#include "Python.h" | |
#include "structmember.h" | |
#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 void | |
init_weakref(PyWeakReference *self, PyObject *ob, PyObject *callback) | |
{ | |
self->hash = -1; | |
self->wr_object = ob; | |
Py_XINCREF(callback); | |
self->wr_callback = callback; | |
} | |
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_call(PyWeakReference *self, PyObject *args, PyObject *kw) | |
{ | |
static char *kwlist[] = {NULL}; | |
if (PyArg_ParseTupleAndKeywords(args, kw, ":__call__", kwlist)) { | |
PyObject *object = PyWeakref_GET_OBJECT(self); | |
Py_INCREF(object); | |
return (object); | |
} | |
return NULL; | |
} | |
static long | |
weakref_hash(PyWeakReference *self) | |
{ | |
if (self->hash != -1) | |
return self->hash; | |
if (PyWeakref_GET_OBJECT(self) == Py_None) { | |
PyErr_SetString(PyExc_TypeError, "weak object has gone away"); | |
return -1; | |
} | |
self->hash = PyObject_Hash(PyWeakref_GET_OBJECT(self)); | |
return self->hash; | |
} | |
static PyObject * | |
weakref_repr(PyWeakReference *self) | |
{ | |
char buffer[256]; | |
if (PyWeakref_GET_OBJECT(self) == Py_None) { | |
PyOS_snprintf(buffer, sizeof(buffer), "<weakref at %p; dead>", self); | |
} | |
else { | |
char *name = NULL; | |
PyObject *nameobj = PyObject_GetAttrString(PyWeakref_GET_OBJECT(self), | |
"__name__"); | |
if (nameobj == NULL) | |
PyErr_Clear(); | |
else if (PyString_Check(nameobj)) | |
name = PyString_AS_STRING(nameobj); | |
if (name != NULL) { | |
PyOS_snprintf(buffer, sizeof(buffer), | |
"<weakref at %p; to '%.50s' at %p (%s)>", | |
self, | |
Py_TYPE(PyWeakref_GET_OBJECT(self))->tp_name, | |
PyWeakref_GET_OBJECT(self), | |
name); | |
} | |
else { | |
PyOS_snprintf(buffer, sizeof(buffer), | |
"<weakref at %p; to '%.50s' at %p>", | |
self, | |
Py_TYPE(PyWeakref_GET_OBJECT(self))->tp_name, | |
PyWeakref_GET_OBJECT(self)); | |
} | |
Py_XDECREF(nameobj); | |
} | |
return PyString_FromString(buffer); | |
} | |
/* 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) || self->ob_type != other->ob_type) { | |
Py_INCREF(Py_NotImplemented); | |
return Py_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; | |
} | |
return PyObject_RichCompare(PyWeakref_GET_OBJECT(self), | |
PyWeakref_GET_OBJECT(other), op); | |
} | |
/* 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(char *funcname, PyObject *args, PyObject *kwargs, | |
PyObject **obp, PyObject **callbackp) | |
{ | |
/* XXX Should check that kwargs == NULL or is empty. */ | |
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 (parse_weakref_init_args("__init__", args, kwargs, &tmp, &tmp)) | |
return 0; | |
else | |
return -1; | |
} | |
PyTypeObject | |
_PyWeakref_RefType = { | |
PyVarObject_HEAD_INIT(&PyType_Type, 0) | |
"weakref", | |
sizeof(PyWeakReference), | |
0, | |
weakref_dealloc, /*tp_dealloc*/ | |
0, /*tp_print*/ | |
0, /*tp_getattr*/ | |
0, /*tp_setattr*/ | |
0, /*tp_compare*/ | |
(reprfunc)weakref_repr, /*tp_repr*/ | |
0, /*tp_as_number*/ | |
0, /*tp_as_sequence*/ | |
0, /*tp_as_mapping*/ | |
(hashfunc)weakref_hash, /*tp_hash*/ | |
(ternaryfunc)weakref_call, /*tp_call*/ | |
0, /*tp_str*/ | |
0, /*tp_getattro*/ | |
0, /*tp_setattro*/ | |
0, /*tp_as_buffer*/ | |
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_HAVE_RICHCOMPARE | |
| Py_TPFLAGS_BASETYPE, /*tp_flags*/ | |
0, /*tp_doc*/ | |
(traverseproc)gc_traverse, /*tp_traverse*/ | |
(inquiry)gc_clear, /*tp_clear*/ | |
(richcmpfunc)weakref_richcompare, /*tp_richcompare*/ | |
0, /*tp_weaklistoffset*/ | |
0, /*tp_iter*/ | |
0, /*tp_iternext*/ | |
0, /*tp_methods*/ | |
0, /*tp_members*/ | |
0, /*tp_getset*/ | |
0, /*tp_base*/ | |
0, /*tp_dict*/ | |
0, /*tp_descr_get*/ | |
0, /*tp_descr_set*/ | |
