Holds data provider key, description, and associated shared library file or function pointer information. More...

#include <qgsprovidermetadata.h>

Public Types
typedef std::function< QgsDataProvider *(const QString &, const QgsDataProvider::ProviderOptions &) >	CreateDataProviderFunction
	Typedef for data provider creation function. More...

enum	FilterType { FilterType::FilterVector = 1, FilterType::FilterRaster, FilterType::FilterMesh, FilterType::FilterMeshDataset }
	Type of file filters. More...

Public Member Functions
	QgsProviderMetadata (const QString &key, const QString &description, const QString &library=QString())
	Constructor for provider metadata. More...

Q_DECL_DEPRECATED	QgsProviderMetadata (const QString &key, const QString &description, const QgsProviderMetadata::CreateDataProviderFunction &createFunc)
	Metadata for provider with direct provider creation function pointer, where no library is involved. More...

virtual	~QgsProviderMetadata ()
	dtor More...

virtual void	cleanupProvider ()
	Cleanup the provider. More...

virtual QMap< QString, QgsAbstractProviderConnection * >	connections (bool cached=true) SIP_THROW(QgsProviderConnectionException)
	Returns a dictionary of stored provider connections, the dictionary key is the connection identifier. More...

template<typename T >
QMap< QString, T * >	connections (bool cached=true)
	Returns a dictionary of provider connections of the specified type T, the dictionary key is the connection identifier. More...

virtual QgsAbstractProviderConnection *	createConnection (const QString &uri, const QVariantMap &configuration)
	Creates a new connection from uri and configuration, the newly created connection is not automatically stored in the settings, call saveConnection() to save it. More...

virtual QgsAbstractProviderConnection *	createConnection (const QString &name)
	Creates a new connection by loading the connection with the given name from the settings. More...

virtual bool	createDb (const QString &dbPath, QString &errCause)
	Creates database by the provider on the path. More...

virtual QgsVectorLayerExporter::ExportError	createEmptyLayer (const QString &uri, const QgsFields &fields, QgsWkbTypes::Type wkbType, const QgsCoordinateReferenceSystem &srs, bool overwrite, QMap< int, int > &oldToNewAttrIdxMap, QString &errorMessage, const QMap< QString, QVariant > *options)
	Creates new empty vector layer. More...

Q_DECL_DEPRECATED CreateDataProviderFunction	createFunction () const
	Returns a pointer to the direct provider creation function, if supported by the provider. More...

virtual QgsDataProvider *	createProvider (const QString &uri, const QgsDataProvider::ProviderOptions &options)
	Class factory to return a pointer to a newly created QgsDataProvider object. More...

virtual QgsRasterDataProvider *	createRasterDataProvider (const QString &uri, const QString &format, int nBands, Qgis::DataType type, int width, int height, double *geoTransform, const QgsCoordinateReferenceSystem &crs, const QStringList &createOptions=QStringList())
	Creates a new instance of the raster data provider. More...

virtual QgsTransaction *	createTransaction (const QString &connString)
	Returns new instance of transaction. More...

virtual QList< QgsDataItemProvider *>	dataItemProviders () const
	Returns data item providers. More...

QMap< QString, QgsAbstractDatabaseProviderConnection * >	dbConnections (bool cached=true) SIP_THROW(QgsProviderConnectionException)
	Returns a dictionary of database provider connections, the dictionary key is the connection identifier. More...

virtual QVariantMap	decodeUri (const QString &uri)
	Breaks a provider data source URI into its component paths (e.g. More...

virtual void	deleteConnection (const QString &name) SIP_THROW(QgsProviderConnectionException)
	Removes the connection with the given name from the settings. More...

virtual bool	deleteStyleById (const QString &uri, QString styleId, QString &errCause)
	Deletes a layer style defined by styleId. More...

QString	description () const
	This returns descriptive text for the provider. More...

virtual QString	filters (FilterType type)
	Builds the list of file filter strings (supported formats) More...

QgsAbstractProviderConnection *	findConnection (const QString &name, bool cached=true) SIP_THROW(QgsProviderConnectionException)
	Searches and returns a (possibly NULL) connection from the stored provider connections. More...

virtual QString	getStyleById (const QString &uri, QString styleId, QString &errCause)
	Gets a layer style defined by uri. More...

virtual void	initProvider ()
	Initialize the provider. More...

QString	key () const
	This returns the unique key associated with the provider. More...

