This class reads data from a WFS server or alternatively from a GML file. More...

#include <qgsgml.h>

Collaboration diagram for QgsGml:

Signals
void	dataReadProgress (int progress)
void	totalStepsUpdate (int totalSteps)
void	dataProgressAndSteps (int progress, int totalSteps)

Public Member Functions
	QgsGml (const QString &typeName, const QString &geometryAttribute, const QgsFields &fields)
	~QgsGml ()
int	getFeatures (const QString &uri, QGis::WkbType wkbType, QgsRectangle extent=0)
	Does the Http GET request to the wfs server Supports only UTF-8, UTF-16, ISO-8859-1, ISO-8859-1 XML encodings.
int	getFeatures (const QByteArray &data, QGis::WkbType wkbType, QgsRectangle extent=0)
	Read from GML data.
QMap< QgsFeatureId, QgsFeature * >	featuresMap () const
	Get parsed features for given type name.
QMap< QgsFeatureId, QString >	idsMap () const
	Get feature ids map.
QgsCoordinateReferenceSystem	crs () const
	Returns features spatial reference system.

Private Types
enum	ParseMode { none, boundingBox, feature, attribute, geometry, coordinate, posList, multiPoint, multiLine, multiPolygon }

Private Slots
void	setFinished ()
void	handleProgressEvent (qint64 progress, qint64 totalSteps)
	Takes progress value and total steps and emit signals 'dataReadProgress' and 'totalStepUpdate'.

Private Member Functions
void	startElement (const XML_Char el, const XML_Char *attr)
	XML handler methods.
void	endElement (const XML_Char *el)
void	characters (const XML_Char *chars, int len)
int	readEpsgFromAttribute (int &epsgNr, const XML_Char **attr) const
	Reads attribute srsName="EpsgCrsId:...".
QString	readAttribute (const QString &attributeName, const XML_Char **attr) const
	Reads attribute as string.
int	createBBoxFromCoordinateString (QgsRectangle &bb, const QString &coordString) const
	Creates a rectangle from a coordinate string.
int	pointsFromCoordinateString (QList< QgsPoint > &points, const QString &coordString) const
	Creates a set of points from a coordinate string.
int	pointsFromPosListString (QList< QgsPoint > &points, const QString &coordString, int dimension) const
	Creates a set of points from a gml:posList or gml:pos coordinate string.
int	pointsFromString (QList< QgsPoint > &points, const QString &coordString) const
int	getPointWKB (unsigned char *wkb, int size, const QgsPoint &) const
int	getLineWKB (unsigned char *wkb, int size, const QList< QgsPoint > &lineCoordinates) const
int	getRingWKB (unsigned char *wkb, int size, const QList< QgsPoint > &ringCoordinates) const
int	createMultiLineFromFragments ()
	Creates a multiline from the information in mCurrentWKBFragments and mCurrentWKBFragmentSizes.
int	createMultiPointFromFragments ()
int	createPolygonFromFragments ()
int	createMultiPolygonFromFragments ()
int	totalWKBFragmentSize () const
	Adds all the integers contained in mCurrentWKBFragmentSizes.
QWidget *	findMainWindow () const
	Returns pointer to main window or 0 if it does not exist.
void	calculateExtentFromFeatures ()
	This function evaluates the layer bounding box from the features and sets it to mExtent.
ParseMode	modeStackTop ()
	Get safely (if empty) top from mode stack.
ParseMode	modeStackPop ()
	Safely (if empty) pop from mode stack.

