Refs #27472 -- Fixed OGRGeometry('POINT EMPTY').geos crash.

django/contrib/gis/gdal/geometries.py

@@ -254,6 +254,10 @@ class OGRGeometry(GDALBase):
         # TODO: Fix Envelope() for Point geometries.
         return Envelope(capi.get_envelope(self.ptr, byref(OGREnvelope())))
 
+    @property
+    def empty(self):
+        return capi.is_empty(self.ptr)
+
     @property
     def extent(self):
         "Returns the envelope as a 4-tuple, instead of as an Envelope object."
@@ -305,11 +309,15 @@ class OGRGeometry(GDALBase):
     srid = property(_get_srid, _set_srid)
 
     # #### Output Methods ####
+    def _geos_ptr(self):
+        from django.contrib.gis.geos import GEOSGeometry
+        return GEOSGeometry._from_wkb(self.wkb)
+
     @property
     def geos(self):
         "Returns a GEOSGeometry object from this OGRGeometry."
         from django.contrib.gis.geos import GEOSGeometry
-        return GEOSGeometry(self.wkb, self.srid)
+        return GEOSGeometry(self._geos_ptr(), self.srid)
 
     @property
     def gml(self):
@@ -504,6 +512,10 @@ class OGRGeometry(GDALBase):
 # The subclasses for OGR Geometry.
 class Point(OGRGeometry):
 
+    def _geos_ptr(self):
+        from django.contrib.gis import geos
+        return geos.Point._create_empty() if self.empty else super(Point, self)._geos_ptr()
+
     @classmethod
     def _create_empty(cls):
         return capi.create_geom(OGRGeomType('point').num)

django/contrib/gis/gdal/prototypes/generation.py

@@ -49,10 +49,12 @@ def geom_output(func, argtypes, offset=None):
     return func
 
 
-def int_output(func, argtypes):
+def int_output(func, argtypes, errcheck=None):
     "Generates a ctypes function that returns an integer value."
     func.argtypes = argtypes
     func.restype = c_int
+    if errcheck:
+        func.errcheck = errcheck
     return func
 
 

django/contrib/gis/gdal/prototypes/geom.py

@@ -79,6 +79,7 @@ get_centroid = void_output(lgdal.OGR_G_Centroid, [c_void_p, c_void_p])
 get_dims = int_output(lgdal.OGR_G_GetDimension, [c_void_p])
 get_coord_dim = int_output(lgdal.OGR_G_GetCoordinateDimension, [c_void_p])
 set_coord_dim = void_output(lgdal.OGR_G_SetCoordinateDimension, [c_void_p, c_int], errcheck=False)
+is_empty = int_output(lgdal.OGR_G_IsEmpty, [c_void_p], errcheck=lambda result, func, cargs: bool(result))
 
 get_geom_count = int_output(lgdal.OGR_G_GetGeometryCount, [c_void_p])
 get_geom_name = const_string_output(lgdal.OGR_G_GetGeometryName, [c_void_p], decoding='ascii')

django/contrib/gis/geos/geometry.py

@@ -168,6 +168,10 @@ class GEOSGeometry(GEOSBase, ListMixin):
         self.ptr = ptr
         self._post_init(srid)
 
+    @classmethod
+    def _from_wkb(cls, wkb):
+        return wkb_r().read(wkb)
+
     @classmethod
     def from_gml(cls, gml_string):
         return gdal.OGRGeometry.from_gml(gml_string).geos

django/contrib/gis/geos/point.py

@@ -47,7 +47,12 @@ class Point(GEOSGeometry):
     def _ogr_ptr(self):
         return gdal.geometries.Point._create_empty() if self.empty else super(Point, self)._ogr_ptr()
 
-    def _create_point(self, ndim, coords):
+    @classmethod
+    def _create_empty(cls):
+        return cls._create_point(None, None)
+
+    @classmethod
+    def _create_point(cls, ndim, coords):
         """
         Create a coordinate sequence, set X, Y, [Z], and create point
         """

tests/gis_tests/gdal_tests/test_geom.py

@@ -549,3 +549,11 @@ class OGRGeomTest(unittest.TestCase, TestDataMixin):
                 '</gml:Point>'
             ),
         )
+
+    def test_empty(self):
+        self.assertIs(OGRGeometry('POINT (0 0)').empty, False)
+        self.assertIs(OGRGeometry('POINT EMPTY').empty, True)
+
+    def test_empty_point_to_geos(self):
+        p = OGRGeometry('POINT EMPTY', srs=4326)
+        self.assertEqual(p.geos.ewkt, p.ewkt)