QGIS API Documentation  3.19.0-Master (5df09f591d)
qgsdataprovider.h
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1 /***************************************************************************
2  qgsdataprovider.h - DataProvider Interface class
3  --------------------------------------
4  Date : 09-Sep-2003
5  Copyright : (C) 2003 by Gary E.Sherman
6  email : sherman at mrcc.com
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 #ifndef QQGSDATAPROVIDER_H
17 #define QQGSDATAPROVIDER_H
18 
19 #include "qgis_core.h"
20 #include <QDateTime>
21 #include <QObject>
22 #include <QString>
23 #include <QStringList>
24 #include <QMutex>
25 
26 //#include "qgsdataitem.h"
27 #include "qgsdatasourceuri.h"
29 #include "qgslayermetadata.h"
30 #include "qgserror.h"
31 
32 class QgsRectangle;
35 
36 
41 class CORE_EXPORT QgsDataProvider : public QObject
42 {
43 
44 #ifdef SIP_RUN
46  if ( qobject_cast<QgsVectorDataProvider *>( sipCpp ) )
47  {
48  sipType = sipType_QgsVectorDataProvider;
49  }
50  else if ( qobject_cast<QgsRasterDataProvider *>( sipCpp ) )
51  {
52  sipType = sipType_QgsRasterDataProvider;
53  }
54  else if ( qobject_cast<QgsMeshDataProvider *>( sipCpp ) )
55  {
56  sipType = sipType_QgsMeshDataProvider;
57  }
58  else if ( qobject_cast<QgsPointCloudDataProvider *>( sipCpp ) )
59  {
60  sipType = sipType_QgsPointCloudDataProvider;
61  }
62  else
63  {
64  sipType = 0;
65  }
66  SIP_END
67 #endif
68  Q_OBJECT
69 
70  public:
71 
72  // TODO QGIS 4: (re)move DataCapability as this enum is really meant for data items rather than data providers
73 
78  {
79  NoDataCapabilities = 0,
80  File = 1,
81  Dir = 1 << 1,
82  Database = 1 << 2,
83  Net = 1 << 3 // Internet source
84  };
85  Q_DECLARE_FLAGS( DataCapabilities, DataCapability )
86 
87 
95  {
97  CustomData = 3000
98  };
99 
100 
109  {
110 
115 
116  };
117 
122  enum ReadFlag
123  {
124  FlagTrustDataSource = 1 << 0,
125  SkipFeatureCount = 1 << 1,
126  };
127  Q_DECLARE_FLAGS( ReadFlags, ReadFlag )
128 
129 
134  QgsDataProvider( const QString &uri = QString(),
136  QgsDataProvider::ReadFlags flags = QgsDataProvider::ReadFlags() );
137 
143  virtual QgsCoordinateReferenceSystem crs() const = 0;
144 
150  virtual void setDataSourceUri( const QString &uri )
151  {
152  mDataSourceURI = uri;
153  }
154 
164  virtual QString dataSourceUri( bool expandAuthConfig = false ) const
165  {
166  if ( expandAuthConfig && mDataSourceURI.contains( QLatin1String( "authcfg" ) ) )
167  {
168  const QgsDataSourceUri uri( mDataSourceURI );
169  return uri.uri( expandAuthConfig );
170  }
171  else
172  {
173  return mDataSourceURI;
174  }
175  }
176 
184  virtual QString dataComment() const { return QString(); };
185 
186 
192  void setUri( const QgsDataSourceUri &uri )
193  {
194  mDataSourceURI = uri.uri( true );
195  }
196 
203  {
204  return QgsDataSourceUri( mDataSourceURI );
205  }
206 
214  virtual QgsDataProviderTemporalCapabilities *temporalCapabilities();
215 
223  virtual const QgsDataProviderTemporalCapabilities *temporalCapabilities() const SIP_SKIP;
224 
229  virtual QgsRectangle extent() const = 0;
230 
231 
236  virtual bool isValid() const = 0;
237 
238 
242  virtual void updateExtents()
243  {
244  // NOP by default
245  }
246 
247 
254  virtual bool setSubsetString( const QString &subset, bool updateFeatureCount = true )
255  {
256  // NOP by default
257  Q_UNUSED( subset )
258  Q_UNUSED( updateFeatureCount )
259  return false;
260  }
261 
262 
266  virtual bool supportsSubsetString() const { return false; }
267 