Static Private Member Functions
static void	start (void data, const XML_Char el, const XML_Char **attr)
static void	end (void data, const XML_Char el)
static void	chars (void data, const XML_Char chars, int len)

Private Attributes
QString	mTypeName
QString	mUri
QgsRectangle	mExtent
	Bounding box of the layer.
QMap< QgsFeatureId, QgsFeature * >	mFeatures
	The features of the layer, map of feature maps for each feature type.
QMap< QgsFeatureId, QString >	mIdMap
	Stores the relation between provider ids and WFS server ids.
QString	mGeometryAttribute
	Name of geometry attribute.
QMap< QString, QPair< int, QgsField > >	mThematicAttributes
QGis::WkbType *	mWkbType
bool	mFinished
	True if the request is finished.
QStack< ParseMode >	mParseModeStack
	Keep track about the most important nested elements.
QString	mStringCash
	This contains the character data if an important element has been encountered.
QgsFeature *	mCurrentFeature
QVector< QVariant >	mCurrentAttributes
QString	mCurrentFeatureId
int	mFeatureCount
unsigned char *	mCurrentWKB
	The total WKB for a feature.
int	mCurrentWKBSize
	The total WKB size for a feature.
QgsRectangle	mCurrentExtent
QList< QList< unsigned char * > >	mCurrentWKBFragments
	WKB intermediate storage during parsing.
QList< QList< int > >	mCurrentWKBFragmentSizes
	Similar to mCurrentWKB, but only the size.
QString	mAttributeName
QgsApplication::endian_t	mEndian
QString	mCoordinateSeparator
	Coordinate separator for coordinate strings.
QString	mTupleSeparator
	Tuple separator for coordinate strings.
int	mDimension
	Number of dimensions in pos or posList.
ParseMode	mCoorMode
	Coordinates mode, coordinate or posList.
int	mEpsg
	EPSG of parsed features geometries.

Detailed Description

This class reads data from a WFS server or alternatively from a GML file.

It uses the expat XML parser and an event based model to keep performance high. The parsing starts when the first data arrives, it does not wait until the request is finished

Definition at line 41 of file qgsgml.h.

Member Enumeration Documentation

enum QgsGml::ParseMode

private

Enumerator:

none
boundingBox
feature
attribute
geometry
coordinate
posList
multiPoint
multiLine
multiPolygon

Definition at line 91 of file qgsgml.h.

Constructor & Destructor Documentation

QgsGml::QgsGml	(	const QString &	typeName,
		const QString &	geometryAttribute,
		const QgsFields &	fields
	)

Definition at line 36 of file qgsgml.cpp.

References QgsApplication::endian(), index, mEndian, mThematicAttributes, mTypeName, and QgsFields::size().

QgsGml::~QgsGml ( )

Definition at line 64 of file qgsgml.cpp.

Member Function Documentation

void QgsGml::calculateExtentFromFeatures ( )

private

This function evaluates the layer bounding box from the features and sets it to mExtent.

Less efficient compared to reading the bbox from the provider, so it is only done if the wfs server does not provider extent information.

Definition at line 930 of file qgsgml.cpp.

References QgsGeometry::boundingBox(), QgsFeature::geometry(), mExtent, mFeatures, and QgsRectangle::unionRect().

Referenced by getFeatures().

void QgsGml::characters	(	const XML_Char *	chars,
		int	len
	)

private

Definition at line 534 of file qgsgml.cpp.

References attribute, coordinate, mParseModeStack, mStringCash, and posList.

static void QgsGml::chars	(	void *	data,
		const XML_Char *	chars,
		int	len
	)

inlinestaticprivate

Definition at line 117 of file qgsgml.h.

Referenced by getFeatures().

int QgsGml::createBBoxFromCoordinateString	(	QgsRectangle &	bb,
		const QString &	coordString
	)		const

private

Creates a rectangle from a coordinate string.

Returns: 0 in case of success

Definition at line 594 of file qgsgml.cpp.

References pointsFromCoordinateString(), and QgsRectangle::set().

Referenced by endElement().

int QgsGml::createMultiLineFromFragments ( )

private

Creates a multiline from the information in mCurrentWKBFragments and mCurrentWKBFragmentSizes.

Assign the result. The multiline is in mCurrentWKB and mCurrentWKBSize. The function deletes the memory in mCurrentWKBFragments. Returns 0 in case of success.

Definition at line 760 of file qgsgml.cpp.

References mCurrentWKB, mCurrentWKBFragments, mCurrentWKBFragmentSizes, mCurrentWKBSize, mEndian, mWkbType, totalWKBFragmentSize(), and QGis::WKBMultiLineString.

