[mirror_edk2.git] / AppPkg / Applications / Python / Python-2.7.2 / Objects / weakrefobject.c

#include "Python.h"\r
#include "structmember.h"\r
\r
\r
#define GET_WEAKREFS_LISTPTR(o) \\r
        ((PyWeakReference **) PyObject_GET_WEAKREFS_LISTPTR(o))\r
\r
\r
Py_ssize_t\r
_PyWeakref_GetWeakrefCount(PyWeakReference *head)\r
{\r
    Py_ssize_t count = 0;\r
\r
    while (head != NULL) {\r
        ++count;\r
        head = head->wr_next;\r
    }\r
    return count;\r
}\r
\r
\r
static void\r
init_weakref(PyWeakReference *self, PyObject *ob, PyObject *callback)\r
{\r
    self->hash = -1;\r
    self->wr_object = ob;\r
    Py_XINCREF(callback);\r
    self->wr_callback = callback;\r
}\r
\r
static PyWeakReference *\r
new_weakref(PyObject *ob, PyObject *callback)\r
{\r
    PyWeakReference *result;\r
\r
    result = PyObject_GC_New(PyWeakReference, &_PyWeakref_RefType);\r
    if (result) {\r
        init_weakref(result, ob, callback);\r
        PyObject_GC_Track(result);\r
    }\r
    return result;\r
}\r
\r
\r
/* This function clears the passed-in reference and removes it from the\r
 * list of weak references for the referent.  This is the only code that\r
 * removes an item from the doubly-linked list of weak references for an\r
 * object; it is also responsible for clearing the callback slot.\r
 */\r
static void\r
clear_weakref(PyWeakReference *self)\r
{\r
    PyObject *callback = self->wr_callback;\r
\r
    if (PyWeakref_GET_OBJECT(self) != Py_None) {\r
        PyWeakReference **list = GET_WEAKREFS_LISTPTR(\r
            PyWeakref_GET_OBJECT(self));\r
\r
        if (*list == self)\r
            /* If 'self' is the end of the list (and thus self->wr_next == NULL)\r
               then the weakref list itself (and thus the value of *list) will\r
               end up being set to NULL. */\r
            *list = self->wr_next;\r
        self->wr_object = Py_None;\r
        if (self->wr_prev != NULL)\r
            self->wr_prev->wr_next = self->wr_next;\r
        if (self->wr_next != NULL)\r
            self->wr_next->wr_prev = self->wr_prev;\r
        self->wr_prev = NULL;\r
        self->wr_next = NULL;\r
    }\r
    if (callback != NULL) {\r
        Py_DECREF(callback);\r
        self->wr_callback = NULL;\r
    }\r
}\r
\r
/* Cyclic gc uses this to *just* clear the passed-in reference, leaving\r
 * the callback intact and uncalled.  It must be possible to call self's\r
 * tp_dealloc() after calling this, so self has to be left in a sane enough\r
 * state for that to work.  We expect tp_dealloc to decref the callback\r
 * then.  The reason for not letting clear_weakref() decref the callback\r
 * right now is that if the callback goes away, that may in turn trigger\r
 * another callback (if a weak reference to the callback exists) -- running\r
 * arbitrary Python code in the middle of gc is a disaster.  The convolution\r
 * here allows gc to delay triggering such callbacks until the world is in\r
 * a sane state again.\r
 */\r
void\r
_PyWeakref_ClearRef(PyWeakReference *self)\r
{\r
    PyObject *callback;\r
\r
    assert(self != NULL);\r
    assert(PyWeakref_Check(self));\r
    /* Preserve and restore the callback around clear_weakref. */\r
    callback = self->wr_callback;\r
    self->wr_callback = NULL;\r
    clear_weakref(self);\r
    self->wr_callback = callback;\r
}\r
\r
static void\r
weakref_dealloc(PyObject *self)\r
{\r
    PyObject_GC_UnTrack(self);\r
    clear_weakref((PyWeakReference *) self);\r
    Py_TYPE(self)->tp_free(self);\r
}\r
\r
\r
static int\r
gc_traverse(PyWeakReference *self, visitproc visit, void *arg)\r
{\r
    Py_VISIT(self->wr_callback);\r
    return 0;\r
}\r
\r
\r
static int\r
gc_clear(PyWeakReference *self)\r
{\r
    clear_weakref(self);\r
    return 0;\r
}\r
\r
\r
static PyObject *\r
weakref_call(PyWeakReference *self, PyObject *args, PyObject *kw)\r
{\r
    static char *kwlist[] = {NULL};\r
\r
    if (PyArg_ParseTupleAndKeywords(args, kw, ":__call__", kwlist)) {\r
        PyObject *object = PyWeakref_GET_OBJECT(self);\r
        Py_INCREF(object);\r
        return (object);\r
    }\r
    return NULL;\r
}\r
\r
\r
static long\r
weakref_hash(PyWeakReference *self)\r
