Simplified GEOSFuncFactory.

django/contrib/gis/geos/libgeos.py

@@ -12,7 +12,7 @@ from ctypes import CDLL, CFUNCTYPE, POINTER, Structure, c_char_p
 from ctypes.util import find_library
 
 from django.core.exceptions import ImproperlyConfigured
-from django.utils.functional import SimpleLazyObject
+from django.utils.functional import SimpleLazyObject, cached_property
 from django.utils.version import get_version_tuple
 
 logger = logging.getLogger('django.contrib.gis')
@@ -148,14 +148,12 @@ class GEOSFuncFactory:
             self.argtypes = argtypes
         self.args = args
         self.kwargs = kwargs
-        self.func = None
 
     def __call__(self, *args, **kwargs):
-        if self.func is None:
-            self.func = self.get_func(*self.args, **self.kwargs)
         return self.func(*args, **kwargs)
 
-    def get_func(self, *args, **kwargs):
+    @cached_property
+    def func(self):
         from django.contrib.gis.geos.prototypes.threadsafe import GEOSFunc
         func = GEOSFunc(self.func_name)
         func.argtypes = self.argtypes or []

django/contrib/gis/geos/prototypes/coordseq.py

@@ -34,30 +34,27 @@ class CsOperation(GEOSFuncFactory):
     "For coordinate sequence operations."
     restype = c_int
 
-    def get_func(self, ordinate=False, get=False):
+    def __init__(self, *args, ordinate=False, get=False, **kwargs):
         if get:
             # Get routines have double parameter passed-in by reference.
-            self.errcheck = check_cs_get
+            errcheck = check_cs_get
             dbl_param = POINTER(c_double)
         else:
-            self.errcheck = check_cs_op
+            errcheck = check_cs_op
             dbl_param = c_double
 
         if ordinate:
             # Get/Set ordinate routines have an extra uint parameter.
-            self.argtypes = [CS_PTR, c_uint, c_uint, dbl_param]
+            argtypes = [CS_PTR, c_uint, c_uint, dbl_param]
         else:
-            self.argtypes = [CS_PTR, c_uint, dbl_param]
-        return super().get_func()
+            argtypes = [CS_PTR, c_uint, dbl_param]
+
+        super().__init__(*args, **dict(kwargs, errcheck=errcheck, argtypes=argtypes))
 
 
 class CsOutput(GEOSFuncFactory):
     restype = CS_PTR
 
-    def get_func(self, argtypes):
-        self.argtypes = argtypes
-        return super().get_func()
-
     @staticmethod
     def errcheck(result, func, cargs):
         if not result:
@@ -71,9 +68,9 @@ class CsOutput(GEOSFuncFactory):
 # ## Coordinate Sequence ctypes prototypes ##
 
 # Coordinate Sequence constructors & cloning.
-cs_clone = CsOutput('GEOSCoordSeq_clone', [CS_PTR])
-create_cs = CsOutput('GEOSCoordSeq_create', [c_uint, c_uint])
-get_cs = CsOutput('GEOSGeom_getCoordSeq', [GEOM_PTR])
+cs_clone = CsOutput('GEOSCoordSeq_clone', argtypes=[CS_PTR])
+create_cs = CsOutput('GEOSCoordSeq_create', argtypes=[c_uint, c_uint])
+get_cs = CsOutput('GEOSGeom_getCoordSeq', argtypes=[GEOM_PTR])
 
 # Getting, setting ordinate
 cs_getordinate = CsOperation('GEOSCoordSeq_getOrdinate', ordinate=True, get=True)

django/contrib/gis/geos/prototypes/errcheck.py

@@ -81,11 +81,3 @@ def check_string(result, func, cargs):
     # Freeing the memory allocated within GEOS
     free(result)
     return s
-
-
-def check_zero(result, func, cargs):
-    "Error checking on routines that should not return 0."
-    if result == 0:
-        raise GEOSException('Error encountered in GEOS C function "%s".' % func.__name__)
-    else:
-        return result

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

@@ -2,7 +2,7 @@ from ctypes import POINTER, c_char_p, c_int, c_size_t, c_ubyte
 
 from django.contrib.gis.geos.libgeos import CS_PTR, GEOM_PTR, GEOSFuncFactory
 from django.contrib.gis.geos.prototypes.errcheck import (
-    check_geom, check_minus_one, check_sized_string, check_string, check_zero,
+    check_geom, check_minus_one, check_sized_string, check_string,
 )
 
 # This is the return type used by binary output (WKB, HEX) routines.
@@ -41,22 +41,12 @@ class GeomOutput(GEOSFuncFactory):
     restype = GEOM_PTR
     errcheck = staticmethod(check_geom)
 