274  virtual QString subsetString() const
275  {
276  return QString();
277  }
278 
279 
288  virtual QStringList subLayers() const
289  {
290  return QStringList(); // Empty
291  }
292 
300  virtual QStringList subLayerStyles() const
301  {
302  return QStringList(); // Empty
303  }
304 
305 
309  virtual uint subLayerCount() const
310  {
311  return 0;
312  }
313 
314 
320  virtual void setLayerOrder( const QStringList &layers )
321  {
322  //prevent unused var warnings
323  if ( layers.count() < 1 )
324  {
325  return;
326  }
327  // NOOP
328  }
329 
330 
334  virtual void setSubLayerVisibility( const QString &name, bool vis )
335  {
336  //prevent unused var warnings
337  if ( name.isEmpty() || !vis )
338  {
339  return;
340  }
341  // NOOP
342  }
343 
344 
360  virtual QString name() const = 0;
361 
362 
375  virtual QString description() const = 0;
376 
377 
388  virtual QString fileVectorFilters() const
389  {
390  return QString();
391  }
392 
393 
404  virtual QString fileRasterFilters() const
405  {
406  return QString();
407  }
408 
409  // TODO QGIS 4 -> Make `reloadData()` non virtual. This should be implemented in `reloadProviderData()`.
410 
418  virtual void reloadData();
419 
421  virtual QDateTime timestamp() const { return mTimestamp; }
422 
424  virtual QDateTime dataTimestamp() const { return QDateTime(); }
425 
431  virtual QgsError error() const { return mError; }
432 
437  virtual void invalidateConnections( const QString &connection ) { Q_UNUSED( connection ) }
438 
461  virtual bool enterUpdateMode() { return true; }
462 
480  virtual bool leaveUpdateMode() { return true; }
481 
488  void setProviderProperty( ProviderProperty property, const QVariant &value );
489 
496  void setProviderProperty( int property, const QVariant &value ); // SIP_SKIP
497 
504  QVariant providerProperty( ProviderProperty property, const QVariant &defaultValue = QVariant() ) const;
505 
512  QVariant providerProperty( int property, const QVariant &defaultValue ) const; // SIP_SKIP
513 
524  virtual void setListening( bool isListening );
525 
526 #ifndef SIP_RUN
527 
534  {
536  double lastRenderingTimeMs = -1;
537 
539  double maxRenderingTimeMs = MAXIMUM_LAYER_PREVIEW_TIME_MS;
540  };
541 #endif
542 
555  virtual bool renderInPreview( const QgsDataProvider::PreviewContext &context ); // SIP_SKIP
556 
565  virtual QgsLayerMetadata layerMetadata() const { return QgsLayerMetadata(); }
566 
575  virtual bool writeLayerMetadata( const QgsLayerMetadata &metadata ) { Q_UNUSED( metadata ) return false; }
576 
584  QgsCoordinateTransformContext transformContext() const SIP_SKIP;
585 
596  virtual void setTransformContext( const QgsCoordinateTransformContext &transformContext ) SIP_SKIP;
597 
604  static QString sublayerSeparator();
605 
606  signals:
607 
614  void fullExtentCalculated();
615 
628  void dataChanged();
629 
637  void notify( const QString &msg );
638 
639 
640  protected:
641 
645  QDateTime mTimestamp;
646 
648  QgsError mError;
649 
651  void appendError( const QgsErrorMessage &message ) { mError.append( message ); }
652 
654  void setError( const QgsError &error ) { mError = error;}
655 
657  QgsDataProvider::ReadFlags mReadFlags = QgsDataProvider::ReadFlags();
658 
659  private:
660 
665  QString mDataSourceURI;
666 
668 
669  QMap< int, QVariant > mProviderProperties;
670 
674  mutable QMutex mOptionsMutex;
675 
680  virtual void reloadProviderData() {}
681 };
682 
683 Q_DECLARE_OPERATORS_FOR_FLAGS( QgsDataProvider::ReadFlags )
684 
685 #endif
This class represents a coordinate reference system (CRS).