{\r
    if (self->hash != -1)\r
        return self->hash;\r
    if (PyWeakref_GET_OBJECT(self) == Py_None) {\r
        PyErr_SetString(PyExc_TypeError, "weak object has gone away");\r
        return -1;\r
    }\r
    self->hash = PyObject_Hash(PyWeakref_GET_OBJECT(self));\r
    return self->hash;\r
}\r
\r
\r
static PyObject *\r
weakref_repr(PyWeakReference *self)\r
{\r
    char buffer[256];\r
    if (PyWeakref_GET_OBJECT(self) == Py_None) {\r
        PyOS_snprintf(buffer, sizeof(buffer), "<weakref at %p; dead>", self);\r
    }\r
    else {\r
        char *name = NULL;\r
        PyObject *nameobj = PyObject_GetAttrString(PyWeakref_GET_OBJECT(self),\r
                                                   "__name__");\r
        if (nameobj == NULL)\r
                PyErr_Clear();\r
        else if (PyString_Check(nameobj))\r
                name = PyString_AS_STRING(nameobj);\r
        PyOS_snprintf(buffer, sizeof(buffer),\r
                      name ? "<weakref at %p; to '%.50s' at %p (%s)>"\r
                           : "<weakref at %p; to '%.50s' at %p>",\r
                      self,\r
                      Py_TYPE(PyWeakref_GET_OBJECT(self))->tp_name,\r
                      PyWeakref_GET_OBJECT(self),\r
                      name);\r
        Py_XDECREF(nameobj);\r
    }\r
    return PyString_FromString(buffer);\r
}\r
\r
/* Weak references only support equality, not ordering. Two weak references\r
   are equal if the underlying objects are equal. If the underlying object has\r
   gone away, they are equal if they are identical. */\r
\r
static PyObject *\r
weakref_richcompare(PyWeakReference* self, PyWeakReference* other, int op)\r
{\r
    if (op != Py_EQ || self->ob_type != other->ob_type) {\r
        Py_INCREF(Py_NotImplemented);\r
        return Py_NotImplemented;\r
    }\r
    if (PyWeakref_GET_OBJECT(self) == Py_None\r
        || PyWeakref_GET_OBJECT(other) == Py_None) {\r
        PyObject *res = self==other ? Py_True : Py_False;\r
        Py_INCREF(res);\r
        return res;\r
    }\r
    return PyObject_RichCompare(PyWeakref_GET_OBJECT(self),\r
                                PyWeakref_GET_OBJECT(other), op);\r
}\r
\r
/* Given the head of an object's list of weak references, extract the\r
 * two callback-less refs (ref and proxy).  Used to determine if the\r
 * shared references exist and to determine the back link for newly\r
 * inserted references.\r
 */\r
static void\r
get_basic_refs(PyWeakReference *head,\r
               PyWeakReference **refp, PyWeakReference **proxyp)\r
{\r
    *refp = NULL;\r
    *proxyp = NULL;\r
\r
    if (head != NULL && head->wr_callback == NULL) {\r
        /* We need to be careful that the "basic refs" aren't\r
           subclasses of the main types.  That complicates this a\r
           little. */\r
        if (PyWeakref_CheckRefExact(head)) {\r
            *refp = head;\r
            head = head->wr_next;\r
        }\r
        if (head != NULL\r
            && head->wr_callback == NULL\r
            && PyWeakref_CheckProxy(head)) {\r
            *proxyp = head;\r
            /* head = head->wr_next; */\r
        }\r
    }\r
}\r
\r
/* Insert 'newref' in the list after 'prev'.  Both must be non-NULL. */\r
static void\r
insert_after(PyWeakReference *newref, PyWeakReference *prev)\r
{\r
    newref->wr_prev = prev;\r
    newref->wr_next = prev->wr_next;\r
    if (prev->wr_next != NULL)\r
        prev->wr_next->wr_prev = newref;\r
    prev->wr_next = newref;\r
}\r
\r
/* Insert 'newref' at the head of the list; 'list' points to the variable\r
 * that stores the head.\r
 */\r
static void\r
insert_head(PyWeakReference *newref, PyWeakReference **list)\r
{\r
    PyWeakReference *next = *list;\r
\r
    newref->wr_prev = NULL;\r
    newref->wr_next = next;\r
    if (next != NULL)\r
        next->wr_prev = newref;\r
    *list = newref;\r
}\r
\r
static int\r
parse_weakref_init_args(char *funcname, PyObject *args, PyObject *kwargs,\r
                        PyObject **obp, PyObject **callbackp)\r
{\r
    /* XXX Should check that kwargs == NULL or is empty. */\r
    return PyArg_UnpackTuple(args, funcname, 1, 2, obp, callbackp);\r
}\r
\r
