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-rw-r--r--Modules/gcmodule.c153
1 files changed, 75 insertions, 78 deletions
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index 81344ca828c..8c524f8309d 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -9,9 +9,14 @@
Eric Tiedemann, and various others.
http://www.arctrix.com/nas/python/gc/
- http://www.python.org/pipermail/python-dev/2000-March/003869.html
- http://www.python.org/pipermail/python-dev/2000-March/004010.html
- http://www.python.org/pipermail/python-dev/2000-March/004022.html
+
+ The following mailing list threads provide a historical perspective on
+ the design of this module. Note that a fair amount of refinement has
+ occurred since those discussions.
+
+ http://mail.python.org/pipermail/python-dev/2000-March/002385.html
+ http://mail.python.org/pipermail/python-dev/2000-March/002434.html
+ http://mail.python.org/pipermail/python-dev/2000-March/002497.html
For a highlevel view of the collection process, read the collect
function.
@@ -156,13 +161,9 @@ static Py_ssize_t long_lived_pending = 0;
#define DEBUG_STATS (1<<0) /* print collection statistics */
#define DEBUG_COLLECTABLE (1<<1) /* print collectable objects */
#define DEBUG_UNCOLLECTABLE (1<<2) /* print uncollectable objects */
-#define DEBUG_INSTANCES (1<<3) /* print instances */
-#define DEBUG_OBJECTS (1<<4) /* print other objects */
#define DEBUG_SAVEALL (1<<5) /* save all garbage in gc.garbage */
#define DEBUG_LEAK DEBUG_COLLECTABLE | \
DEBUG_UNCOLLECTABLE | \
- DEBUG_INSTANCES | \
- DEBUG_OBJECTS | \
DEBUG_SAVEALL
static int debug;
static PyObject *tmod = NULL;
@@ -493,28 +494,6 @@ move_unreachable(PyGC_Head *young, PyGC_Head *unreachable)
}
}
-/* Return true if object has a finalization method.
- * CAUTION: An instance of an old-style class has to be checked for a
- *__del__ method, and earlier versions of this used to call PyObject_HasAttr,
- * which in turn could call the class's __getattr__ hook (if any). That
- * could invoke arbitrary Python code, mutating the object graph in arbitrary
- * ways, and that was the source of some excruciatingly subtle bugs.
- */
-static int
-has_finalizer(PyObject *op)
-{
- if (PyInstance_Check(op)) {
- assert(delstr != NULL);
- return _PyInstance_Lookup(op, delstr) != NULL;
- }
- else if (PyType_HasFeature(op->ob_type, Py_TPFLAGS_HEAPTYPE))
- return op->ob_type->tp_del != NULL;
- else if (PyGen_CheckExact(op))
- return PyGen_NeedsFinalizing((PyGenObject *)op);
- else
- return 0;
-}
-
/* Try to untrack all currently tracked dictionaries */
static void
untrack_dicts(PyGC_Head *head)
@@ -529,6 +508,16 @@ untrack_dicts(PyGC_Head *head)
}
}
+/* Return true if object has a finalization method. */
+static int
+has_finalizer(PyObject *op)
+{
+ if (PyGen_CheckExact(op))
+ return PyGen_NeedsFinalizing((PyGenObject *)op);
+ else
+ return op->ob_type->tp_del != NULL;
+}
+
/* Move the objects in unreachable with __del__ methods into `finalizers`.
* Objects moved into `finalizers` have gc_refs set to GC_REACHABLE; the
* objects remaining in unreachable are left at GC_TENTATIVELY_UNREACHABLE.
@@ -740,29 +729,10 @@ handle_weakrefs(PyGC_Head *unreachable, PyGC_Head *old)
}
static void
-debug_instance(char *msg, PyInstanceObject *inst)
-{
- char *cname;
- /* simple version of instance_repr */
- PyObject *classname = inst->in_class->cl_name;
- if (classname != NULL && PyString_Check(classname))
- cname = PyString_AsString(classname);
- else
- cname = "?";
- PySys_WriteStderr("gc: %.100s <%.100s instance at %p>\n",
- msg, cname, inst);
-}
-
-static void
debug_cycle(char *msg, PyObject *op)
{
- if ((debug & DEBUG_INSTANCES) && PyInstance_Check(op)) {
- debug_instance(msg, (PyInstanceObject *)op);
- }
- else if (debug & DEBUG_OBJECTS) {
- PySys_WriteStderr("gc: %.100s <%.100s %p>\n",
- msg, Py_TYPE(op)->tp_name, op);
- }
+ PySys_WriteStderr("gc: %.100s <%.100s %p>\n",
+ msg, Py_TYPE(op)->tp_name, op);
}
/* Handle uncollectable garbage (cycles with finalizers, and stuff reachable
