[Patches] [ python-Patches-536407 ] Comprehensibility patch (typeobject.c)

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Patches item #536407, was opened at 2002-03-28 13:56
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http://sourceforge.net/tracker/?func=detail&atid=305470&aid=536407&group_id=5470

Category: Core (C code)
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: David Abrahams (david_abrahams)
Assigned to: Nobody/Anonymous (nobody)
Summary: Comprehensibility patch (typeobject.c)

Initial Comment:
--- typeobject.c	Mon Dec 17 12:14:22 2001
+++ typeobject.c.new	Thu Mar 28 13:46:03 2002
@@ -1186,8 +1186,8 @@
 type_getattro(PyTypeObject *type, PyObject *name)
 {
 	PyTypeObject *metatype = type->ob_type;
-	PyObject *descr, *res;
-	descrgetfunc f;
+	PyObject *meta_attribute, *attribute;
+	descrgetfunc meta_get;
 
 	/* Initialize this type (we'll assume the 
metatype is initialized) */
 	if (type->tp_dict == NULL) {
@@ -1195,34 +1195,50 @@
 			return NULL;
 	}
 
-	/* Get a descriptor from the metatype */
-	descr = _PyType_Lookup(metatype, name);
-	f = NULL;
-	if (descr != NULL) {
-		f = descr->ob_type->tp_descr_get;
-		if (f != NULL && PyDescr_IsData
(descr))
-			return f(descr,
-				 (PyObject *)type, 
(PyObject *)metatype);
-	}
+	/* No readable descriptor found yet */
+	meta_get = NULL;
+        
+	/* Look for the attribute in the metatype */
+	meta_attribute = _PyType_Lookup(metatype, 
name);
 
-	/* Look in tp_dict of this type and its bases 
*/
-	res = _PyType_Lookup(type, name);
-	if (res != NULL) {
-		f = res->ob_type->tp_descr_get;
-		if (f != NULL)
-			return f(res, (PyObject *)
NULL, (PyObject *)type);
-		Py_INCREF(res);
-		return res;
+	if (meta_attribute != NULL) {
+		meta_get = meta_attribute->ob_type-
>tp_descr_get;
+                
+		if (meta_get != NULL && PyDescr_IsData
(meta_attribute)) {
+            /* Data descriptors implement 
tp_descr_set to intercept
+             * writes. Assume the attribute is not 
overridden in
+             * type's tp_dict (and bases): call the 
descriptor now.
+             */
+			return meta_get
(meta_attribute,
+                            (PyObject *)type, 
(PyObject *)metatype);
+        }
 	}
 
-	/* Use the descriptor from the metatype */
-	if (f != NULL) {
-		res = f(descr, (PyObject *)type, 
(PyObject *)metatype);
-		return res;
+	/* No data descriptor found on metatype. Look 
in tp_dict of this
+     * type and its bases */
+	attribute = _PyType_Lookup(type, name);
+	if (attribute != NULL) {
+        /* Implement descriptor functionality, if 
any */
+		descrgetfunc local_get = attribute-
>ob_type->tp_descr_get;
+		if (local_get != NULL) {
+            /* NULL 2nd argument indicates the 
descriptor was found on
+             * the target object itself (or a base)  
*/
+			return local_get(attribute, 
(PyObject *)NULL, (PyObject *)type);
+        }
+        
+		Py_INCREF(attribute);
+		return attribute;
 	}
-	if (descr != NULL) {
-		Py_INCREF(descr);
-		return descr;
+
+	/* No attribute found in local __dict__ (or 
bases): use the
+     * descriptor from the metatype, if any */
+	if (meta_get != NULL)
+		return meta_get(meta_attribute, 
(PyObject *)type, (PyObject *)metatype);
+
+    /* If an ordinary attribute was found on the 
metatype, return it now. */
+	if (meta_attribute != NULL) {
+		Py_INCREF(meta_attribute);
+		return meta_attribute;
 	}
 
 	/* Give up */


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