add ydb deps

1 files changed, 1018 insertions, 0 deletions

diff --git a/contrib/tools/python3/src/Objects/weakrefobject.c b/contrib/tools/python3/src/Objects/weakrefobject.c
new file mode 100644
index 0000000000..c76c92843c
--- /dev/null
+++ b/contrib/tools/python3/src/Objects/weakrefobject.c
@@ -0,0 +1,1018 @@
+#include "Python.h"
+#include "pycore_object.h"        // _PyObject_GET_WEAKREFS_LISTPTR()
+#include "structmember.h"         // PyMemberDef
+
+
+#define GET_WEAKREFS_LISTPTR(o) \
+        ((PyWeakReference **) _PyObject_GET_WEAKREFS_LISTPTR(o))
+
+
+Py_ssize_t
+_PyWeakref_GetWeakrefCount(PyWeakReference *head)
+{
+    Py_ssize_t count = 0;
+
+    while (head != NULL) {
+        ++count;
+        head = head->wr_next;
+    }
+    return count;
+}
+
+static PyObject *weakref_vectorcall(PyWeakReference *self, PyObject *const *args, size_t nargsf, PyObject *kwnames);
+
+static void
+init_weakref(PyWeakReference *self, PyObject *ob, PyObject *callback)
+{
+    self->hash = -1;
+    self->wr_object = ob;
+    self->wr_prev = NULL;
+    self->wr_next = NULL;
+    self->wr_callback = Py_XNewRef(callback);
+    self->vectorcall = (vectorcallfunc)weakref_vectorcall;
+}
+
+static PyWeakReference *
+new_weakref(PyObject *ob, PyObject *callback)
+{
+    PyWeakReference *result;
+
+    result = PyObject_GC_New(PyWeakReference, &_PyWeakref_RefType);
+    if (result) {
+        init_weakref(result, ob, callback);
+        PyObject_GC_Track(result);
+    }
+    return result;
+}
+
+
+/* This function clears the passed-in reference and removes it from the
+ * list of weak references for the referent.  This is the only code that
+ * removes an item from the doubly-linked list of weak references for an
+ * object; it is also responsible for clearing the callback slot.
+ */
+static void
+clear_weakref(PyWeakReference *self)
+{
+    PyObject *callback = self->wr_callback;
+
+    if (self->wr_object != Py_None) {
+        PyWeakReference **list = GET_WEAKREFS_LISTPTR(self->wr_object);
+
+        if (*list == self)
+            /* If 'self' is the end of the list (and thus self->wr_next == NULL)
+               then the weakref list itself (and thus the value of *list) will
+               end up being set to NULL. */
+            *list = self->wr_next;
+        self->wr_object = Py_None;
+        if (self->wr_prev != NULL)
+            self->wr_prev->wr_next = self->wr_next;
+        if (self->wr_next != NULL)
+            self->wr_next->wr_prev = self->wr_prev;
+        self->wr_prev = NULL;
+        self->wr_next = NULL;
+    }
+    if (callback != NULL) {
+        Py_DECREF(callback);
+        self->wr_callback = NULL;
+    }
+}
+
+/* Cyclic gc uses this to *just* clear the passed-in reference, leaving
+ * the callback intact and uncalled.  It must be possible to call self's
+ * tp_dealloc() after calling this, so self has to be left in a sane enough
+ * state for that to work.  We expect tp_dealloc to decref the callback
+ * then.  The reason for not letting clear_weakref() decref the callback
+ * right now is that if the callback goes away, that may in turn trigger
+ * another callback (if a weak reference to the callback exists) -- running
+ * arbitrary Python code in the middle of gc is a disaster.  The convolution
+ * here allows gc to delay triggering such callbacks until the world is in
+ * a sane state again.