static PyObject *\r
weakref___new__(PyTypeObject *type, PyObject *args, PyObject *kwargs)\r
{\r
    PyWeakReference *self = NULL;\r
    PyObject *ob, *callback = NULL;\r
\r
    if (parse_weakref_init_args("__new__", args, kwargs, &ob, &callback)) {\r
        PyWeakReference *ref, *proxy;\r
        PyWeakReference **list;\r
\r
        if (!PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob))) {\r
            PyErr_Format(PyExc_TypeError,\r
                         "cannot create weak reference to '%s' object",\r
                         Py_TYPE(ob)->tp_name);\r
            return NULL;\r
        }\r
        if (callback == Py_None)\r
            callback = NULL;\r
        list = GET_WEAKREFS_LISTPTR(ob);\r
        get_basic_refs(*list, &ref, &proxy);\r
        if (callback == NULL && type == &_PyWeakref_RefType) {\r
            if (ref != NULL) {\r
                /* We can re-use an existing reference. */\r
                Py_INCREF(ref);\r
                return (PyObject *)ref;\r
            }\r
        }\r
        /* We have to create a new reference. */\r
        /* Note: the tp_alloc() can trigger cyclic GC, so the weakref\r
           list on ob can be mutated.  This means that the ref and\r
           proxy pointers we got back earlier may have been collected,\r
           so we need to compute these values again before we use\r
           them. */\r
        self = (PyWeakReference *) (type->tp_alloc(type, 0));\r
        if (self != NULL) {\r
            init_weakref(self, ob, callback);\r
            if (callback == NULL && type == &_PyWeakref_RefType) {\r
                insert_head(self, list);\r
            }\r
            else {\r
                PyWeakReference *prev;\r
\r
                get_basic_refs(*list, &ref, &proxy);\r
                prev = (proxy == NULL) ? ref : proxy;\r
                if (prev == NULL)\r
                    insert_head(self, list);\r
                else\r
                    insert_after(self, prev);\r
            }\r
        }\r
    }\r
    return (PyObject *)self;\r
}\r
\r
static int\r
weakref___init__(PyObject *self, PyObject *args, PyObject *kwargs)\r
{\r
    PyObject *tmp;\r
\r
    if (parse_weakref_init_args("__init__", args, kwargs, &tmp, &tmp))\r
        return 0;\r
    else\r
        return -1;\r
}\r
\r
\r
PyTypeObject\r
_PyWeakref_RefType = {\r
    PyVarObject_HEAD_INIT(&PyType_Type, 0)\r
    "weakref",\r
    sizeof(PyWeakReference),\r
    0,\r
    weakref_dealloc,            /*tp_dealloc*/\r
    0,                          /*tp_print*/\r
    0,                          /*tp_getattr*/\r
    0,                          /*tp_setattr*/\r
    0,                          /*tp_compare*/\r
    (reprfunc)weakref_repr,     /*tp_repr*/\r
    0,                          /*tp_as_number*/\r
    0,                          /*tp_as_sequence*/\r
    0,                          /*tp_as_mapping*/\r
    (hashfunc)weakref_hash,     /*tp_hash*/\r
    (ternaryfunc)weakref_call,  /*tp_call*/\r
    0,                          /*tp_str*/\r
    0,                          /*tp_getattro*/\r
    0,                          /*tp_setattro*/\r
    0,                          /*tp_as_buffer*/\r
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_HAVE_RICHCOMPARE\r
        | Py_TPFLAGS_BASETYPE,  /*tp_flags*/\r
    0,                          /*tp_doc*/\r
    (traverseproc)gc_traverse,  /*tp_traverse*/\r
    (inquiry)gc_clear,          /*tp_clear*/\r
    (richcmpfunc)weakref_richcompare,   /*tp_richcompare*/\r
    0,                          /*tp_weaklistoffset*/\r
    0,                          /*tp_iter*/\r
    0,                          /*tp_iternext*/\r
    0,                          /*tp_methods*/\r
    0,                          /*tp_members*/\r
    0,                          /*tp_getset*/\r
    0,                          /*tp_base*/\r
    0,                          /*tp_dict*/\r
    0,                          /*tp_descr_get*/\r
    0,                          /*tp_descr_set*/\r
    0,                          /*tp_dictoffset*/\r
    weakref___init__,           /*tp_init*/\r
    PyType_GenericAlloc,        /*tp_alloc*/\r
