently in use by the layer and used by the provider to limit ...
QgsCoordinateTransformContext transformContext() const
Returns data provider coordinate transform context.
virtual void setListening(bool isListening)
Set whether the provider will listen to datasource notifications If set, the provider will issue noti...
virtual Qgis::DataProviderFlags flags() const
Returns the generic data provider flags.
void setProviderProperty(ProviderProperty property, const QVariant &value)
Allows setting arbitrary properties on the provider.
virtual bool supportsSubsetString() const
Returns true if the provider supports setting of subset strings.
void dataChanged()
Emitted whenever a change is made to the data provider which may have caused changes in the provider'...
virtual QString subsetStringHelpUrl() const
Returns a URL pointing to documentation describing the dialect which is supported for subset strings ...
virtual Qgis::ProviderStyleStorageCapabilities styleStorageCapabilities() const
Returns the style storage capabilities.
ProviderProperty
Properties are used to pass custom configuration options into data providers.
QgsDataProvider(const QString &uri=QString(), const QgsDataProvider::ProviderOptions &providerOptions=QgsDataProvider::ProviderOptions(), Qgis::DataProviderReadFlags flags=Qgis::DataProviderReadFlags())
Create a new dataprovider with the specified in the uri.
virtual QgsDataProviderTemporalCapabilities * temporalCapabilities()
Returns the provider's temporal capabilities.
virtual bool setSubsetString(const QString &subset, bool updateFeatureCount=true)
Set the subset string used to create a subset of features in the layer.
static QString sublayerSeparator()
String sequence used for separating components of sublayers strings.
QVariant providerProperty(ProviderProperty property, const QVariant &defaultValue=QVariant()) const
Gets the current value of a certain provider property.
virtual QString subsetStringDialect() const
Returns a user-friendly string describing the dialect which is supported for subset strings by the pr...
Qgis::DataProviderReadFlags mReadFlags
Read flags. It's up to the subclass to respect these when needed.
virtual QString htmlMetadata() const
Obtain a formatted HTML string containing assorted metadata for this data provider.
virtual QgsDataProviderElevationProperties * elevationProperties()
Returns the provider's elevation properties.
virtual bool renderInPreview(const QgsDataProvider::PreviewContext &context)
Returns whether the layer must be rendered in preview jobs.
virtual void reloadData()
Reloads the data from the source for providers with data caches to synchronize, changes in the data s...
virtual void setTransformContext(const QgsCoordinateTransformContext &transformContext)
Sets data coordinate transform context to transformContext.
#define SUBLAYER_SEPARATOR
#define QGIS_PROTECT_QOBJECT_THREAD_ACCESS_NON_FATAL
#define QGIS_PROTECT_QOBJECT_THREAD_ACCESS
Stores settings related to the context in which a preview job runs.
double maxRenderingTimeMs
Default maximum allowable render time, in ms.
double lastRenderingTimeMs
Previous rendering time for the layer, in ms.
Setting options for creating vector data providers.
QgsCoordinateTransformContext transformContext
Coordinate transform context.