+ */
+void
+_PyWeakref_ClearRef(PyWeakReference *self)
+{
+    PyObject *callback;
+
+    assert(self != NULL);
+    assert(PyWeakref_Check(self));
+    /* Preserve and restore the callback around clear_weakref. */
+    callback = self->wr_callback;
+    self->wr_callback = NULL;
+    clear_weakref(self);
+    self->wr_callback = callback;
+}
+
+static void
+weakref_dealloc(PyObject *self)
+{
+    PyObject_GC_UnTrack(self);
+    clear_weakref((PyWeakReference *) self);
+    Py_TYPE(self)->tp_free(self);
+}
+
+
+static int
+gc_traverse(PyWeakReference *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->wr_callback);
+    return 0;
+}
+
+
+static int
+gc_clear(PyWeakReference *self)
+{
+    clear_weakref(self);
+    return 0;
+}
+
+
+static PyObject *
+weakref_vectorcall(PyWeakReference *self, PyObject *const *args,
+                   size_t nargsf, PyObject *kwnames)
+{
+    if (!_PyArg_NoKwnames("weakref", kwnames)) {
+        return NULL;
+    }
+    Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);
+    if (!_PyArg_CheckPositional("weakref", nargs, 0, 0)) {
+        return NULL;
+    }
+    return Py_NewRef(PyWeakref_GET_OBJECT(self));
+}
+
+static Py_hash_t
+weakref_hash(PyWeakReference *self)
+{
+    if (self->hash != -1)
+        return self->hash;
+    PyObject* obj = PyWeakref_GET_OBJECT(self);
+    if (obj == Py_None) {
+        PyErr_SetString(PyExc_TypeError, "weak object has gone away");
+        return -1;
+    }
+    Py_INCREF(obj);
+    self->hash = PyObject_Hash(obj);
+    Py_DECREF(obj);
+    return self->hash;
+}
+
+
+static PyObject *
+weakref_repr(PyWeakReference *self)
+{
+    PyObject *name, *repr;
+    PyObject* obj = PyWeakref_GET_OBJECT(self);
+
+    if (obj == Py_None) {
+        return PyUnicode_FromFormat("<weakref at %p; dead>", self);
+    }
+
+    Py_INCREF(obj);
+    name = _PyObject_LookupSpecial(obj, &_Py_ID(__name__));
+    if (name == NULL || !PyUnicode_Check(name)) {
+        repr = PyUnicode_FromFormat(
+            "<weakref at %p; to '%s' at %p>",
+            self,
+            Py_TYPE(PyWeakref_GET_OBJECT(self))->tp_name,
+            obj);
+    }
+    else {
+        repr = PyUnicode_FromFormat(
+            "<weakref at %p; to '%s' at %p (%U)>",
+            self,
+            Py_TYPE(PyWeakref_GET_OBJECT(self))->tp_name,
+            obj,
+            name);
+    }
+    Py_DECREF(obj);
+    Py_XDECREF(name);
+    return repr;
+}
+
+/* Weak references only support equality, not ordering. Two weak references
+   are equal if the underlying objects are equal. If the underlying object has
+   gone away, they are equal if they are identical. */
+
+static PyObject *
+weakref_richcompare(PyWeakReference* self, PyWeakReference* other, int op)
+{
+    if ((op != Py_EQ && op != Py_NE) ||
+        !PyWeakref_Check(self) ||
+        !PyWeakref_Check(other)) {
+        Py_RETURN_NOTIMPLEMENTED;
+    }
+    if (PyWeakref_GET_OBJECT(self) == Py_None
+        || PyWeakref_GET_OBJECT(other) == Py_None) {
+        int res = (self == other);
+        if (op == Py_NE)
+            res = !res;
+        if (res)
+            Py_RETURN_TRUE;
+        else
+            Py_RETURN_FALSE;
+    }
+    PyObject* obj = PyWeakref_GET_OBJECT(self);
+    PyObject* other_obj = PyWeakref_GET_OBJECT(other);
+    Py_INCREF(obj);
+    Py_INCREF(other_obj);
+    PyObject* res = PyObject_RichCompare(obj, other_obj, op);
+    Py_DECREF(obj);
+    Py_DECREF(other_obj);
+    return res;
+}
+
+/* Given the head of an object's list of weak references, extract the
+ * two callback-less refs (ref and proxy).  Used to determine if the
+ * shared references exist and to determine the back link for newly
+ * inserted references.
+ */
+static void
+get_basic_refs(PyWeakReference *head,
+               PyWeakReference **refp, PyWeakReference **proxyp)
+{
+    *refp = NULL;
+    *proxyp = NULL;
+
+    if (head != NULL && head->wr_callback == NULL) {
+        /* We need to be careful that the "basic refs" aren't
+           subclasses of the main types.  That complicates this a
+           little. */
+        if (PyWeakref_CheckRefExact(head)) {
+            *refp = head;
+            head = head->wr_next;
+        }
+        if (head != NULL
+            && head->wr_callback == NULL
+            && PyWeakref_CheckProxy(head)) {
+            *proxyp = head;
+            /* head = head->wr_next; */
+        }
+    }
+}
+
+/* Insert 'newref' in the list after 'prev'.  Both must be non-NULL. */
+static void
+insert_after(PyWeakReference *newref, PyWeakReference *prev)
+{
+    newref->wr_prev = prev;
+    newref->wr_next = prev->wr_next;
+    if (prev->wr_next != NULL)
+        prev->wr_next->wr_prev = newref;
+    prev->wr_next = newref;
+}
+
+/* Insert 'newref' at the head of the list; 'list' points to the variable
+ * that stores the head.