@@ -841,10 +811,7 @@ clear_freelists(void)
(void)PyFrame_ClearFreeList();
(void)PyCFunction_ClearFreeList();
(void)PyTuple_ClearFreeList();
-#ifdef Py_USING_UNICODE
(void)PyUnicode_ClearFreeList();
-#endif
- (void)PyInt_ClearFreeList();
(void)PyFloat_ClearFreeList();
}
@@ -882,7 +849,7 @@ collect(int generation)
double t1 = 0.0;
if (delstr == NULL) {
- delstr = PyString_InternFromString("__del__");
+ delstr = PyUnicode_InternFromString("__del__");
if (delstr == NULL)
Py_FatalError("gc couldn't allocate \"__del__\"");
}
@@ -1022,7 +989,7 @@ collect(int generation)
if (PyErr_Occurred()) {
if (gc_str == NULL)
- gc_str = PyString_FromString("garbage collection");
+ gc_str = PyUnicode_FromString("garbage collection");
PyErr_WriteUnraisable(gc_str);
Py_FatalError("unexpected exception during garbage collection");
}
@@ -1122,7 +1089,7 @@ gc_collect(PyObject *self, PyObject *args, PyObject *kws)
collecting = 0;
}
- return PyInt_FromSsize_t(n);
+ return PyLong_FromSsize_t(n);
}
PyDoc_STRVAR(gc_set_debug__doc__,
@@ -1136,8 +1103,6 @@ PyDoc_STRVAR(gc_set_debug__doc__,
" DEBUG_STATS - Print statistics during collection.\n"
" DEBUG_COLLECTABLE - Print collectable objects found.\n"
" DEBUG_UNCOLLECTABLE - Print unreachable but uncollectable objects found.\n"
-" DEBUG_INSTANCES - Print instance objects.\n"
-" DEBUG_OBJECTS - Print objects other than instances.\n"
" DEBUG_SAVEALL - Save objects to gc.garbage rather than freeing them.\n"
" DEBUG_LEAK - Debug leaking programs (everything but STATS).\n");
@@ -1382,27 +1347,36 @@ static PyMethodDef GcMethods[] = {
{NULL, NULL} /* Sentinel */
};
+static struct PyModuleDef gcmodule = {
+ PyModuleDef_HEAD_INIT,
+ "gc", /* m_name */
+ gc__doc__, /* m_doc */
+ -1, /* m_size */
+ GcMethods, /* m_methods */
+ NULL, /* m_reload */
+ NULL, /* m_traverse */
+ NULL, /* m_clear */
+ NULL /* m_free */
+};
+
PyMODINIT_FUNC
-initgc(void)
+PyInit_gc(void)
{
PyObject *m;
- m = Py_InitModule4("gc",
- GcMethods,
- gc__doc__,
- NULL,
- PYTHON_API_VERSION);
+ m = PyModule_Create(&gcmodule);
+
if (m == NULL)
- return;
+ return NULL;
if (garbage == NULL) {
garbage = PyList_New(0);
if (garbage == NULL)
- return;
+ return NULL;
}
Py_INCREF(garbage);
if (PyModule_AddObject(m, "garbage", garbage) < 0)
- return;
+ return NULL;
/* Importing can't be done in collect() because collect()
* can be called via PyGC_Collect() in Py_Finalize().
@@ -1416,15 +1390,14 @@ initgc(void)
PyErr_Clear();
}
-#define ADD_INT(NAME) if (PyModule_AddIntConstant(m, #NAME, NAME) < 0) return
+#define ADD_INT(NAME) if (PyModule_AddIntConstant(m, #NAME, NAME) < 0) return NULL
ADD_INT(DEBUG_STATS);
ADD_INT(DEBUG_COLLECTABLE);
ADD_INT(DEBUG_UNCOLLECTABLE);
- ADD_INT(DEBUG_INSTANCES);
- ADD_INT(DEBUG_OBJECTS);
ADD_INT(DEBUG_SAVEALL);
ADD_INT(DEBUG_LEAK);
#undef ADD_INT
+ return m;
}
/* API to invoke gc.collect() from C */
@@ -1444,6 +1417,38 @@ PyGC_Collect(void)
return n;
}
+void
+_PyGC_Fini(void)
+{
+ if (!(debug & DEBUG_SAVEALL)
+ && garbage != NULL && PyList_GET_SIZE(garbage) > 0) {
+ char *message;
+ if (debug & DEBUG_UNCOLLECTABLE)
+ message = "gc: %zd uncollectable objects at " \
+ "shutdown";
+ else
+ message = "gc: %zd uncollectable objects at " \
+ "shutdown; use gc.set_debug(gc.DEBUG_UNCOLLECTABLE) to list them";
+ if (PyErr_WarnFormat(PyExc_ResourceWarning, 0, message,
+ PyList_GET_SIZE(garbage)) < 0)
+ PyErr_WriteUnraisable(NULL);
+ if (debug & DEBUG_UNCOLLECTABLE) {
+ PyObject *repr = NULL, *bytes = NULL;
+ repr = PyObject_Repr(garbage);
+ if (!repr || !(bytes = PyUnicode_EncodeFSDefault(repr)))
+ PyErr_WriteUnraisable(garbage);
+ else {
+ PySys_WriteStderr(
+ " %s\n",
+ PyBytes_AS_STRING(bytes)
+ );
+ }
+ Py_XDECREF(repr);
+ Py_XDECREF(bytes);
+ }
+ }
+}
+
/* for debugging */
void
_PyGC_Dump(PyGC_Head *g)
@@ -1560,11 +1565,3 @@ PyObject_GC_Del(void *op)
}
PyObject_FREE(g);
}
-
-/* for binary compatibility with 2.2 */
-#undef _PyObject_GC_Del
-void
-_PyObject_GC_Del(PyObject *op)
-{
- PyObject_GC_Del(op);
-}
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