    weakref___new__,            /*tp_new*/\r
    PyObject_GC_Del,            /*tp_free*/\r
};\r
\r
\r
static int\r
proxy_checkref(PyWeakReference *proxy)\r
{\r
    if (PyWeakref_GET_OBJECT(proxy) == Py_None) {\r
        PyErr_SetString(PyExc_ReferenceError,\r
                        "weakly-referenced object no longer exists");\r
        return 0;\r
    }\r
    return 1;\r
}\r
\r
\r
/* If a parameter is a proxy, check that it is still "live" and wrap it,\r
 * replacing the original value with the raw object.  Raises ReferenceError\r
 * if the param is a dead proxy.\r
 */\r
#define UNWRAP(o) \\r
        if (PyWeakref_CheckProxy(o)) { \\r
            if (!proxy_checkref((PyWeakReference *)o)) \\r
                return NULL; \\r
            o = PyWeakref_GET_OBJECT(o); \\r
        }\r
\r
#define UNWRAP_I(o) \\r
        if (PyWeakref_CheckProxy(o)) { \\r
            if (!proxy_checkref((PyWeakReference *)o)) \\r
                return -1; \\r
            o = PyWeakref_GET_OBJECT(o); \\r
        }\r
\r
#define WRAP_UNARY(method, generic) \\r
    static PyObject * \\r
    method(PyObject *proxy) { \\r
        UNWRAP(proxy); \\r
        return generic(proxy); \\r
    }\r
\r
#define WRAP_BINARY(method, generic) \\r
    static PyObject * \\r
    method(PyObject *x, PyObject *y) { \\r
        UNWRAP(x); \\r
        UNWRAP(y); \\r
        return generic(x, y); \\r
    }\r
\r
/* Note that the third arg needs to be checked for NULL since the tp_call\r
 * slot can receive NULL for this arg.\r
 */\r
#define WRAP_TERNARY(method, generic) \\r
    static PyObject * \\r
    method(PyObject *proxy, PyObject *v, PyObject *w) { \\r
        UNWRAP(proxy); \\r
        UNWRAP(v); \\r
        if (w != NULL) \\r
            UNWRAP(w); \\r
        return generic(proxy, v, w); \\r
    }\r
\r
#define WRAP_METHOD(method, special) \\r
    static PyObject * \\r
    method(PyObject *proxy) { \\r
            UNWRAP(proxy); \\r
                return PyObject_CallMethod(proxy, special, ""); \\r
        }\r
\r
\r
/* direct slots */\r
\r
WRAP_BINARY(proxy_getattr, PyObject_GetAttr)\r
WRAP_UNARY(proxy_str, PyObject_Str)\r
WRAP_TERNARY(proxy_call, PyEval_CallObjectWithKeywords)\r
\r
static PyObject *\r
proxy_repr(PyWeakReference *proxy)\r
{\r
    char buf[160];\r
    PyOS_snprintf(buf, sizeof(buf),\r
                  "<weakproxy at %p to %.100s at %p>", proxy,\r
                  Py_TYPE(PyWeakref_GET_OBJECT(proxy))->tp_name,\r
                  PyWeakref_GET_OBJECT(proxy));\r
    return PyString_FromString(buf);\r
}\r
\r
\r
static int\r
proxy_setattr(PyWeakReference *proxy, PyObject *name, PyObject *value)\r
{\r
    if (!proxy_checkref(proxy))\r
        return -1;\r
    return PyObject_SetAttr(PyWeakref_GET_OBJECT(proxy), name, value);\r
}\r
\r
static int\r
proxy_compare(PyObject *proxy, PyObject *v)\r
{\r
    UNWRAP_I(proxy);\r
    UNWRAP_I(v);\r
    return PyObject_Compare(proxy, v);\r
}\r
\r
/* number slots */\r
WRAP_BINARY(proxy_add, PyNumber_Add)\r
WRAP_BINARY(proxy_sub, PyNumber_Subtract)\r
WRAP_BINARY(proxy_mul, PyNumber_Multiply)\r
WRAP_BINARY(proxy_div, PyNumber_Divide)\r
WRAP_BINARY(proxy_floor_div, PyNumber_FloorDivide)\r
WRAP_BINARY(proxy_true_div, PyNumber_TrueDivide)\r
WRAP_BINARY(proxy_mod, PyNumber_Remainder)\r
WRAP_BINARY(proxy_divmod, PyNumber_Divmod)\r
WRAP_TERNARY(proxy_pow, PyNumber_Power)\r
WRAP_UNARY(proxy_neg, PyNumber_Negative)\r
WRAP_UNARY(proxy_pos, PyNumber_Positive)\r
WRAP_UNARY(proxy_abs, PyNumber_Absolute)\r
WRAP_UNARY(proxy_invert, PyNumber_Invert)\r
WRAP_BINARY(proxy_lshift, PyNumber_Lshift)\r
WRAP_BINARY(proxy_rshift, PyNumber_Rshift)\r
WRAP_BINARY(proxy_and, PyNumber_And)\r
WRAP_BINARY(proxy_xor, PyNumber_Xor)\r
WRAP_BINARY(proxy_or, PyNumber_Or)\r
WRAP_UNARY(proxy_int, PyNumber_Int)\r
WRAP_UNARY(proxy_long, PyNumber_Long)\r
WRAP_UNARY(proxy_float, PyNumber_Float)\r
WRAP_BINARY(proxy_iadd, PyNumber_InPlaceAdd)\r
WRAP_BINARY(proxy_isub, PyNumber_InPlaceSubtract)\r
WRAP_BINARY(proxy_imul, PyNumber_InPlaceMultiply)\r
WRAP_BINARY(proxy_idiv, PyNumber_InPlaceDivide)\r
WRAP_BINARY(proxy_ifloor_div, PyNumber_InPlaceFloorDivide)\r
WRAP_BINARY(proxy_itrue_div, PyNumber_InPlaceTrueDivide)\r