+ */
+static void
+insert_head(PyWeakReference *newref, PyWeakReference **list)
+{
+    PyWeakReference *next = *list;
+
+    newref->wr_prev = NULL;
+    newref->wr_next = next;
+    if (next != NULL)
+        next->wr_prev = newref;
+    *list = newref;
+}
+
+static int
+parse_weakref_init_args(const char *funcname, PyObject *args, PyObject *kwargs,
+                        PyObject **obp, PyObject **callbackp)
+{
+    return PyArg_UnpackTuple(args, funcname, 1, 2, obp, callbackp);
+}
+
+static PyObject *
+weakref___new__(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyWeakReference *self = NULL;
+    PyObject *ob, *callback = NULL;
+
+    if (parse_weakref_init_args("__new__", args, kwargs, &ob, &callback)) {
+        PyWeakReference *ref, *proxy;
+        PyWeakReference **list;
+
+        if (!_PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob))) {
+            PyErr_Format(PyExc_TypeError,
+                         "cannot create weak reference to '%s' object",
+                         Py_TYPE(ob)->tp_name);
+            return NULL;
+        }
+        if (callback == Py_None)
+            callback = NULL;
+        list = GET_WEAKREFS_LISTPTR(ob);
+        get_basic_refs(*list, &ref, &proxy);
+        if (callback == NULL && type == &_PyWeakref_RefType) {
+            if (ref != NULL) {
+                /* We can re-use an existing reference. */
+                Py_INCREF(ref);
+                return (PyObject *)ref;
+            }
+        }
+        /* We have to create a new reference. */
+        /* Note: the tp_alloc() can trigger cyclic GC, so the weakref
+           list on ob can be mutated.  This means that the ref and
+           proxy pointers we got back earlier may have been collected,
+           so we need to compute these values again before we use
+           them. */
+        self = (PyWeakReference *) (type->tp_alloc(type, 0));
+        if (self != NULL) {
+            init_weakref(self, ob, callback);
+            if (callback == NULL && type == &_PyWeakref_RefType) {
+                insert_head(self, list);
+            }
+            else {
+                PyWeakReference *prev;
+
+                get_basic_refs(*list, &ref, &proxy);
+                prev = (proxy == NULL) ? ref : proxy;
+                if (prev == NULL)
+                    insert_head(self, list);
+                else
+                    insert_after(self, prev);
+            }
+        }
+    }
+    return (PyObject *)self;
+}
+
+static int
+weakref___init__(PyObject *self, PyObject *args, PyObject *kwargs)
+{
+    PyObject *tmp;
+
+    if (!_PyArg_NoKeywords("ref", kwargs))
+        return -1;
+
+    if (parse_weakref_init_args("__init__", args, kwargs, &tmp, &tmp))
+        return 0;
+    else
+        return -1;
+}
+
+
+static PyMemberDef weakref_members[] = {
+    {"__callback__", T_OBJECT, offsetof(PyWeakReference, wr_callback), READONLY},
+    {NULL} /* Sentinel */
+};
+
+static PyMethodDef weakref_methods[] = {
+    {"__class_getitem__",    Py_GenericAlias,
+    METH_O|METH_CLASS,       PyDoc_STR("See PEP 585")},
+    {NULL} /* Sentinel */
+};
+
+PyTypeObject
+_PyWeakref_RefType = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    .tp_name = "weakref.ReferenceType",
+    .tp_basicsize = sizeof(PyWeakReference),
+    .tp_dealloc = weakref_dealloc,
+    .tp_vectorcall_offset = offsetof(PyWeakReference, vectorcall),
+    .tp_call = PyVectorcall_Call,
+    .tp_repr = (reprfunc)weakref_repr,
+    .tp_hash = (hashfunc)weakref_hash,
+    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
+                Py_TPFLAGS_HAVE_VECTORCALL | Py_TPFLAGS_BASETYPE,
+    .tp_traverse = (traverseproc)gc_traverse,
+    .tp_clear = (inquiry)gc_clear,
+    .tp_richcompare = (richcmpfunc)weakref_richcompare,
+    .tp_methods = weakref_methods,
+    .tp_members = weakref_members,
+    .tp_init = weakref___init__,
+    .tp_alloc = PyType_GenericAlloc,
+    .tp_new = weakref___new__,
+    .tp_free = PyObject_GC_Del,
+};
+
+
+static int
+proxy_checkref(PyWeakReference *proxy)
+{
+    if (PyWeakref_GET_OBJECT(proxy) == Py_None) {
+        PyErr_SetString(PyExc_ReferenceError,
+                        "weakly-referenced object no longer exists");
+        return 0;
+    }
+    return 1;
+}
+
+
+/* If a parameter is a proxy, check that it is still "live" and wrap it,
+ * replacing the original value with the raw object.  Raises ReferenceError
+ * if the param is a dead proxy.
