Merge pull request #4624 from nyalldawson/feature_source

QgsFeatureSource
qgis · May 26, 2017 · 9cfe70c · 9cfe70c
2 parents 13e39da + 47ffb58
commit 9cfe70c
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diff --git a/python/core/core.sip b/python/core/core.sip
@@ -56,6 +56,7 @@
 %Include qgsfeatureiterator.sip
 %Include qgsfeaturerequest.sip
 %Include qgsfeaturesink.sip
+%Include qgsfeaturesource.sip
 %Include qgsfeedback.sip
 %Include qgsfield.sip
 %Include qgsfieldconstraints.sip

diff --git a/python/core/qgsfeaturesource.sip b/python/core/qgsfeaturesource.sip
@@ -0,0 +1,81 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/qgsfeaturesource.h                                          *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+
+class QgsFeatureSource
+{
+%Docstring
+ An interface for objects which provide features via a getFeatures method.
+
+.. versionadded:: 3.0
+%End
+
+%TypeHeaderCode
+#include "qgsfeaturesource.h"
+%End
+  public:
+
+    virtual ~QgsFeatureSource();
+
+    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const = 0;
+%Docstring
+ Returns an iterator for the features in the source.
+ An optional ``request`` can be used to optimise the returned
+ iterator, eg by restricting the returned attributes or geometry.
+ :rtype: QgsFeatureIterator
+%End
+
+    virtual QgsCoordinateReferenceSystem sourceCrs() const = 0;
+%Docstring
+ Returns the coordinate reference system for features in the source.
+ :rtype: QgsCoordinateReferenceSystem
+%End
+
+    virtual QgsFields fields() const = 0;
+%Docstring
+ Returns the fields associated with features in the source.
+ :rtype: QgsFields
+%End
+
+    virtual QgsWkbTypes::Type wkbType() const = 0;
+%Docstring
+ Returns the geometry type for features returned by this source.
+ :rtype: QgsWkbTypes.Type
+%End
+
+
+    int __len__() const;
+%Docstring
+ Returns the number of features contained in the source, or -1
+ if the feature count is unknown.
+ :rtype: int
+%End
+%MethodCode
+    sipRes = sipCpp->featureCount();
+%End
+
+    virtual long featureCount() const = 0;
+%Docstring
+ Returns the number of features contained in the source, or -1
+ if the feature count is unknown.
+ :rtype: long
+%End
+
+};
+
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/qgsfeaturesource.h                                          *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
diff --git a/python/core/qgsvectordataprovider.sip b/python/core/qgsvectordataprovider.sip
@@ -13,7 +13,7 @@ typedef QHash<int, QString> QgsAttrPalIndexNameHash;
 
 
 
-class QgsVectorDataProvider : QgsDataProvider, QgsFeatureSink
+class QgsVectorDataProvider : QgsDataProvider, QgsFeatureSink, QgsFeatureSource
 {
 %Docstring
  This is the base class for vector data providers.
@@ -124,6 +124,9 @@ Bitmask of all provider's editing capabilities
  :rtype: QgsFields
 %End
 
+    virtual QgsCoordinateReferenceSystem sourceCrs() const;
+
+
     virtual QString dataComment() const;
 %Docstring
  Return a short comment for the data that this provider is

diff --git a/python/core/qgsvectorlayer.sip b/python/core/qgsvectorlayer.sip
@@ -17,7 +17,7 @@ typedef QList<int> QgsAttributeList;
 typedef QSet<int> QgsAttributeIds;
 
 
-class QgsVectorLayer : QgsMapLayer, QgsExpressionContextGenerator, QgsFeatureSink
+class QgsVectorLayer : QgsMapLayer, QgsExpressionContextGenerator, QgsFeatureSink, QgsFeatureSource
 {
 %Docstring
  Represents a vector layer which manages a vector based data sets.
@@ -685,7 +685,8 @@ Returns true if this is a geometry layer and false in case of NoGeometry (table
  :rtype: bool
 %End
 
-    QgsWkbTypes::Type wkbType() const;
+    virtual QgsWkbTypes::Type wkbType() const;
+
 %Docstring
 Returns the WKBType or WKBUnknown in case of error
  :rtype: QgsWkbTypes.Type
@@ -697,6 +698,9 @@ Return the provider type for this layer
  :rtype: str
 %End
 