Referenced by endElement().

int QgsGml::createMultiPointFromFragments ( )

private

Definition at line 794 of file qgsgml.cpp.

References mCurrentWKB, mCurrentWKBFragments, mCurrentWKBFragmentSizes, mCurrentWKBSize, mEndian, mWkbType, totalWKBFragmentSize(), and QGis::WKBMultiPoint.

Referenced by endElement().

int QgsGml::createMultiPolygonFromFragments ( )

private

Definition at line 861 of file qgsgml.cpp.

References mCurrentWKB, mCurrentWKBFragments, mCurrentWKBFragmentSizes, mCurrentWKBSize, mEndian, mWkbType, totalWKBFragmentSize(), QGis::WKBMultiPolygon, and QGis::WKBPolygon.

Referenced by endElement().

int QgsGml::createPolygonFromFragments ( )

private

Definition at line 829 of file qgsgml.cpp.

References mCurrentWKB, mCurrentWKBFragments, mCurrentWKBFragmentSizes, mCurrentWKBSize, mEndian, mWkbType, totalWKBFragmentSize(), and QGis::WKBPolygon.

Referenced by endElement().

QgsCoordinateReferenceSystem QgsGml::crs ( ) const

Returns features spatial reference system.

Note: Added in QGIS 2.1

Definition at line 964 of file qgsgml.cpp.

References QgsCoordinateReferenceSystem::createFromOgcWmsCrs(), and mEpsg.

void QgsGml::dataProgressAndSteps	(	int	progress,
		int	totalSteps
	)

signal

Referenced by handleProgressEvent().

void QgsGml::dataReadProgress ( int progress )

signal

Referenced by getFeatures(), and handleProgressEvent().

static void QgsGml::end	(	void *	data,
		const XML_Char *	el
	)

inlinestaticprivate

Definition at line 113 of file qgsgml.h.

Referenced by getFeatures().

void QgsGml::endElement ( const XML_Char * el )

private

Definition at line 312 of file qgsgml.cpp.

References attribute, boundingBox, coordinate, createBBoxFromCoordinateString(), createMultiLineFromFragments(), createMultiPointFromFragments(), createMultiPolygonFromFragments(), createPolygonFromFragments(), feature, QgsGeometry::fromRect(), geometry, getLineWKB(), getPointWKB(), getRingWKB(), GML_NAMESPACE, QgsFeature::id(), QgsRectangle::isEmpty(), mAttributeName, mCurrentExtent, mCurrentFeature, mCurrentFeatureId, mCurrentWKB, mCurrentWKBFragments, mCurrentWKBFragmentSizes, mCurrentWKBSize, mFeatureCount, mFeatures, mGeometryAttribute, mIdMap, mParseModeStack, mStringCash, mThematicAttributes, mTypeName, multiLine, multiPoint, multiPolygon, mWkbType, none, NS_SEPARATOR, pointsFromString(), posList, QgsDebugMsg, QgsFeature::setAttribute(), QgsFeature::setGeometry(), QgsFeature::setGeometryAndOwnership(), QgsFeature::setValid(), QGis::WKBLineString, QGis::WKBMultiLineString, QGis::WKBMultiPoint, QGis::WKBMultiPolygon, QGis::WKBPoint, and QGis::WKBPolygon.

QMap<QgsFeatureId, QgsFeature* > QgsGml::featuresMap ( ) const

inline

Get parsed features for given type name.

Definition at line 67 of file qgsgml.h.

QWidget* QgsGml::findMainWindow ( ) const

private

Returns pointer to main window or 0 if it does not exist.

int QgsGml::getFeatures	(	const QString &	uri,
		QGis::WkbType *	wkbType,
		QgsRectangle *	extent = `0`
	)

Does the Http GET request to the wfs server Supports only UTF-8, UTF-16, ISO-8859-1, ISO-8859-1 XML encodings.

Parameters

uri	GML URL
wkbType	wkbType to retrieve
extent	retrieved extents

Returns: 0 in case of success

Definition at line 68 of file qgsgml.cpp.