WRAP_BINARY(proxy_imod, PyNumber_InPlaceRemainder)\r
WRAP_TERNARY(proxy_ipow, PyNumber_InPlacePower)\r
WRAP_BINARY(proxy_ilshift, PyNumber_InPlaceLshift)\r
WRAP_BINARY(proxy_irshift, PyNumber_InPlaceRshift)\r
WRAP_BINARY(proxy_iand, PyNumber_InPlaceAnd)\r
WRAP_BINARY(proxy_ixor, PyNumber_InPlaceXor)\r
WRAP_BINARY(proxy_ior, PyNumber_InPlaceOr)\r
WRAP_UNARY(proxy_index, PyNumber_Index)\r
\r
static int\r
proxy_nonzero(PyWeakReference *proxy)\r
{\r
    PyObject *o = PyWeakref_GET_OBJECT(proxy);\r
    if (!proxy_checkref(proxy))\r
        return -1;\r
    return PyObject_IsTrue(o);\r
}\r
\r
static void\r
proxy_dealloc(PyWeakReference *self)\r
{\r
    if (self->wr_callback != NULL)\r
        PyObject_GC_UnTrack((PyObject *)self);\r
    clear_weakref(self);\r
    PyObject_GC_Del(self);\r
}\r
\r
/* sequence slots */\r
\r
static PyObject *\r
proxy_slice(PyWeakReference *proxy, Py_ssize_t i, Py_ssize_t j)\r
{\r
    if (!proxy_checkref(proxy))\r
        return NULL;\r
    return PySequence_GetSlice(PyWeakref_GET_OBJECT(proxy), i, j);\r
}\r
\r
static int\r
proxy_ass_slice(PyWeakReference *proxy, Py_ssize_t i, Py_ssize_t j, PyObject *value)\r
{\r
    if (!proxy_checkref(proxy))\r
        return -1;\r
    return PySequence_SetSlice(PyWeakref_GET_OBJECT(proxy), i, j, value);\r
}\r
\r
static int\r
proxy_contains(PyWeakReference *proxy, PyObject *value)\r
{\r
    if (!proxy_checkref(proxy))\r
        return -1;\r
    return PySequence_Contains(PyWeakref_GET_OBJECT(proxy), value);\r
}\r
\r
\r
/* mapping slots */\r
\r
static Py_ssize_t\r
proxy_length(PyWeakReference *proxy)\r
{\r
    if (!proxy_checkref(proxy))\r
        return -1;\r
    return PyObject_Length(PyWeakref_GET_OBJECT(proxy));\r
}\r
\r
WRAP_BINARY(proxy_getitem, PyObject_GetItem)\r
\r
static int\r
proxy_setitem(PyWeakReference *proxy, PyObject *key, PyObject *value)\r
{\r
    if (!proxy_checkref(proxy))\r
        return -1;\r
\r
    if (value == NULL)\r
        return PyObject_DelItem(PyWeakref_GET_OBJECT(proxy), key);\r
    else\r
        return PyObject_SetItem(PyWeakref_GET_OBJECT(proxy), key, value);\r
}\r
\r
/* iterator slots */\r
\r
static PyObject *\r
proxy_iter(PyWeakReference *proxy)\r
{\r
    if (!proxy_checkref(proxy))\r
        return NULL;\r
    return PyObject_GetIter(PyWeakref_GET_OBJECT(proxy));\r
}\r
\r
static PyObject *\r
proxy_iternext(PyWeakReference *proxy)\r
{\r
    if (!proxy_checkref(proxy))\r
        return NULL;\r
    return PyIter_Next(PyWeakref_GET_OBJECT(proxy));\r
}\r
\r
\r
WRAP_METHOD(proxy_unicode, "__unicode__");\r
\r
\r
static PyMethodDef proxy_methods[] = {\r
        {"__unicode__", (PyCFunction)proxy_unicode, METH_NOARGS},\r
        {NULL, NULL}\r
};\r
\r
\r
static PyNumberMethods proxy_as_number = {\r
    proxy_add,              /*nb_add*/\r
    proxy_sub,              /*nb_subtract*/\r
    proxy_mul,              /*nb_multiply*/\r
    proxy_div,              /*nb_divide*/\r
    proxy_mod,              /*nb_remainder*/\r
    proxy_divmod,           /*nb_divmod*/\r
    proxy_pow,              /*nb_power*/\r
    proxy_neg,              /*nb_negative*/\r
    proxy_pos,              /*nb_positive*/\r
    proxy_abs,              /*nb_absolute*/\r
    (inquiry)proxy_nonzero, /*nb_nonzero*/\r
    proxy_invert,           /*nb_invert*/\r
    proxy_lshift,           /*nb_lshift*/\r
    proxy_rshift,           /*nb_rshift*/\r
    proxy_and,              /*nb_and*/\r
    proxy_xor,              /*nb_xor*/\r
    proxy_or,               /*nb_or*/\r
    0,                      /*nb_coerce*/\r
    proxy_int,              /*nb_int*/\r
    proxy_long,             /*nb_long*/\r
    proxy_float,            /*nb_float*/\r
    0,                      /*nb_oct*/\r
    0,                      /*nb_hex*/\r
    proxy_iadd,             /*nb_inplace_add*/\r
    proxy_isub,             /*nb_inplace_subtract*/\r
    proxy_imul,             /*nb_inplace_multiply*/\r
    proxy_idiv,             /*nb_inplace_divide*/\r
    proxy_imod,             /*nb_inplace_remainder*/\r
    proxy_ipow,             /*nb_inplace_power*/\r
    proxy_ilshift,          /*nb_inplace_lshift*/\r
    proxy_irshift,          /*nb_inplace_rshift*/\r