+ */
+#define UNWRAP(o) \
+        if (PyWeakref_CheckProxy(o)) { \
+            if (!proxy_checkref((PyWeakReference *)o)) \
+                return NULL; \
+            o = PyWeakref_GET_OBJECT(o); \
+        }
+
+#define WRAP_UNARY(method, generic) \
+    static PyObject * \
+    method(PyObject *proxy) { \
+        UNWRAP(proxy); \
+        Py_INCREF(proxy); \
+        PyObject* res = generic(proxy); \
+        Py_DECREF(proxy); \
+        return res; \
+    }
+
+#define WRAP_BINARY(method, generic) \
+    static PyObject * \
+    method(PyObject *x, PyObject *y) { \
+        UNWRAP(x); \
+        UNWRAP(y); \
+        Py_INCREF(x); \
+        Py_INCREF(y); \
+        PyObject* res = generic(x, y); \
+        Py_DECREF(x); \
+        Py_DECREF(y); \
+        return res; \
+    }
+
+/* Note that the third arg needs to be checked for NULL since the tp_call
+ * slot can receive NULL for this arg.
+ */
+#define WRAP_TERNARY(method, generic) \
+    static PyObject * \
+    method(PyObject *proxy, PyObject *v, PyObject *w) { \
+        UNWRAP(proxy); \
+        UNWRAP(v); \
+        if (w != NULL) \
+            UNWRAP(w); \
+        Py_INCREF(proxy); \
+        Py_INCREF(v); \
+        Py_XINCREF(w); \
+        PyObject* res = generic(proxy, v, w); \
+        Py_DECREF(proxy); \
+        Py_DECREF(v); \
+        Py_XDECREF(w); \
+        return res; \
+    }
+
+#define WRAP_METHOD(method, SPECIAL) \
+    static PyObject * \
+    method(PyObject *proxy, PyObject *Py_UNUSED(ignored)) { \
+            UNWRAP(proxy); \
+            Py_INCREF(proxy); \
+            PyObject* res = PyObject_CallMethodNoArgs(proxy, &_Py_ID(SPECIAL)); \
+            Py_DECREF(proxy); \
+            return res; \
+        }
+
+
+/* direct slots */
+
+WRAP_BINARY(proxy_getattr, PyObject_GetAttr)
+WRAP_UNARY(proxy_str, PyObject_Str)
+WRAP_TERNARY(proxy_call, PyObject_Call)
+
+static PyObject *
+proxy_repr(PyWeakReference *proxy)
+{
+    return PyUnicode_FromFormat(
+        "<weakproxy at %p to %s at %p>",
+        proxy,
+        Py_TYPE(PyWeakref_GET_OBJECT(proxy))->tp_name,
+        PyWeakref_GET_OBJECT(proxy));
+}
+
+
+static int
+proxy_setattr(PyWeakReference *proxy, PyObject *name, PyObject *value)
+{
+    if (!proxy_checkref(proxy))
+        return -1;
+    PyObject *obj = PyWeakref_GET_OBJECT(proxy);
+    Py_INCREF(obj);
+    int res = PyObject_SetAttr(obj, name, value);
+    Py_DECREF(obj);
+    return res;
+}
+
+static PyObject *
+proxy_richcompare(PyObject *proxy, PyObject *v, int op)
+{
+    UNWRAP(proxy);
+    UNWRAP(v);
+    return PyObject_RichCompare(proxy, v, op);
+}
+
+/* number slots */
+WRAP_BINARY(proxy_add, PyNumber_Add)
+WRAP_BINARY(proxy_sub, PyNumber_Subtract)
+WRAP_BINARY(proxy_mul, PyNumber_Multiply)
+WRAP_BINARY(proxy_floor_div, PyNumber_FloorDivide)
+WRAP_BINARY(proxy_true_div, PyNumber_TrueDivide)
+WRAP_BINARY(proxy_mod, PyNumber_Remainder)
+WRAP_BINARY(proxy_divmod, PyNumber_Divmod)
+WRAP_TERNARY(proxy_pow, PyNumber_Power)
+WRAP_UNARY(proxy_neg, PyNumber_Negative)
+WRAP_UNARY(proxy_pos, PyNumber_Positive)
+WRAP_UNARY(proxy_abs, PyNumber_Absolute)
+WRAP_UNARY(proxy_invert, PyNumber_Invert)
+WRAP_BINARY(proxy_lshift, PyNumber_Lshift)
+WRAP_BINARY(proxy_rshift, PyNumber_Rshift)
+WRAP_BINARY(proxy_and, PyNumber_And)