-    def get_func(self, argtypes):
-        self.argtypes = argtypes
-        return super().get_func()
-
 
 class IntFromGeom(GEOSFuncFactory):
     "Argument is a geometry, return type is an integer."
     argtypes = [GEOM_PTR]
     restype = c_int
-
-    def get_func(self, zero=False):
-        if zero:
-            self.errcheck = check_zero
-        else:
-            self.errcheck = check_minus_one
-        return super().get_func()
+    errcheck = staticmethod(check_minus_one)
 
 
 class StringFromGeom(GEOSFuncFactory):
@@ -77,23 +67,23 @@ get_num_coords = IntFromGeom('GEOSGetNumCoordinates')
 get_num_geoms = IntFromGeom('GEOSGetNumGeometries')
 
 # Geometry creation factories
-create_point = GeomOutput('GEOSGeom_createPoint', [CS_PTR])
-create_linestring = GeomOutput('GEOSGeom_createLineString', [CS_PTR])
-create_linearring = GeomOutput('GEOSGeom_createLinearRing', [CS_PTR])
+create_point = GeomOutput('GEOSGeom_createPoint', argtypes=[CS_PTR])
+create_linestring = GeomOutput('GEOSGeom_createLineString', argtypes=[CS_PTR])
+create_linearring = GeomOutput('GEOSGeom_createLinearRing', argtypes=[CS_PTR])
 
 # Polygon and collection creation routines are special and will not
 # have their argument types defined.
-create_polygon = GeomOutput('GEOSGeom_createPolygon', None)
-create_empty_polygon = GeomOutput('GEOSGeom_createEmptyPolygon', None)
-create_collection = GeomOutput('GEOSGeom_createCollection', None)
+create_polygon = GeomOutput('GEOSGeom_createPolygon')
+create_empty_polygon = GeomOutput('GEOSGeom_createEmptyPolygon')
+create_collection = GeomOutput('GEOSGeom_createCollection')
 
 # Ring routines
-get_extring = GeomOutput('GEOSGetExteriorRing', [GEOM_PTR])
-get_intring = GeomOutput('GEOSGetInteriorRingN', [GEOM_PTR, c_int])
+get_extring = GeomOutput('GEOSGetExteriorRing', argtypes=[GEOM_PTR])
+get_intring = GeomOutput('GEOSGetInteriorRingN', argtypes=[GEOM_PTR, c_int])
 get_nrings = IntFromGeom('GEOSGetNumInteriorRings')
 
 # Collection Routines
-get_geomn = GeomOutput('GEOSGetGeometryN', [GEOM_PTR, c_int])
+get_geomn = GeomOutput('GEOSGetGeometryN', argtypes=[GEOM_PTR, c_int])
 
 # Cloning
 geom_clone = GEOSFuncFactory('GEOSGeom_clone', argtypes=[GEOM_PTR], restype=GEOM_PTR)

django/contrib/gis/geos/prototypes/io.py

@@ -118,9 +118,7 @@ class IOBase(GEOSBase):
         self.ptr = self._constructor()
         # Loading the real destructor function at this point as doing it in
         # __del__ is too late (import error).
-        self.destructor.func = self.destructor.get_func(
-            *self.destructor.args, **self.destructor.kwargs
-        )
+        self.destructor.func
 
 # ### Base WKB/WKT Reading and Writing objects ###
 

django/contrib/gis/geos/prototypes/misc.py

@@ -19,19 +19,13 @@ class DblFromGeom(GEOSFuncFactory):
     restype = c_int  # Status code returned
     errcheck = staticmethod(check_dbl)
 
-    def get_func(self, num_geom=1):
-        argtypes = [GEOM_PTR for i in range(num_geom)]
-        argtypes += [POINTER(c_double)]
-        self.argtypes = argtypes
-        return super().get_func()
-
 
 # ### ctypes prototypes ###
 
 # Area, distance, and length prototypes.
-geos_area = DblFromGeom('GEOSArea')
-geos_distance = DblFromGeom('GEOSDistance', num_geom=2)
-geos_length = DblFromGeom('GEOSLength')
+geos_area = DblFromGeom('GEOSArea', argtypes=[GEOM_PTR, POINTER(c_double)])
+geos_distance = DblFromGeom('GEOSDistance', argtypes=[GEOM_PTR, GEOM_PTR, POINTER(c_double)])
+geos_length = DblFromGeom('GEOSLength', argtypes=[GEOM_PTR, POINTER(c_double)])
 geos_isvalidreason = GEOSFuncFactory(
     'GEOSisValidReason', restype=geos_char_p, errcheck=check_string, argtypes=[GEOM_PTR]
 )