    proxy_iand,             /*nb_inplace_and*/\r
    proxy_ixor,             /*nb_inplace_xor*/\r
    proxy_ior,              /*nb_inplace_or*/\r
    proxy_floor_div,        /*nb_floor_divide*/\r
    proxy_true_div,         /*nb_true_divide*/\r
    proxy_ifloor_div,       /*nb_inplace_floor_divide*/\r
    proxy_itrue_div,        /*nb_inplace_true_divide*/\r
    proxy_index,            /*nb_index*/\r
};\r
\r
static PySequenceMethods proxy_as_sequence = {\r
    (lenfunc)proxy_length,      /*sq_length*/\r
    0,                          /*sq_concat*/\r
    0,                          /*sq_repeat*/\r
    0,                          /*sq_item*/\r
    (ssizessizeargfunc)proxy_slice, /*sq_slice*/\r
    0,                          /*sq_ass_item*/\r
    (ssizessizeobjargproc)proxy_ass_slice, /*sq_ass_slice*/\r
    (objobjproc)proxy_contains, /* sq_contains */\r
};\r
\r
static PyMappingMethods proxy_as_mapping = {\r
    (lenfunc)proxy_length,        /*mp_length*/\r
    proxy_getitem,                /*mp_subscript*/\r
    (objobjargproc)proxy_setitem, /*mp_ass_subscript*/\r
};\r
\r
\r
PyTypeObject\r
_PyWeakref_ProxyType = {\r
    PyVarObject_HEAD_INIT(&PyType_Type, 0)\r
    "weakproxy",\r
    sizeof(PyWeakReference),\r
    0,\r
    /* methods */\r
    (destructor)proxy_dealloc,          /* tp_dealloc */\r
    0,                                  /* tp_print */\r
    0,                                  /* tp_getattr */\r
    0,                                  /* tp_setattr */\r
    proxy_compare,                      /* tp_compare */\r
    (reprfunc)proxy_repr,               /* tp_repr */\r
    &proxy_as_number,                   /* tp_as_number */\r
    &proxy_as_sequence,                 /* tp_as_sequence */\r
    &proxy_as_mapping,                  /* tp_as_mapping */\r
    0,                                  /* tp_hash */\r
    0,                                  /* tp_call */\r
    proxy_str,                          /* tp_str */\r
    proxy_getattr,                      /* tp_getattro */\r
    (setattrofunc)proxy_setattr,        /* tp_setattro */\r
    0,                                  /* tp_as_buffer */\r
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC\r
    | Py_TPFLAGS_CHECKTYPES,            /* tp_flags */\r
    0,                                  /* tp_doc */\r
    (traverseproc)gc_traverse,          /* tp_traverse */\r
    (inquiry)gc_clear,                  /* tp_clear */\r
    0,                                  /* tp_richcompare */\r
    0,                                  /* tp_weaklistoffset */\r
    (getiterfunc)proxy_iter,            /* tp_iter */\r
    (iternextfunc)proxy_iternext,       /* tp_iternext */\r
        proxy_methods,                      /* tp_methods */\r
};\r
\r
\r
PyTypeObject\r
_PyWeakref_CallableProxyType = {\r
    PyVarObject_HEAD_INIT(&PyType_Type, 0)\r
    "weakcallableproxy",\r
    sizeof(PyWeakReference),\r
    0,\r
    /* methods */\r
    (destructor)proxy_dealloc,          /* tp_dealloc */\r
    0,                                  /* tp_print */\r
    0,                                  /* tp_getattr */\r
    0,                                  /* tp_setattr */\r
    proxy_compare,                      /* tp_compare */\r
    (unaryfunc)proxy_repr,              /* tp_repr */\r
    &proxy_as_number,                   /* tp_as_number */\r
    &proxy_as_sequence,                 /* tp_as_sequence */\r
    &proxy_as_mapping,                  /* tp_as_mapping */\r
    0,                                  /* tp_hash */\r
    proxy_call,                         /* tp_call */\r
    proxy_str,                          /* tp_str */\r
    proxy_getattr,                      /* tp_getattro */\r
    (setattrofunc)proxy_setattr,        /* tp_setattro */\r
    0,                                  /* tp_as_buffer */\r
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC\r
    | Py_TPFLAGS_CHECKTYPES,            /* tp_flags */\r
    0,                                  /* tp_doc */\r
    (traverseproc)gc_traverse,          /* tp_traverse */\r
    (inquiry)gc_clear,                  /* tp_clear */\r
    0,                                  /* tp_richcompare */\r
