Add QgsFeatureSource interface as interface for classes which

provide feature iterators via a getFeatures method

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

python/core/qgsfeaturesource.sip

@@ -0,0 +1,43 @@
+/************************************************************************
+ * 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
+
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/qgsfeaturesource.h                                          *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

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

src/core/qgsfeaturesource.h

@@ -0,0 +1,48 @@
+/***************************************************************************
+                         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"
+#include "qgsfeature.h"
+#include "qgsfeatureiterator.h"
+
+/**
+ * \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;
+
+};
+
+#endif // QGSFEATURESOURCE_H