+    virtual QgsCoordinateReferenceSystem sourceCrs() const;
+
+
     virtual bool readXml( const QDomNode &layer_node, const QgsReadWriteContext &context );
 %Docstring
  Reads vector layer specific state from project file Dom node.
@@ -890,7 +894,8 @@ Return the provider type for this layer
  :rtype: str
 %End
 
-    QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const;
+    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const;
+
 %Docstring
  Query the layer for features specified in request.
  \param request feature request describing parameters of features to return
@@ -1103,7 +1108,7 @@ Return the extent of the layer
  :rtype: QgsRectangle
 %End
 
-    QgsFields fields() const;
+    virtual QgsFields fields() const;
 %Docstring
  Returns the list of fields of this layer.
  This also includes fields which have not yet been saved to the provider.
@@ -1156,7 +1161,8 @@ Returns list of attributes making up the primary key
  :rtype: long
 %End
 
-    long featureCount() const;
+    virtual long featureCount() const;
+
 %Docstring
  Returns feature count including changes which have not yet been committed
  If you need only the count of committed features call this method on this layer's provider.

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
@@ -753,6 +753,7 @@ SET(QGIS_CORE_HDRS
   qgsfeatureiterator.h
   qgsfeaturerequest.h
   qgsfeaturesink.h
+  qgsfeaturesource.h
   qgsfeaturestore.h
   qgsfieldformatter.h
   qgsfield_p.h

diff --git a/src/core/qgsfeaturesink.h b/src/core/qgsfeaturesink.h
@@ -94,5 +94,6 @@ class CORE_EXPORT QgsProxyFeatureSink : public QgsFeatureSink
     QgsFeatureSink *mSink;
 };
 
+Q_DECLARE_METATYPE( QgsFeatureSink * )
 
 #endif // QGSFEATURESINK_H
diff --git a/src/core/qgsfeaturesource.h b/src/core/qgsfeaturesource.h
@@ -0,0 +1,86 @@
+/***************************************************************************
+                         qgsfeaturesource.h
+                         ----------------
+    begin                : May 2017
+    copyright            : (C) 2017 by Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSFEATURESOURCE_H
+#define QGSFEATURESOURCE_H
+
+#include "qgis_core.h"
+#include "qgis.h"
+
+class QgsFeatureIterator;
+class QgsFeatureRequest;
+class QgsCoordinateReferenceSystem;
+class QgsFields;
+
+/**
+ * \class QgsFeatureSource
+ * \ingroup core
+ * An interface for objects which provide features via a getFeatures method.
+ *
+ * \since QGIS 3.0
+ */
+class CORE_EXPORT QgsFeatureSource
+{
+  public:
+
+    virtual ~QgsFeatureSource() = default;
+
+    /**
+     * Returns an iterator for the features in the source.
+     * An optional \a request can be used to optimise the returned
+     * iterator, eg by restricting the returned attributes or geometry.
+     */
+    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const = 0;
+
+    /**
+     * Returns the coordinate reference system for features in the source.
+     */
+    virtual QgsCoordinateReferenceSystem sourceCrs() const = 0;
+
+    /**
+     * Returns the fields associated with features in the source.
+     */
+    virtual QgsFields fields() const = 0;
+
+    /**
+     * Returns the geometry type for features returned by this source.
+     */
+    virtual QgsWkbTypes::Type wkbType() const = 0;
+
+#ifdef SIP_RUN
+
+    /**
+     * Returns the number of features contained in the source, or -1
+     * if the feature count is unknown.
+     */
+    int __len__() const;
+    % MethodCode
+    sipRes = sipCpp->featureCount();
+    % End
+#endif
+
+    /**
+     * Returns the number of features contained in the source, or -1
+     * if the feature count is unknown.
+     */
+    virtual long featureCount() const = 0;
+
+};
+
+Q_DECLARE_METATYPE( QgsFeatureSource * )
+
+#endif // QGSFEATURESOURCE_H
diff --git a/src/core/qgsvectordataprovider.cpp b/src/core/qgsvectordataprovider.cpp
@@ -47,6 +47,11 @@ QString QgsVectorDataProvider::storageType() const
   return QStringLiteral( "Generic vector file" );
 }
 