+WRAP_BINARY(proxy_xor, PyNumber_Xor)
+WRAP_BINARY(proxy_or, PyNumber_Or)
+WRAP_UNARY(proxy_int, PyNumber_Long)
+WRAP_UNARY(proxy_float, PyNumber_Float)
+WRAP_BINARY(proxy_iadd, PyNumber_InPlaceAdd)
+WRAP_BINARY(proxy_isub, PyNumber_InPlaceSubtract)
+WRAP_BINARY(proxy_imul, PyNumber_InPlaceMultiply)
+WRAP_BINARY(proxy_ifloor_div, PyNumber_InPlaceFloorDivide)
+WRAP_BINARY(proxy_itrue_div, PyNumber_InPlaceTrueDivide)
+WRAP_BINARY(proxy_imod, PyNumber_InPlaceRemainder)
+WRAP_TERNARY(proxy_ipow, PyNumber_InPlacePower)
+WRAP_BINARY(proxy_ilshift, PyNumber_InPlaceLshift)
+WRAP_BINARY(proxy_irshift, PyNumber_InPlaceRshift)
+WRAP_BINARY(proxy_iand, PyNumber_InPlaceAnd)
+WRAP_BINARY(proxy_ixor, PyNumber_InPlaceXor)
+WRAP_BINARY(proxy_ior, PyNumber_InPlaceOr)
+WRAP_UNARY(proxy_index, PyNumber_Index)
+WRAP_BINARY(proxy_matmul, PyNumber_MatrixMultiply)
+WRAP_BINARY(proxy_imatmul, PyNumber_InPlaceMatrixMultiply)
+
+static int
+proxy_bool(PyWeakReference *proxy)
+{
+    PyObject *o = PyWeakref_GET_OBJECT(proxy);
+    if (!proxy_checkref(proxy)) {
+        return -1;
+    }
+    Py_INCREF(o);
+    int res = PyObject_IsTrue(o);
+    Py_DECREF(o);
+    return res;
+}
+
+static void
+proxy_dealloc(PyWeakReference *self)
+{
+    PyObject_GC_UnTrack(self);
+    if (self->wr_callback != NULL)
+        PyObject_GC_UnTrack((PyObject *)self);
+    clear_weakref(self);
+    PyObject_GC_Del(self);
+}
+
+/* sequence slots */
+
+static int
+proxy_contains(PyWeakReference *proxy, PyObject *value)
+{
+    if (!proxy_checkref(proxy))
+        return -1;
+
+    PyObject *obj = PyWeakref_GET_OBJECT(proxy);
+    Py_INCREF(obj);
+    int res = PySequence_Contains(obj, value);
+    Py_DECREF(obj);
+    return res;
+}
+
+/* mapping slots */
+
+static Py_ssize_t
+proxy_length(PyWeakReference *proxy)
+{
+    if (!proxy_checkref(proxy))
+        return -1;
+
+    PyObject *obj = PyWeakref_GET_OBJECT(proxy);
+    Py_INCREF(obj);
+    Py_ssize_t res = PyObject_Length(obj);
+    Py_DECREF(obj);
+    return res;
+}
+
+WRAP_BINARY(proxy_getitem, PyObject_GetItem)
+
+static int
+proxy_setitem(PyWeakReference *proxy, PyObject *key, PyObject *value)
+{
+    if (!proxy_checkref(proxy))
+        return -1;
+
+    PyObject *obj = PyWeakref_GET_OBJECT(proxy);
+    Py_INCREF(obj);
+    int res;
+    if (value == NULL) {
+        res = PyObject_DelItem(obj, key);
+    } else {
+        res = PyObject_SetItem(obj, key, value);
+    }
+    Py_DECREF(obj);
+    return res;
+}
+
+/* iterator slots */
+
+static PyObject *
+proxy_iter(PyWeakReference *proxy)
+{
+    if (!proxy_checkref(proxy))
+        return NULL;
+    PyObject *obj = PyWeakref_GET_OBJECT(proxy);
+    Py_INCREF(obj);
+    PyObject* res = PyObject_GetIter(obj);
+    Py_DECREF(obj);
+    return res;
+}
+
+static PyObject *
+proxy_iternext(PyWeakReference *proxy)
+{
+    if (!proxy_checkref(proxy))
+        return NULL;
+
+    PyObject *obj = PyWeakref_GET_OBJECT(proxy);
+    if (!PyIter_Check(obj)) {
+        PyErr_Format(PyExc_TypeError,
+            "Weakref proxy referenced a non-iterator '%.200s' object",
+            Py_TYPE(obj)->tp_name);
+        return NULL;
+    }
+    Py_INCREF(obj);
+    PyObject* res = PyIter_Next(obj);
+    Py_DECREF(obj);
+    return res;
+}
+
+
+WRAP_METHOD(proxy_bytes, __bytes__)