0, /*tp_dictoffset*/ | |
weakref___init__, /*tp_init*/ | |
PyType_GenericAlloc, /*tp_alloc*/ | |
weakref___new__, /*tp_new*/ | |
PyObject_GC_Del, /*tp_free*/ | |
}; | |
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 UNWRAP_I(o) \ | |
if (PyWeakref_CheckProxy(o)) { \ | |
if (!proxy_checkref((PyWeakReference *)o)) \ | |
return -1; \ | |
o = PyWeakref_GET_OBJECT(o); \ | |
} | |
#define WRAP_UNARY(method, generic) \ | |
static PyObject * \ | |
method(PyObject *proxy) { \ | |
UNWRAP(proxy); \ | |
return generic(proxy); \ | |
} | |
#define WRAP_BINARY(method, generic) \ | |
static PyObject * \ | |
method(PyObject *x, PyObject *y) { \ | |
UNWRAP(x); \ | |
UNWRAP(y); \ | |
return generic(x, y); \ | |
} | |
/* 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); \ | |
return generic(proxy, v, w); \ | |
} | |
#define WRAP_METHOD(method, special) \ | |
static PyObject * \ | |
method(PyObject *proxy) { \ | |
UNWRAP(proxy); \ | |
return PyObject_CallMethod(proxy, special, ""); \ | |
} | |
/* direct slots */ | |
WRAP_BINARY(proxy_getattr, PyObject_GetAttr) | |
WRAP_UNARY(proxy_str, PyObject_Str) | |
WRAP_TERNARY(proxy_call, PyEval_CallObjectWithKeywords) | |
static PyObject * | |
proxy_repr(PyWeakReference *proxy) | |
{ | |
char buf[160]; | |
PyOS_snprintf(buf, sizeof(buf), | |
"<weakproxy at %p to %.100s at %p>", proxy, | |
Py_TYPE(PyWeakref_GET_OBJECT(proxy))->tp_name, | |
PyWeakref_GET_OBJECT(proxy)); | |
return PyString_FromString(buf); | |
} | |
static int | |
proxy_setattr(PyWeakReference *proxy, PyObject *name, PyObject *value) | |
{ | |
if (!proxy_checkref(proxy)) | |
return -1; | |
return PyObject_SetAttr(PyWeakref_GET_OBJECT(proxy), name, value); | |
} | |
static int | |
proxy_compare(PyObject *proxy, PyObject *v) | |
{ | |
UNWRAP_I(proxy); | |
UNWRAP_I(v); | |
return PyObject_Compare(proxy, v); | |
} | |
/* number slots */ | |
WRAP_BINARY(proxy_add, PyNumber_Add) | |
WRAP_BINARY(proxy_sub, PyNumber_Subtract) | |
WRAP_BINARY(proxy_mul, PyNumber_Multiply) | |
WRAP_BINARY(proxy_div, PyNumber_Divide) | |
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_Int) | |
WRAP_UNARY(proxy_long, 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_idiv, PyNumber_InPlaceDivide) | |
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) | |
static int | |
proxy_nonzero(PyWeakReference *proxy) | |
{ | |
PyObject *o = PyWeakref_GET_OBJECT(proxy); | |
if (!proxy_checkref(proxy)) | |
return -1; | |
return PyObject_IsTrue(o); | |
} | |
static void | |
proxy_dealloc(PyWeakReference *self) | |
{ | |
if (self->wr_callback != NULL) | |
PyObject_GC_UnTrack((PyObject *)self); | |
clear_weakref(self); | |
PyObject_GC_Del(self); | |
} | |
/* sequence slots */ | |
static PyObject * | |
proxy_slice(PyWeakReference *proxy, Py_ssize_t i, Py_ssize_t j) | |
{ | |
if (!proxy_checkref(proxy)) | |
return NULL; | |
return PySequence_GetSlice(PyWeakref_GET_OBJECT(proxy), i, j); | |
} | |
static int | |
proxy_ass_slice(PyWeakReference *proxy, Py_ssize_t i, Py_ssize_t j, PyObject *value) | |
{ | |
if (!proxy_checkref(proxy)) | |
return -1; | |
return PySequence_SetSlice(PyWeakref_GET_OBJECT(proxy), i, j, value); | |
} | |
static int | |
proxy_contains(PyWeakReference *proxy, PyObject *value) | |
{ | |
if (!proxy_checkref(proxy)) | |
return -1; | |
return PySequence_Contains(PyWeakref_GET_OBJECT(proxy), value); | |
} | |
/* mapping slots */ | |
static Py_ssize_t | |
proxy_length(PyWeakReference *proxy) | |
{ | |
if (!proxy_checkref(proxy)) | |
return -1; | |
return PyObject_Length(PyWeakref_GET_OBJECT(proxy)); | |
} | |
WRAP_BINARY(proxy_getitem, PyObject_GetItem) | |
static int | |
proxy_setitem(PyWeakReference *proxy, PyObject *key, PyObject *value) | |
