Mercurial > cpython-lru_cache-weakref

diff Modules/_weakref.c @ 17497:6a3776201750 legacy-trunk

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cleanup_helper(): Make sure we invalidate all reference objects before calling any callbacks. This is important since the callback objects only look at themselves to determine that they are invalide. This change avoids a segfault when callbacks use a different reference to an object in the process of being deallocated. This fixes SF bug #415660.
author Fred Drake <fdrake@acm.org>
date Fri, 13 Apr 2001 17:15:47 +0000
parents 8df0f65e3860
children 8d9eb5a4ebcd
line wrap: on
line diff
--- a/Modules/_weakref.c	Fri Apr 13 17:08:15 2001 +0000
+++ b/Modules/_weakref.c	Fri Apr 13 17:15:47 2001 +0000
@@ -740,15 +740,22 @@
         return;
     }
     list = GET_WEAKREFS_LISTPTR(object);
-    while (*list != NULL) {
-        PyWeakReference *current = *list;
-        PyObject *callback = current->wr_callback;
+    /* Remove the callback-less basic and proxy references */
+    if (*list != NULL && (*list)->wr_callback == NULL) {
+        clear_weakref(*list);
+        if (*list != NULL && (*list)->wr_callback == NULL)
+            clear_weakref(*list);
+    }
+    if (*list != NULL) {
+        int count = getweakrefcount(*list);
 
-        Py_XINCREF(callback);
-        clear_weakref(current);
-        if (callback != NULL) {
+        if (count == 1) {
+            PyWeakReference *current = *list;
+            PyObject *callback = current->wr_callback;
             PyObject *cbresult;
 
+            Py_INCREF(callback);
+            clear_weakref(current);
             cbresult = PyObject_CallFunction(callback, "O", current);
             if (cbresult == NULL)
                 PyErr_WriteUnraisable(callback);
@@ -756,6 +763,34 @@
                 Py_DECREF(cbresult);
             Py_DECREF(callback);
         }
+        else {
+            PyObject *tuple = PyTuple_New(count * 2);
+            PyWeakReference *current = *list;
+            int i = 0;
+
+            for (i = 0; i < count; ++i) {
+                PyWeakReference *next = current->wr_next;
+
+                Py_INCREF(current);
+                PyTuple_SET_ITEM(tuple, i * 2, (PyObject *) current);
+                PyTuple_SET_ITEM(tuple, i * 2 + 1, current->wr_callback);
+                current->wr_callback = NULL;
+                next = current->wr_next;
+                clear_weakref(current);
+                current = next;
+            }
+            for (i = 0; i < count; ++i) {
+                PyObject *current = PyTuple_GET_ITEM(tuple, i * 2);
+                PyObject *callback = PyTuple_GET_ITEM(tuple, i * 2 + 1);
+                PyObject *cbresult = PyObject_CallFunction(callback, "O",
+                                                           current);
+                if (cbresult == NULL)
+                    PyErr_WriteUnraisable(callback);
+                else
+                    Py_DECREF(cbresult);
+            }
+            Py_DECREF(tuple);
+        }
     }
     return;
 }