Changeset 107794 in vbox for trunk/src/libs/xpcom18a4/python

Timestamp:

Jan 15, 2025 4:28:07 PM (5 weeks ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

166933

Message:

libs/xpcom/python: Python 3.12 flags a size discrepancy when calling
PyType_FromSpec() for 'Py_nsIID' where the base class '&PyType_Type' is
larger than the derived class of 'Py_nsIID'. Thus the size required for
the 'Py_nsIID' heap object created by PyType_FromSpec() needs to be
increased to accommodate both of the objects in question. bugref:10832

File:

• trunk/src/libs/xpcom18a4/python/src/PyIID.cpp (modified) (1 diff)

trunk/src/libs/xpcom18a4/python/src/PyIID.cpp

@@ -240 +240 @@
                 { 0, NULL } /* terminator */
         };
+
+    /* The parent/base class specified in Py_tp_base (&PyType_Type) here is larger
+     * than the Py_nsIID derived class so we need to ensure enough space is allocated
+     * for both when calling PyType_FromSpec(), i.e.: PyType_Type.tp_basicsize +
+     * sizeof(Py_nsIID).  Starting with Python 3.12 when 'basicsize' is negative "the
+     * absolute value specifies how much space instances of the class need in addition
+     * to the superclass".  Earlier Python releases require calculating the total size
+     * by hand. */
+#if PY_VERSION_HEX >= 0x030C0000
+    int basicsize = -(int)sizeof(Py_nsIID);
+#else
+    /* PyObjects are opaque in the Py_LIMITED_API so we must use PyObject_GetAttrString() here. */
+    PyObject *sizeObj = PyObject_GetAttrString((PyObject*)&PyType_Type, "__basicsize__");
+    int basicsize = (int)PyLong_AsLong(sizeObj) + (int)sizeof(Py_nsIID);
+#endif
         PyType_Spec TypeSpec = {
                 /* .name: */            "IID",
-                /* .basicsize: */       sizeof(Py_nsIID),
+                /* .basicsize: */       basicsize,
                 /* .itemsize: */        0,
                 /* .flags: */           Py_TPFLAGS_DEFAULT,