Q_DECL_DEPRECATED QString	library () const
	This returns the library file name. More...

virtual int	listStyles (const QString &uri, QStringList &ids, QStringList &names, QStringList &descriptions, QString &errCause)
	Lists stored layer styles in the provider defined by uri. More...

virtual QString	loadStyle (const QString &uri, QString &errCause)
	Loads a layer style defined by uri. More...

virtual QList< QPair< QString, QString > >	pyramidResamplingMethods ()
	Returns pyramid resampling methods available for provider. More...

virtual void	saveConnection (const QgsAbstractProviderConnection *connection, const QString &name)
	Stores the connection in the settings. More...

virtual bool	saveStyle (const QString &uri, const QString &qmlStyle, const QString &sldStyle, const QString &styleName, const QString &styleDescription, const QString &uiFileContent, bool useAsDefault, QString &errCause)
	Saves a layer style to provider. More...

Detailed Description

Holds data provider key, description, and associated shared library file or function pointer information.

Provider metadata refers either to providers which are loaded via libraries or which are native providers that are included in the core QGIS installation and accessed through function pointers.

For library based providers, the metadata class is used in a lazy load implementation in QgsProviderRegistry. To save memory, data providers are only actually loaded via QLibrary calls if they're to be used. (Though they're all iteratively loaded once to get their metadata information, and then unloaded when the QgsProviderRegistry is created.) QgsProviderMetadata supplies enough information to be able to later load the associated shared library object.

Definition at line 64 of file qgsprovidermetadata.h.

Member Typedef Documentation

◆ CreateDataProviderFunction

typedef std::function< QgsDataProvider*( const QString &, const QgsDataProvider::ProviderOptions & ) > QgsProviderMetadata::CreateDataProviderFunction

Typedef for data provider creation function.

Since: QGIS 3.0

Definition at line 72 of file qgsprovidermetadata.h.

Member Enumeration Documentation

◆ FilterType

enum QgsProviderMetadata::FilterType

strong

Type of file filters.

Since: QGIS 3.10

Enumerator
FilterVector
FilterRaster
FilterMesh
FilterMeshDataset

Definition at line 141 of file qgsprovidermetadata.h.

Constructor & Destructor Documentation

◆ QgsProviderMetadata() [1/2]

QgsProviderMetadata::QgsProviderMetadata	(	const QString &	key,
		const QString &	description,
		const QString &	library = `QString()`
	)

Constructor for provider metadata.

Parameters

key	provider key
description	provider description
library	plugin library file name (empty if the provider is not loaded from a library)

Definition at line 24 of file qgsprovidermetadata.cpp.

◆ QgsProviderMetadata() [2/2]

QgsProviderMetadata::QgsProviderMetadata	(	const QString &	key,
		const QString &	description,
		const QgsProviderMetadata::CreateDataProviderFunction &	createFunc
	)

Metadata for provider with direct provider creation function pointer, where no library is involved.

Since: QGIS 3.0

Deprecated:: QGIS 3.10

Definition at line 32 of file qgsprovidermetadata.cpp.

◆ ~QgsProviderMetadata()

QgsProviderMetadata::~QgsProviderMetadata ( )

virtual

dtor

Definition at line 38 of file qgsprovidermetadata.cpp.

Member Function Documentation

◆ cleanupProvider()

void QgsProviderMetadata::cleanupProvider ( )

virtual

Cleanup the provider.

Since: QGIS 3.10

Definition at line 68 of file qgsprovidermetadata.cpp.

◆ connections() [1/2]

QMap< QString, QgsAbstractProviderConnection * > QgsProviderMetadata::connections ( bool cached = true )

virtual

Returns a dictionary of stored provider connections, the dictionary key is the connection identifier.

Ownership is not transferred. Raises a QgsProviderConnectionException if any errors are encountered.

Parameters

cached if false connections will be re-read from the settings

Exceptions

QgsProviderConnectionException

Since: QGIS 3.10

Definition at line 165 of file qgsprovidermetadata.cpp.

◆ connections() [2/2]

template<typename T >

QMap< QString, T * > QgsProviderMetadata::connections ( bool cached = true )

Returns a dictionary of provider connections of the specified type T, the dictionary key is the connection identifier.

Parameters

cached if false connections will be re-read from the settings

Note: not available in Python bindings

Since: QGIS 3.10

Definition at line 226 of file qgsprovidermetadata.cpp.

◆ createConnection() [1/2]

QgsAbstractProviderConnection * QgsProviderMetadata::createConnection	(	const QString &	uri,
		const QVariantMap &	configuration
	)

virtual

Creates a new connection from uri and configuration, the newly created connection is not automatically stored in the settings, call saveConnection() to save it.

Ownership is transferred to the caller.

See also: saveConnection()

Since: QGIS 3.10

Definition at line 197 of file qgsprovidermetadata.cpp.

◆ createConnection() [2/2]

QgsAbstractProviderConnection * QgsProviderMetadata::createConnection ( const QString & name )

virtual

Creates a new connection by loading the connection with the given name from the settings.

Ownership is transferred to the caller.

See also: findConnection()

Definition at line 190 of file qgsprovidermetadata.cpp.