References calculateExtentFromFeatures(), chars(), QgsMessageLog::CRITICAL, dataReadProgress(), end(), handleProgressEvent(), QgsNetworkAccessManager::instance(), QgsRectangle::isEmpty(), QgsMessageLog::logMessage(), mExtent, mFinished, mTypeName, mUri, mWkbType, NS_SEPARATOR, setFinished(), QgsRectangle::setMinimal(), start(), totalStepsUpdate(), tr, and QGis::WKBNoGeometry.

int QgsGml::getFeatures	(	const QByteArray &	data,
		QGis::WkbType *	wkbType,
		QgsRectangle *	extent = `0`
	)

Read from GML data.

Constructor uri param is ignored Supports only UTF-8, UTF-16, ISO-8859-1, ISO-8859-1 XML encodings.

Definition at line 165 of file qgsgml.cpp.

References chars(), end(), mExtent, mWkbType, NS_SEPARATOR, QgsRectangle::setMinimal(), and start().

int QgsGml::getLineWKB	(	unsigned char **	wkb,
		int *	size,
		const QList< QgsPoint > &	lineCoordinates
	)		const

private

Definition at line 705 of file qgsgml.cpp.

References mEndian, and QGis::WKBLineString.

Referenced by endElement().

int QgsGml::getPointWKB	(	unsigned char **	wkb,
		int *	size,
		const QgsPoint &	point
	)		const

private

Definition at line 685 of file qgsgml.cpp.

References mEndian, QGis::WKBPoint, QgsPoint::x(), and QgsPoint::y().

Referenced by endElement().

int QgsGml::getRingWKB	(	unsigned char **	wkb,
		int *	size,
		const QList< QgsPoint > &	ringCoordinates
	)		const

private

Definition at line 736 of file qgsgml.cpp.

Referenced by endElement().

void QgsGml::handleProgressEvent	(	qint64	progress,
		qint64	totalSteps
	)

privateslot

Takes progress value and total steps and emit signals 'dataReadProgress' and 'totalStepUpdate'.

Definition at line 188 of file qgsgml.cpp.

References dataProgressAndSteps(), dataReadProgress(), and totalStepsUpdate().

Referenced by getFeatures().

QMap<QgsFeatureId, QString > QgsGml::idsMap ( ) const

inline

Get feature ids map.

Definition at line 70 of file qgsgml.h.

ParseMode QgsGml::modeStackPop ( )

inlineprivate

Safely (if empty) pop from mode stack.

Definition at line 183 of file qgsgml.h.

ParseMode QgsGml::modeStackTop ( )

inlineprivate

Get safely (if empty) top from mode stack.

Definition at line 180 of file qgsgml.h.

int QgsGml::pointsFromCoordinateString	(	QList< QgsPoint > &	points,
		const QString &	coordString
	)		const

private

Creates a set of points from a coordinate string.

Parameters

points	list that will contain the created points
coordString	the text containing the coordinates

Returns: 0 in case of success

Definition at line 612 of file qgsgml.cpp.

References mCoordinateSeparator, and mTupleSeparator.

Referenced by createBBoxFromCoordinateString(), and pointsFromString().

int QgsGml::pointsFromPosListString	(	QList< QgsPoint > &	points,
		const QString &	coordString,
		int	dimension
	)		const

private

Creates a set of points from a gml:posList or gml:pos coordinate string.

Parameters

points	list that will contain the created points
coordString	the text containing the coordinates
dimension	number of dimensions

Returns: 0 in case of success

Definition at line 643 of file qgsgml.cpp.

References QgsDebugMsg.

Referenced by pointsFromString().

int QgsGml::pointsFromString	(	QList< QgsPoint > &	points,
		const QString &	coordString
	)		const

private

Definition at line 672 of file qgsgml.cpp.

References coordinate, mCoorMode, mDimension, pointsFromCoordinateString(), pointsFromPosListString(), and posList.

Referenced by endElement().

QString QgsGml::readAttribute	(	const QString &	attributeName,
		const XML_Char **	attr
	)		const

private

Reads attribute as string.