+WRAP_METHOD(proxy_reversed, __reversed__)
+
+
+static PyMethodDef proxy_methods[] = {
+        {"__bytes__", proxy_bytes, METH_NOARGS},
+        {"__reversed__", proxy_reversed, METH_NOARGS},
+        {NULL, NULL}
+};
+
+
+static PyNumberMethods proxy_as_number = {
+    proxy_add,              /*nb_add*/
+    proxy_sub,              /*nb_subtract*/
+    proxy_mul,              /*nb_multiply*/
+    proxy_mod,              /*nb_remainder*/
+    proxy_divmod,           /*nb_divmod*/
+    proxy_pow,              /*nb_power*/
+    proxy_neg,              /*nb_negative*/
+    proxy_pos,              /*nb_positive*/
+    proxy_abs,              /*nb_absolute*/
+    (inquiry)proxy_bool,    /*nb_bool*/
+    proxy_invert,           /*nb_invert*/
+    proxy_lshift,           /*nb_lshift*/
+    proxy_rshift,           /*nb_rshift*/
+    proxy_and,              /*nb_and*/
+    proxy_xor,              /*nb_xor*/
+    proxy_or,               /*nb_or*/
+    proxy_int,              /*nb_int*/
+    0,                      /*nb_reserved*/
+    proxy_float,            /*nb_float*/
+    proxy_iadd,             /*nb_inplace_add*/
+    proxy_isub,             /*nb_inplace_subtract*/
+    proxy_imul,             /*nb_inplace_multiply*/
+    proxy_imod,             /*nb_inplace_remainder*/
+    proxy_ipow,             /*nb_inplace_power*/
+    proxy_ilshift,          /*nb_inplace_lshift*/
+    proxy_irshift,          /*nb_inplace_rshift*/
+    proxy_iand,             /*nb_inplace_and*/
+    proxy_ixor,             /*nb_inplace_xor*/
+    proxy_ior,              /*nb_inplace_or*/
+    proxy_floor_div,        /*nb_floor_divide*/
+    proxy_true_div,         /*nb_true_divide*/
+    proxy_ifloor_div,       /*nb_inplace_floor_divide*/
+    proxy_itrue_div,        /*nb_inplace_true_divide*/
+    proxy_index,            /*nb_index*/
+    proxy_matmul,           /*nb_matrix_multiply*/
+    proxy_imatmul,          /*nb_inplace_matrix_multiply*/
+};
+
+static PySequenceMethods proxy_as_sequence = {
+    (lenfunc)proxy_length,      /*sq_length*/
+    0,                          /*sq_concat*/
+    0,                          /*sq_repeat*/
+    0,                          /*sq_item*/
+    0,                          /*sq_slice*/
+    0,                          /*sq_ass_item*/
+    0,                           /*sq_ass_slice*/
+    (objobjproc)proxy_contains, /* sq_contains */
+};
+
+static PyMappingMethods proxy_as_mapping = {
+    (lenfunc)proxy_length,        /*mp_length*/
+    proxy_getitem,                /*mp_subscript*/
+    (objobjargproc)proxy_setitem, /*mp_ass_subscript*/
+};
+
+
+PyTypeObject
+_PyWeakref_ProxyType = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    "weakref.ProxyType",
+    sizeof(PyWeakReference),
+    0,
+    /* methods */
+    (destructor)proxy_dealloc,          /* tp_dealloc */
+    0,                                  /* tp_vectorcall_offset */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_as_async */
+    (reprfunc)proxy_repr,               /* tp_repr */
+    &proxy_as_number,                   /* tp_as_number */
+    &proxy_as_sequence,                 /* tp_as_sequence */
+    &proxy_as_mapping,                  /* tp_as_mapping */
+// Notice that tp_hash is intentionally omitted as proxies are "mutable" (when the reference dies).