+QgsCoordinateReferenceSystem QgsVectorDataProvider::sourceCrs() const
+{
+  return crs();
+}
+
 QString QgsVectorDataProvider::dataComment() const
 {
   return QString();

diff --git a/src/core/qgsvectordataprovider.h b/src/core/qgsvectordataprovider.h
@@ -31,6 +31,7 @@ class QTextCodec;
 #include "qgsmaplayerdependency.h"
 #include "qgsrelation.h"
 #include "qgsfeaturesink.h"
+#include "qgsfeaturesource.h"
 
 typedef QList<int> QgsAttributeList SIP_SKIP;
 typedef QSet<int> QgsAttributeIds SIP_SKIP;
@@ -50,7 +51,7 @@ class QgsFeedback;
  *
  *
  */
-class CORE_EXPORT QgsVectorDataProvider : public QgsDataProvider, public QgsFeatureSink
+class CORE_EXPORT QgsVectorDataProvider : public QgsDataProvider, public QgsFeatureSink, public QgsFeatureSource
 {
     Q_OBJECT
 
@@ -139,23 +140,25 @@ class CORE_EXPORT QgsVectorDataProvider : public QgsDataProvider, public QgsFeat
      * \param request feature request describing parameters of features to return
      * \returns iterator for matching features from provider
      */
-    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const = 0;
+    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const override = 0;
 
     /**
      * Returns the geometry type which is returned by this layer
      */
-    virtual QgsWkbTypes::Type wkbType() const = 0;
+    virtual QgsWkbTypes::Type wkbType() const override = 0;
 
     /**
      * Number of features in the layer
      * \returns long containing number of features
      */
-    virtual long featureCount() const = 0;
+    virtual long featureCount() const override = 0;
 
     /**
      * Returns the fields associated with this data provider.
      */
-    virtual QgsFields fields() const = 0;
+    virtual QgsFields fields() const override = 0;
+
+    QgsCoordinateReferenceSystem sourceCrs() const override;
 
     /**
      * Return a short comment for the data that this provider is

diff --git a/src/core/qgsvectorlayer.cpp b/src/core/qgsvectorlayer.cpp
@@ -309,6 +309,11 @@ QString QgsVectorLayer::providerType() const
   return mProviderKey;
 }
 
+QgsCoordinateReferenceSystem QgsVectorLayer::sourceCrs() const
+{
+  return crs();
+}
+
 void QgsVectorLayer::reload()
 {
   if ( mDataProvider )

diff --git a/src/core/qgsvectorlayer.h b/src/core/qgsvectorlayer.h
@@ -31,6 +31,7 @@
 #include "qgsmaplayer.h"
 #include "qgsfeature.h"
 #include "qgsfeaturerequest.h"
+#include "qgsfeaturesource.h"
 #include "qgsfields.h"
 #include "qgsvectordataprovider.h"
 #include "qgsvectorsimplifymethod.h"
@@ -346,7 +347,7 @@ typedef QSet<int> QgsAttributeIds;
  * TODO QGIS3: Remove virtual from non-inherited methods (like isModified)
  * \see QgsVectorLayerUtils()
  */
-class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionContextGenerator, public QgsFeatureSink
+class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionContextGenerator, public QgsFeatureSink, public QgsFeatureSource
 {
     Q_OBJECT
 
@@ -690,11 +691,13 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
     bool hasGeometryType() const;
 
     //! Returns the WKBType or WKBUnknown in case of error
-    QgsWkbTypes::Type wkbType() const;
+    QgsWkbTypes::Type wkbType() const override;
 
     //! Return the provider type for this layer
     QString providerType() const;
 
+    QgsCoordinateReferenceSystem sourceCrs() const override;
+
     /** Reads vector layer specific state from project file Dom node.
      * \note Called by QgsMapLayer::readXml().
      */
@@ -859,7 +862,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      * \param request feature request describing parameters of features to return
      * \returns iterator for matching features from provider
      */
-    QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const;
+    QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const override;
 
     /**
      * Query the layer for features matching a given expression.
@@ -1082,7 +1085,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      *
      * \returns A list of fields
      */
-    inline QgsFields fields() const { return mFields; }
+    inline QgsFields fields() const override { return mFields; }
 
     /**
      * Returns the list of fields of this layer.
@@ -1124,7 +1127,7 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      * Returns feature count including changes which have not yet been committed
      * If you need only the count of committed features call this method on this layer's provider.
      */
-    long featureCount() const;
+    long featureCount() const override;
 
     /** Make layer read-only (editing disabled) or not
      *  \returns false if the layer is in editing yet