[Python-checkins] cpython: Issue #14065: Added cyclic GC support to ET.Element
eli.bendersky
python-checkins at python.org
Fri Mar 30 15:39:50 CEST 2012
http://hg.python.org/cpython/rev/0ca32013d77e
changeset: 75997:0ca32013d77e
parent: 75995:cf2e74e0b7d4
user: Eli Bendersky <eliben at gmail.com>
date: Fri Mar 30 16:38:33 2012 +0300
summary:
Issue #14065: Added cyclic GC support to ET.Element
files:
Lib/test/test_xml_etree.py | 27 ++++++++++-
Modules/_elementtree.c | 63 +++++++++++++++++++------
2 files changed, 74 insertions(+), 16 deletions(-)
diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
--- a/Lib/test/test_xml_etree.py
+++ b/Lib/test/test_xml_etree.py
@@ -14,9 +14,10 @@
# Don't re-import "xml.etree.ElementTree" module in the docstring,
# except if the test is specific to the Python implementation.
-import sys
+import gc
import html
import io
+import sys
import unittest
from test import support
@@ -1846,6 +1847,30 @@
self.assertRaises(TypeError, e.extend, [ET.Element('bar'), 'foo'])
self.assertRaises(TypeError, e.insert, 0, 'foo')
+ def test_cyclic_gc(self):
+ class ShowGC:
+ def __init__(self, flaglist):
+ self.flaglist = flaglist
+ def __del__(self):
+ self.flaglist.append(1)
+
+ # Test the shortest cycle: lst->element->lst
+ fl = []
+ lst = [ShowGC(fl)]
+ lst.append(ET.Element('joe', attr=lst))
+ del lst
+ gc.collect()
+ self.assertEqual(fl, [1])
+
+ # A longer cycle: lst->e->e2->lst
+ fl = []
+ e = ET.Element('joe')
+ lst = [ShowGC(fl), e]
+ e2 = ET.SubElement(e, 'foo', attr=lst)
+ del lst, e, e2
+ gc.collect()
+ self.assertEqual(fl, [1])
+
class ElementTreeTest(unittest.TestCase):
def test_istype(self):
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -282,7 +282,7 @@
{
ElementObject* self;
- self = PyObject_New(ElementObject, &Element_Type);
+ self = PyObject_GC_New(ElementObject, &Element_Type);
if (self == NULL)
return NULL;
@@ -309,7 +309,7 @@
self->tail = Py_None;
ALLOC(sizeof(ElementObject), "create element");
-
+ PyObject_GC_Track(self);
return (PyObject*) self;
}
@@ -556,19 +556,51 @@
return elem;
}
+static int
+element_gc_traverse(ElementObject *self, visitproc visit, void *arg)
+{
+ Py_VISIT(self->tag);
+ Py_VISIT(JOIN_OBJ(self->text));
+ Py_VISIT(JOIN_OBJ(self->tail));
+
+ if (self->extra) {
+ int i;
+ Py_VISIT(self->extra->attrib);
+
+ for (i = 0; i < self->extra->length; ++i)
+ Py_VISIT(self->extra->children[i]);
+ }
+ return 0;
+}
+
+static int
+element_gc_clear(ElementObject *self)
+{
+ PyObject *text = JOIN_OBJ(self->text);
+ PyObject *tail = JOIN_OBJ(self->tail);
+ Py_CLEAR(self->tag);
+ Py_CLEAR(text);
+ Py_CLEAR(tail);
+
+ /* After dropping all references from extra, it's no longer valid anyway,
+ ** so fully deallocate it (see also element_clearmethod)
+ */
+ if (self->extra) {
+ dealloc_extra(self);
+ self->extra = NULL;
+ }
+ return 0;
+}
+
static void
element_dealloc(ElementObject* self)
{
- if (self->extra)
- dealloc_extra(self);
-
- /* discard attributes */
- Py_DECREF(self->tag);
- Py_DECREF(JOIN_OBJ(self->text));
- Py_DECREF(JOIN_OBJ(self->tail));
+ PyObject_GC_UnTrack(self);
+ /* element_gc_clear clears all references and deallocates extra
+ */
+ element_gc_clear(self);
RELEASE(sizeof(ElementObject), "destroy element");
-
Py_TYPE(self)->tp_free((PyObject *)self);
}
@@ -589,7 +621,7 @@
}
static PyObject*
-element_clear(ElementObject* self, PyObject* args)
+element_clearmethod(ElementObject* self, PyObject* args)
{
if (!PyArg_ParseTuple(args, ":clear"))
return NULL;
@@ -1505,7 +1537,7 @@
static PyMethodDef element_methods[] = {
- {"clear", (PyCFunction) element_clear, METH_VARARGS},
+ {"clear", (PyCFunction) element_clearmethod, METH_VARARGS},
{"get", (PyCFunction) element_get, METH_VARARGS},
{"set", (PyCFunction) element_set, METH_VARARGS},
@@ -1655,10 +1687,11 @@
(getattrofunc)element_getattro, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
- Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
+ /* tp_flags */
0, /* tp_doc */
- 0, /* tp_traverse */
- 0, /* tp_clear */
+ (traverseproc)element_gc_traverse, /* tp_traverse */
+ (inquiry)element_gc_clear, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
--
Repository URL: http://hg.python.org/cpython
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