+    0,                                  /* tp_hash */
+    0,                                  /* tp_call */
+    proxy_str,                          /* tp_str */
+    proxy_getattr,                      /* tp_getattro */
+    (setattrofunc)proxy_setattr,        /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
+    0,                                  /* tp_doc */
+    (traverseproc)gc_traverse,          /* tp_traverse */
+    (inquiry)gc_clear,                  /* tp_clear */
+    proxy_richcompare,                  /* tp_richcompare */
+    0,                                  /* tp_weaklistoffset */
+    (getiterfunc)proxy_iter,            /* tp_iter */
+    (iternextfunc)proxy_iternext,       /* tp_iternext */
+        proxy_methods,                      /* tp_methods */
+};
+
+
+PyTypeObject
+_PyWeakref_CallableProxyType = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    "weakref.CallableProxyType",
+    sizeof(PyWeakReference),
+    0,
+    /* methods */
+    (destructor)proxy_dealloc,          /* tp_dealloc */
+    0,                                  /* tp_vectorcall_offset */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_as_async */
+    (unaryfunc)proxy_repr,              /* tp_repr */
+    &proxy_as_number,                   /* tp_as_number */
+    &proxy_as_sequence,                 /* tp_as_sequence */
+    &proxy_as_mapping,                  /* tp_as_mapping */
+    0,                                  /* tp_hash */
+    proxy_call,                         /* tp_call */
+    proxy_str,                          /* tp_str */
+    proxy_getattr,                      /* tp_getattro */
+    (setattrofunc)proxy_setattr,        /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
+    0,                                  /* tp_doc */
+    (traverseproc)gc_traverse,          /* tp_traverse */
+    (inquiry)gc_clear,                  /* tp_clear */
+    proxy_richcompare,                  /* tp_richcompare */
+    0,                                  /* tp_weaklistoffset */
+    (getiterfunc)proxy_iter,            /* tp_iter */
+    (iternextfunc)proxy_iternext,       /* tp_iternext */
+};
+
+
+
+PyObject *
+PyWeakref_NewRef(PyObject *ob, PyObject *callback)
+{
+    PyWeakReference *result = NULL;
+    PyWeakReference **list;
+    PyWeakReference *ref, *proxy;
+
+    if (!_PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob))) {
+        PyErr_Format(PyExc_TypeError,
+                     "cannot create weak reference to '%s' object",
+                     Py_TYPE(ob)->tp_name);
+        return NULL;
+    }
+    list = GET_WEAKREFS_LISTPTR(ob);
+    get_basic_refs(*list, &ref, &proxy);
+    if (callback == Py_None)
+        callback = NULL;
+    if (callback == NULL)
+        /* return existing weak reference if it exists */
+        result = ref;
+    if (result != NULL)
+        Py_INCREF(result);
+    else {
+        /* Note: new_weakref() can trigger cyclic GC, so the weakref
+           list on ob can be mutated.  This means that the ref and
+           proxy pointers we got back earlier may have been collected,
+           so we need to compute these values again before we use
+           them. */
+        result = new_weakref(ob, callback);
+        if (result != NULL) {
+            get_basic_refs(*list, &ref, &proxy);
+            if (callback == NULL) {
+                if (ref == NULL)
+                    insert_head(result, list);
+                else {
+                    /* Someone else added a ref without a callback
+                       during GC.  Return that one instead of this one
+                       to avoid violating the invariants of the list
+                       of weakrefs for ob. */
+                    Py_DECREF(result);
+                    Py_INCREF(ref);
+                    result = ref;
+                }
+            }
+            else {
+                PyWeakReference *prev;
+
+                prev = (proxy == NULL) ? ref : proxy;
+                if (prev == NULL)
+                    insert_head(result, list);
+                else
+                    insert_after(result, prev);
+            }
+        }
+    }
+    return (PyObject *) result;
+}
+
+
+PyObject *
+PyWeakref_NewProxy(PyObject *ob, PyObject *callback)
+{
+    PyWeakReference *result = NULL;
+    PyWeakReference **list;
+    PyWeakReference *ref, *proxy;
+
+    if (!_PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob))) {
+        PyErr_Format(PyExc_TypeError,
+                     "cannot create weak reference to '%s' object",
+                     Py_TYPE(ob)->tp_name);
+        return NULL;
+    }
+    list = GET_WEAKREFS_LISTPTR(ob);
+    get_basic_refs(*list, &ref, &proxy);
+    if (callback == Py_None)
+        callback = NULL;
+    if (callback == NULL)
+        /* attempt to return an existing weak reference if it exists */