    0,                                  /* tp_weaklistoffset */\r
    (getiterfunc)proxy_iter,            /* tp_iter */\r
    (iternextfunc)proxy_iternext,       /* tp_iternext */\r
};\r
\r
\r
\r
PyObject *\r
PyWeakref_NewRef(PyObject *ob, PyObject *callback)\r
{\r
    PyWeakReference *result = NULL;\r
    PyWeakReference **list;\r
    PyWeakReference *ref, *proxy;\r
\r
    if (!PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob))) {\r
        PyErr_Format(PyExc_TypeError,\r
                     "cannot create weak reference to '%s' object",\r
                     Py_TYPE(ob)->tp_name);\r
        return NULL;\r
    }\r
    list = GET_WEAKREFS_LISTPTR(ob);\r
    get_basic_refs(*list, &ref, &proxy);\r
    if (callback == Py_None)\r
        callback = NULL;\r
    if (callback == NULL)\r
        /* return existing weak reference if it exists */\r
        result = ref;\r
    if (result != NULL)\r
        Py_INCREF(result);\r
    else {\r
        /* Note: new_weakref() can trigger cyclic GC, so the weakref\r
           list on ob can be mutated.  This means that the ref and\r
           proxy pointers we got back earlier may have been collected,\r
           so we need to compute these values again before we use\r
           them. */\r
        result = new_weakref(ob, callback);\r
        if (result != NULL) {\r
            get_basic_refs(*list, &ref, &proxy);\r
            if (callback == NULL) {\r
                if (ref == NULL)\r
                    insert_head(result, list);\r
                else {\r
                    /* Someone else added a ref without a callback\r
                       during GC.  Return that one instead of this one\r
                       to avoid violating the invariants of the list\r
                       of weakrefs for ob. */\r
                    Py_DECREF(result);\r
                    Py_INCREF(ref);\r
                    result = ref;\r
                }\r
            }\r
            else {\r
                PyWeakReference *prev;\r
\r
                prev = (proxy == NULL) ? ref : proxy;\r
                if (prev == NULL)\r
                    insert_head(result, list);\r
                else\r
                    insert_after(result, prev);\r
            }\r
        }\r
    }\r
    return (PyObject *) result;\r
}\r
\r
\r
PyObject *\r
PyWeakref_NewProxy(PyObject *ob, PyObject *callback)\r
{\r
    PyWeakReference *result = NULL;\r
    PyWeakReference **list;\r
    PyWeakReference *ref, *proxy;\r
\r
    if (!PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob))) {\r
        PyErr_Format(PyExc_TypeError,\r
                     "cannot create weak reference to '%s' object",\r
                     Py_TYPE(ob)->tp_name);\r
        return NULL;\r
    }\r
    list = GET_WEAKREFS_LISTPTR(ob);\r
    get_basic_refs(*list, &ref, &proxy);\r
    if (callback == Py_None)\r
        callback = NULL;\r
    if (callback == NULL)\r
        /* attempt to return an existing weak reference if it exists */\r
        result = proxy;\r
    if (result != NULL)\r
        Py_INCREF(result);\r
    else {\r
        /* Note: new_weakref() can trigger cyclic GC, so the weakref\r
           list on ob can be mutated.  This means that the ref and\r
           proxy pointers we got back earlier may have been collected,\r
           so we need to compute these values again before we use\r
           them. */\r
        result = new_weakref(ob, callback);\r
        if (result != NULL) {\r
            PyWeakReference *prev;\r
\r
            if (PyCallable_Check(ob))\r
                Py_TYPE(result) = &_PyWeakref_CallableProxyType;\r
            else\r
                Py_TYPE(result) = &_PyWeakref_ProxyType;\r
            get_basic_refs(*list, &ref, &proxy);\r
            if (callback == NULL) {\r
                if (proxy != NULL) {\r
                    /* Someone else added a proxy without a callback\r
                       during GC.  Return that one instead of this one\r
                       to avoid violating the invariants of the list\r
                       of weakrefs for ob. */\r
                    Py_DECREF(result);\r
                    Py_INCREF(result = proxy);\r