Parameters

attributeName
attr

Returns: attribute value or an empty string if no such attribute

Definition at line 580 of file qgsgml.cpp.

Referenced by startElement().

int QgsGml::readEpsgFromAttribute	(	int &	epsgNr,
		const XML_Char **	attr
	)		const

private

Reads attribute srsName="EpsgCrsId:...".

Parameters

epsgNr	result
attr	attribute strings

Returns: 0 in case of success

Definition at line 549 of file qgsgml.cpp.

Referenced by startElement().

void QgsGml::setFinished ( )

privateslot

Definition at line 183 of file qgsgml.cpp.

References mFinished.

Referenced by getFeatures().

static void QgsGml::start	(	void *	data,
		const XML_Char *	el,
		const XML_Char **	attr
	)

inlinestaticprivate

Definition at line 109 of file qgsgml.h.

Referenced by getFeatures().

void QgsGml::startElement	(	const XML_Char *	el,
		const XML_Char **	attr
	)

private

XML handler methods.

Definition at line 200 of file qgsgml.cpp.

References attribute, boundingBox, coordinate, feature, geometry, GML_NAMESPACE, mAttributeName, mCoordinateSeparator, mCoorMode, mCurrentFeature, mCurrentFeatureId, mCurrentWKBFragments, mCurrentWKBFragmentSizes, mDimension, mEpsg, mFeatureCount, mGeometryAttribute, mParseModeStack, mStringCash, mThematicAttributes, mTupleSeparator, mTypeName, multiLine, multiPoint, multiPolygon, none, NS_SEPARATOR, posList, QgsDebugMsg, readAttribute(), readEpsgFromAttribute(), and QgsFeature::setAttributes().

void QgsGml::totalStepsUpdate ( int totalSteps )

signal

Referenced by getFeatures(), and handleProgressEvent().

int QgsGml::totalWKBFragmentSize ( ) const

private

Adds all the integers contained in mCurrentWKBFragmentSizes.

Definition at line 917 of file qgsgml.cpp.

References mCurrentWKBFragmentSizes.

Referenced by createMultiLineFromFragments(), createMultiPointFromFragments(), createMultiPolygonFromFragments(), and createPolygonFromFragments().

Member Data Documentation

QString QgsGml::mAttributeName

private

Definition at line 226 of file qgsgml.h.

Referenced by endElement(), and startElement().

QString QgsGml::mCoordinateSeparator

private

Coordinate separator for coordinate strings.

Usually ","

Definition at line 229 of file qgsgml.h.

Referenced by pointsFromCoordinateString(), and startElement().

ParseMode QgsGml::mCoorMode

private

Coordinates mode, coordinate or posList.

Definition at line 235 of file qgsgml.h.

Referenced by pointsFromString(), and startElement().

QVector<QVariant> QgsGml::mCurrentAttributes

private

Definition at line 211 of file qgsgml.h.

QgsRectangle QgsGml::mCurrentExtent

private

Definition at line 218 of file qgsgml.h.

Referenced by endElement().

QgsFeature* QgsGml::mCurrentFeature

private

Definition at line 210 of file qgsgml.h.

Referenced by endElement(), and startElement().

QString QgsGml::mCurrentFeatureId

private

Definition at line 212 of file qgsgml.h.

Referenced by endElement(), and startElement().

unsigned char* QgsGml::mCurrentWKB

private

The total WKB for a feature.

Definition at line 215 of file qgsgml.h.

Referenced by createMultiLineFromFragments(), createMultiPointFromFragments(), createMultiPolygonFromFragments(), createPolygonFromFragments(), and endElement().

QList< QList<unsigned char*> > QgsGml::mCurrentWKBFragments

private

WKB intermediate storage during parsing.

For points and lines, no intermediate WKB is stored at all. For multipoints and multilines and polygons, only one nested list is used. For multipolygons, both nested lists are used

Definition at line 223 of file qgsgml.h.

Referenced by createMultiLineFromFragments(), createMultiPointFromFragments(), createMultiPolygonFromFragments(), createPolygonFromFragments(), endElement(), and startElement().