+        result = proxy;
+    if (result != NULL)
+        Py_INCREF(result);
+    else {
+        /* Note: new_weakref() can trigger cyclic GC, so the weakref
+           list on ob can be mutated.  This means that the ref and
+           proxy pointers we got back earlier may have been collected,
+           so we need to compute these values again before we use
+           them. */
+        result = new_weakref(ob, callback);
+        if (result != NULL) {
+            PyWeakReference *prev;
+
+            if (PyCallable_Check(ob)) {
+                Py_SET_TYPE(result, &_PyWeakref_CallableProxyType);
+            }
+            else {
+                Py_SET_TYPE(result, &_PyWeakref_ProxyType);
+            }
+            get_basic_refs(*list, &ref, &proxy);
+            if (callback == NULL) {
+                if (proxy != NULL) {
+                    /* Someone else added a proxy without a callback
+                       during GC.  Return that one instead of this one
+                       to avoid violating the invariants of the list
+                       of weakrefs for ob. */
+                    Py_DECREF(result);
+                    result = proxy;
+                    Py_INCREF(result);
+                    goto skip_insert;
+                }
+                prev = ref;
+            }
+            else
+                prev = (proxy == NULL) ? ref : proxy;
+
+            if (prev == NULL)
+                insert_head(result, list);
+            else
+                insert_after(result, prev);
+        skip_insert:
+            ;
+        }
+    }
+    return (PyObject *) result;
+}
+
+
+PyObject *
+PyWeakref_GetObject(PyObject *ref)
+{
+    if (ref == NULL || !PyWeakref_Check(ref)) {
+        PyErr_BadInternalCall();
+        return NULL;
+    }
+    return PyWeakref_GET_OBJECT(ref);
+}
+
+/* Note that there's an inlined copy-paste of handle_callback() in gcmodule.c's
+ * handle_weakrefs().
+ */
+static void
+handle_callback(PyWeakReference *ref, PyObject *callback)
+{
+    PyObject *cbresult = PyObject_CallOneArg(callback, (PyObject *)ref);
+
+    if (cbresult == NULL)
+        PyErr_WriteUnraisable(callback);
+    else
+        Py_DECREF(cbresult);
+}
+
+/* This function is called by the tp_dealloc handler to clear weak references.
+ *
+ * This iterates through the weak references for 'object' and calls callbacks
+ * for those references which have one.  It returns when all callbacks have
+ * been attempted.
+ */
+void
+PyObject_ClearWeakRefs(PyObject *object)
+{
+    PyWeakReference **list;
+
+    if (object == NULL
+        || !_PyType_SUPPORTS_WEAKREFS(Py_TYPE(object))
+        || Py_REFCNT(object) != 0)
+    {
+        PyErr_BadInternalCall();
+        return;
+    }
+    list = GET_WEAKREFS_LISTPTR(object);
+    /* 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) {
+        PyWeakReference *current = *list;
+        Py_ssize_t count = _PyWeakref_GetWeakrefCount(current);
+        PyObject *err_type, *err_value, *err_tb;
+
+        PyErr_Fetch(&err_type, &err_value, &err_tb);
+        if (count == 1) {
+            PyObject *callback = current->wr_callback;
+
+            current->wr_callback = NULL;
+            clear_weakref(current);
+            if (callback != NULL) {
+                if (Py_REFCNT((PyObject *)current) > 0) {
+                    handle_callback(current, callback);
+                }
+                Py_DECREF(callback);
+            }
+        }
+        else {
+            PyObject *tuple;
+            Py_ssize_t i = 0;
+
+            tuple = PyTuple_New(count * 2);
+            if (tuple == NULL) {
+                _PyErr_ChainExceptions(err_type, err_value, err_tb);
+                return;
+            }
+
+            for (i = 0; i < count; ++i) {
+                PyWeakReference *next = current->wr_next;
+
+                if (Py_REFCNT((PyObject *)current) > 0) {
+                    Py_INCREF(current);
+                    PyTuple_SET_ITEM(tuple, i * 2, (PyObject *) current);
+                    PyTuple_SET_ITEM(tuple, i * 2 + 1, current->wr_callback);
+                }
+                else {
+                    Py_DECREF(current->wr_callback);
+                }
+                current->wr_callback = NULL;
+                clear_weakref(current);
+                current = next;
+            }
+            for (i = 0; i < count; ++i) {
+                PyObject *callback = PyTuple_GET_ITEM(tuple, i * 2 + 1);
+
+                /* The tuple may have slots left to NULL */
+                if (callback != NULL) {
+                    PyObject *item = PyTuple_GET_ITEM(tuple, i * 2);
+                    handle_callback((PyWeakReference *)item, callback);
+                }
+            }
+            Py_DECREF(tuple);
+        }
+        assert(!PyErr_Occurred());
+        PyErr_Restore(err_type, err_value, err_tb);
+    }
+}