Contains information about the context in which a coordinate transform is executed.
Base class for handling properties relating to a data provider's temporal capabilities.
Abstract base class for spatial data provider implementations.
virtual void invalidateConnections(const QString &connection)
Invalidate connections corresponding to specified name.
virtual bool leaveUpdateMode()
Leave update mode.
void setUri(const QgsDataSourceUri &uri)
Set the data source specification.
virtual void setLayerOrder(const QStringList &layers)
Reorder the list of layer names to be rendered by this provider (in order from bottom to top)
ReadFlag
Flags which control dataprovider construction.
virtual QString name() const =0
Returns a provider name.
void setError(const QgsError &error)
Sets error message.
virtual QDateTime timestamp() const
Time stamp of data source in the moment when data/metadata were loaded by provider.
virtual QgsCoordinateReferenceSystem crs() const =0
Returns the coordinate system for the data source.
virtual QString dataComment() const
Returns a short comment for the data that this provider is providing access to (e....
ProviderProperty
Properties are used to pass custom configuration options into data providers.
@ EvaluateDefaultValues
Evaluate default values on provider side when calling QgsVectorDataProvider::defaultValue( int index ...
virtual QString subsetString() const
Returns the subset definition string (typically sql) currently in use by the layer and used by the pr...
virtual QgsLayerMetadata layerMetadata() const
Returns layer metadata collected from the provider's source.
virtual void setDataSourceUri(const QString &uri)
Set the data source specification.
virtual QString fileRasterFilters() const
Returns raster file filter string.
virtual QgsError error() const
Gets current status error.
DataCapability
Used in browser model to understand which items for which providers should be populated.
virtual QDateTime dataTimestamp() const
Current time stamp of data source.
virtual bool supportsSubsetString() const
Returns true if the provider supports setting of subset strings.
virtual QString dataSourceUri(bool expandAuthConfig=false) const
Gets the data source specification.
virtual QString description() const =0
Returns description.
QgsDataSourceUri uri() const
Gets the data source specification.
virtual QString fileVectorFilters() const
Returns vector file filter string.
virtual QStringList subLayerStyles() const
Sub-layer styles for each sub-layer handled by this provider, in order from bottom to top.
virtual bool setSubsetString(const QString &subset, bool updateFeatureCount=true)
Set the subset string used to create a subset of features in the layer.
virtual uint subLayerCount() const
Returns the number of layers for the current data source.
virtual QStringList subLayers() const
Sub-layers handled by this provider, in order from bottom to top.
virtual bool writeLayerMetadata(const QgsLayerMetadata &metadata)
Writes layer metadata to the underlying provider source.
virtual bool enterUpdateMode()
Enter update mode.
virtual void setSubLayerVisibility(const QString &name, bool vis)
Set the visibility of the given sublayer name.
Class for storing the component parts of a RDBMS data source URI (e.g.
QString uri(bool expandAuthConfig=true) const
Returns the complete URI as a string.
QgsErrorMessage represents single error message.
Definition: qgserror.h:33
QgsError is container for error messages (report).
Definition: qgserror.h:81
void append(const QString &message, const QString &tag)
Append new error message.
Definition: qgserror.cpp:39
A structured metadata store for a map layer.
A rectangle specified with double values.
Definition: qgsrectangle.h:42
#define SIP_CONVERT_TO_SUBCLASS_CODE(code)
Definition: qgis_sip.h:177
#define SIP_SKIP
Definition: qgis_sip.h:126
#define SIP_END
Definition: qgis_sip.h:194
Q_DECLARE_OPERATORS_FOR_FLAGS(QgsField::ConfigurationFlags) CORE_EXPORT QDataStream &operator<<(QDataStream &out
Writes the field to stream out. QGIS version compatibility is not guaranteed.
Stores settings related to the context in which a preview job runs.
Setting options for creating vector data providers.
QgsCoordinateTransformContext transformContext
Coordinate transform context.