                    goto skip_insert;\r
                }\r
                prev = ref;\r
            }\r
            else\r
                prev = (proxy == NULL) ? ref : proxy;\r
\r
            if (prev == NULL)\r
                insert_head(result, list);\r
            else\r
                insert_after(result, prev);\r
        skip_insert:\r
            ;\r
        }\r
    }\r
    return (PyObject *) result;\r
}\r
\r
\r
PyObject *\r
PyWeakref_GetObject(PyObject *ref)\r
{\r
    if (ref == NULL || !PyWeakref_Check(ref)) {\r
        PyErr_BadInternalCall();\r
        return NULL;\r
    }\r
    return PyWeakref_GET_OBJECT(ref);\r
}\r
\r
/* Note that there's an inlined copy-paste of handle_callback() in gcmodule.c's\r
 * handle_weakrefs().\r
 */\r
static void\r
handle_callback(PyWeakReference *ref, PyObject *callback)\r
{\r
    PyObject *cbresult = PyObject_CallFunctionObjArgs(callback, ref, NULL);\r
\r
    if (cbresult == NULL)\r
        PyErr_WriteUnraisable(callback);\r
    else\r
        Py_DECREF(cbresult);\r
}\r
\r
/* This function is called by the tp_dealloc handler to clear weak references.\r
 *\r
 * This iterates through the weak references for 'object' and calls callbacks\r
 * for those references which have one.  It returns when all callbacks have\r
 * been attempted.\r
 */\r
void\r
PyObject_ClearWeakRefs(PyObject *object)\r
{\r
    PyWeakReference **list;\r
\r
    if (object == NULL\r
        || !PyType_SUPPORTS_WEAKREFS(Py_TYPE(object))\r
        || object->ob_refcnt != 0) {\r
        PyErr_BadInternalCall();\r
        return;\r
    }\r
    list = GET_WEAKREFS_LISTPTR(object);\r
    /* Remove the callback-less basic and proxy references */\r
    if (*list != NULL && (*list)->wr_callback == NULL) {\r
        clear_weakref(*list);\r
        if (*list != NULL && (*list)->wr_callback == NULL)\r
            clear_weakref(*list);\r
    }\r
    if (*list != NULL) {\r
        PyWeakReference *current = *list;\r
        Py_ssize_t count = _PyWeakref_GetWeakrefCount(current);\r
        int restore_error = PyErr_Occurred() ? 1 : 0;\r
        PyObject *err_type    = NULL,\r
                 *err_value   = NULL,\r
                 *err_tb      = NULL;\r
\r
        if (restore_error)\r
            PyErr_Fetch(&err_type, &err_value, &err_tb);\r
        if (count == 1) {\r
            PyObject *callback = current->wr_callback;\r
\r
            current->wr_callback = NULL;\r
            clear_weakref(current);\r
            if (callback != NULL) {\r
                if (current->ob_refcnt > 0)\r
                    handle_callback(current, callback);\r
                Py_DECREF(callback);\r
            }\r
        }\r
        else {\r
            PyObject *tuple;\r
            Py_ssize_t i = 0;\r
\r
            tuple = PyTuple_New(count * 2);\r
            if (tuple == NULL) {\r
                if (restore_error)\r
                    PyErr_Fetch(&err_type, &err_value, &err_tb);\r
                return;\r
            }\r
\r
            for (i = 0; i < count; ++i) {\r
                PyWeakReference *next = current->wr_next;\r
\r
                if (current->ob_refcnt > 0)\r
                {\r
                    Py_INCREF(current);\r
                    PyTuple_SET_ITEM(tuple, i * 2, (PyObject *) current);\r
                    PyTuple_SET_ITEM(tuple, i * 2 + 1, current->wr_callback);\r
                }\r
                else {\r
                    Py_DECREF(current->wr_callback);\r
                }\r
                current->wr_callback = NULL;\r
                clear_weakref(current);\r
                current = next;\r
            }\r
            for (i = 0; i < count; ++i) {\r
                PyObject *callback = PyTuple_GET_ITEM(tuple, i * 2 + 1);\r
\r
                /* The tuple may have slots left to NULL */\r
                if (callback != NULL) {\r
                    PyObject *item = PyTuple_GET_ITEM(tuple, i * 2);\r
                    handle_callback((PyWeakReference *)item, callback);\r
                }\r
            }\r
            Py_DECREF(tuple);\r
        }\r
        if (restore_error)\r
            PyErr_Restore(err_type, err_value, err_tb);\r
    }\r
}\r