add expression is_empty_or_null

qgis · Dec 13, 2019 · c7bc3af · c7bc3af
1 parent 780d9e9
commit c7bc3af
Show file tree

Hide file tree

Showing 3 changed files with 27 additions and 0 deletions.
diff --git a/resources/function_help/json/is_empty_or_null b/resources/function_help/json/is_empty_or_null
@@ -0,0 +1,11 @@
+{
+  "name": "is_empty_or_null",
+  "type": "function",
+  "description": "Returns true if a geometry is NULL or empty (without coordinates) or false otherwise. This function is like the expression '$geometry IS NULL or is_empty($geometry)'",
+  "arguments": [ {"arg":"geom","description":"a geometry"}],
+  "examples": [ { "expression":"is_empty_or_null(NULL)", "returns":"true"},
+                { "expression":"is_empty_or_null(geom_from_wkt('LINESTRING(0 0, 1 1, 2 2)'))", "returns":"false"},
+                { "expression":"is_empty_or_null(geom_from_wkt('LINESTRING EMPTY'))", "returns":"true"},
+                { "expression":"is_empty_or_null(geom_from_wkt('POINT(7 4)'))", "returns":"false"},
+                { "expression":"is_empty_or_null(geom_from_wkt('POINT EMPTY'))", "returns":"true"} ]
+}
diff --git a/src/core/expression/qgsexpressionfunction.cpp b/src/core/expression/qgsexpressionfunction.cpp
@@ -3077,6 +3077,15 @@ static QVariant fcnIsEmpty( const QVariantList &values, const QgsExpressionConte
   return QVariant::fromValue( fGeom.isEmpty() );
 }
 
+static QVariant fcnIsEmptyOrNull( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
+{
+  if ( values.at( 0 ).isNull() )
+    return QVariant::fromValue( true );
+
+  QgsGeometry fGeom = QgsExpressionUtils::getGeometry( values.at( 0 ), parent );
+  return QVariant::fromValue( fGeom.isNull() || fGeom.isEmpty() );
+}
+
 static QVariant fcnRelate( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
 {
   if ( values.length() < 2 || values.length() > 3 )
@@ -5606,6 +5615,7 @@ const QList<QgsExpressionFunction *> &QgsExpression::Functions()
         << new QgsStaticExpressionFunction( QStringLiteral( "bounds_height" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "geom" ) ), fcnBoundsHeight, QStringLiteral( "GeometryGroup" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "is_closed" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "geom" ) ), fcnIsClosed, QStringLiteral( "GeometryGroup" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "is_empty" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "geom" ) ), fcnIsEmpty, QStringLiteral( "GeometryGroup" ) )
+        << new QgsStaticExpressionFunction( QStringLiteral( "is_empty_or_null" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "geom" ) ), fcnIsEmptyOrNull, QStringLiteral( "GeometryGroup" ), QString(), false, QSet<QString>(), false, QStringList(), true )
         << new QgsStaticExpressionFunction( QStringLiteral( "convex_hull" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "geometry" ) ), fcnConvexHull, QStringLiteral( "GeometryGroup" ), QString(), false, QSet<QString>(), false, QStringList() << QStringLiteral( "convexHull" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "oriented_bbox" ), QgsExpressionFunction::ParameterList()
                                             << QgsExpressionFunction::Parameter( QStringLiteral( "geometry" ) ),

diff --git a/tests/src/core/testqgsexpression.cpp b/tests/src/core/testqgsexpression.cpp
@@ -986,6 +986,12 @@ class TestQgsExpression: public QObject
       QTest::newRow( "is_empty empty point" ) << "is_empty(geom_from_wkt('POINT EMPTY'))" << false << QVariant( true );
       QTest::newRow( "is_empty polygon" ) << "is_empty(geom_from_wkt('POLYGON((-1 -1, 4 0, 4 2, 0 2, -1 -1))'))" << false << QVariant( false );
       QTest::newRow( "is_empty empty polygon" ) << "is_empty(geom_from_wkt('POLYGON EMPTY'))" << false << QVariant( true );
+      QTest::newRow( "is_empty_or_null not geom" ) << "is_empty_or_null('g')" << true << QVariant();
+      QTest::newRow( "is_empty_or_null null" ) << "is_empty_or_null(NULL)" << false << QVariant( true );
+      QTest::newRow( "is_empty_or_null point" ) << "is_empty_or_null(geom_from_wkt('POINT(1 2)'))" << false << QVariant( false );
+      QTest::newRow( "is_empty_or_null empty point" ) << "is_empty_or_null(geom_from_wkt('POINT EMPTY'))" << false << QVariant( true );
+      QTest::newRow( "is_empty_or_null polygon" ) << "is_empty_or_null(geom_from_wkt('POLYGON((-1 -1, 4 0, 4 2, 0 2, -1 -1))'))" << false << QVariant( false );
+      QTest::newRow( "is_empty_or_null empty polygon" ) << "is_empty_or_null(geom_from_wkt('POLYGON EMPTY'))" << false << QVariant( true );
       QTest::newRow( "collect_geometries none" ) << "geom_to_wkt(collect_geometries())" << false << QVariant( "" );
       QTest::newRow( "collect_geometries not" ) << "geom_to_wkt(collect_geometries(45))" << true << QVariant();
       QTest::newRow( "collect_geometries one" ) << "geom_to_wkt(collect_geometries(make_point(4,5)))" << false << QVariant( "MultiPoint ((4 5))" );