◆ createDb()

bool QgsProviderMetadata::createDb	(	const QString &	dbPath,
		QString &	errCause
	)

virtual

Creates database by the provider on the path.

Since: QGIS 3.10

Definition at line 154 of file qgsprovidermetadata.cpp.

◆ createEmptyLayer()

QgsVectorLayerExporter::ExportError QgsProviderMetadata::createEmptyLayer	(	const QString &	uri,
		const QgsFields &	fields,
		QgsWkbTypes::Type	wkbType,
		const QgsCoordinateReferenceSystem &	srs,
		bool	overwrite,
		QMap< int, int > &	oldToNewAttrIdxMap,
		QString &	errorMessage,
		const QMap< QString, QVariant > *	options
	)

virtual

Creates new empty vector layer.

Note: not available in Python bindings

Since: QGIS 3.10

Definition at line 92 of file qgsprovidermetadata.cpp.

◆ createFunction()

QgsProviderMetadata::CreateDataProviderFunction QgsProviderMetadata::createFunction ( ) const

Returns a pointer to the direct provider creation function, if supported by the provider.

Note: not available in Python bindings

Since: QGIS 3.0

Deprecated:: QGIS 3.10

Definition at line 58 of file qgsprovidermetadata.cpp.

◆ createProvider()

QgsDataProvider * QgsProviderMetadata::createProvider	(	const QString &	uri,
		const QgsDataProvider::ProviderOptions &	options
	)

virtual

Class factory to return a pointer to a newly created QgsDataProvider object.

Since: QGIS 3.10

Definition at line 78 of file qgsprovidermetadata.cpp.

◆ createRasterDataProvider()

QgsRasterDataProvider * QgsProviderMetadata::createRasterDataProvider	(	const QString &	uri,
		const QString &	format,
		int	nBands,
		Qgis::DataType	type,
		int	width,
		int	height,
		double *	geoTransform,
		const QgsCoordinateReferenceSystem &	crs,
		const QStringList &	createOptions = `QStringList()`
	)

virtual

Creates a new instance of the raster data provider.

Since: QGIS 3.10

Definition at line 102 of file qgsprovidermetadata.cpp.

◆ createTransaction()

QgsTransaction * QgsProviderMetadata::createTransaction ( const QString & connString )

virtual

Returns new instance of transaction.

Ownership is transferred to the caller

Since: QGIS 3.10

Definition at line 160 of file qgsprovidermetadata.cpp.

◆ dataItemProviders()

QList< QgsDataItemProvider * > QgsProviderMetadata::dataItemProviders ( ) const

virtual

Returns data item providers.

Caller is responsible for ownership of the item providers

See also: QgsProviderGuiMetadata::dataItemGuiProviders()

Note: Ownership of created data item providers is passed to the caller.

Since: QGIS 3.10

Definition at line 117 of file qgsprovidermetadata.cpp.

◆ dbConnections()

QMap< QString, QgsAbstractDatabaseProviderConnection * > QgsProviderMetadata::dbConnections ( bool cached = true )

Returns a dictionary of database provider connections, the dictionary key is the connection identifier.

Ownership is not transferred. Raises a QgsProviderConnectionException if any errors are encountered.

Parameters

cached if false connections will be re-read from the settings

Exceptions

QgsProviderConnectionException

Since: QGIS 3.10

Definition at line 171 of file qgsprovidermetadata.cpp.

◆ decodeUri()

QVariantMap QgsProviderMetadata::decodeUri ( const QString & uri )

virtual

Breaks a provider data source URI into its component paths (e.g.

file path, layer name).

Parameters

uri	uri string

Returns: map containing components. Standard components include "path", "layerName", "url".

Note: this function may not be supported by all providers, an empty map will be returned in such case

Since: QGIS 3.10

Definition at line 87 of file qgsprovidermetadata.cpp.

◆ deleteConnection()

void QgsProviderMetadata::deleteConnection ( const QString & name )

virtual

Removes the connection with the given name from the settings.

Raises a QgsProviderConnectionException if any errors are encountered.

Exceptions

QgsProviderConnectionException

Since: QGIS 3.10

Definition at line 204 of file qgsprovidermetadata.cpp.

◆ deleteStyleById()

bool QgsProviderMetadata::deleteStyleById	(	const QString &	uri,
		QString	styleId,
		QString &	errCause
	)

virtual

Deletes a layer style defined by styleId.

Since: QGIS 3.10

Definition at line 135 of file qgsprovidermetadata.cpp.

◆ description()

QString QgsProviderMetadata::description ( ) const

This returns descriptive text for the provider.

This is used to provide a descriptive list of available data providers.

Definition at line 48 of file qgsprovidermetadata.cpp.

◆ filters()

QString QgsProviderMetadata::filters ( FilterType type )

virtual

Builds the list of file filter strings (supported formats)

Suitable for use in a QFileDialog::getOpenFileNames() call.