{ | |
if (!proxy_checkref(proxy)) | |
return -1; | |
if (value == NULL) | |
return PyObject_DelItem(PyWeakref_GET_OBJECT(proxy), key); | |
else | |
return PyObject_SetItem(PyWeakref_GET_OBJECT(proxy), key, value); | |
} | |
/* iterator slots */ | |
static PyObject * | |
proxy_iter(PyWeakReference *proxy) | |
{ | |
if (!proxy_checkref(proxy)) | |
return NULL; | |
return PyObject_GetIter(PyWeakref_GET_OBJECT(proxy)); | |
} | |
static PyObject * | |
proxy_iternext(PyWeakReference *proxy) | |
{ | |
if (!proxy_checkref(proxy)) | |
return NULL; | |
return PyIter_Next(PyWeakref_GET_OBJECT(proxy)); | |
} | |
WRAP_METHOD(proxy_unicode, "__unicode__"); | |
static PyMethodDef proxy_methods[] = { | |
{"__unicode__", (PyCFunction)proxy_unicode, METH_NOARGS}, | |
{NULL, NULL} | |
}; | |
static PyNumberMethods proxy_as_number = { | |
proxy_add, /*nb_add*/ | |
proxy_sub, /*nb_subtract*/ | |
proxy_mul, /*nb_multiply*/ | |
proxy_div, /*nb_divide*/ | |
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_nonzero, /*nb_nonzero*/ | |
proxy_invert, /*nb_invert*/ | |
proxy_lshift, /*nb_lshift*/ | |
proxy_rshift, /*nb_rshift*/ | |
proxy_and, /*nb_and*/ | |
proxy_xor, /*nb_xor*/ | |
proxy_or, /*nb_or*/ | |
0, /*nb_coerce*/ | |
proxy_int, /*nb_int*/ | |
proxy_long, /*nb_long*/ | |
proxy_float, /*nb_float*/ | |
0, /*nb_oct*/ | |
0, /*nb_hex*/ | |
proxy_iadd, /*nb_inplace_add*/ | |
proxy_isub, /*nb_inplace_subtract*/ | |
proxy_imul, /*nb_inplace_multiply*/ | |
proxy_idiv, /*nb_inplace_divide*/ | |
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*/ | |
}; | |
static PySequenceMethods proxy_as_sequence = { | |
(lenfunc)proxy_length, /*sq_length*/ | |
0, /*sq_concat*/ | |
0, /*sq_repeat*/ | |
0, /*sq_item*/ | |
(ssizessizeargfunc)proxy_slice, /*sq_slice*/ | |
0, /*sq_ass_item*/ | |
(ssizessizeobjargproc)proxy_ass_slice, /*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) | |
"weakproxy", | |
sizeof(PyWeakReference), | |
0, | |
/* methods */ | |
(destructor)proxy_dealloc, /* tp_dealloc */ | |
0, /* tp_print */ | |
0, /* tp_getattr */ | |
0, /* tp_setattr */ | |
proxy_compare, /* tp_compare */ | |
(reprfunc)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 */ | |
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 | |
| Py_TPFLAGS_CHECKTYPES, /* tp_flags */ | |
0, /* tp_doc */ | |
(traverseproc)gc_traverse, /* tp_traverse */ | |
(inquiry)gc_clear, /* tp_clear */ | |
0, /* 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) | |
"weakcallableproxy", | |
sizeof(PyWeakReference), | |
0, | |
/* methods */ | |
(destructor)proxy_dealloc, /* tp_dealloc */ | |
0, /* tp_print */ | |
0, /* tp_getattr */ | |
0, /* tp_setattr */ | |
proxy_compare, /* tp_compare */ | |
(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 | |
| Py_TPFLAGS_CHECKTYPES, /* tp_flags */ | |
0, /* tp_doc */ | |
(traverseproc)gc_traverse, /* tp_traverse */ | |
(inquiry)gc_clear, /* tp_clear */ | |
0, /* 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_TYPE(result) = &_PyWeakref_CallableProxyType; | |
else | |
Py_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); | |
Py_INCREF(result = proxy); | |
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_CallFunctionObjArgs(callback, ref, NULL); | |
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)) | |
|| object->ob_refcnt != 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 (current->ob_refcnt > 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_ReplaceException(err_type, err_value, err_tb); | |
return; | |
} | |
for (i = 0; i < count; ++i) { | |
PyWeakReference *next = current->wr_next; | |
if (current->ob_refcnt > 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); | |
} | |
} |