Implement GC protocol for template and interpolation types

Author: lysnikolaou

Objects/interpolationobject.c

@@ -77,13 +77,24 @@ interpolation_new_impl(PyTypeObject *type, PyObject *value,
 static void
 interpolation_dealloc(interpolationobject *self)
 {
+    PyObject_GC_UnTrack(self);
     Py_CLEAR(self->value);
     Py_CLEAR(self->expression);
     Py_CLEAR(self->conversion);
     Py_CLEAR(self->format_spec);
     Py_TYPE(self)->tp_free(self);
 }
 
+static int
+interpolation_traverse(interpolationobject *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->value);
+    Py_VISIT(self->expression);
+    Py_VISIT(self->conversion);
+    Py_VISIT(self->format_spec);
+    return 0;
+}
+
 static PyObject *
 interpolation_repr(interpolationobject *self)
 {
@@ -107,11 +118,14 @@ PyTypeObject _PyInterpolation_Type = {
     .tp_doc = PyDoc_STR("Interpolation object"),
     .tp_basicsize = sizeof(interpolationobject),
     .tp_itemsize = 0,
-    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | _Py_TPFLAGS_MATCH_SELF,
+    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | _Py_TPFLAGS_MATCH_SELF,
     .tp_new = (newfunc) interpolation_new,
+    .tp_alloc = PyType_GenericAlloc,
     .tp_dealloc = (destructor) interpolation_dealloc,
+    .tp_free = PyObject_GC_Del,
     .tp_repr = (reprfunc) interpolation_repr,
     .tp_members = interpolation_members,
+    .tp_traverse = (traverseproc) interpolation_traverse,
 };
 
 static PyObject *

Objects/templateobject.c

@@ -32,18 +32,31 @@ templateiter_next(templateiterobject *self)
 static void
 templateiter_dealloc(templateiterobject *self)
 {
+    PyObject_GC_UnTrack(self);
     Py_CLEAR(self->stringsiter);
     Py_CLEAR(self->interpolationsiter);
     Py_TYPE(self)->tp_free(self);
 }
 
+static int
+templateiter_traverse(templateiterobject *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->stringsiter);
+    Py_VISIT(self->interpolationsiter);
+    return 0;
+}
+
 PyTypeObject _PyTemplateIter_Type = {
     PyVarObject_HEAD_INIT(NULL, 0)
     .tp_name = "string.templatelib.TemplateIter",
     .tp_doc = PyDoc_STR("Template iterator object"),
     .tp_basicsize = sizeof(templateiterobject),
     .tp_itemsize = 0,
+    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
+    .tp_alloc = PyType_GenericAlloc,
     .tp_dealloc = (destructor) templateiter_dealloc,
+    .tp_free = PyObject_GC_Del,
+    .tp_traverse = (traverseproc) templateiter_traverse,
     .tp_iter = PyObject_SelfIter,
     .tp_iternext = (iternextfunc) templateiter_next,
 };
@@ -155,11 +168,20 @@ template_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 static void
 template_dealloc(templateobject *self)
 {
+    PyObject_GC_UnTrack(self);
     Py_CLEAR(self->strings);
     Py_CLEAR(self->interpolations);
     Py_TYPE(self)->tp_free(self);
 }
 
+static int
+template_traverse(templateobject *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->strings);
+    Py_VISIT(self->interpolations);
+    return 0;
+}
+
 static PyObject *
 template_repr(templateobject *self)
 {
@@ -172,7 +194,7 @@ template_repr(templateobject *self)
 static templateiterobject *
 template_iter(templateobject *self)
 {
-    templateiterobject *iter = PyObject_New(templateiterobject, &_PyTemplateIter_Type);
+    templateiterobject *iter = PyObject_GC_New(templateiterobject, &_PyTemplateIter_Type);
     if (iter == NULL) {
         return NULL;
     }
@@ -193,6 +215,7 @@ template_iter(templateobject *self)
     iter->stringsiter = stringsiter;
     iter->interpolationsiter = interpolationsiter;
     iter->from_strings = 1;
+    PyObject_GC_Track(iter);
     return iter;
 }
 
@@ -456,14 +479,17 @@ PyTypeObject _PyTemplate_Type = {
     .tp_doc = PyDoc_STR("Template object"),
     .tp_basicsize = sizeof(templateobject),
     .tp_itemsize = 0,
-    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
     .tp_as_sequence = &template_as_sequence,
     .tp_new = (newfunc) template_new,
+    .tp_alloc = PyType_GenericAlloc,
     .tp_dealloc = (destructor) template_dealloc,
+    .tp_free = PyObject_GC_Del,
     .tp_repr = (reprfunc) template_repr,
     .tp_members = template_members,
     .tp_getset = template_getset,
     .tp_iter = (getiterfunc) template_iter,
+    .tp_traverse = (traverseproc) template_traverse,
 };
 
 PyObject *