Since: QGIS 3.10

Definition at line 73 of file qgsprovidermetadata.cpp.

◆ findConnection()

QgsAbstractProviderConnection * QgsProviderMetadata::findConnection	(	const QString &	name,
		bool	cached = `true`
	)

Searches and returns a (possibly NULL) connection from the stored provider connections.

Ownership is not transferred. Raises a QgsProviderConnectionException if any errors are encountered.

Parameters

name	the connection name
cached	if `false` connections will be re-read from the settings

Exceptions

QgsProviderConnectionException

Since: QGIS 3.10

Definition at line 176 of file qgsprovidermetadata.cpp.

◆ getStyleById()

QString QgsProviderMetadata::getStyleById	(	const QString &	uri,
		QString	styleId,
		QString &	errCause
	)

virtual

Gets a layer style defined by uri.

Since: QGIS 3.10

Definition at line 129 of file qgsprovidermetadata.cpp.

◆ initProvider()

void QgsProviderMetadata::initProvider ( )

virtual

Initialize the provider.

Since: QGIS 3.10

Definition at line 63 of file qgsprovidermetadata.cpp.

◆ key()

QString QgsProviderMetadata::key ( ) const

This returns the unique key associated with the provider.

This key string is used for the associative container in QgsProviderRegistry

Definition at line 43 of file qgsprovidermetadata.cpp.

◆ library()

QString QgsProviderMetadata::library ( ) const

This returns the library file name.

This is used to QLibrary calls to load the data provider (only for dynamically loaded libraries)

Deprecated:: QGIS 3.10 - providers may not need to be loaded from a library (empty string returned)

Definition at line 53 of file qgsprovidermetadata.cpp.

◆ listStyles()

int QgsProviderMetadata::listStyles	(	const QString &	uri,
		QStringList &	ids,
		QStringList &	names,
		QStringList &	descriptions,
		QString &	errCause
	)

virtual

Lists stored layer styles in the provider defined by uri.

Returns: -1 if not implemented by provider, otherwise number of styles stored

Since: QGIS 3.10

Definition at line 122 of file qgsprovidermetadata.cpp.

◆ loadStyle()

QString QgsProviderMetadata::loadStyle	(	const QString &	uri,
		QString &	errCause
	)

virtual

Loads a layer style defined by uri.

Since: QGIS 3.10

Definition at line 148 of file qgsprovidermetadata.cpp.

◆ pyramidResamplingMethods()

QList< QPair< QString, QString > > QgsProviderMetadata::pyramidResamplingMethods ( )

virtual

Returns pyramid resampling methods available for provider.

Since: QGIS 3.10

Definition at line 112 of file qgsprovidermetadata.cpp.

◆ saveConnection()

void QgsProviderMetadata::saveConnection	(	const QgsAbstractProviderConnection *	connection,
		const QString &	name
	)

virtual

Stores the connection in the settings.

Parameters

connection	the connection to be stored in the settings
name	the name under which the connection will be stored

Since: QGIS 3.10

Definition at line 210 of file qgsprovidermetadata.cpp.

◆ saveStyle()

bool QgsProviderMetadata::saveStyle	(	const QString &	uri,
		const QString &	qmlStyle,
		const QString &	sldStyle,
		const QString &	styleName,
		const QString &	styleDescription,
		const QString &	uiFileContent,
		bool	useAsDefault,
		QString &	errCause
	)

virtual

Saves a layer style to provider.

Since: QGIS 3.10

Definition at line 141 of file qgsprovidermetadata.cpp.

The documentation for this class was generated from the following files:

/build/qgis-3.10.0+15buster/src/core/qgsprovidermetadata.h
/build/qgis-3.10.0+15buster/src/core/qgsprovidermetadata.cpp

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

◆ CreateDataProviderFunction

Member Enumeration Documentation

◆ FilterType

Constructor & Destructor Documentation

◆ QgsProviderMetadata() [1/2]

◆ QgsProviderMetadata() [2/2]

◆ ~QgsProviderMetadata()

Member Function Documentation

◆ cleanupProvider()

◆ connections() [1/2]

◆ connections() [2/2]

◆ createConnection() [1/2]

◆ createConnection() [2/2]

◆ createDb()

◆ createEmptyLayer()

◆ createFunction()

◆ createProvider()

◆ createRasterDataProvider()

◆ createTransaction()

◆ dataItemProviders()

◆ dbConnections()

◆ decodeUri()

◆ deleteConnection()

◆ deleteStyleById()

◆ description()

◆ filters()

◆ findConnection()

◆ getStyleById()

◆ initProvider()

◆ key()

◆ library()

◆ listStyles()

◆ loadStyle()

◆ pyramidResamplingMethods()

◆ saveConnection()

◆ saveStyle()